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Updated GLSL decoder for new normal packing scheme.

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This commit is contained in:
David Williams 2014-07-24 22:38:21 +02:00
parent 2b7ef5b966
commit 112b277452
1 changed files with 19 additions and 6 deletions
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25
examples/DecodeOnGPU/decode.vert
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@ -13,17 +13,30 @@ uniform mat4 modelToWorldMatrix;
out vec4 worldPosition;
out vec4 worldNormal;
// Returns +/- 1
vec2 signNotZero(vec2 v)
{
return vec2((v.x >= 0.0) ? +1.0 : -1.0, (v.y >= 0.0) ? +1.0 : -1.0);
}
void main()
{
vec4 decodedPosition = position;
decodedPosition.xyz = decodedPosition.xyz * (1.0 / 256.0);
uint encodedX = (normal >> 10u) & 0x1Fu;
uint encodedY = (normal >> 5u) & 0x1Fu;
uint encodedZ = (normal) & 0x1Fu;
worldNormal.xyz = vec3(encodedX, encodedY, encodedZ);
worldNormal.xyz = worldNormal.xyz / 15.5;
worldNormal.xyz = worldNormal.xyz - vec3(1.0, 1.0, 1.0);
//Get the encoded bytes of the normal
uint encodedX = (normal >> 8u) & 0xFFu;
uint encodedY = (normal) & 0xFFu;
// Map to range [-1.0, +1.0]
vec2 e = vec2(encodedX, encodedY);
e = e * vec2(1.0 / 127.5, 1.0 / 127.5);
e = e - vec2(1.0, 1.0);
// Now decode normal using listing 2 of http://jcgt.org/published/0003/02/01/
vec3 v = vec3(e.xy, 1.0 - abs(e.x) - abs(e.y));
if (v.z < 0) v.xy = (1.0 - abs(v.yx)) * signNotZero(v.xy);
worldNormal.xyz = normalize(v);
worldNormal.w = 1.0;
// Standard sequence of OpenGL transformations.