29 lines
1.0 KiB
GLSL
29 lines
1.0 KiB
GLSL
#define PI 3.14159
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extern float xresolution;
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//sample from 1D vis-depth map
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float samp(vec2 coord,float r,Image u_texture){
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return step(r,Texel(u_texture,coord).r);
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}
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vec4 effect(vec4 color,Image texture,vec2 texture_coords,vec2 screen_coords){
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//cartesian to polar, y of 1D sample is always 0
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vec2 norm=texture_coords.st*2.-1.;
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vec2 tc=vec2((atan(norm.y,norm.x)+PI)/(2.*PI),0.);
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float r=length(norm);
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//enlarge blur parameter by distance, light scattering simulation
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float blur=(1./xresolution)*smoothstep(0.3,1.,r);
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//Simple Gaussian blur
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float sum=//brightness(0~1)
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samp(vec2(tc.x-3.*blur,tc.y),r,texture)*0.1
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+samp(vec2(tc.x-2.*blur,tc.y),r,texture)*0.13
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+samp(vec2(tc.x-1.*blur,tc.y),r,texture)*0.17
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+samp(tc,r,texture)*0.2//The center tex coord,which gives us hard shadows.
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+samp(vec2(tc.x+1.*blur,tc.y),r,texture)*0.17
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+samp(vec2(tc.x+2.*blur,tc.y),r,texture)*0.13
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+samp(vec2(tc.x+3.*blur,tc.y),r,texture)*0.1;
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//Multiply the distance to get a soft fading
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return vec4(vec3(1.),sum*smoothstep(1.,0.,r));
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} |