52 lines
1.6 KiB
GLSL
52 lines
1.6 KiB
GLSL
/*
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* Bloom - upsampling step
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* "Next Generation Post Processing in Call of Duty Advanced Warfare"
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* ACM Siggraph (2014)
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* Based on the implementation by Alexander Christensen
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* https://learnopengl.com/Guest-Articles/2022/Phys.-Based-Bloom
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*/
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#version 330 core
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layout(location = 0) out vec3 fragColor;
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in vec2 texcoord;
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uniform sampler2D tex;
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uniform float filter_radius;
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void main()
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{
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// The filter kernel is applied with a radius, specified in texture
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// coordinates, so that the radius will vary across mip resolutions.
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float x = filter_radius;
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float y = filter_radius;
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// Take 9 samples around current texel:
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// a - b - c
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// d - e - f
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// g - h - i
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// === ('e' is the current texel) ===
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vec3 a = texture(tex, vec2(texcoord.x - x, texcoord.y + y)).rgb;
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vec3 b = texture(tex, vec2(texcoord.x, texcoord.y + y)).rgb;
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vec3 c = texture(tex, vec2(texcoord.x + x, texcoord.y + y)).rgb;
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vec3 d = texture(tex, vec2(texcoord.x - x, texcoord.y)).rgb;
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vec3 e = texture(tex, vec2(texcoord.x, texcoord.y)).rgb;
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vec3 f = texture(tex, vec2(texcoord.x + x, texcoord.y)).rgb;
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vec3 g = texture(tex, vec2(texcoord.x - x, texcoord.y - y)).rgb;
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vec3 h = texture(tex, vec2(texcoord.x, texcoord.y - y)).rgb;
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vec3 i = texture(tex, vec2(texcoord.x + x, texcoord.y - y)).rgb;
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// Apply weighted distribution, by using a 3x3 tent filter:
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// 1 | 1 2 1 |
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// -- * | 2 4 2 |
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// 16 | 1 2 1 |
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vec3 upsample = e * 4.0;
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upsample += (b+d+f+h) * 2.0;
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upsample += (a+c+g+i);
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upsample /= 16.0;
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fragColor = upsample;
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}
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