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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
// When using a solid color with clip masking, the cost of loading the clip mask
// in the blend stage exceeds the cost of processing the color. Here we handle
// the entire span of clip mask texture before the blend stage to more
// efficiently process it and modulate it with color without incurring blend
// stage overheads.
template <typename P, typename C>
static void commit_masked_solid_span(P* buf, C color, int len) {
override_clip_mask();
uint8_t* mask = get_clip_mask(buf);
for (P* end = &buf[len]; buf < end; buf += 4, mask += 4) {
commit_span(
buf,
blend_span(
buf,
applyColor(expand_mask(buf, unpack(unaligned_load<PackedR8>(mask))),
color)));
}
restore_clip_mask();
}
// When using a solid color with anti-aliasing, most of the solid span will not
// benefit from anti-aliasing in the opaque region. We only want to apply the AA
// blend stage in the non-opaque start and end of the span where AA is needed.
template <typename P, typename R>
static ALWAYS_INLINE void commit_aa_solid_span(P* buf, R r, int len) {
if (int start = min((get_aa_opaque_start(buf) + 3) & ~3, len)) {
commit_solid_span<true>(buf, r, start);
buf += start;
len -= start;
}
if (int opaque = min((get_aa_opaque_size(buf) + 3) & ~3, len)) {
override_aa();
commit_solid_span<true>(buf, r, opaque);
restore_aa();
buf += opaque;
len -= opaque;
}
if (len > 0) {
commit_solid_span<true>(buf, r, len);
}
}
// Forces a value with vector run-class to have scalar run-class.
template <typename T>
static ALWAYS_INLINE auto swgl_forceScalar(T v) -> decltype(force_scalar(v)) {
return force_scalar(v);
}
// Advance all varying inperpolants by a single chunk
#define swgl_stepInterp() step_interp_inputs()
// Pseudo-intrinsic that accesses the interpolation step for a given varying
#define swgl_interpStep(v) (interp_step.v)
// Commit an entire span of a solid color. This dispatches to clip-masked and
// anti-aliased fast-paths as appropriate.
#define swgl_commitSolid(format, v, n) \
do { \
int len = (n); \
if (blend_key) { \
if (swgl_ClipFlags & SWGL_CLIP_FLAG_MASK) { \
commit_masked_solid_span(swgl_Out##format, \
packColor(swgl_Out##format, (v)), len); \
} else if (swgl_ClipFlags & SWGL_CLIP_FLAG_AA) { \
commit_aa_solid_span(swgl_Out##format, \
pack_span(swgl_Out##format, (v)), len); \
} else { \
commit_solid_span<true>(swgl_Out##format, \
pack_span(swgl_Out##format, (v)), len); \
} \
} else { \
commit_solid_span<false>(swgl_Out##format, \
pack_span(swgl_Out##format, (v)), len); \
} \
swgl_Out##format += len; \
swgl_SpanLength -= len; \
} while (0)
#define swgl_commitSolidRGBA8(v) swgl_commitSolid(RGBA8, v, swgl_SpanLength)
#define swgl_commitSolidR8(v) swgl_commitSolid(R8, v, swgl_SpanLength)
#define swgl_commitPartialSolidRGBA8(len, v) \
swgl_commitSolid(RGBA8, v, min(int(len), swgl_SpanLength))
#define swgl_commitPartialSolidR8(len, v) \
swgl_commitSolid(R8, v, min(int(len), swgl_SpanLength))
#define swgl_commitChunk(format, chunk) \
do { \
auto r = chunk; \
if (blend_key) r = blend_span(swgl_Out##format, r); \
commit_span(swgl_Out##format, r); \
swgl_Out##format += swgl_StepSize; \
swgl_SpanLength -= swgl_StepSize; \
} while (0)
// Commit a single chunk of a color
#define swgl_commitColor(format, color) \
swgl_commitChunk(format, pack_pixels_##format(color))
#define swgl_commitColorRGBA8(color) swgl_commitColor(RGBA8, color)
#define swgl_commitColorR8(color) swgl_commitColor(R8, color)
template <typename S>
static ALWAYS_INLINE bool swgl_isTextureLinear(S s) {
return s->filter == TextureFilter::LINEAR;
}
template <typename S>
static ALWAYS_INLINE bool swgl_isTextureRGBA8(S s) {
return s->format == TextureFormat::RGBA8;
}
template <typename S>
static ALWAYS_INLINE bool swgl_isTextureR8(S s) {
return s->format == TextureFormat::R8;
}
// Use the default linear quantization scale of 128. This gives 7 bits of
// fractional precision, which when multiplied with a signed 9 bit value
// still fits in a 16 bit integer.
const int swgl_LinearQuantizeScale = 128;
// Quantizes UVs for access into a linear texture.
template <typename S, typename T>
static ALWAYS_INLINE T swgl_linearQuantize(S s, T p) {
return linearQuantize(p, swgl_LinearQuantizeScale, s);
}
// Quantizes an interpolation step for UVs for access into a linear texture.
template <typename S, typename T>
static ALWAYS_INLINE T swgl_linearQuantizeStep(S s, T p) {
return samplerScale(s, p) * swgl_LinearQuantizeScale;
}
template <typename S>
static ALWAYS_INLINE WideRGBA8 textureLinearUnpacked(UNUSED uint32_t* buf,
S sampler, ivec2 i) {
return textureLinearUnpackedRGBA8(sampler, i);
}
template <typename S>
static ALWAYS_INLINE WideR8 textureLinearUnpacked(UNUSED uint8_t* buf,
S sampler, ivec2 i) {
return textureLinearUnpackedR8(sampler, i);
}
template <typename S>
static ALWAYS_INLINE bool matchTextureFormat(S s, UNUSED uint32_t* buf) {
return swgl_isTextureRGBA8(s);
}
template <typename S>
static ALWAYS_INLINE bool matchTextureFormat(S s, UNUSED uint8_t* buf) {
return swgl_isTextureR8(s);
}
// Quantizes the UVs to the 2^7 scale needed for calculating fractional offsets
// for linear sampling.
#define LINEAR_QUANTIZE_UV(sampler, uv, uv_step, uv_rect, min_uv, max_uv) \
uv = swgl_linearQuantize(sampler, uv); \
vec2_scalar uv_step = \
float(swgl_StepSize) * vec2_scalar{uv.x.y - uv.x.x, uv.y.y - uv.y.x}; \
vec2_scalar min_uv = max( \
swgl_linearQuantize(sampler, vec2_scalar{uv_rect.x, uv_rect.y}), 0.0f); \
vec2_scalar max_uv = \
max(swgl_linearQuantize(sampler, vec2_scalar{uv_rect.z, uv_rect.w}), \
min_uv);
// Implements the fallback linear filter that can deal with clamping and
// arbitrary scales.
template <bool BLEND, typename S, typename C, typename P>
static P* blendTextureLinearFallback(S sampler, vec2 uv, int span,
vec2_scalar uv_step, vec2_scalar min_uv,
vec2_scalar max_uv, C color, P* buf) {
for (P* end = buf + span; buf < end; buf += swgl_StepSize, uv += uv_step) {
commit_blend_span<BLEND>(
buf, applyColor(textureLinearUnpacked(buf, sampler,
ivec2(clamp(uv, min_uv, max_uv))),
color));
}
return buf;
}
static ALWAYS_INLINE U64 castForShuffle(V16<int16_t> r) {
return bit_cast<U64>(r);
}
static ALWAYS_INLINE U16 castForShuffle(V4<int16_t> r) {
return bit_cast<U16>(r);
}
static ALWAYS_INLINE V16<int16_t> applyFracX(V16<int16_t> r, I16 fracx) {
return r * fracx.xxxxyyyyzzzzwwww;
}
static ALWAYS_INLINE V4<int16_t> applyFracX(V4<int16_t> r, I16 fracx) {
return r * fracx;
}
// Implements a faster linear filter that works with axis-aligned constant Y but
// scales less than 1, i.e. upscaling. In this case we can optimize for the
// constant Y fraction as well as load all chunks from memory in a single tap
// for each row.
template <bool BLEND, typename S, typename C, typename P>
static void blendTextureLinearUpscale(S sampler, vec2 uv, int span,
vec2_scalar uv_step, vec2_scalar min_uv,
vec2_scalar max_uv, C color, P* buf) {
typedef VectorType<uint8_t, 4 * sizeof(P)> packed_type;
typedef VectorType<uint16_t, 4 * sizeof(P)> unpacked_type;
typedef VectorType<int16_t, 4 * sizeof(P)> signed_unpacked_type;
ivec2 i(clamp(uv, min_uv, max_uv));
ivec2 frac = i;
i >>= 7;
P* row0 = (P*)sampler->buf + computeRow(sampler, ivec2_scalar(0, i.y.x));
P* row1 = row0 + computeNextRowOffset(sampler, ivec2_scalar(0, i.y.x));
I16 fracx = computeFracX(sampler, i, frac);
int16_t fracy = computeFracY(frac).x;
auto src0 =
CONVERT(unaligned_load<packed_type>(&row0[i.x.x]), signed_unpacked_type);
auto src1 =
CONVERT(unaligned_load<packed_type>(&row1[i.x.x]), signed_unpacked_type);
auto src = castForShuffle(src0 + (((src1 - src0) * fracy) >> 7));
// We attempt to sample ahead by one chunk and interpolate it with the current
// one. However, due to the complication of upscaling, we may not necessarily
// shift in all the next set of samples.
for (P* end = buf + span; buf < end; buf += 4) {
uv.x += uv_step.x;
I32 ixn = cast(uv.x);
I16 fracn = computeFracNoClamp(ixn);
ixn >>= 7;
auto src0n = CONVERT(unaligned_load<packed_type>(&row0[ixn.x]),
signed_unpacked_type);
auto src1n = CONVERT(unaligned_load<packed_type>(&row1[ixn.x]),
signed_unpacked_type);
auto srcn = castForShuffle(src0n + (((src1n - src0n) * fracy) >> 7));
// Since we're upscaling, we know that a source pixel has a larger footprint
// than the destination pixel, and thus all the source pixels needed for
// this chunk will fall within a single chunk of texture data. However,
// since the source pixels don't map 1:1 with destination pixels, we need to
// shift the source pixels over based on their offset from the start of the
// chunk. This could conceivably be optimized better with usage of PSHUFB or
// VTBL instructions However, since PSHUFB requires SSSE3, instead we resort
// to masking in the correct pixels to avoid having to index into memory.
// For the last sample to interpolate with, we need to potentially shift in
// a sample from the next chunk over in the case the samples fill out an
// entire chunk.
auto shuf = src;
auto shufn = SHUFFLE(src, ixn.x == i.x.w ? srcn.yyyy : srcn, 1, 2, 3, 4);
if (i.x.y == i.x.x) {
shuf = shuf.xxyz;
shufn = shufn.xxyz;
}
if (i.x.z == i.x.y) {
shuf = shuf.xyyz;
shufn = shufn.xyyz;
}
if (i.x.w == i.x.z) {
shuf = shuf.xyzz;
shufn = shufn.xyzz;
}
// Convert back to a signed unpacked type so that we can interpolate the
// final result.
auto interp = bit_cast<signed_unpacked_type>(shuf);
auto interpn = bit_cast<signed_unpacked_type>(shufn);
interp += applyFracX(interpn - interp, fracx) >> 7;
commit_blend_span<BLEND>(
buf, applyColor(bit_cast<unpacked_type>(interp), color));
i.x = ixn;
fracx = fracn;
src = srcn;
}
}
// This is the fastest variant of the linear filter that still provides
// filtering. In cases where there is no scaling required, but we have a
// subpixel offset that forces us to blend in neighboring pixels, we can
// optimize away most of the memory loads and shuffling that is required by the
// fallback filter.
template <bool BLEND, typename S, typename C, typename P>
static void blendTextureLinearFast(S sampler, vec2 uv, int span,
vec2_scalar min_uv, vec2_scalar max_uv,
C color, P* buf) {
typedef VectorType<uint8_t, 4 * sizeof(P)> packed_type;
typedef VectorType<uint16_t, 4 * sizeof(P)> unpacked_type;
typedef VectorType<int16_t, 4 * sizeof(P)> signed_unpacked_type;
ivec2 i(clamp(uv, min_uv, max_uv));
ivec2 frac = i;
i >>= 7;
P* row0 = (P*)sampler->buf + computeRow(sampler, force_scalar(i));
P* row1 = row0 + computeNextRowOffset(sampler, force_scalar(i));
int16_t fracx = computeFracX(sampler, i, frac).x;
int16_t fracy = computeFracY(frac).x;
auto src0 = CONVERT(unaligned_load<packed_type>(row0), signed_unpacked_type);
auto src1 = CONVERT(unaligned_load<packed_type>(row1), signed_unpacked_type);
auto src = castForShuffle(src0 + (((src1 - src0) * fracy) >> 7));
// Since there is no scaling, we sample ahead by one chunk and interpolate it
// with the current one. We can then reuse this value on the next iteration.
for (P* end = buf + span; buf < end; buf += 4) {
row0 += 4;
row1 += 4;
auto src0n =
CONVERT(unaligned_load<packed_type>(row0), signed_unpacked_type);
auto src1n =
CONVERT(unaligned_load<packed_type>(row1), signed_unpacked_type);
auto srcn = castForShuffle(src0n + (((src1n - src0n) * fracy) >> 7));
// For the last sample to interpolate with, we need to potentially shift in
// a sample from the next chunk over since the samples fill out an entire
// chunk.
auto interp = bit_cast<signed_unpacked_type>(src);
auto interpn =
bit_cast<signed_unpacked_type>(SHUFFLE(src, srcn, 1, 2, 3, 4));
interp += ((interpn - interp) * fracx) >> 7;
commit_blend_span<BLEND>(
buf, applyColor(bit_cast<unpacked_type>(interp), color));
src = srcn;
}
}
// Implements a faster linear filter that works with axis-aligned constant Y but
// downscaling the texture by half. In this case we can optimize for the
// constant X/Y fractions and reduction factor while minimizing shuffling.
template <bool BLEND, typename S, typename C, typename P>
static NO_INLINE void blendTextureLinearDownscale(S sampler, vec2 uv, int span,
vec2_scalar min_uv,
vec2_scalar max_uv, C color,
P* buf) {
typedef VectorType<uint8_t, 4 * sizeof(P)> packed_type;
typedef VectorType<uint16_t, 4 * sizeof(P)> unpacked_type;
typedef VectorType<int16_t, 4 * sizeof(P)> signed_unpacked_type;
ivec2 i(clamp(uv, min_uv, max_uv));
ivec2 frac = i;
i >>= 7;
P* row0 = (P*)sampler->buf + computeRow(sampler, force_scalar(i));
P* row1 = row0 + computeNextRowOffset(sampler, force_scalar(i));
int16_t fracx = computeFracX(sampler, i, frac).x;
int16_t fracy = computeFracY(frac).x;
for (P* end = buf + span; buf < end; buf += 4) {
auto src0 =
CONVERT(unaligned_load<packed_type>(row0), signed_unpacked_type);
auto src1 =
CONVERT(unaligned_load<packed_type>(row1), signed_unpacked_type);
auto src = castForShuffle(src0 + (((src1 - src0) * fracy) >> 7));
row0 += 4;
row1 += 4;
auto src0n =
CONVERT(unaligned_load<packed_type>(row0), signed_unpacked_type);
auto src1n =
CONVERT(unaligned_load<packed_type>(row1), signed_unpacked_type);
auto srcn = castForShuffle(src0n + (((src1n - src0n) * fracy) >> 7));
row0 += 4;
row1 += 4;
auto interp =
bit_cast<signed_unpacked_type>(SHUFFLE(src, srcn, 0, 2, 4, 6));
auto interpn =
bit_cast<signed_unpacked_type>(SHUFFLE(src, srcn, 1, 3, 5, 7));
interp += ((interpn - interp) * fracx) >> 7;
commit_blend_span<BLEND>(
buf, applyColor(bit_cast<unpacked_type>(interp), color));
}
}
enum LinearFilter {
// No linear filter is needed.
LINEAR_FILTER_NEAREST = 0,
// The most general linear filter that handles clamping and varying scales.
LINEAR_FILTER_FALLBACK,
// A linear filter optimized for axis-aligned upscaling.
LINEAR_FILTER_UPSCALE,
// A linear filter with no scaling but with subpixel offset.
LINEAR_FILTER_FAST,
// A linear filter optimized for 2x axis-aligned downscaling.
LINEAR_FILTER_DOWNSCALE
};
// Dispatches to an appropriate linear filter depending on the selected filter.
template <bool BLEND, typename S, typename C, typename P>
static P* blendTextureLinearDispatch(S sampler, vec2 uv, int span,
vec2_scalar uv_step, vec2_scalar min_uv,
vec2_scalar max_uv, C color, P* buf,
LinearFilter filter) {
P* end = buf + span;
if (filter != LINEAR_FILTER_FALLBACK) {
// If we're not using the fallback, then Y is constant across the entire
// row. We just need to ensure that we handle any samples that might pull
// data from before the start of the row and require clamping.
float beforeDist = max(0.0f, min_uv.x) - uv.x.x;
if (beforeDist > 0) {
int before = clamp(int(ceil(beforeDist / uv_step.x)) * swgl_StepSize, 0,
int(end - buf));
buf = blendTextureLinearFallback<BLEND>(sampler, uv, before, uv_step,
min_uv, max_uv, color, buf);
uv.x += (before / swgl_StepSize) * uv_step.x;
}
// We need to check how many samples we can take from inside the row without
// requiring clamping. In case the filter oversamples the row by a step, we
// subtract off a step from the width to leave some room.
float insideDist =
min(max_uv.x, float((int(sampler->width) - swgl_StepSize) *
swgl_LinearQuantizeScale)) -
uv.x.x;
if (uv_step.x > 0.0f && insideDist >= uv_step.x) {
int32_t inside = int(end - buf);
if (filter == LINEAR_FILTER_DOWNSCALE) {
inside = min(int(insideDist * (0.5f / swgl_LinearQuantizeScale)) &
~(swgl_StepSize - 1),
inside);
if (inside > 0) {
blendTextureLinearDownscale<BLEND>(sampler, uv, inside, min_uv,
max_uv, color, buf);
buf += inside;
uv.x += (inside / swgl_StepSize) * uv_step.x;
}
} else if (filter == LINEAR_FILTER_UPSCALE) {
inside = min(int(insideDist / uv_step.x) * swgl_StepSize, inside);
if (inside > 0) {
blendTextureLinearUpscale<BLEND>(sampler, uv, inside, uv_step, min_uv,
max_uv, color, buf);
buf += inside;
uv.x += (inside / swgl_StepSize) * uv_step.x;
}
} else {
inside = min(int(insideDist * (1.0f / swgl_LinearQuantizeScale)) &
~(swgl_StepSize - 1),
inside);
if (inside > 0) {
blendTextureLinearFast<BLEND>(sampler, uv, inside, min_uv, max_uv,
color, buf);
buf += inside;
uv.x += (inside / swgl_StepSize) * uv_step.x;
}
}
}
}
// If the fallback filter was requested, or if there are any samples left that
// may be outside the row and require clamping, then handle that with here.
if (buf < end) {
buf = blendTextureLinearFallback<BLEND>(
sampler, uv, int(end - buf), uv_step, min_uv, max_uv, color, buf);
}
return buf;
}
// Helper function to quantize UVs for linear filtering before dispatch
template <bool BLEND, typename S, typename C, typename P>
static inline int blendTextureLinear(S sampler, vec2 uv, int span,
const vec4_scalar& uv_rect, C color,
P* buf, LinearFilter filter) {
if (!matchTextureFormat(sampler, buf)) {
return 0;
}
LINEAR_QUANTIZE_UV(sampler, uv, uv_step, uv_rect, min_uv, max_uv);
blendTextureLinearDispatch<BLEND>(sampler, uv, span, uv_step, min_uv, max_uv,
color, buf, filter);
return span;
}
// Samples an axis-aligned span of on a single row of a texture using 1:1
// nearest filtering. Sampling is constrained to only fall within the given UV
// bounds. This requires a pointer to the destination buffer. An optional color
// modulus can be supplied.
template <bool BLEND, typename S, typename C, typename P>
static int blendTextureNearestFast(S sampler, vec2 uv, int span,
const vec4_scalar& uv_rect, C color,
P* buf) {
if (!matchTextureFormat(sampler, buf)) {
return 0;
}
typedef VectorType<uint8_t, 4 * sizeof(P)> packed_type;
ivec2_scalar i = make_ivec2(samplerScale(sampler, force_scalar(uv)));
ivec2_scalar minUV =
make_ivec2(samplerScale(sampler, vec2_scalar{uv_rect.x, uv_rect.y}));
ivec2_scalar maxUV =
make_ivec2(samplerScale(sampler, vec2_scalar{uv_rect.z, uv_rect.w}));
// Calculate the row pointer within the buffer, clamping to within valid row
// bounds.
P* row =
&((P*)sampler
->buf)[clampCoord(clamp(i.y, minUV.y, maxUV.y), sampler->height) *
sampler->stride];
// Find clamped X bounds within the row.
int minX = clamp(minUV.x, 0, sampler->width - 1);
int maxX = clamp(maxUV.x, minX, sampler->width - 1);
int curX = i.x;
int endX = i.x + span;
// If we need to start sampling below the valid sample bounds, then we need to
// fill this section with a constant clamped sample.
if (curX < minX) {
int n = min(minX, endX) - curX;
auto src =
applyColor(unpack(bit_cast<packed_type>(V4<P>(row[minX]))), color);
commit_solid_span<BLEND>(buf, src, n);
buf += n;
curX += n;
}
// Here we only deal with valid samples within the sample bounds. No clamping
// should occur here within these inner loops.
int n = max(min(maxX + 1, endX) - curX, 0);
// Try to process as many chunks as possible with full loads and stores.
for (int end = curX + (n & ~3); curX < end; curX += 4, buf += 4) {
auto src = applyColor(unaligned_load<packed_type>(&row[curX]), color);
commit_blend_span<BLEND>(buf, src);
}
n &= 3;
// If we have any leftover samples after processing chunks, use partial loads
// and stores.
if (n > 0) {
auto src = applyColor(partial_load_span<packed_type>(&row[curX], n), color);
commit_blend_span<BLEND>(buf, src, n);
buf += n;
curX += n;
}
// If we still have samples left above the valid sample bounds, then we again
// need to fill this section with a constant clamped sample.
if (curX < endX) {
auto src =
applyColor(unpack(bit_cast<packed_type>(V4<P>(row[maxX]))), color);
commit_solid_span<BLEND>(buf, src, endX - curX);
}
return span;
}
// We need to verify that the pixel step reasonably approximates stepping by a
// single texel for every pixel we need to reproduce. Try to ensure that the
// margin of error is no more than approximately 2^-7. Also, we check here if
// the scaling can be quantized for acceleration.
template <typename T>
static ALWAYS_INLINE int spanNeedsScale(int span, T P) {
span &= ~(128 - 1);
span += 128;
int scaled = round((P.x.y - P.x.x) * span);
return scaled != span ? (scaled == span * 2 ? 2 : 1) : 0;
}
// Helper function to decide whether we can safely apply 1:1 nearest filtering
// without diverging too much from the linear filter.
template <typename S, typename T>
static inline LinearFilter needsTextureLinear(S sampler, T P, int span) {
// If each row is not wide enough for linear filtering, then just use nearest
// filtering.
if (sampler->width < 2) {
return LINEAR_FILTER_NEAREST;
}
// First verify if the row Y doesn't change across samples
if (P.y.x != P.y.y) {
return LINEAR_FILTER_FALLBACK;
}
P = samplerScale(sampler, P);
if (int scale = spanNeedsScale(span, P)) {
// If the source region is not flipped and smaller than the destination,
// then we can use the upscaling filter since row Y is constant.
return P.x.x < P.x.y && P.x.y - P.x.x <= 1
? LINEAR_FILTER_UPSCALE
: (scale == 2 ? LINEAR_FILTER_DOWNSCALE
: LINEAR_FILTER_FALLBACK);
}
// Also verify that we're reasonably close to the center of a texel
// so that it doesn't look that much different than if a linear filter
// was used.
if ((int(P.x.x * 4.0f + 0.5f) & 3) != 2 ||
(int(P.y.x * 4.0f + 0.5f) & 3) != 2) {
// The source and destination regions are the same, but there is a
// significant subpixel offset. We can use a faster linear filter to deal
// with the offset in this case.
return LINEAR_FILTER_FAST;
}
// Otherwise, we have a constant 1:1 step and we're stepping reasonably close
// to the center of each pixel, so it's safe to disable the linear filter and
// use nearest.
return LINEAR_FILTER_NEAREST;
}
// Commit an entire span with linear filtering
#define swgl_commitTextureLinear(format, s, p, uv_rect, color, n) \
do { \
auto packed_color = packColor(swgl_Out##format, color); \
int len = (n); \
int drawn = 0; \
if (LinearFilter filter = needsTextureLinear(s, p, len)) { \
if (blend_key) { \
drawn = blendTextureLinear<true>(s, p, len, uv_rect, packed_color, \
swgl_Out##format, filter); \
} else { \
drawn = blendTextureLinear<false>(s, p, len, uv_rect, packed_color, \
swgl_Out##format, filter); \
} \
} else if (blend_key) { \
drawn = blendTextureNearestFast<true>(s, p, len, uv_rect, packed_color, \
swgl_Out##format); \
} else { \
drawn = blendTextureNearestFast<false>(s, p, len, uv_rect, packed_color, \
swgl_Out##format); \
} \
swgl_Out##format += drawn; \
swgl_SpanLength -= drawn; \
} while (0)
#define swgl_commitTextureLinearRGBA8(s, p, uv_rect) \
swgl_commitTextureLinear(RGBA8, s, p, uv_rect, NoColor(), swgl_SpanLength)
#define swgl_commitTextureLinearR8(s, p, uv_rect) \
swgl_commitTextureLinear(R8, s, p, uv_rect, NoColor(), swgl_SpanLength)
// Commit a partial span with linear filtering, optionally inverting the color
#define swgl_commitPartialTextureLinearR8(len, s, p, uv_rect) \
swgl_commitTextureLinear(R8, s, p, uv_rect, NoColor(), \
min(int(len), swgl_SpanLength))
#define swgl_commitPartialTextureLinearInvertR8(len, s, p, uv_rect) \
swgl_commitTextureLinear(R8, s, p, uv_rect, InvertColor(), \
min(int(len), swgl_SpanLength))
// Commit an entire span with linear filtering that is scaled by a color
#define swgl_commitTextureLinearColorRGBA8(s, p, uv_rect, color) \
swgl_commitTextureLinear(RGBA8, s, p, uv_rect, color, swgl_SpanLength)
#define swgl_commitTextureLinearColorR8(s, p, uv_rect, color) \
swgl_commitTextureLinear(R8, s, p, uv_rect, color, swgl_SpanLength)
// Helper function that samples from an R8 texture while expanding it to support
// a differing framebuffer format.
template <bool BLEND, typename S, typename C, typename P>
static inline int blendTextureLinearR8(S sampler, vec2 uv, int span,
const vec4_scalar& uv_rect, C color,
P* buf) {
if (!swgl_isTextureR8(sampler) || sampler->width < 2) {
return 0;
}
LINEAR_QUANTIZE_UV(sampler, uv, uv_step, uv_rect, min_uv, max_uv);
for (P* end = buf + span; buf < end; buf += swgl_StepSize, uv += uv_step) {
commit_blend_span<BLEND>(
buf, applyColor(expand_mask(buf, textureLinearUnpackedR8(
sampler,
ivec2(clamp(uv, min_uv, max_uv)))),
color));
}
return span;
}
// Commit an entire span with linear filtering while expanding from R8 to RGBA8
#define swgl_commitTextureLinearColorR8ToRGBA8(s, p, uv_rect, color) \
do { \
auto packed_color = packColor(swgl_OutRGBA8, color); \
int drawn = 0; \
if (blend_key) { \
drawn = blendTextureLinearR8<true>(s, p, swgl_SpanLength, uv_rect, \
packed_color, swgl_OutRGBA8); \
} else { \
drawn = blendTextureLinearR8<false>(s, p, swgl_SpanLength, uv_rect, \
packed_color, swgl_OutRGBA8); \
} \
swgl_OutRGBA8 += drawn; \
swgl_SpanLength -= drawn; \
} while (0)
#define swgl_commitTextureLinearR8ToRGBA8(s, p, uv_rect) \
swgl_commitTextureLinearColorR8ToRGBA8(s, p, uv_rect, NoColor())
// Compute repeating UVs, possibly constrained by tile repeat limits
static inline vec2 tileRepeatUV(vec2 uv, const vec2_scalar& tile_repeat) {
if (tile_repeat.x > 0.0f) {
// Clamp to a number slightly less than the tile repeat limit so that
// it results in a number close to but not equal to 1 after fract().
// This avoids fract() yielding 0 if the limit was left as whole integer.
uv = clamp(uv, vec2_scalar(0.0f), tile_repeat - 1.0e-6f);
}
return fract(uv);
}
// Compute the number of non-repeating steps before we need to potentially
// repeat the UVs.
static inline int computeNoRepeatSteps(Float uv, float uv_step,
float tile_repeat, int steps) {
if (uv.w < uv.x) {
// Ensure the UV taps are ordered low to high.
uv = uv.wzyx;
}
// Check if the samples cross the boundary of the next whole integer or the
// tile repeat limit, whichever is lower.
float limit = floor(uv.x) + 1.0f;
if (tile_repeat > 0.0f) {
limit = min(limit, tile_repeat);
}
return uv.x >= 0.0f && uv.w < limit
? (uv_step != 0.0f
? int(clamp((limit - uv.x) / uv_step, 0.0f, float(steps)))
: steps)
: 0;
}
// Blends an entire span of texture with linear filtering and repeating UVs.
template <bool BLEND, typename S, typename C, typename P>
static int blendTextureLinearRepeat(S sampler, vec2 uv, int span,
const vec2_scalar& tile_repeat,
const vec4_scalar& uv_repeat,
const vec4_scalar& uv_rect, C color,
P* buf) {
if (!matchTextureFormat(sampler, buf)) {
return 0;
}
vec2_scalar uv_scale = {uv_repeat.z - uv_repeat.x, uv_repeat.w - uv_repeat.y};
vec2_scalar uv_offset = {uv_repeat.x, uv_repeat.y};
// Choose a linear filter to use for no-repeat sub-spans
LinearFilter filter =
needsTextureLinear(sampler, uv * uv_scale + uv_offset, span);
// We need to step UVs unscaled and unquantized so that we can modulo them
// with fract. We use uv_scale and uv_offset to map them into the correct
// range.
vec2_scalar uv_step =
float(swgl_StepSize) * vec2_scalar{uv.x.y - uv.x.x, uv.y.y - uv.y.x};
uv_scale = swgl_linearQuantizeStep(sampler, uv_scale);
uv_offset = swgl_linearQuantize(sampler, uv_offset);
vec2_scalar min_uv = max(
swgl_linearQuantize(sampler, vec2_scalar{uv_rect.x, uv_rect.y}), 0.0f);
vec2_scalar max_uv = max(
swgl_linearQuantize(sampler, vec2_scalar{uv_rect.z, uv_rect.w}), min_uv);
for (P* end = buf + span; buf < end; buf += swgl_StepSize, uv += uv_step) {
int steps = int(end - buf) / swgl_StepSize;
// Find the sub-span before UVs repeat to avoid expensive repeat math
steps = computeNoRepeatSteps(uv.x, uv_step.x, tile_repeat.x, steps);
if (steps > 0) {
steps = computeNoRepeatSteps(uv.y, uv_step.y, tile_repeat.y, steps);
if (steps > 0) {
buf = blendTextureLinearDispatch<BLEND>(
sampler, fract(uv) * uv_scale + uv_offset, steps * swgl_StepSize,
uv_step * uv_scale, min_uv, max_uv, color, buf, filter);
if (buf >= end) {
break;
}
uv += steps * uv_step;
}
}
// UVs might repeat within this step, so explicitly compute repeated UVs
vec2 repeated_uv = clamp(
tileRepeatUV(uv, tile_repeat) * uv_scale + uv_offset, min_uv, max_uv);
commit_blend_span<BLEND>(
buf, applyColor(textureLinearUnpacked(buf, sampler, ivec2(repeated_uv)),
color));
}
return span;
}
// Commit an entire span with linear filtering and repeating UVs
#define swgl_commitTextureLinearRepeat(format, s, p, tile_repeat, uv_repeat, \
uv_rect, color) \
do { \
auto packed_color = packColor(swgl_Out##format, color); \
int drawn = 0; \
if (blend_key) { \
drawn = blendTextureLinearRepeat<true>(s, p, swgl_SpanLength, \
tile_repeat, uv_repeat, uv_rect, \
packed_color, swgl_Out##format); \
} else { \
drawn = blendTextureLinearRepeat<false>(s, p, swgl_SpanLength, \
tile_repeat, uv_repeat, uv_rect, \
packed_color, swgl_Out##format); \
} \
swgl_Out##format += drawn; \
swgl_SpanLength -= drawn; \
} while (0)
#define swgl_commitTextureLinearRepeatRGBA8(s, p, tile_repeat, uv_repeat, \
uv_rect) \
swgl_commitTextureLinearRepeat(RGBA8, s, p, tile_repeat, uv_repeat, uv_rect, \
NoColor())
#define swgl_commitTextureLinearRepeatColorRGBA8(s, p, tile_repeat, uv_repeat, \
uv_rect, color) \
swgl_commitTextureLinearRepeat(RGBA8, s, p, tile_repeat, uv_repeat, uv_rect, \
color)
template <typename S>
static ALWAYS_INLINE PackedRGBA8 textureNearestPacked(UNUSED uint32_t* buf,
S sampler, ivec2 i) {
return textureNearestPackedRGBA8(sampler, i);
}
// Blends an entire span of texture with nearest filtering and either
// repeated or clamped UVs.
template <bool BLEND, bool REPEAT, typename S, typename C, typename P>
static int blendTextureNearestRepeat(S sampler, vec2 uv, int span,
const vec2_scalar& tile_repeat,
const vec4_scalar& uv_rect, C color,
P* buf) {
if (!matchTextureFormat(sampler, buf)) {
return 0;
}
if (!REPEAT) {
// If clamping, then we step pre-scaled to the sampler. For repeat modes,
// this will be accomplished via uv_scale instead.
uv = samplerScale(sampler, uv);
}
vec2_scalar uv_step =
float(swgl_StepSize) * vec2_scalar{uv.x.y - uv.x.x, uv.y.y - uv.y.x};
vec2_scalar min_uv = samplerScale(sampler, vec2_scalar{uv_rect.x, uv_rect.y});
vec2_scalar max_uv = samplerScale(sampler, vec2_scalar{uv_rect.z, uv_rect.w});
vec2_scalar uv_scale = max_uv - min_uv;
// If the effective sampling area of this texture is only a single pixel, then
// treat it as a solid span. For repeat modes, the bounds are specified on
// pixel boundaries, whereas for clamp modes, bounds are on pixel centers, so
// the test varies depending on which. If the sample range on an axis is
// greater than one pixel, we can still check if we don't move far enough from
// the pixel center on that axis to hit the next pixel.
if ((int(min_uv.x) + (REPEAT ? 1 : 0) >= int(max_uv.x) ||
(abs(uv_step.x) * span * (REPEAT ? uv_scale.x : 1.0f) < 0.5f)) &&
(int(min_uv.y) + (REPEAT ? 1 : 0) >= int(max_uv.y) ||
(abs(uv_step.y) * span * (REPEAT ? uv_scale.y : 1.0f) < 0.5f))) {
vec2 repeated_uv = REPEAT
? tileRepeatUV(uv, tile_repeat) * uv_scale + min_uv
: clamp(uv, min_uv, max_uv);
commit_solid_span<BLEND>(buf,
applyColor(unpack(textureNearestPacked(
buf, sampler, ivec2(repeated_uv))),
color),
span);
} else {
for (P* end = buf + span; buf < end; buf += swgl_StepSize, uv += uv_step) {
if (REPEAT) {
int steps = int(end - buf) / swgl_StepSize;
// Find the sub-span before UVs repeat to avoid expensive repeat math
steps = computeNoRepeatSteps(uv.x, uv_step.x, tile_repeat.x, steps);
if (steps > 0) {
steps = computeNoRepeatSteps(uv.y, uv_step.y, tile_repeat.y, steps);
if (steps > 0) {
vec2 inside_uv = fract(uv) * uv_scale + min_uv;
vec2 inside_step = uv_step * uv_scale;
for (P* outside = &buf[steps * swgl_StepSize]; buf < outside;
buf += swgl_StepSize, inside_uv += inside_step) {
commit_blend_span<BLEND>(
buf, applyColor(
textureNearestPacked(buf, sampler, ivec2(inside_uv)),
color));
}
if (buf >= end) {
break;
}
uv += steps * uv_step;
}
}
}
// UVs might repeat within this step, so explicitly compute repeated UVs
vec2 repeated_uv = REPEAT
? tileRepeatUV(uv, tile_repeat) * uv_scale + min_uv
: clamp(uv, min_uv, max_uv);
commit_blend_span<BLEND>(
buf,
applyColor(textureNearestPacked(buf, sampler, ivec2(repeated_uv)),
color));
}
}
return span;
}
// Determine if we can use the fast nearest filter for the given nearest mode.
// If the Y coordinate varies more than half a pixel over
// the span (which might cause the texel to alias to the next one), or the span
// needs X scaling, then we have to use the fallback.
template <typename S, typename T>
static ALWAYS_INLINE bool needsNearestFallback(S sampler, T P, int span) {
P = samplerScale(sampler, P);
return (P.y.y - P.y.x) * span >= 0.5f || spanNeedsScale(span, P);
}
// Commit an entire span with nearest filtering and either clamped or repeating
// UVs
#define swgl_commitTextureNearest(format, s, p, uv_rect, color) \
do { \
auto packed_color = packColor(swgl_Out##format, color); \
int drawn = 0; \
if (needsNearestFallback(s, p, swgl_SpanLength)) { \
if (blend_key) { \
drawn = blendTextureNearestRepeat<true, false>( \
s, p, swgl_SpanLength, 0.0f, uv_rect, packed_color, \
swgl_Out##format); \
} else { \
drawn = blendTextureNearestRepeat<false, false>( \
s, p, swgl_SpanLength, 0.0f, uv_rect, packed_color, \
swgl_Out##format); \
} \
} else if (blend_key) { \
drawn = blendTextureNearestFast<true>(s, p, swgl_SpanLength, uv_rect, \
packed_color, swgl_Out##format); \
} else { \
drawn = blendTextureNearestFast<false>(s, p, swgl_SpanLength, uv_rect, \
packed_color, swgl_Out##format); \
} \
swgl_Out##format += drawn; \
swgl_SpanLength -= drawn; \
} while (0)
#define swgl_commitTextureNearestRGBA8(s, p, uv_rect) \
swgl_commitTextureNearest(RGBA8, s, p, uv_rect, NoColor())
#define swgl_commitTextureNearestColorRGBA8(s, p, uv_rect, color) \
swgl_commitTextureNearest(RGBA8, s, p, uv_rect, color)
#define swgl_commitTextureNearestRepeat(format, s, p, tile_repeat, uv_rect, \
color) \
do { \
auto packed_color = packColor(swgl_Out##format, color); \
int drawn = 0; \
if (blend_key) { \
drawn = blendTextureNearestRepeat<true, true>( \
s, p, swgl_SpanLength, tile_repeat, uv_rect, packed_color, \
swgl_Out##format); \
} else { \
drawn = blendTextureNearestRepeat<false, true>( \
s, p, swgl_SpanLength, tile_repeat, uv_rect, packed_color, \
swgl_Out##format); \
} \
swgl_Out##format += drawn; \
swgl_SpanLength -= drawn; \
} while (0)
#define swgl_commitTextureNearestRepeatRGBA8(s, p, tile_repeat, uv_repeat, \
uv_rect) \
swgl_commitTextureNearestRepeat(RGBA8, s, p, tile_repeat, uv_repeat, \
NoColor())
#define swgl_commitTextureNearestRepeatColorRGBA8(s, p, tile_repeat, \
uv_repeat, uv_rect, color) \
swgl_commitTextureNearestRepeat(RGBA8, s, p, tile_repeat, uv_repeat, color)
// Commit an entire span of texture with filtering determined by sampler state.
#define swgl_commitTexture(format, s, ...) \
do { \
if (s->filter == TextureFilter::LINEAR) { \
swgl_commitTextureLinear##format(s, __VA_ARGS__); \
} else { \
swgl_commitTextureNearest##format(s, __VA_ARGS__); \
} \
} while (0)
#define swgl_commitTextureRGBA8(...) swgl_commitTexture(RGBA8, __VA_ARGS__)
#define swgl_commitTextureColorRGBA8(...) \
swgl_commitTexture(ColorRGBA8, __VA_ARGS__)
#define swgl_commitTextureRepeatRGBA8(...) \
swgl_commitTexture(RepeatRGBA8, __VA_ARGS__)
#define swgl_commitTextureRepeatColorRGBA8(...) \
swgl_commitTexture(RepeatColorRGBA8, __VA_ARGS__)
// Commit an entire span of a separable pass of a Gaussian blur that falls
// within the given radius scaled by supplied coefficients, clamped to uv_rect
// bounds.
template <bool BLEND, typename S, typename P>
static int blendGaussianBlur(S sampler, vec2 uv, const vec4_scalar& uv_rect,
P* buf, int span, bool hori, int radius,
vec2_scalar coeffs) {
if (!matchTextureFormat(sampler, buf)) {
return 0;
}
vec2_scalar size = {float(sampler->width), float(sampler->height)};
ivec2_scalar curUV = make_ivec2(force_scalar(uv) * size);
ivec4_scalar bounds = make_ivec4(uv_rect * make_vec4(size, size));
int startX = curUV.x;
int endX = min(min(bounds.z, curUV.x + span), int(size.x));
if (hori) {
for (; curUV.x + swgl_StepSize <= endX;
buf += swgl_StepSize, curUV.x += swgl_StepSize) {
commit_blend_span<BLEND>(
buf, gaussianBlurHorizontal<P>(sampler, curUV, bounds.x, bounds.z,
radius, coeffs.x, coeffs.y));
}
} else {
for (; curUV.x + swgl_StepSize <= endX;
buf += swgl_StepSize, curUV.x += swgl_StepSize) {
commit_blend_span<BLEND>(
buf, gaussianBlurVertical<P>(sampler, curUV, bounds.y, bounds.w,
radius, coeffs.x, coeffs.y));
}
}
return curUV.x - startX;
}
#define swgl_commitGaussianBlur(format, s, p, uv_rect, hori, radius, coeffs) \
do { \
int drawn = 0; \
if (blend_key) { \
drawn = blendGaussianBlur<true>(s, p, uv_rect, swgl_Out##format, \
swgl_SpanLength, hori, radius, coeffs); \
} else { \
drawn = blendGaussianBlur<false>(s, p, uv_rect, swgl_Out##format, \
swgl_SpanLength, hori, radius, coeffs); \
} \
swgl_Out##format += drawn; \
swgl_SpanLength -= drawn; \
} while (0)
#define swgl_commitGaussianBlurRGBA8(s, p, uv_rect, hori, radius, coeffs) \
swgl_commitGaussianBlur(RGBA8, s, p, uv_rect, hori, radius, coeffs)
#define swgl_commitGaussianBlurR8(s, p, uv_rect, hori, radius, coeffs) \
swgl_commitGaussianBlur(R8, s, p, uv_rect, hori, radius, coeffs)
// Convert and pack planar YUV samples to RGB output using a color space
static ALWAYS_INLINE PackedRGBA8 convertYUV(const YUVMatrix& rgb_from_ycbcr,
U16 y, U16 u, U16 v) {
auto yy = V8<int16_t>(zip(y, y));
auto uv = V8<int16_t>(zip(u, v));
return rgb_from_ycbcr.convert(yy, uv);
}
// Helper functions to sample from planar YUV textures before converting to RGB
template <typename S0>
static ALWAYS_INLINE PackedRGBA8 sampleYUV(S0 sampler0, ivec2 uv0,
const YUVMatrix& rgb_from_ycbcr,
UNUSED int rescaleFactor) {
switch (sampler0->format) {
case TextureFormat::RGBA8: {
auto planar = textureLinearPlanarRGBA8(sampler0, uv0);
return convertYUV(rgb_from_ycbcr, highHalf(planar.rg), lowHalf(planar.rg),
lowHalf(planar.ba));
}
case TextureFormat::YUV422: {
auto planar = textureLinearPlanarYUV422(sampler0, uv0);
return convertYUV(rgb_from_ycbcr, planar.y, planar.u, planar.v);
}
default:
assert(false);
return PackedRGBA8(0);
}
}
template <bool BLEND, typename S0, typename P, typename C = NoColor>
static int blendYUV(P* buf, int span, S0 sampler0, vec2 uv0,
const vec4_scalar& uv_rect0, const vec3_scalar& ycbcr_bias,
const mat3_scalar& rgb_from_debiased_ycbcr,
int rescaleFactor, C color = C()) {
if (!swgl_isTextureLinear(sampler0)) {
return 0;
}
LINEAR_QUANTIZE_UV(sampler0, uv0, uv_step0, uv_rect0, min_uv0, max_uv0);
const auto rgb_from_ycbcr =
YUVMatrix::From(ycbcr_bias, rgb_from_debiased_ycbcr, rescaleFactor);
auto c = packColor(buf, color);
auto* end = buf + span;
for (; buf < end; buf += swgl_StepSize, uv0 += uv_step0) {
commit_blend_span<BLEND>(
buf, applyColor(sampleYUV(sampler0, ivec2(clamp(uv0, min_uv0, max_uv0)),
rgb_from_ycbcr, rescaleFactor),
c));
}
return span;
}
template <typename S0, typename S1>
static ALWAYS_INLINE PackedRGBA8 sampleYUV(S0 sampler0, ivec2 uv0, S1 sampler1,
ivec2 uv1,
const YUVMatrix& rgb_from_ycbcr,
int rescaleFactor) {
switch (sampler1->format) {
case TextureFormat::RG8: {
assert(sampler0->format == TextureFormat::R8);
auto y = textureLinearUnpackedR8(sampler0, uv0);
auto planar = textureLinearPlanarRG8(sampler1, uv1);
return convertYUV(rgb_from_ycbcr, y, lowHalf(planar.rg),
highHalf(planar.rg));
}
case TextureFormat::RGBA8: {
assert(sampler0->format == TextureFormat::R8);
auto y = textureLinearUnpackedR8(sampler0, uv0);
auto planar = textureLinearPlanarRGBA8(sampler1, uv1);
return convertYUV(rgb_from_ycbcr, y, lowHalf(planar.ba),
highHalf(planar.rg));
}
case TextureFormat::RG16: {
assert(sampler0->format == TextureFormat::R16);
// The rescaling factor represents how many bits to add to renormalize the
// texture to 16 bits, and so the color depth is actually 16 minus the
// rescaling factor.
// Need to right shift the sample by the amount of bits over 8 it
// occupies. On output from textureLinearUnpackedR16, we have lost 1 bit
// of precision at the low end already, hence 1 is subtracted from the
// color depth.
int colorDepth = 16 - rescaleFactor;
int rescaleBits = (colorDepth - 1) - 8;
auto y = textureLinearUnpackedR16(sampler0, uv0) >> rescaleBits;
auto uv = textureLinearUnpackedRG16(sampler1, uv1) >> rescaleBits;
return rgb_from_ycbcr.convert(zip(y, y), uv);
}
default:
assert(false);
return PackedRGBA8(0);
}
}
template <bool BLEND, typename S0, typename S1, typename P,
typename C = NoColor>
static int blendYUV(P* buf, int span, S0 sampler0, vec2 uv0,
const vec4_scalar& uv_rect0, S1 sampler1, vec2 uv1,
const vec4_scalar& uv_rect1, const vec3_scalar& ycbcr_bias,
const mat3_scalar& rgb_from_debiased_ycbcr,
int rescaleFactor, C color = C()) {
if (!swgl_isTextureLinear(sampler0) || !swgl_isTextureLinear(sampler1)) {
return 0;
}
LINEAR_QUANTIZE_UV(sampler0, uv0, uv_step0, uv_rect0, min_uv0, max_uv0);
LINEAR_QUANTIZE_UV(sampler1, uv1, uv_step1, uv_rect1, min_uv1, max_uv1);
const auto rgb_from_ycbcr =
YUVMatrix::From(ycbcr_bias, rgb_from_debiased_ycbcr, rescaleFactor);
auto c = packColor(buf, color);
auto* end = buf + span;
for (; buf < end; buf += swgl_StepSize, uv0 += uv_step0, uv1 += uv_step1) {
commit_blend_span<BLEND>(
buf, applyColor(sampleYUV(sampler0, ivec2(clamp(uv0, min_uv0, max_uv0)),
sampler1, ivec2(clamp(uv1, min_uv1, max_uv1)),
rgb_from_ycbcr, rescaleFactor),
c));
}
return span;
}
template <typename S0, typename S1, typename S2>
static ALWAYS_INLINE PackedRGBA8 sampleYUV(S0 sampler0, ivec2 uv0, S1 sampler1,
ivec2 uv1, S2 sampler2, ivec2 uv2,
const YUVMatrix& rgb_from_ycbcr,
int rescaleFactor) {
assert(sampler0->format == sampler1->format &&
sampler0->format == sampler2->format);
switch (sampler0->format) {
case TextureFormat::R8: {
auto y = textureLinearUnpackedR8(sampler0, uv0);
auto u = textureLinearUnpackedR8(sampler1, uv1);
auto v = textureLinearUnpackedR8(sampler2, uv2);
return convertYUV(rgb_from_ycbcr, y, u, v);
}
case TextureFormat::R16: {
// The rescaling factor represents how many bits to add to renormalize the
// texture to 16 bits, and so the color depth is actually 16 minus the
// rescaling factor.
// Need to right shift the sample by the amount of bits over 8 it
// occupies. On output from textureLinearUnpackedR16, we have lost 1 bit
// of precision at the low end already, hence 1 is subtracted from the
// color depth.
int colorDepth = 16 - rescaleFactor;
int rescaleBits = (colorDepth - 1) - 8;
auto y = textureLinearUnpackedR16(sampler0, uv0) >> rescaleBits;
auto u = textureLinearUnpackedR16(sampler1, uv1) >> rescaleBits;
auto v = textureLinearUnpackedR16(sampler2, uv2) >> rescaleBits;
return convertYUV(rgb_from_ycbcr, U16(y), U16(u), U16(v));
}
default:
assert(false);
return PackedRGBA8(0);
}
}
// Fallback helper for when we can't specifically accelerate YUV with
// composition.
template <bool BLEND, typename S0, typename S1, typename S2, typename P,
typename C>
static void blendYUVFallback(P* buf, int span, S0 sampler0, vec2 uv0,
vec2_scalar uv_step0, vec2_scalar min_uv0,
vec2_scalar max_uv0, S1 sampler1, vec2 uv1,
vec2_scalar uv_step1, vec2_scalar min_uv1,
vec2_scalar max_uv1, S2 sampler2, vec2 uv2,
vec2_scalar uv_step2, vec2_scalar min_uv2,
vec2_scalar max_uv2, const vec3_scalar& ycbcr_bias,
const mat3_scalar& rgb_from_debiased_ycbcr,
int rescaleFactor, C color) {
const auto rgb_from_ycbcr =
YUVMatrix::From(ycbcr_bias, rgb_from_debiased_ycbcr, rescaleFactor);
for (auto* end = buf + span; buf < end; buf += swgl_StepSize, uv0 += uv_step0,
uv1 += uv_step1, uv2 += uv_step2) {
commit_blend_span<BLEND>(
buf, applyColor(sampleYUV(sampler0, ivec2(clamp(uv0, min_uv0, max_uv0)),
sampler1, ivec2(clamp(uv1, min_uv1, max_uv1)),
sampler2, ivec2(clamp(uv2, min_uv2, max_uv2)),
rgb_from_ycbcr, rescaleFactor),
color));
}
}
template <bool BLEND, typename S0, typename S1, typename S2, typename P,
typename C = NoColor>
static int blendYUV(P* buf, int span, S0 sampler0, vec2 uv0,
const vec4_scalar& uv_rect0, S1 sampler1, vec2 uv1,
const vec4_scalar& uv_rect1, S2 sampler2, vec2 uv2,
const vec4_scalar& uv_rect2, const vec3_scalar& ycbcr_bias,
const mat3_scalar& rgb_from_debiased_ycbcr,
int rescaleFactor, C color = C()) {
if (!swgl_isTextureLinear(sampler0) || !swgl_isTextureLinear(sampler1) ||
!swgl_isTextureLinear(sampler2)) {
return 0;
}
LINEAR_QUANTIZE_UV(sampler0, uv0, uv_step0, uv_rect0, min_uv0, max_uv0);
LINEAR_QUANTIZE_UV(sampler1, uv1, uv_step1, uv_rect1, min_uv1, max_uv1);
LINEAR_QUANTIZE_UV(sampler2, uv2, uv_step2, uv_rect2, min_uv2, max_uv2);
auto c = packColor(buf, color);
blendYUVFallback<BLEND>(buf, span, sampler0, uv0, uv_step0, min_uv0, max_uv0,
sampler1, uv1, uv_step1, min_uv1, max_uv1, sampler2,
uv2, uv_step2, min_uv2, max_uv2, ycbcr_bias,
rgb_from_debiased_ycbcr, rescaleFactor, c);
return span;
}
// A variant of the blendYUV that attempts to reuse the inner loops from the
// CompositeYUV infrastructure. CompositeYUV imposes stricter requirements on
// the source data, which in turn allows it to be much faster than blendYUV.
// At a minimum, we need to ensure that we are outputting to a BGRA8 framebuffer
// and that no color scaling is applied, which we can accomplish via template
// specialization. We need to further validate inside that texture formats
// and dimensions are sane for video and that the video is axis-aligned before
// acceleration can proceed.
template <bool BLEND>
static int blendYUV(uint32_t* buf, int span, sampler2DRect sampler0, vec2 uv0,
const vec4_scalar& uv_rect0, sampler2DRect sampler1,
vec2 uv1, const vec4_scalar& uv_rect1,
sampler2DRect sampler2, vec2 uv2,
const vec4_scalar& uv_rect2, const vec3_scalar& ycbcr_bias,
const mat3_scalar& rgb_from_debiased_ycbcr,
int rescaleFactor, NoColor noColor = NoColor()) {
if (!swgl_isTextureLinear(sampler0) || !swgl_isTextureLinear(sampler1) ||
!swgl_isTextureLinear(sampler2)) {
return 0;
}
LINEAR_QUANTIZE_UV(sampler0, uv0, uv_step0, uv_rect0, min_uv0, max_uv0);
LINEAR_QUANTIZE_UV(sampler1, uv1, uv_step1, uv_rect1, min_uv1, max_uv1);
LINEAR_QUANTIZE_UV(sampler2, uv2, uv_step2, uv_rect2, min_uv2, max_uv2);
auto* end = buf + span;
// CompositeYUV imposes further restrictions on the source textures, such that
// the the Y/U/V samplers must all have a matching format, the U/V samplers
// must have matching sizes and sample coordinates, and there must be no
// change in row across the entire span.
if (sampler0->format == sampler1->format &&
sampler1->format == sampler2->format &&
sampler1->width == sampler2->width &&
sampler1->height == sampler2->height && uv_step0.y == 0 &&
uv_step0.x > 0 && uv_step1.y == 0 && uv_step1.x > 0 &&
uv_step1 == uv_step2 && uv1.x.x == uv2.x.x && uv1.y.x == uv2.y.x) {
// CompositeYUV does not support a clamp rect, so we must take care to
// advance till we're inside the bounds of the clamp rect.
int outside = min(int(ceil(max((min_uv0.x - uv0.x.x) / uv_step0.x,
(min_uv1.x - uv1.x.x) / uv_step1.x))),
(end - buf) / swgl_StepSize);
if (outside > 0) {
blendYUVFallback<BLEND>(buf, outside * swgl_StepSize, sampler0, uv0,
uv_step0, min_uv0, max_uv0, sampler1, uv1,
uv_step1, min_uv1, max_uv1, sampler2, uv2,
uv_step2, min_uv2, max_uv2, ycbcr_bias,
rgb_from_debiased_ycbcr, rescaleFactor, noColor);
buf += outside * swgl_StepSize;
uv0.x += outside * uv_step0.x;
uv1.x += outside * uv_step1.x;
uv2.x += outside * uv_step2.x;
}
// Find the amount of chunks inside the clamp rect before we hit the
// maximum. If there are any chunks inside, we can finally dispatch to
// CompositeYUV.
int inside = min(int(min((max_uv0.x - uv0.x.x) / uv_step0.x,
(max_uv1.x - uv1.x.x) / uv_step1.x)),
(end - buf) / swgl_StepSize);
if (inside > 0) {
// We need the color depth, which is relative to the texture format and
// rescale factor.
int colorDepth =
(sampler0->format == TextureFormat::R16 ? 16 : 8) - rescaleFactor;
// Finally, call the inner loop of CompositeYUV.
const auto rgb_from_ycbcr =
YUVMatrix::From(ycbcr_bias, rgb_from_debiased_ycbcr, rescaleFactor);
linear_row_yuv<BLEND>(
buf, inside * swgl_StepSize, sampler0, force_scalar(uv0),
uv_step0.x / swgl_StepSize, sampler1, sampler2, force_scalar(uv1),
uv_step1.x / swgl_StepSize, colorDepth, rgb_from_ycbcr);
// Now that we're done, advance past the processed inside portion.
buf += inside * swgl_StepSize;
uv0.x += inside * uv_step0.x;
uv1.x += inside * uv_step1.x;
uv2.x += inside * uv_step2.x;
}
}
// We either got here because we have some samples outside the clamp rect, or
// because some of the preconditions were not satisfied. Process whatever is
// left of the span.
blendYUVFallback<BLEND>(buf, end - buf, sampler0, uv0, uv_step0, min_uv0,
max_uv0, sampler1, uv1, uv_step1, min_uv1, max_uv1,
sampler2, uv2, uv_step2, min_uv2, max_uv2, ycbcr_bias,
rgb_from_debiased_ycbcr, rescaleFactor, noColor);
return span;
}
// Commit a single chunk of a YUV surface represented by multiple planar
// textures. This requires a color space specifier selecting how to convert
// from YUV to RGB output. In the case of HDR formats, a rescaling factor
// selects how many bits of precision must be utilized on conversion. See the
// sampleYUV dispatcher functions for the various supported plane
// configurations this intrinsic accepts.
#define swgl_commitTextureLinearYUV(...) \
do { \
int drawn = 0; \
if (blend_key) { \
drawn = blendYUV<true>(swgl_OutRGBA8, swgl_SpanLength, __VA_ARGS__); \
} else { \
drawn = blendYUV<false>(swgl_OutRGBA8, swgl_SpanLength, __VA_ARGS__); \
} \
swgl_OutRGBA8 += drawn; \
swgl_SpanLength -= drawn; \
} while (0)
// Commit a single chunk of a YUV surface scaled by a color.
#define swgl_commitTextureLinearColorYUV(...) \
swgl_commitTextureLinearYUV(__VA_ARGS__)
// Each gradient stops entry is a pair of RGBA32F start color and end step.
struct GradientStops {
Float startColor;
union {
Float stepColor;
vec4_scalar stepData;
};
// Whether this gradient entry can be merged with an adjacent entry. The
// step will be equal with the adjacent step if and only if they can be
// merged, or rather, that the stops are actually part of a single larger
// gradient.
bool can_merge(const GradientStops& next) const {
return stepData == next.stepData;
}
// Get the interpolated color within the entry based on the offset from its
// start.
Float interpolate(float offset) const {
return startColor + stepColor * offset;
}
// Get the end color of the entry where interpolation stops.
Float end_color() const { return startColor + stepColor; }
};
// Checks if a gradient table of the specified size exists at the UV coords of
// the address within an RGBA32F texture. If so, a linear address within the
// texture is returned that may be used to sample the gradient table later. If
// the address doesn't describe a valid gradient, then a negative value is
// returned.
static inline int swgl_validateGradient(sampler2D sampler, ivec2_scalar address,
int entries) {
return sampler->format == TextureFormat::RGBA32F && address.y >= 0 &&
address.y < int(sampler->height) && address.x >= 0 &&
address.x < int(sampler->width) && entries > 0 &&
address.x +
int(sizeof(GradientStops) / sizeof(Float)) * entries <=
int(sampler->width)
? address.y * sampler->stride + address.x * 4
: -1;
}
static inline WideRGBA8 sampleGradient(sampler2D sampler, int address,
Float entry) {
assert(sampler->format == TextureFormat::RGBA32F);
assert(address >= 0 && address < int(sampler->height * sampler->stride));
// Get the integer portion of the entry index to find the entry colors.
I32 index = cast(entry);
// Use the fractional portion of the entry index to control blending between
// entry colors.
Float offset = entry - cast(index);
// Every entry is a pair of colors blended by the fractional offset.
assert(test_all(index >= 0 &&
index * int(sizeof(GradientStops) / sizeof(Float)) <
int(sampler->width)));
GradientStops* stops = (GradientStops*)&sampler->buf[address];
// Blend between the colors for each SIMD lane, then pack them to RGBA8
// result. Since the layout of the RGBA8 framebuffer is actually BGRA while
// the gradient table has RGBA colors, swizzling is required.
return combine(
packRGBA8(round_pixel(stops[index.x].interpolate(offset.x).zyxw),
round_pixel(stops[index.y].interpolate(offset.y).zyxw)),
packRGBA8(round_pixel(stops[index.z].interpolate(offset.z).zyxw),
round_pixel(stops[index.w].interpolate(offset.w).zyxw)));
}
// Samples a gradient entry from the gradient at the provided linearized
// address. The integer portion of the entry index is used to find the entry
// within the table whereas the fractional portion is used to blend between
// adjacent table entries.
#define swgl_commitGradientRGBA8(sampler, address, entry) \
swgl_commitChunk(RGBA8, sampleGradient(sampler, address, entry))
// Variant that allows specifying a color multiplier of the gradient result.
#define swgl_commitGradientColorRGBA8(sampler, address, entry, color) \
swgl_commitChunk(RGBA8, applyColor(sampleGradient(sampler, address, entry), \
packColor(swgl_OutRGBA, color)))
// Samples an entire span of a linear gradient by crawling the gradient table
// and looking for consecutive stops that can be merged into a single larger
// gradient, then interpolating between those larger gradients within the span.
template <bool BLEND>
static bool commitLinearGradient(sampler2D sampler, int address, float size,
bool tileRepeat, bool gradientRepeat, vec2 pos,
const vec2_scalar& scaleDir, float startOffset,
uint32_t* buf, int span) {
assert(sampler->format == TextureFormat::RGBA32F);
assert(address >= 0 && address < int(sampler->height * sampler->stride));
GradientStops* stops = (GradientStops*)&sampler->buf[address];
// Get the chunk delta from the difference in offset steps. This represents
// how far within the gradient table we advance for every step in output,
// normalized to gradient table size.
vec2_scalar posStep = dFdx(pos) * 4.0f;
float delta = dot(posStep, scaleDir);
if (!isfinite(delta)) {
return false;
}
// If we have a repeating brush, then the position will be modulo the [0,1)
// interval. Compute coefficients that can be used to quickly evaluate the
// distance to the interval boundary where the offset will wrap.
vec2_scalar distCoeffsX = {0.25f * span, 0.0f};
vec2_scalar distCoeffsY = distCoeffsX;
if (tileRepeat) {
if (posStep.x != 0.0f) {
distCoeffsX = vec2_scalar{step(0.0f, posStep.x), 1.0f} * recip(posStep.x);
}
if (posStep.y != 0.0f) {
distCoeffsY = vec2_scalar{step(0.0f, posStep.y), 1.0f} * recip(posStep.y);
}
}
for (; span > 0;) {
// Try to process as many chunks as are within the span if possible.
float chunks = 0.25f * span;
vec2 repeatPos = pos;
if (tileRepeat) {
// If this is a repeating brush, then limit the chunks to not cross the
// interval boundaries.
repeatPos = fract(pos);
chunks = min(chunks, distCoeffsX.x - repeatPos.x.x * distCoeffsX.y);
chunks = min(chunks, distCoeffsY.x - repeatPos.y.x * distCoeffsY.y);
}
// Compute the gradient offset from the position.
Float offset =
repeatPos.x * scaleDir.x + repeatPos.y * scaleDir.y - startOffset;
// If repeat is desired, we need to limit the offset to a fractional value.
if (gradientRepeat) {
offset = fract(offset);
}
// To properly handle both clamping and repeating of the table offset, we
// need to ensure we don't run past the 0 and 1 points. Here we compute the
// intercept points depending on whether advancing forwards or backwards in
// the gradient table to ensure the chunk count is limited by the amount
// before intersection. If there is no delta, then we compute no intercept.
float startEntry;
int minIndex, maxIndex;
if (offset.x < 0) {
// If we're below the gradient table, use the first color stop. We can
// only intercept the table if walking forward.
startEntry = 0;
minIndex = int(startEntry);
maxIndex = minIndex;
if (delta > 0) {
chunks = min(chunks, -offset.x / delta);
}
} else if (offset.x < 1) {
// Otherwise, we're inside the gradient table. Depending on the direction
// we're walking the the table, we may intersect either the 0 or 1 offset.
// Compute the start entry based on our initial offset, and compute the
// end entry based on the available chunks limited by intercepts. Clamp
// them into the valid range of the table.
startEntry = 1.0f + offset.x * size;
if (delta < 0) {
chunks = min(chunks, -offset.x / delta);
} else if (delta > 0) {
chunks = min(chunks, (1 - offset.x) / delta);
}
float endEntry = clamp(1.0f + (offset.x + delta * int(chunks)) * size,
0.0f, 1.0f + size);
// Now that we know the range of entries we need to sample, we want to
// find the largest possible merged gradient within that range. Depending
// on which direction we are advancing in the table, we either walk up or
// down the table trying to merge the current entry with the adjacent
// entry. We finally limit the chunks to only sample from this merged
// gradient.
minIndex = int(startEntry);
maxIndex = minIndex;
if (delta > 0) {
while (maxIndex + 1 < endEntry &&
stops[maxIndex].can_merge(stops[maxIndex + 1])) {
maxIndex++;
}
chunks = min(chunks, (maxIndex + 1 - startEntry) / (delta * size));
} else if (delta < 0) {
while (minIndex - 1 > endEntry &&
stops[minIndex - 1].can_merge(stops[minIndex])) {
minIndex--;
}
chunks = min(chunks, (minIndex - startEntry) / (delta * size));
}
} else {
// If we're above the gradient table, use the last color stop. We can
// only intercept the table if walking backward.
startEntry = 1.0f + size;
minIndex = int(startEntry);
maxIndex = minIndex;
if (delta < 0) {
chunks = min(chunks, (1 - offset.x) / delta);
}
}
// If there are any amount of whole chunks of a merged gradient found,
// then we want to process that as a single gradient span with the start
// and end colors from the min and max entries.
if (chunks >= 1.0f) {
int inside = int(chunks);
// Sample the start color from the min entry and the end color from the
// max entry of the merged gradient. These are scaled to a range of
// 0..0xFF00, as that is the largest shifted value that can fit in a U16.
// Since we are only doing addition with the step value, we can still
// represent negative step values without having to use an explicit sign
// bit, as the result will still come out the same, allowing us to gain an
// extra bit of precision. We will later shift these into 8 bit output
// range while committing the span, but stepping with higher precision to
// avoid banding. We convert from RGBA to BGRA here to avoid doing this in
// the inner loop.
auto minColorF = stops[minIndex].startColor.zyxw * float(0xFF00);
auto maxColorF = stops[maxIndex].end_color().zyxw * float(0xFF00);
// Get the color range of the merged gradient, normalized to its size.
auto colorRangeF =
(maxColorF - minColorF) * (1.0f / (maxIndex + 1 - minIndex));
// Compute the actual starting color of the current start offset within
// the merged gradient. The value 0.5 is added to the low bits (0x80) so
// that the color will effectively round to the nearest increment below.
auto colorF =
minColorF + colorRangeF * (startEntry - minIndex) + float(0x80);
// Compute the portion of the color range that we advance on each chunk.
Float deltaColorF = colorRangeF * (delta * size);
// Quantize the color delta and current color. These have already been
// scaled to the 0..0xFF00 range, so we just need to round them to U16.
auto deltaColor = repeat4(CONVERT(round_pixel(deltaColorF, 1), U16));
for (int remaining = inside;;) {
auto color =
combine(CONVERT(round_pixel(colorF, 1), U16),
CONVERT(round_pixel(colorF + deltaColorF * 0.25f, 1), U16),
CONVERT(round_pixel(colorF + deltaColorF * 0.5f, 1), U16),
CONVERT(round_pixel(colorF + deltaColorF * 0.75f, 1), U16));
// Finally, step the current color through the output chunks, shifting
// it into 8 bit range and outputting as we go. Only process a segment
// at a time to avoid overflowing 8-bit precision due to rounding of
// deltas.
int segment = min(remaining, 256 / 4);
for (auto* end = buf + segment * 4; buf < end; buf += 4) {
commit_blend_span<BLEND>(buf, bit_cast<WideRGBA8>(color >> 8));
color += deltaColor;
}
remaining -= segment;
if (remaining <= 0) {
break;
}
colorF += deltaColorF * segment;
}
// Deduct the number of chunks inside the gradient from the remaining
// overall span. If we exhausted the span, bail out.
span -= inside * 4;
if (span <= 0) {
break;
}
// Otherwise, assume we're in a transitional section of the gradient that
// will probably require per-sample table lookups, so fall through below.
// We need to re-evaluate the position and offset first, though.
pos += posStep * float(inside);
repeatPos = tileRepeat ? fract(pos) : pos;
offset =
repeatPos.x * scaleDir.x + repeatPos.y * scaleDir.y - startOffset;
if (gradientRepeat) {
offset = fract(offset);
}
}
// If we get here, there were no whole chunks of a merged gradient found
// that we could process, but we still have a non-zero amount of span left.
// That means we have segments of gradient that begin or end at the current
// entry we're on. For this case, we just fall back to sampleGradient which
// will calculate a table entry for each sample, assuming the samples may
// have different table entries.
Float entry = clamp(offset * size + 1.0f, 0.0f, 1.0f + size);
commit_blend_span<BLEND>(buf, sampleGradient(sampler, address, entry));
span -= 4;
buf += 4;
pos += posStep;
}
return true;
}
// Commits an entire span of a linear gradient, given the address of a table
// previously resolved with swgl_validateGradient. The size of the inner portion
// of the table is given, assuming the table start and ends with a single entry
// each to deal with clamping. Repeating will be handled if necessary. The
// initial offset within the table is used to designate where to start the span
// and how to step through the gradient table.
#define swgl_commitLinearGradientRGBA8(sampler, address, size, tileRepeat, \
gradientRepeat, pos, scaleDir, \
startOffset) \
do { \
bool drawn = false; \
if (blend_key) { \
drawn = commitLinearGradient<true>( \
sampler, address, size, tileRepeat, gradientRepeat, pos, scaleDir, \
startOffset, swgl_OutRGBA8, swgl_SpanLength); \
} else { \
drawn = commitLinearGradient<false>( \
sampler, address, size, tileRepeat, gradientRepeat, pos, scaleDir, \
startOffset, swgl_OutRGBA8, swgl_SpanLength); \
} \
if (drawn) { \
swgl_OutRGBA8 += swgl_SpanLength; \
swgl_SpanLength = 0; \
} \
} while (0)
template <bool CLAMP, typename V>
static ALWAYS_INLINE V fastSqrt(V v) {
if (CLAMP) {
// Clamp to avoid zero or negative.
v = max(v, V(1.0e-12f));
}
#if USE_SSE2 || USE_NEON
return v * inversesqrt(v);
#else
return sqrt(v);
#endif
}
template <bool CLAMP, typename V>
static ALWAYS_INLINE auto fastLength(V v) {
return fastSqrt<CLAMP>(dot(v, v));
}
// Samples an entire span of a radial gradient by crawling the gradient table
// and looking for consecutive stops that can be merged into a single larger
// gradient, then interpolating between those larger gradients within the span
// based on the computed position relative to a radius.
template <bool BLEND>
static bool commitRadialGradient(sampler2D sampler, int address, float size,
bool repeat, vec2 pos, float radius,
uint32_t* buf, int span) {
assert(sampler->format == TextureFormat::RGBA32F);
assert(address >= 0 && address < int(sampler->height * sampler->stride));
GradientStops* stops = (GradientStops*)&sampler->buf[address];
// clang-format off
// Given position p, delta d, and radius r, we need to repeatedly solve the
// following quadratic for the pixel offset t:
// length(p + t*d) = r
// (px + t*dx)^2 + (py + t*dy)^2 = r^2
// Rearranged into quadratic equation form (t^2*a + t*b + c = 0) this is:
// t^2*(dx^2+dy^2) + t*2*(dx*px+dy*py) + (px^2+py^2-r^2) = 0
// t^2*d.d + t*2*d.p + (p.p-r^2) = 0
// The solution of the quadratic formula t=(-b+-sqrt(b^2-4ac))/2a reduces to:
// t = -d.p/d.d +- sqrt((d.p/d.d)^2 - (p.p-r^2)/d.d)
// Note that d.p, d.d, p.p, and r^2 are constant across the gradient, and so
// we cache them below for faster computation.
//
// The quadratic has two solutions, representing the span intersecting the
// given radius of gradient, which can occur at two offsets. If there is only
// one solution (where b^2-4ac = 0), this represents the point at which the
// span runs tangent to the radius. This middle point is significant in that
// before it, we walk down the gradient ramp, and after it, we walk up the
// ramp.
// clang-format on
vec2_scalar pos0 = {pos.x.x, pos.y.x};
vec2_scalar delta = {pos.x.y - pos.x.x, pos.y.y - pos.y.x};
float deltaDelta = dot(delta, delta);
if (!isfinite(deltaDelta) || !isfinite(radius)) {
return false;
}
float invDelta, middleT, middleB;
if (deltaDelta > 0) {
invDelta = 1.0f / deltaDelta;
middleT = -dot(delta, pos0) * invDelta;
middleB = middleT * middleT - dot(pos0, pos0) * invDelta;
} else {
// If position is invariant, just set the coefficients so the quadratic
// always reduces to the end of the span.
invDelta = 0.0f;
middleT = float(span);
middleB = 0.0f;
}
// We only want search for merged gradients up to the minimum of either the
// mid-point or the span length. Cache those offsets here as they don't vary
// in the inner loop.
Float middleEndRadius = fastLength<true>(
pos0 + delta * (Float){middleT, float(span), 0.0f, 0.0f});
float middleRadius = span < middleT ? middleEndRadius.y : middleEndRadius.x;
float endRadius = middleEndRadius.y;
// Convert delta to change in position per chunk.
delta *= 4;
deltaDelta *= 4 * 4;
// clang-format off
// Given current position p and delta d, we reduce:
// length(p) = sqrt(dot(p,p)) = dot(p,p) * invsqrt(dot(p,p))
// where dot(p+d,p+d) can be accumulated as:
// (x+dx)^2+(y+dy)^2 = (x^2+y^2) + 2(x*dx+y*dy) + (dx^2+dy^2)
// = p.p + 2p.d + d.d
// Since p increases by d every loop iteration, p.d increases by d.d, and thus
// we can accumulate d.d to calculate 2p.d, then allowing us to get the next
// dot-product by adding it to dot-product p.p of the prior iteration. This
// saves us some multiplications and an expensive sqrt inside the inner loop.
// clang-format on
Float dotPos = dot(pos, pos);
Float dotPosDelta = 2.0f * dot(pos, delta) + deltaDelta;
float deltaDelta2 = 2.0f * deltaDelta;
for (int t = 0; t < span;) {
// Compute the gradient table offset from the current position.
Float offset = fastSqrt<true>(dotPos) - radius;
float startRadius = radius;
// If repeat is desired, we need to limit the offset to a fractional value.
if (repeat) {
// The non-repeating radius at which the gradient table actually starts,
// radius + floor(offset) = radius + (offset - fract(offset)).
startRadius += offset.x;
offset = fract(offset);
startRadius -= offset.x;
}
// We need to find the min/max index in the table of the gradient we want to
// use as well as the intercept point where we leave this gradient.
float intercept = -1;
int minIndex = 0;
int maxIndex = int(1.0f + size);
if (offset.x < 0) {
// If inside the inner radius of the gradient table, then use the first
// stop. Set the intercept to advance forward to the start of the gradient
// table.
maxIndex = minIndex;
if (t >= middleT) {
intercept = radius;
}
} else if (offset.x < 1) {
// Otherwise, we're inside the valid part of the gradient table.
minIndex = int(1.0f + offset.x * size);
maxIndex = minIndex;
// Find the offset in the gradient that corresponds to the search limit.
// We only search up to the minimum of either the mid-point or the span
// length. Get the table index that corresponds to this offset, clamped so
// that we avoid hitting the beginning (0) or end (1 + size) of the table.
float searchOffset =
(t >= middleT ? endRadius : middleRadius) - startRadius;
int searchIndex = int(clamp(1.0f + size * searchOffset, 1.0f, size));
// If we are past the mid-point, walk up the gradient table trying to
// merge stops. If we're below the mid-point, we need to walk down the
// table. We note the table index at which we need to look for an
// intercept to determine a valid span.
if (t >= middleT) {
while (maxIndex + 1 <= searchIndex &&
stops[maxIndex].can_merge(stops[maxIndex + 1])) {
maxIndex++;
}
intercept = maxIndex + 1;
} else {
while (minIndex - 1 >= searchIndex &&
stops[minIndex - 1].can_merge(stops[minIndex])) {
minIndex--;
}
intercept = minIndex;
}
// Convert from a table index into units of radius from the center of the
// gradient.
intercept = clamp((intercept - 1.0f) / size, 0.0f, 1.0f) + startRadius;
} else {
// If outside the outer radius of the gradient table, then use the last
// stop. Set the intercept to advance toward the valid part of the
// gradient table if going in, or just run to the end of the span if going
// away from the gradient.
minIndex = maxIndex;
if (t < middleT) {
intercept = radius + 1;
}
}
// Solve the quadratic for t to find where the merged gradient ends. If no
// intercept is found, just go to the middle or end of the span.
float endT = t >= middleT ? span : min(span, int(middleT));
if (intercept >= 0) {
float b = middleB + intercept * intercept * invDelta;
if (b > 0) {
b = fastSqrt<false>(b);
endT = min(endT, t >= middleT ? middleT + b : middleT - b);
} else {
// Due to the imprecision of fastSqrt in offset calculations, solving
// the quadratic may fail. However, if the discriminant is still close
// to 0, then just assume it is 0.
endT = min(endT, middleT);
}
}
// Figure out how many chunks are actually inside the merged gradient.
if (t + 4.0f <= endT) {
int inside = int(endT - t) & ~3;
// Convert start and end colors to BGRA and scale to 0..255 range later.
auto minColorF = stops[minIndex].startColor.zyxw * 255.0f;
auto maxColorF = stops[maxIndex].end_color().zyxw * 255.0f;
// Compute the change in color per change in gradient offset.
auto deltaColorF =
(maxColorF - minColorF) * (size / (maxIndex + 1 - minIndex));
// Subtract off the color difference of the beginning of the current span
// from the beginning of the gradient.
Float colorF =
minColorF - deltaColorF * (startRadius + (minIndex - 1) / size);
// Finally, walk over the span accumulating the position dot product and
// getting its sqrt as an offset into the color ramp. Since we're already
// in BGRA format and scaled to 255, we just need to round to an integer
// and pack down to pixel format.
for (auto* end = buf + inside; buf < end; buf += 4) {
Float offsetG = fastSqrt<false>(dotPos);
commit_blend_span<BLEND>(
buf,
combine(
packRGBA8(round_pixel(colorF + deltaColorF * offsetG.x, 1),
round_pixel(colorF + deltaColorF * offsetG.y, 1)),
packRGBA8(round_pixel(colorF + deltaColorF * offsetG.z, 1),
round_pixel(colorF + deltaColorF * offsetG.w, 1))));
dotPos += dotPosDelta;
dotPosDelta += deltaDelta2;
}
// Advance past the portion of gradient we just processed.
t += inside;
// If we hit the end of the span, exit out now.
if (t >= span) {
break;
}
// Otherwise, we are most likely in a transitional section of the gradient
// between stops that will likely require doing per-sample table lookups.
// Rather than having to redo all the searching above to figure that out,
// just assume that to be the case and fall through below to doing the
// table lookups to hopefully avoid an iteration.
offset = fastSqrt<true>(dotPos) - radius;
if (repeat) {
offset = fract(offset);
}
}
// If we got here, that means we still have span left to process but did not
// have any whole chunks that fell within a merged gradient. Just fall back
// to doing a table lookup for each sample.
Float entry = clamp(offset * size + 1.0f, 0.0f, 1.0f + size);
commit_blend_span<BLEND>(buf, sampleGradient(sampler, address, entry));
buf += 4;
t += 4;
dotPos += dotPosDelta;
dotPosDelta += deltaDelta2;
}
return true;
}
// Commits an entire span of a radial gradient similar to
// swglcommitLinearGradient, but given a varying 2D position scaled to
// gradient-space and a radius at which the distance from the origin maps to the
// start of the gradient table.
#define swgl_commitRadialGradientRGBA8(sampler, address, size, repeat, pos, \
radius) \
do { \
bool drawn = false; \
if (blend_key) { \
drawn = \
commitRadialGradient<true>(sampler, address, size, repeat, pos, \
radius, swgl_OutRGBA8, swgl_SpanLength); \
} else { \
drawn = \
commitRadialGradient<false>(sampler, address, size, repeat, pos, \
radius, swgl_OutRGBA8, swgl_SpanLength); \
} \
if (drawn) { \
swgl_OutRGBA8 += swgl_SpanLength; \
swgl_SpanLength = 0; \
} \
} while (0)
// Extension to set a clip mask image to be sampled during blending. The offset
// specifies the positioning of the clip mask image relative to the viewport
// origin. The bounding box specifies the rectangle relative to the clip mask's
// origin that constrains sampling within the clip mask. Blending must be
// enabled for this to work.
static sampler2D swgl_ClipMask = nullptr;
static IntPoint swgl_ClipMaskOffset = {0, 0};
static IntRect swgl_ClipMaskBounds = {0, 0, 0, 0};
#define swgl_clipMask(mask, offset, bb_origin, bb_size) \
do { \
if (bb_size != vec2_scalar(0.0f, 0.0f)) { \
swgl_ClipFlags |= SWGL_CLIP_FLAG_MASK; \
swgl_ClipMask = mask; \
swgl_ClipMaskOffset = make_ivec2(offset); \
swgl_ClipMaskBounds = \
IntRect(make_ivec2(bb_origin), make_ivec2(bb_size)); \
} \
} while (0)
// Extension to enable anti-aliasing for the given edges of a quad.
// Blending must be enable for this to work.
static int swgl_AAEdgeMask = 0;
static ALWAYS_INLINE int calcAAEdgeMask(bool on) { return on ? 0xF : 0; }
static ALWAYS_INLINE int calcAAEdgeMask(int mask) { return mask; }
static ALWAYS_INLINE int calcAAEdgeMask(bvec4_scalar mask) {
return (mask.x ? 1 : 0) | (mask.y ? 2 : 0) | (mask.z ? 4 : 0) |
(mask.w ? 8 : 0);
}
#define swgl_antiAlias(edges) \
do { \
swgl_AAEdgeMask = calcAAEdgeMask(edges); \
if (swgl_AAEdgeMask) { \
swgl_ClipFlags |= SWGL_CLIP_FLAG_AA; \
} \
} while (0)
#define swgl_blendDropShadow(color) \
do { \
swgl_ClipFlags |= SWGL_CLIP_FLAG_BLEND_OVERRIDE; \
swgl_BlendOverride = BLEND_KEY(SWGL_BLEND_DROP_SHADOW); \
swgl_BlendColorRGBA8 = packColor<uint32_t>(color); \
} while (0)
#define swgl_blendSubpixelText(color) \
do { \
swgl_ClipFlags |= SWGL_CLIP_FLAG_BLEND_OVERRIDE; \
swgl_BlendOverride = BLEND_KEY(SWGL_BLEND_SUBPIXEL_TEXT); \
swgl_BlendColorRGBA8 = packColor<uint32_t>(color); \
swgl_BlendAlphaRGBA8 = alphas(swgl_BlendColorRGBA8); \
} while (0)
// Dispatch helper used by the GLSL translator to swgl_drawSpan functions.
// The number of pixels committed is tracked by checking for the difference in
// swgl_SpanLength. Any varying interpolants used will be advanced past the
// committed part of the span in case the fragment shader must be executed for
// any remaining pixels that were not committed by the span shader.
#define DISPATCH_DRAW_SPAN(self, format) \
do { \
int total = self->swgl_SpanLength; \
self->swgl_drawSpan##format(); \
int drawn = total - self->swgl_SpanLength; \
if (drawn) self->step_interp_inputs(drawn); \
return drawn; \
} while (0)