70 lines
1.6 KiB
C
70 lines
1.6 KiB
C
// -*- mode: C; -*-
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#version 120
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// Licence: GPL v2
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// Author: Frederic Bouvier.
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uniform vec3 fg_Planes;
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uniform bool fg_DepthInColor;
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// normal compression functions from
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// http://aras-p.info/texts/CompactNormalStorage.html#method04spheremap
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vec2 normal_encode(vec3 n)
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{
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float p = sqrt(n.z * 8.0 + 8.0);
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return n.xy / p + 0.5;
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}
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vec3 normal_decode(vec2 enc)
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{
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vec2 fenc = enc * 4.0 - 2.0;
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float f = dot(fenc,fenc);
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float g = sqrt(1.0 - f / 4.0);
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vec3 n;
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n.xy = fenc * g;
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n.z = 1.0 - f / 2.0;
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return n;
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}
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// depth to color encoding and decoding functions from
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// Deferred Shading Tutorial by Fabio Policarpo and Francisco Fonseca
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// (corrected by Frederic Bouvier)
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vec3 float_to_color(in float f)
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{
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vec3 color;
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f *= 255.0;
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color.x = floor(f);
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f = (f-color.x)*255.0;
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color.y = floor(f);
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color.z = f-color.y;
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color.xy /= 255.0;
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return color;
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}
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float color_to_float(vec3 color)
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{
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const vec3 byte_to_float = vec3(1.0, 1.0/255.0, 1.0/(255.0*255.0));
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return dot(color,byte_to_float);
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}
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vec3 position( vec3 viewDir, float depth )
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{
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vec3 pos;
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pos.z = - fg_Planes.y / (fg_Planes.x + depth * fg_Planes.z);
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pos.xy = viewDir.xy / viewDir.z * pos.z;
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return pos;
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}
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vec3 position( vec3 viewDir, vec3 depthColor )
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{
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return position( viewDir, color_to_float(depthColor) );
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}
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vec3 position( vec3 viewDir, vec2 coords, sampler2D depth_tex )
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{
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float depth;
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if (fg_DepthInColor)
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depth = color_to_float( texture2D( depth_tex, coords ).rgb );
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else
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depth = texture2D( depth_tex, coords ).r;
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return position( viewDir, depth );
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}
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