Simon Schneegans
33 lines
1.2 KiB
GLSL
33 lines
1.2 KiB
GLSL
// The math for the whirling is inspired by this post:
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// http://www.geeks3d.com/20110428/shader-library-swirl-post-processing-filter-in-glsl
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// We simply inverse the progress for opening windows.
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float progress = uForOpening ? 1.0 - uProgress : uProgress;
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// Choose a random suction center.
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vec2 center = uSeed * uRandomness + 0.5 * (1.0 - uRandomness);
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vec2 coords = cogl_tex_coord_in[0].st * ACTOR_SCALE - PADDING - center;
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// Add some shaking.
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coords.x +=
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progress * 0.05 * uShake * sin((progress + uSeed.x) * (1.0 + uSeed.x) * uShake);
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coords.y +=
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progress * 0.05 * uShake * cos((progress + uSeed.y) * (1.0 + uSeed.y) * uShake);
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// "Suck" the texture into the center.
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float dist = length(coords) / sqrt(2);
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coords += progress * coords / dist * 0.5 * uSuction;
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// Apply some whirling.
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float angle = pow(1.0 - dist, 2.0) * uTwirl * progress;
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float s = sin(angle);
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float c = cos(angle);
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coords = vec2(dot(coords, vec2(c, -s)), dot(coords, vec2(s, c)));
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// Shell.GLSLEffect uses straight alpha. So we have to convert from premultiplied.
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cogl_color_out = texture2D(uTexture, coords + center);
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if (cogl_color_out.a > 0) {
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cogl_color_out.rgb /= cogl_color_out.a;
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}
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// Fade out the window texture.
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cogl_color_out.a *= 1.0 - progress; |