cs_radial_gradient.glsl

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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

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include shared,rect,render_task,gpu_cache,gpu_buffer,gradient

varying highp vec2 v_pos;

// Start radius. Packed in to a vector to work around bug 1630356.

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