40 lines
1.1 KiB
GLSL
40 lines
1.1 KiB
GLSL
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/* simple depth reconstruction, see http://www.derschmale.com/2014/01/26/reconstructing-positions-from-the-depth-buffer
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* we change the factors from the article to fit the OpennGL model. */
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#ifdef PERSP_MATRIX
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/* perspective camera code */
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vec3 get_view_space_from_depth(in vec2 uvcoords, in vec3 viewvec_origin, in vec3 viewvec_diff, in float depth)
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{
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float d = 2.0 * depth - 1.0;
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float zview = -gl_ProjectionMatrix[3][2] / (d + gl_ProjectionMatrix[2][2]);
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return zview * (viewvec_origin + vec3(uvcoords, 0.0) * viewvec_diff);
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}
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vec4 get_view_space_z_from_depth(in vec4 near, in vec4 range, in vec4 depth)
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{
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vec4 d = 2.0 * depth - vec4(1.0);
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/* return positive value, so sign differs! */
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return vec4(gl_ProjectionMatrix[3][2]) / (d + vec4(gl_ProjectionMatrix[2][2]));
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}
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#else
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/* orthographic camera code */
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vec3 get_view_space_from_depth(in vec2 uvcoords, in vec3 viewvec_origin, in vec3 viewvec_diff, in float depth)
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{
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vec3 offset = vec3(uvcoords, depth);
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return vec3(viewvec_origin + offset * viewvec_diff);
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}
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vec4 get_view_space_z_from_depth(in vec4 near, in vec4 range, in vec4 depth)
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{
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return -(near + depth * range);
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}
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#endif
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