зеркало из https://github.com/mozilla/gecko-dev.git
116 строки
3.3 KiB
GLSL
116 строки
3.3 KiB
GLSL
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include shared,prim_shared
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flat varying int vGradientAddress;
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flat varying float vGradientRepeat;
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flat varying vec2 vStartCenter;
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flat varying vec2 vEndCenter;
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flat varying float vStartRadius;
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flat varying float vEndRadius;
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flat varying vec2 vTileSize;
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flat varying vec2 vTileRepeat;
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varying vec2 vPos;
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#ifdef WR_VERTEX_SHADER
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void main(void) {
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Primitive prim = load_primitive();
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RadialGradient gradient = fetch_radial_gradient(prim.specific_prim_address);
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VertexInfo vi = write_vertex(prim.local_rect,
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prim.local_clip_rect,
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prim.z,
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prim.layer,
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prim.task,
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prim.local_rect);
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vPos = vi.local_pos - prim.local_rect.p0;
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vStartCenter = gradient.start_end_center.xy;
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vEndCenter = gradient.start_end_center.zw;
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vStartRadius = gradient.start_end_radius_ratio_xy_extend_mode.x;
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vEndRadius = gradient.start_end_radius_ratio_xy_extend_mode.y;
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vTileSize = gradient.tile_size_repeat.xy;
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vTileRepeat = gradient.tile_size_repeat.zw;
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// Transform all coordinates by the y scale so the
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// fragment shader can work with circles
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float ratio_xy = gradient.start_end_radius_ratio_xy_extend_mode.z;
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vPos.y *= ratio_xy;
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vStartCenter.y *= ratio_xy;
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vEndCenter.y *= ratio_xy;
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vTileSize.y *= ratio_xy;
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vTileRepeat.y *= ratio_xy;
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vGradientAddress = prim.specific_prim_address + VECS_PER_GRADIENT;
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// Whether to repeat the gradient instead of clamping.
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vGradientRepeat = float(int(gradient.start_end_radius_ratio_xy_extend_mode.w) != EXTEND_MODE_CLAMP);
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write_clip(vi.screen_pos, prim.clip_area);
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}
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#endif
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#ifdef WR_FRAGMENT_SHADER
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void main(void) {
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vec2 pos = mod(vPos, vTileRepeat);
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if (pos.x >= vTileSize.x ||
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pos.y >= vTileSize.y) {
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discard;
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}
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vec2 cd = vEndCenter - vStartCenter;
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vec2 pd = pos - vStartCenter;
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float rd = vEndRadius - vStartRadius;
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// Solve for t in length(t * cd - pd) = vStartRadius + t * rd
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// using a quadratic equation in form of At^2 - 2Bt + C = 0
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float A = dot(cd, cd) - rd * rd;
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float B = dot(pd, cd) + vStartRadius * rd;
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float C = dot(pd, pd) - vStartRadius * vStartRadius;
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float offset;
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if (A == 0.0) {
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// Since A is 0, just solve for -2Bt + C = 0
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if (B == 0.0) {
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discard;
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}
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float t = 0.5 * C / B;
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if (vStartRadius + rd * t >= 0.0) {
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offset = t;
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} else {
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discard;
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}
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} else {
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float discr = B * B - A * C;
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if (discr < 0.0) {
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discard;
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}
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discr = sqrt(discr);
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float t0 = (B + discr) / A;
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float t1 = (B - discr) / A;
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if (vStartRadius + rd * t0 >= 0.0) {
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offset = t0;
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} else if (vStartRadius + rd * t1 >= 0.0) {
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offset = t1;
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} else {
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discard;
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}
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}
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vec4 color = sample_gradient(vGradientAddress,
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offset,
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vGradientRepeat);
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oFragColor = color * do_clip();
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}
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#endif
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