Kévin Dietrich
116bab702e
transparency. The issue is that we are rendering to a 0..1 clamped sRGB buffer with unpremultiplied alpha, where the correct thing to do would be to render to an unclamped linear premultiplied alpha buffer. Then we would just make fire purely emissive without affecting the alpha channel at all, but that doesn't work here. So for now, draw fire and smoke separately using different shaders and blend modes, like it used to before the smoke programs were rewritten (see rB0372b642).
37 lines
843 B
GLSL
37 lines
843 B
GLSL
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varying vec3 coords;
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uniform vec3 active_color;
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uniform float step_size;
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uniform float density_scale;
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uniform sampler3D soot_texture;
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uniform sampler3D shadow_texture;
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void main()
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{
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/* compute color and density from volume texture */
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vec4 soot = texture3D(soot_texture, coords);
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vec3 soot_color;
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if (soot.a != 0) {
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soot_color = active_color * soot.rgb / soot.a;
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}
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else {
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soot_color = vec3(0, 0, 0);
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}
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float soot_density = density_scale * soot.a;
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/* compute transmittance and alpha */
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float soot_transmittance = pow(2.71828182846, -soot_density * step_size);
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float soot_alpha = 1.0 - soot_transmittance;
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/* shade */
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float shadow = texture3D(shadow_texture, coords).r;
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soot_color *= soot_transmittance * shadow;
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/* premultiply alpha */
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vec4 color = vec4(soot_alpha * soot_color, soot_alpha);
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gl_FragColor = color;
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}
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