forked from AuroraMiddleware/gtk
85 lines
2.2 KiB
GLSL
85 lines
2.2 KiB
GLSL
// VERTEX_SHADER
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uniform float u_start;
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uniform float u_end;
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uniform float u_color_stops[6 * 5];
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uniform int u_num_color_stops;
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uniform vec2 u_radius;
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uniform vec2 u_center;
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_OUT_ vec2 center;
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_OUT_ vec4 color_stops[6];
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_OUT_ float color_offsets[6];
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_OUT_ float start;
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_OUT_ float end;
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void main() {
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gl_Position = u_projection * u_modelview * vec4(aPosition, 0.0, 1.0);
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center = (u_modelview * vec4(u_center, 0, 1)).xy;
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start = u_start;
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end = u_end;
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for (int i = 0; i < u_num_color_stops; i ++) {
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color_offsets[i] = u_color_stops[(i * 5) + 0];
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color_stops[i] = gsk_premultiply(vec4(u_color_stops[(i * 5) + 1],
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u_color_stops[(i * 5) + 2],
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u_color_stops[(i * 5) + 3],
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u_color_stops[(i * 5) + 4]));
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}
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}
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// FRAGMENT_SHADER:
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#ifdef GSK_LEGACY
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uniform int u_num_color_stops;
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#else
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uniform highp int u_num_color_stops;
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#endif
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uniform vec2 u_radius;
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uniform float u_end;
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_IN_ vec2 center;
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_IN_ vec4 color_stops[6];
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_IN_ float color_offsets[6];
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_IN_ float start;
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_IN_ float end;
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// The offsets in the color stops are relative to the
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// start and end values of the gradient.
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float abs_offset(float offset) {
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return start + ((end - start) * offset);
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}
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void main() {
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vec2 pixel = gsk_get_frag_coord();
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vec2 rel = (center - pixel) / (u_radius);
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float d = sqrt(dot(rel, rel));
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if (d < abs_offset (color_offsets[0])) {
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gskSetOutputColor(color_stops[0] * u_alpha);
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return;
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}
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if (d > end) {
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gskSetOutputColor(color_stops[u_num_color_stops - 1] * u_alpha);
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return;
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}
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vec4 color = vec4(0, 0, 0, 0);
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for (int i = 1; i < u_num_color_stops; i++) {
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float last_offset = abs_offset(color_offsets[i - 1]);
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float this_offset = abs_offset(color_offsets[i]);
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// We have color_stops[i - 1] at last_offset and color_stops[i] at this_offset.
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// We now need to map `d` between those two offsets and simply mix linearly between them
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if (d >= last_offset && d <= this_offset) {
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float f = (d - last_offset) / (this_offset - last_offset);
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color = mix(color_stops[i - 1], color_stops[i], f);
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break;
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}
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}
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gskSetOutputColor(color * u_alpha);
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}
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