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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
#include shared,clip_shared
varying highp vec4 vLocalPos;
varying highp vec2 vUv;
flat varying highp vec4 vUvBounds;
flat varying mediump vec4 vEdge;
flat varying highp vec4 vUvBounds_NoClamp;
flat varying mediump vec2 vClipMode;
#define MODE_STRETCH 0
#define MODE_SIMPLE 1
#ifdef WR_VERTEX_SHADER
PER_INSTANCE in ivec2 aClipDataResourceAddress;
PER_INSTANCE in vec2 aClipSrcRectSize;
PER_INSTANCE in int aClipMode;
PER_INSTANCE in ivec2 aStretchMode;
PER_INSTANCE in vec4 aClipDestRect;
struct ClipMaskInstanceBoxShadow {
ClipMaskInstanceCommon base;
ivec2 resource_address;
};
ClipMaskInstanceBoxShadow fetch_clip_item() {
ClipMaskInstanceBoxShadow cmi;
cmi.base = fetch_clip_item_common();
cmi.resource_address = aClipDataResourceAddress;
return cmi;
}
struct BoxShadowData {
vec2 src_rect_size;
int clip_mode;
int stretch_mode_x;
int stretch_mode_y;
RectWithEndpoint dest_rect;
};
BoxShadowData fetch_data() {
BoxShadowData bs_data = BoxShadowData(
aClipSrcRectSize,
aClipMode,
aStretchMode.x,
aStretchMode.y,
RectWithEndpoint(aClipDestRect.xy, aClipDestRect.zw)
);
return bs_data;
}
void main(void) {
ClipMaskInstanceBoxShadow cmi = fetch_clip_item();
Transform clip_transform = fetch_transform(cmi.base.clip_transform_id);
Transform prim_transform = fetch_transform(cmi.base.prim_transform_id);
BoxShadowData bs_data = fetch_data();
ImageSource res = fetch_image_source_direct(cmi.resource_address);
RectWithEndpoint dest_rect = bs_data.dest_rect;
ClipVertexInfo vi = write_clip_tile_vertex(
dest_rect,
prim_transform,
clip_transform,
cmi.base.sub_rect,
cmi.base.task_origin,
cmi.base.screen_origin,
cmi.base.device_pixel_scale
);
vClipMode.x = float(bs_data.clip_mode);
vec2 texture_size = vec2(TEX_SIZE(sColor0));
vec2 local_pos = vi.local_pos.xy / vi.local_pos.w;
vLocalPos = vi.local_pos;
vec2 dest_rect_size = rect_size(dest_rect);
switch (bs_data.stretch_mode_x) {
case MODE_STRETCH: {
vEdge.x = 0.5;
vEdge.z = (dest_rect_size.x / bs_data.src_rect_size.x) - 0.5;
vUv.x = (local_pos.x - dest_rect.p0.x) / bs_data.src_rect_size.x;
break;
}
case MODE_SIMPLE:
default: {
vEdge.xz = vec2(1.0);
vUv.x = (local_pos.x - dest_rect.p0.x) / dest_rect_size.x;
break;
}
}
switch (bs_data.stretch_mode_y) {
case MODE_STRETCH: {
vEdge.y = 0.5;
vEdge.w = (dest_rect_size.y / bs_data.src_rect_size.y) - 0.5;
vUv.y = (local_pos.y - dest_rect.p0.y) / bs_data.src_rect_size.y;
break;
}
case MODE_SIMPLE:
default: {
vEdge.yw = vec2(1.0);
vUv.y = (local_pos.y - dest_rect.p0.y) / dest_rect_size.y;
break;
}
}
vUv *= vi.local_pos.w;
vec2 uv0 = res.uv_rect.p0;
vec2 uv1 = res.uv_rect.p1;
vUvBounds = vec4(uv0 + vec2(0.5), uv1 - vec2(0.5)) / texture_size.xyxy;
vUvBounds_NoClamp = vec4(uv0, uv1) / texture_size.xyxy;
}
#endif
#ifdef WR_FRAGMENT_SHADER
void main(void) {
vec2 uv_linear = vUv / vLocalPos.w;
vec2 uv = clamp(uv_linear, vec2(0.0), vEdge.xy);
uv += max(vec2(0.0), uv_linear - vEdge.zw);
uv = mix(vUvBounds_NoClamp.xy, vUvBounds_NoClamp.zw, uv);
uv = clamp(uv, vUvBounds.xy, vUvBounds.zw);
float in_shadow_rect = init_transform_rough_fs(vLocalPos.xy / vLocalPos.w);
float texel = TEX_SAMPLE(sColor0, uv).r;
float alpha = mix(texel, 1.0 - texel, vClipMode.x);
float result = vLocalPos.w > 0.0 ? mix(vClipMode.x, alpha, in_shadow_rect) : 0.0;
oFragColor = vec4(result);
}
#ifdef SWGL_DRAW_SPAN
// As with cs_clip_rectangle, this shader spends a lot of time doing clipping and
// combining for every fragment, even if outside of the primitive to initialize
// the clip tile, or inside the inner bounds of the primitive, where the shadow
// is unnecessary. To alleviate this, the span shader attempts to first intersect
// the the local clip bounds, outside of which we can just use a solid fill
// to initialize those clip tile fragments. Once inside the primitive bounds,
// we further intersect with the inner region where no shadow is necessary either
// so that we can commit entire spans of texture within this nine-patch region
// instead of having to do the work of mapping per fragment.
void swgl_drawSpanR8() {
// Perspective is not supported.
if (swgl_interpStep(vLocalPos).w != 0.0) {
return;
}
// If the span is completely outside the Z-range and clipped out, just
// output clear so we don't need to consider invalid W in the rest of the
// shader.
float w = swgl_forceScalar(vLocalPos.w);
if (w <= 0.0) {
swgl_commitSolidR8(0.0);
return;
}
// To start, we evaluate the box shadow in both UV and local space relative
// to the local-space position. This will be interpolated across the span to
// track whether we intersect the nine-patch.
w = 1.0 / w;
vec2 uv_linear = vUv * w;
vec2 uv_linear0 = swgl_forceScalar(uv_linear);
vec2 uv_linear_step = swgl_interpStep(vUv).xy * w;
vec2 local_pos = vLocalPos.xy * w;
vec2 local_pos0 = swgl_forceScalar(local_pos);
vec2 local_step = swgl_interpStep(vLocalPos).xy * w;
// We need to compute the local-space distance to the bounding box and then
// figure out how many processing steps that maps to. If we are stepping in
// a negative direction on an axis, we need to swap the sides of the box
// which we consider as the start or end. If there is no local-space step
// on an axis (i.e. constant Y), we need to take care to force the steps to
// either the start or end of the span depending on if we are inside or
// outside of the bounding box.
vec4 clip_dist =
mix(vTransformBounds, vTransformBounds.zwxy, lessThan(local_step, vec2(0.0)).xyxy)
- local_pos0.xyxy;
clip_dist =
mix(1.0e6 * step(0.0, clip_dist),
clip_dist * recip(local_step).xyxy,
notEqual(local_step, vec2(0.0)).xyxy);
// Find the start and end of the shadowed region on this span.
float shadow_start = max(clip_dist.x, clip_dist.y);
float shadow_end = min(clip_dist.z, clip_dist.w);
// Flip the offsets from the start of the span so we can compare against the
// remaining span length which automatically deducts as we commit fragments.
ivec2 shadow_steps = ivec2(clamp(
swgl_SpanLength - swgl_StepSize * vec2(floor(shadow_start), ceil(shadow_end)),
0.0, swgl_SpanLength));
int shadow_start_len = shadow_steps.x;
int shadow_end_len = shadow_steps.y;
// Likewise, once inside the primitive bounds, we also need to track which
// sector of the nine-patch we are in which requires intersecting against
// the inner box instead of the outer box.
vec4 opaque_dist =
mix(vEdge, vEdge.zwxy, lessThan(uv_linear_step, vec2(0.0)).xyxy)
- uv_linear0.xyxy;
opaque_dist =
mix(1.0e6 * step(0.0, opaque_dist),
opaque_dist * recip(uv_linear_step).xyxy,
notEqual(uv_linear_step, vec2(0.0)).xyxy);
// Unlike for the shadow clipping bounds, here we need to rather find the floor of all
// the offsets so that we don't accidentally process any chunks in the transitional areas
// between sectors of the nine-patch.
ivec4 opaque_steps = ivec4(clamp(
swgl_SpanLength -
swgl_StepSize *
vec4(floor(opaque_dist.x), floor(opaque_dist.y), floor(opaque_dist.z), floor(opaque_dist.w)),
shadow_end_len, swgl_SpanLength));
// Fill any initial sections of the span that are clipped out based on clip mode.
if (swgl_SpanLength > shadow_start_len) {
int num_before = swgl_SpanLength - shadow_start_len;
swgl_commitPartialSolidR8(num_before, vClipMode.x);
float steps_before = float(num_before / swgl_StepSize);
uv_linear += steps_before * uv_linear_step;
local_pos += steps_before * local_step;
}
// This loop tries to repeatedly process entire spans of the nine-patch that map
// to a contiguous spans of texture in the source box shadow. First, we process
// a chunk with per-fragment clipping and mapping in case we're starting on a
// transitional region between sectors of the nine-patch which may need to map
// to different spans of texture per-fragment. After, we find the largest span
// within the current sector before we hit the next transitional region, and
// attempt to commit an entire span of texture therein.
while (swgl_SpanLength > 0) {
// Here we might be in a transitional chunk, so do everything per-fragment.
{
vec2 uv = clamp(uv_linear, vec2(0.0), vEdge.xy);
uv += max(vec2(0.0), uv_linear - vEdge.zw);
uv = mix(vUvBounds_NoClamp.xy, vUvBounds_NoClamp.zw, uv);
uv = clamp(uv, vUvBounds.xy, vUvBounds.zw);
float in_shadow_rect = init_transform_rough_fs(local_pos);
float texel = TEX_SAMPLE(sColor0, uv).r;
float alpha = mix(texel, 1.0 - texel, vClipMode.x);
float result = mix(vClipMode.x, alpha, in_shadow_rect);
swgl_commitColorR8(result);
uv_linear += uv_linear_step;
local_pos += local_step;
}
// If we now hit the end of the clip bounds, just bail out since there is
// no more shadow to map.
if (swgl_SpanLength <= shadow_end_len) {
break;
}
// By here we've determined to be still inside the nine-patch. We need to
// compare against the inner rectangle thresholds to see which sector of
// the nine-patch to use and thus how to map the box shadow texture. Stop
// at least one step before the end of the shadow region to properly clip
// on the boundary.
int num_inside = swgl_SpanLength - swgl_StepSize - shadow_end_len;
vec4 uv_bounds = vUvBounds;
if (swgl_SpanLength >= opaque_steps.y) {
// We're in the top Y band of the nine-patch.
num_inside = min(num_inside, swgl_SpanLength - opaque_steps.y);
} else if (swgl_SpanLength >= opaque_steps.w) {
// We're in the middle Y band of the nine-patch. Set the UV clamp bounds
// to the vertical center texel of the box shadow.
num_inside = min(num_inside, swgl_SpanLength - opaque_steps.w);
uv_bounds.yw = vec2(clamp(mix(vUvBounds_NoClamp.y, vUvBounds_NoClamp.w, vEdge.y),
vUvBounds.y, vUvBounds.w));
}
if (swgl_SpanLength >= opaque_steps.x) {
// We're in the left X column of the nine-patch.
num_inside = min(num_inside, swgl_SpanLength - opaque_steps.x);
} else if (swgl_SpanLength >= opaque_steps.z) {
// We're in the middle X band of the nine-patch. Set the UV clamp bounds
// to the horizontal center texel of the box shadow.
num_inside = min(num_inside, swgl_SpanLength - opaque_steps.z);
uv_bounds.xz = vec2(clamp(mix(vUvBounds_NoClamp.x, vUvBounds_NoClamp.z, vEdge.x),
vUvBounds.x, vUvBounds.z));
}
if (num_inside > 0) {
// We have a non-zero span of fragments within the sector. Map to the UV
// start offset of the sector and the UV offset within the sector.
vec2 uv = clamp(uv_linear, vec2(0.0), vEdge.xy);
uv += max(vec2(0.0), uv_linear - vEdge.zw);
uv = mix(vUvBounds_NoClamp.xy, vUvBounds_NoClamp.zw, uv);
// If we're in the center sector of the nine-patch, then we only need to
// sample from a single texel of the box shadow. Just sample that single
// texel once and output it for the entire span. Otherwise, we just need
// to commit an actual span of texture from the box shadow. Depending on
// if we are in clip-out mode, we may need to invert the source texture.
if (uv_bounds.xy == uv_bounds.zw) {
uv = clamp(uv, uv_bounds.xy, uv_bounds.zw);
float texel = TEX_SAMPLE(sColor0, uv).r;
float alpha = mix(texel, 1.0 - texel, vClipMode.x);
swgl_commitPartialSolidR8(num_inside, alpha);
} else if (vClipMode.x != 0.0) {
swgl_commitPartialTextureLinearInvertR8(num_inside, sColor0, uv, uv_bounds);
} else {
swgl_commitPartialTextureLinearR8(num_inside, sColor0, uv, uv_bounds);
}
float steps_inside = float(num_inside / swgl_StepSize);
uv_linear += steps_inside * uv_linear_step;
local_pos += steps_inside * local_step;
}
// By here we're probably in a transitional chunk of the nine-patch that
// requires per-fragment processing, so loop around again to the handler
// for that case.
}
// Fill any remaining sections of the span that are clipped out.
if (swgl_SpanLength > 0) {
swgl_commitPartialSolidR8(swgl_SpanLength, vClipMode.x);
}
}
#endif
#endif