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#define SWGL 1
#define __VERSION__ 150
#define WR_MAX_VERTEX_TEXTURE_WIDTH 1024U
/* 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
/* 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
#ifdef WR_FEATURE_TEXTURE_EXTERNAL
// Please check https://www.khronos.org/registry/OpenGL/extensions/OES/OES_EGL_image_external_essl3.txt
// for this extension.
#endif
#ifdef WR_FEATURE_TEXTURE_EXTERNAL_ESSL1
// Some GLES 3 devices do not support GL_OES_EGL_image_external_essl3, so we
// must use GL_OES_EGL_image_external instead and make the shader ESSL1
// compatible.
#endif
#ifdef WR_FEATURE_TEXTURE_EXTERNAL_BT709
#endif
#ifdef WR_FEATURE_ADVANCED_BLEND
#endif
#ifdef WR_FEATURE_DUAL_SOURCE_BLENDING
#ifdef GL_ES
#else
#endif
#endif
/* 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
#if defined(GL_ES)
#if GL_ES == 1
// Sampler default precision is lowp on mobile GPUs.
// This causes RGBA32F texture data to be clamped to 16 bit floats on some GPUs (e.g. Mali-T880).
// Define highp precision macro to allow lossless FLOAT texture sampling.
#define HIGHP_SAMPLER_FLOAT highp
// Default int precision in GLES 3 is highp (32 bits) in vertex shaders
// and mediump (16 bits) in fragment shaders. If an int is being used as
// a texel address in a fragment shader it, and therefore requires > 16
// bits, it must be qualified with this.
#define HIGHP_FS_ADDRESS highp
// texelFetchOffset is buggy on some Android GPUs (see issue #1694).
// Fallback to texelFetch on mobile GPUs.
#define TEXEL_FETCH(sampler, position, lod, offset) texelFetch(sampler, position + offset, lod)
#else
#define HIGHP_SAMPLER_FLOAT
#define HIGHP_FS_ADDRESS
#define TEXEL_FETCH(sampler, position, lod, offset) texelFetchOffset(sampler, position, lod, offset)
#endif
#else
#define HIGHP_SAMPLER_FLOAT
#define HIGHP_FS_ADDRESS
#if defined(PLATFORM_MACOS) && !defined(SWGL)
// texelFetchOffset introduces a variety of shader compilation bugs on macOS Intel so avoid it.
#define TEXEL_FETCH(sampler, position, lod, offset) texelFetch(sampler, position + offset, lod)
#else
#define TEXEL_FETCH(sampler, position, lod, offset) texelFetchOffset(sampler, position, lod, offset)
#endif
#endif
#ifdef SWGL
#define SWGL_DRAW_SPAN
#define SWGL_CLIP_MASK
#define SWGL_ANTIALIAS
#define SWGL_BLEND
#define SWGL_CLIP_DIST
#endif
#ifdef WR_VERTEX_SHADER
#ifdef SWGL
// Annotate a vertex attribute as being flat per each drawn primitive instance.
// SWGL can use this information to avoid redundantly loading the attribute in all SIMD lanes.
#define PER_INSTANCE flat
#else
#define PER_INSTANCE
#endif
#if __VERSION__ != 100
#define varying out
#define attribute in
#endif
#endif
#ifdef WR_FRAGMENT_SHADER
precision highp float;
#if __VERSION__ != 100
#define varying in
#endif
#endif
// Flat interpolation is not supported on ESSL 1
#if __VERSION__ == 100
#define flat
#endif
#if defined(WR_FEATURE_TEXTURE_EXTERNAL_ESSL1)
#define TEX_SAMPLE(sampler, tex_coord) texture2D(sampler, tex_coord.xy)
#elif defined(WR_FEATURE_TEXTURE_EXTERNAL_BT709)
// Force conversion from yuv to rgb using BT709 colorspace
#define TEX_SAMPLE(sampler, tex_coord) vec4(yuv_2_rgb(texture(sampler, tex_coord.xy).xyz, itu_709), 1.0)
#else
#define TEX_SAMPLE(sampler, tex_coord) texture(sampler, tex_coord.xy)
#endif
#if defined(WR_FEATURE_TEXTURE_EXTERNAL) && defined(PLATFORM_ANDROID)
// On some Mali GPUs we have encountered crashes in glDrawElements when using
// textureSize(samplerExternalOES) in a vertex shader without potentially
// sampling from the texture. This tricks the driver in to thinking the texture
uniform bool u_mali_workaround_dummy;
#define TEX_SIZE(sampler) (u_mali_workaround_dummy ? ivec2(texture(sampler, vec2(0.0, 0.0)).rr) : textureSize(sampler, 0))
#else
#define TEX_SIZE(sampler) textureSize(sampler, 0)
#endif
//======================================================================================
// Vertex shader attributes and uniforms
//======================================================================================
#ifdef WR_VERTEX_SHADER
// Uniform inputs
uniform mat4 uTransform; // Orthographic projection
// Attribute inputs
attribute vec2 aPosition;
// get_fetch_uv is a macro to work around a macOS Intel driver parsing bug.
// TODO: convert back to a function once the driver issues are resolved, if ever.
// Do the division with unsigned ints because that's more efficient with D3D
#define get_fetch_uv(i, vpi) ivec2(int(vpi * (uint(i) % (WR_MAX_VERTEX_TEXTURE_WIDTH/vpi))), int(uint(i) / (WR_MAX_VERTEX_TEXTURE_WIDTH/vpi)))
#endif
//======================================================================================
// Fragment shader attributes and uniforms
//======================================================================================
#ifdef WR_FRAGMENT_SHADER
// Uniform inputs
// Fragment shader outputs
#ifdef WR_FEATURE_ADVANCED_BLEND
layout(blend_support_all_equations) out;
#endif
#if __VERSION__ == 100
#define oFragColor gl_FragColor
#elif defined(WR_FEATURE_DUAL_SOURCE_BLENDING)
layout(location = 0, index = 0) out vec4 oFragColor;
layout(location = 0, index = 1) out vec4 oFragBlend;
#else
out vec4 oFragColor;
#endif
// Write an output color in normal shaders.
void write_output(vec4 color) {
oFragColor = color;
}
#define EPSILON 0.0001
// "Show Overdraw" color. Premultiplied.
#define WR_DEBUG_OVERDRAW_COLOR vec4(0.110, 0.077, 0.027, 0.125)
float distance_to_line(vec2 p0, vec2 perp_dir, vec2 p) {
vec2 dir_to_p0 = p0 - p;
return dot(normalize(perp_dir), dir_to_p0);
}
// fwidth is not defined in ESSL 1, but that's okay because we don't need
// it for any ESSL 1 shader variants.
#if __VERSION__ != 100
/// Find the appropriate half range to apply the AA approximation over.
/// This range represents a coefficient to go from one CSS pixel to half a device pixel.
vec2 compute_aa_range_xy(vec2 position) {
return fwidth(position);
}
float compute_aa_range(vec2 position) {
// The constant factor is chosen to compensate for the fact that length(fw) is equal
// to sqrt(2) times the device pixel ratio in the typical case.
//
// This coefficient is chosen to ensure that any sample 0.5 pixels or more inside of
// the shape has no anti-aliasing applied to it (since pixels are sampled at their center,
// such a pixel (axis aligned) is fully inside the border). We need this so that antialiased
// curves properly connect with non-antialiased vertical or horizontal lines, among other things.
//
// Lines over a half-pixel away from the pixel center *can* intersect with the pixel square;
// indeed, unless they are horizontal or vertical, they are guaranteed to. However, choosing
// a nonzero area for such pixels causes noticeable artifacts at the junction between an anti-
// aliased corner and a straight edge.
//
// We may want to adjust this constant in specific scenarios (for example keep the principled
// value for straight edges where we want pixel-perfect equivalence with non antialiased lines
// when axis aligned, while selecting a larger and smoother aa range on curves).
//
// As a further optimization, we compute the reciprocal of this range, such that we
// can then use the cheaper inversesqrt() instead of length(). This also elides a
// division that would otherwise be necessary inside distance_aa.
#ifdef SWGL
// SWGL uses an approximation for fwidth() such that it returns equal x and y.
// Thus, sqrt(2)/length(w) = sqrt(2)/sqrt(x*x + x*x) = recip(x).
return recip(fwidth(position).x);
#else
// sqrt(2)/length(w) = inversesqrt(0.5 * dot(w, w))
vec2 w = fwidth(position);
return inversesqrt(0.5 * dot(w, w));
#endif
}
#endif
/// Return the blending coefficient for distance antialiasing.
///
/// 0.0 means inside the shape, 1.0 means outside.
///
/// This makes the simplifying assumption that the area of a 1x1 pixel square
/// under a line is reasonably similar to just the signed Euclidian distance
/// from the center of the square to that line. This diverges slightly from
/// better approximations of the exact area, but the difference between the
/// methods is not perceptibly noticeable, while this approximation is much
/// faster to compute.
///
/// See the comments in `compute_aa_range()` for more information on the
/// cutoff values of -0.5 and 0.5.
float distance_aa_xy(vec2 aa_range, vec2 signed_distance) {
// The aa_range is the raw per-axis filter width, so we need to divide
// the local signed distance by the filter width to get an approximation
// of screen distance.
#ifdef SWGL
// The SWGL fwidth() approximation returns uniform X and Y ranges.
vec2 dist = signed_distance * recip(aa_range.x);
#else
vec2 dist = signed_distance / aa_range;
#endif
// Choose whichever axis is further outside the rectangle for AA.
return clamp(0.5 - max(dist.x, dist.y), 0.0, 1.0);
}
float distance_aa(float aa_range, float signed_distance) {
// The aa_range is already stored as a reciprocal with uniform scale,
// so just multiply it, then use that for AA.
float dist = signed_distance * aa_range;
return clamp(0.5 - dist, 0.0, 1.0);
}
/// Component-wise selection.
///
/// The idea of using this is to ensure both potential branches are executed before
/// selecting the result, to avoid observable timing differences based on the condition.
///
/// Example usage: color = if_then_else(LessThanEqual(color, vec3(0.5)), vec3(0.0), vec3(1.0));
///
/// The above example sets each component to 0.0 or 1.0 independently depending on whether
/// their values are below or above 0.5.
///
/// This is written as a macro in order to work with vectors of any dimension.
///
/// Note: Some older android devices don't support mix with bvec. If we ever run into them
/// the only option we have is to polyfill it with a branch per component.
#define if_then_else(cond, then_branch, else_branch) mix(else_branch, then_branch, cond)
#endif
//======================================================================================
// Shared shader uniforms
//======================================================================================
#ifdef WR_FEATURE_TEXTURE_2D
uniform sampler2D sColor0;
uniform sampler2D sColor1;
uniform sampler2D sColor2;
#elif defined WR_FEATURE_TEXTURE_RECT
uniform sampler2DRect sColor0;
uniform sampler2DRect sColor1;
uniform sampler2DRect sColor2;
#elif defined(WR_FEATURE_TEXTURE_EXTERNAL) || defined(WR_FEATURE_TEXTURE_EXTERNAL_ESSL1)
uniform samplerExternalOES sColor0;
uniform samplerExternalOES sColor1;
uniform samplerExternalOES sColor2;
#elif defined(WR_FEATURE_TEXTURE_EXTERNAL_BT709)
uniform __samplerExternal2DY2YEXT sColor0;
uniform __samplerExternal2DY2YEXT sColor1;
uniform __samplerExternal2DY2YEXT sColor2;
#endif
#ifdef WR_FEATURE_DITHERING
uniform sampler2D sDither;
#endif
//======================================================================================
// Interpolator definitions
//======================================================================================
//======================================================================================
// VS only types and UBOs
//======================================================================================
//======================================================================================
// VS only functions
//======================================================================================
/* 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
struct RectWithSize {
vec2 p0;
vec2 size;
};
struct RectWithEndpoint {
vec2 p0;
vec2 p1;
};
float point_inside_rect(vec2 p, vec2 p0, vec2 p1) {
vec2 s = step(p0, p) - step(p1, p);
return s.x * s.y;
}
vec2 signed_distance_rect_xy(vec2 pos, vec2 p0, vec2 p1) {
// Instead of using a true signed distance to rect here, we just use the
// simpler approximation of the maximum distance on either axis from the
// outside of the rectangle. This avoids expensive use of length() and only
// causes mostly imperceptible differences at corner pixels.
return max(p0 - pos, pos - p1);
}
float signed_distance_rect(vec2 pos, vec2 p0, vec2 p1) {
// Collapse the per-axis distances to edges to a single approximate value.
vec2 d = signed_distance_rect_xy(pos, p0, p1);
return max(d.x, d.y);
}
vec2 rect_clamp(RectWithEndpoint rect, vec2 pt) {
return clamp(pt, rect.p0, rect.p1);
}
vec2 rect_size(RectWithEndpoint rect) {
return rect.p1 - rect.p0;
}
/* 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
#ifdef WR_VERTEX_SHADER
#define VECS_PER_RENDER_TASK 2U
uniform HIGHP_SAMPLER_FLOAT sampler2D sRenderTasks;
struct RenderTaskData {
RectWithEndpoint task_rect;
vec4 user_data;
};
// See RenderTaskData in render_task.rs
RenderTaskData fetch_render_task_data(int index) {
ivec2 uv = get_fetch_uv(index, VECS_PER_RENDER_TASK);
vec4 texel0 = TEXEL_FETCH(sRenderTasks, uv, 0, ivec2(0, 0));
vec4 texel1 = TEXEL_FETCH(sRenderTasks, uv, 0, ivec2(1, 0));
RectWithEndpoint task_rect = RectWithEndpoint(
texel0.xy,
texel0.zw
);
RenderTaskData data = RenderTaskData(
task_rect,
texel1
);
return data;
}
RectWithEndpoint fetch_render_task_rect(int index) {
ivec2 uv = get_fetch_uv(index, VECS_PER_RENDER_TASK);
vec4 texel0 = TEXEL_FETCH(sRenderTasks, uv, 0, ivec2(0, 0));
vec4 texel1 = TEXEL_FETCH(sRenderTasks, uv, 0, ivec2(1, 0));
RectWithEndpoint task_rect = RectWithEndpoint(
texel0.xy,
texel0.zw
);
return task_rect;
}
#define PIC_TYPE_IMAGE 1
#define PIC_TYPE_TEXT_SHADOW 2
/*
The dynamic picture that this brush exists on. Right now, it
contains minimal information. In the future, it will describe
the transform mode of primitives on this picture, among other things.
*/
struct PictureTask {
RectWithEndpoint task_rect;
float device_pixel_scale;
vec2 content_origin;
};
PictureTask fetch_picture_task(int address) {
RenderTaskData task_data = fetch_render_task_data(address);
PictureTask task = PictureTask(
task_data.task_rect,
task_data.user_data.x,
task_data.user_data.yz
);
return task;
}
#define CLIP_TASK_EMPTY 0x7FFFFFFF
struct ClipArea {
RectWithEndpoint task_rect;
float device_pixel_scale;
vec2 screen_origin;
};
ClipArea fetch_clip_area(int index) {
RenderTaskData task_data;
if (index >= CLIP_TASK_EMPTY) {
// We deliberately create a dummy RenderTaskData here then convert to a
// ClipArea after this if-else statement, rather than initialize the
// ClipArea in separate branches, to avoid a miscompile in some Adreno
// are unknown, so please take extra care not to regress this when
// refactoring.
task_data = RenderTaskData(RectWithEndpoint(vec2(0.0), vec2(0.0)),
vec4(0.0));
} else {
task_data = fetch_render_task_data(index);
}
return ClipArea(task_data.task_rect, task_data.user_data.x,
task_data.user_data.yz);
}
#endif //WR_VERTEX_SHADER
/* 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
uniform HIGHP_SAMPLER_FLOAT sampler2D sGpuCache;
#define VECS_PER_IMAGE_RESOURCE 2
// TODO(gw): This is here temporarily while we have
// both GPU store and cache. When the GPU
// store code is removed, we can change the
// PrimitiveInstance instance structure to
// use 2x unsigned shorts as vertex attributes
// instead of an int, and encode the UV directly
// in the vertices.
ivec2 get_gpu_cache_uv(HIGHP_FS_ADDRESS int address) {
return ivec2(uint(address) % WR_MAX_VERTEX_TEXTURE_WIDTH,
uint(address) / WR_MAX_VERTEX_TEXTURE_WIDTH);
}
vec4[2] fetch_from_gpu_cache_2_direct(ivec2 address) {
return vec4[2](
TEXEL_FETCH(sGpuCache, address, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuCache, address, 0, ivec2(1, 0))
);
}
vec4[2] fetch_from_gpu_cache_2(HIGHP_FS_ADDRESS int address) {
ivec2 uv = get_gpu_cache_uv(address);
return vec4[2](
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(1, 0))
);
}
vec4 fetch_from_gpu_cache_1_direct(ivec2 address) {
return texelFetch(sGpuCache, address, 0);
}
vec4 fetch_from_gpu_cache_1(HIGHP_FS_ADDRESS int address) {
ivec2 uv = get_gpu_cache_uv(address);
return texelFetch(sGpuCache, uv, 0);
}
#ifdef WR_VERTEX_SHADER
vec4[8] fetch_from_gpu_cache_8(int address) {
ivec2 uv = get_gpu_cache_uv(address);
return vec4[8](
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(1, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(2, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(3, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(4, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(5, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(6, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(7, 0))
);
}
vec4[3] fetch_from_gpu_cache_3(int address) {
ivec2 uv = get_gpu_cache_uv(address);
return vec4[3](
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(1, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(2, 0))
);
}
vec4[3] fetch_from_gpu_cache_3_direct(ivec2 address) {
return vec4[3](
TEXEL_FETCH(sGpuCache, address, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuCache, address, 0, ivec2(1, 0)),
TEXEL_FETCH(sGpuCache, address, 0, ivec2(2, 0))
);
}
vec4[4] fetch_from_gpu_cache_4_direct(ivec2 address) {
return vec4[4](
TEXEL_FETCH(sGpuCache, address, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuCache, address, 0, ivec2(1, 0)),
TEXEL_FETCH(sGpuCache, address, 0, ivec2(2, 0)),
TEXEL_FETCH(sGpuCache, address, 0, ivec2(3, 0))
);
}
vec4[4] fetch_from_gpu_cache_4(int address) {
ivec2 uv = get_gpu_cache_uv(address);
return vec4[4](
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(1, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(2, 0)),
TEXEL_FETCH(sGpuCache, uv, 0, ivec2(3, 0))
);
}
//TODO: image resource is too specific for this module
struct ImageSource {
RectWithEndpoint uv_rect;
vec4 user_data;
};
ImageSource fetch_image_source(int address) {
//Note: number of blocks has to match `renderer::BLOCKS_PER_UV_RECT`
vec4 data[2] = fetch_from_gpu_cache_2(address);
RectWithEndpoint uv_rect = RectWithEndpoint(data[0].xy, data[0].zw);
return ImageSource(uv_rect, data[1]);
}
ImageSource fetch_image_source_direct(ivec2 address) {
vec4 data[2] = fetch_from_gpu_cache_2_direct(address);
RectWithEndpoint uv_rect = RectWithEndpoint(data[0].xy, data[0].zw);
return ImageSource(uv_rect, data[1]);
}
// Fetch optional extra data for a texture cache resource. This can contain
// a polygon defining a UV rect within the texture cache resource.
// Note: the polygon coordinates are in homogeneous space.
struct ImageSourceExtra {
vec4 st_tl;
vec4 st_tr;
vec4 st_bl;
vec4 st_br;
};
ImageSourceExtra fetch_image_source_extra(int address) {
vec4 data[4] = fetch_from_gpu_cache_4(address + VECS_PER_IMAGE_RESOURCE);
return ImageSourceExtra(
data[0],
data[1],
data[2],
data[3]
);
}
#endif //WR_VERTEX_SHADER
/* 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
uniform HIGHP_SAMPLER_FLOAT sampler2D sGpuBufferF;
uniform HIGHP_SAMPLER_FLOAT isampler2D sGpuBufferI;
ivec2 get_gpu_buffer_uv(HIGHP_FS_ADDRESS int address) {
return ivec2(uint(address) % WR_MAX_VERTEX_TEXTURE_WIDTH,
uint(address) / WR_MAX_VERTEX_TEXTURE_WIDTH);
}
vec4 fetch_from_gpu_buffer_1f(HIGHP_FS_ADDRESS int address) {
ivec2 uv = get_gpu_buffer_uv(address);
return texelFetch(sGpuBufferF, uv, 0);
}
vec4[2] fetch_from_gpu_buffer_2f(HIGHP_FS_ADDRESS int address) {
ivec2 uv = get_gpu_buffer_uv(address);
return vec4[2](
TEXEL_FETCH(sGpuBufferF, uv, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuBufferF, uv, 0, ivec2(1, 0))
);
}
vec4[3] fetch_from_gpu_buffer_3f(HIGHP_FS_ADDRESS int address) {
ivec2 uv = get_gpu_buffer_uv(address);
return vec4[3](
TEXEL_FETCH(sGpuBufferF, uv, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuBufferF, uv, 0, ivec2(1, 0)),
TEXEL_FETCH(sGpuBufferF, uv, 0, ivec2(2, 0))
);
}
vec4[4] fetch_from_gpu_buffer_4f(HIGHP_FS_ADDRESS int address) {
ivec2 uv = get_gpu_buffer_uv(address);
return vec4[4](
TEXEL_FETCH(sGpuBufferF, uv, 0, ivec2(0, 0)),
TEXEL_FETCH(sGpuBufferF, uv, 0, ivec2(1, 0)),
TEXEL_FETCH(sGpuBufferF, uv, 0, ivec2(2, 0)),
TEXEL_FETCH(sGpuBufferF, uv, 0, ivec2(3, 0))
);
}
ivec4 fetch_from_gpu_buffer_1i(HIGHP_FS_ADDRESS int address) {
ivec2 uv = get_gpu_buffer_uv(address);
return texelFetch(sGpuBufferI, uv, 0);
}
/* 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
// Gradient GPU cache address.
flat varying highp ivec2 v_gradient_address;
// Repetition along the gradient stops.
flat varying mediump vec2 v_gradient_repeat;
#ifdef WR_FRAGMENT_SHADER
#ifdef WR_FEATURE_DITHERING
vec4 dither(vec4 color) {
const int matrix_mask = 7;
ivec2 pos = ivec2(gl_FragCoord.xy) & ivec2(matrix_mask);
float noise_normalized = (texelFetch(sDither, pos, 0).r * 255.0 + 0.5) / 64.0;
float noise = (noise_normalized - 0.5) / 256.0; // scale down to the unit length
return color + vec4(noise, noise, noise, 0);
}
#else
vec4 dither(vec4 color) {
return color;
}
#endif //WR_FEATURE_DITHERING
#define GRADIENT_ENTRIES 128.0
float clamp_gradient_entry(float offset) {
// Calculate the color entry index to use for this offset:
// offsets < 0 use the first color entry, 0
// offsets from [0, 1) use the color entries in the range of [1, N-1)
// offsets >= 1 use the last color entry, N-1
// so transform the range [0, 1) -> [1, N-1)
// TODO(gw): In the future we might consider making the size of the
// LUT vary based on number / distribution of stops in the gradient.
// Ensure we don't fetch outside the valid range of the LUT.
return clamp(1.0 + offset * GRADIENT_ENTRIES, 0.0, 1.0 + GRADIENT_ENTRIES);
}
vec4 sample_gradient(float offset) {
// Modulo the offset if the gradient repeats.
offset -= floor(offset) * v_gradient_repeat.x;
// Calculate the texel to index into the gradient color entries:
// floor(x) is the gradient color entry index
// fract(x) is the linear filtering factor between start and end
float x = clamp_gradient_entry(offset);
float entry_index = floor(x);
float entry_fract = x - entry_index;
// Fetch the start and end color. There is a [start, end] color per entry.
vec4 texels[2] = fetch_from_gpu_buffer_2f(v_gradient_address.x + 2 * int(entry_index));
// Finally interpolate and apply dithering
return dither(texels[0] + texels[1] * entry_fract);
}
#endif //WR_FRAGMENT_SHADER
varying highp vec2 v_pos;
flat varying highp vec2 v_start_radius;
#ifdef WR_VERTEX_SHADER
#define EXTEND_MODE_REPEAT 1
PER_INSTANCE in vec4 aTaskRect;
PER_INSTANCE in vec2 aCenter;
PER_INSTANCE in vec2 aScale;
PER_INSTANCE in float aStartRadius;
PER_INSTANCE in float aEndRadius;
PER_INSTANCE in float aXYRatio;
PER_INSTANCE in int aExtendMode;
PER_INSTANCE in int aGradientStopsAddress;
void main(void) {
// Store 1/rd where rd = end_radius - start_radius
// If rd = 0, we can't get its reciprocal. Instead, just use a zero scale.
float rd = aEndRadius - aStartRadius;
float radius_scale = rd != 0.0 ? 1.0 / rd : 0.0;
vec2 pos = mix(aTaskRect.xy, aTaskRect.zw, aPosition.xy);
gl_Position = uTransform * vec4(pos, 0.0, 1.0);
v_start_radius.x = aStartRadius * radius_scale;
// Transform all coordinates by the y scale so the
// fragment shader can work with circles
// v_pos is in a coordinate space relative to the task rect
// (so it is independent of the task origin).
v_pos = ((aTaskRect.zw - aTaskRect.xy) * aPosition.xy * aScale - aCenter) * radius_scale;
v_pos.y *= aXYRatio;
v_gradient_repeat.x = float(aExtendMode == EXTEND_MODE_REPEAT);
v_gradient_address.x = aGradientStopsAddress;
}
#endif
#ifdef WR_FRAGMENT_SHADER
void main(void) {
// Solve for t in length(pd) = v_start_radius + t * rd
float offset = length(v_pos) - v_start_radius.x;
oFragColor = sample_gradient(offset);
}
#ifdef SWGL_DRAW_SPAN
void swgl_drawSpanRGBA8() {
int address = swgl_validateGradient(sGpuBufferF, get_gpu_buffer_uv(v_gradient_address.x),
int(GRADIENT_ENTRIES + 2.0));
if (address < 0) {
return;
}
swgl_commitRadialGradientRGBA8(sGpuBufferF, address, GRADIENT_ENTRIES, v_gradient_repeat.x != 0.0,
v_pos, v_start_radius.x);
}
#endif
#endif