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- fixed precision issue with dot product.

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Apparently the shader math is not precise enough to ensure that two supposedly orthogonal vectors are truly orthogonal, resulting in a non-zero dot product

(cherry picked from commit cce6c9a085)
This commit is contained in:
Christoph Oelckers 2018-05-24 20:31:06 +02:00 committed by drfrag666
parent c637d32113
commit b3da533033
1 changed files with 1 additions and 1 deletions
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wadsrc/static/shaders/glsl/material_normal.fp
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@ -12,7 +12,7 @@ vec3 lightContribution(int i, vec3 normal)
vec3 lightdir = normalize(lightpos.xyz - pixelpos.xyz);
float dotprod = dot(normal, lightdir);
if (dotprod < 0.0) return vec3(0.0); // light hits from the backside. This can happen with full sector light lists and must be rejected for all cases.
if (dotprod < -0.0001) return vec3(0.0); // light hits from the backside. This can happen with full sector light lists and must be rejected for all cases. Note that this can cause precision issues.
float attenuation = clamp((lightpos.w - lightdistance) / lightpos.w, 0.0, 1.0);