GLSL Equivalent to HLSL ViewInverse
Author
In the following HLSL vertex shader snippet, there's a variable being set called 'WorldView'
OUT.WorldNormal = mul(NormO, tWIT).xyz;
half4 Po = half4(PosO.xyz,1);
half3 Pw = mul(Po, tW).xyz;
OUT.LightVec = normalize(lPos - Pw);
OUT.TexCoord = TexCd.xyxx;
OUT.WorldView = normalize(tVI[3].xyz - Pw);
OUT.HPosition = mul(Po, tWVP);
I'm trying to work out how to to do the same thing in GLSL.
tVI is defined as:
float4x4 tVI : ViewInverse;
and is clearly a transformation matrix, but doesn't have a direct equivalent in GLSL/OpenGL, as far as I can tell.
Can anyone tell me to how recreate this in a GLSL shader?
Cheers,
a|x
http://machinesdontcare.wordpress.com
Calculate and upload it as a uniform - OpenGL (and thus GLSL) doesn't differentiate between view and model matrices, so you have to maintain them yourself.
Author
Quote:Original post by swiftcoder
Calculate and upload it as a uniform - OpenGL (and thus GLSL) doesn't differentiate between view and model matrices, so you have to maintain them yourself.
i swiftcoder,
thanks for getting back to me!
Would I be right in assuming that 'WorldView' in the the above code is basically the position of the virtual camera in the scene minus the vertex position after multiplication by the gl_ModelViewMatrix? If this is the case, could I extract this value from the ModelView Matrix itself, perhaps?
a|x
Quote:Original post by toneburstThe ModelView matrix is typically the concatenation of two matrices: the Model and the View. The Model matrix is the transform matrix of the currently rendered object, and the View matrix is the transform matrix of the camera.
Would I be right in assuming that 'WorldView' in the the above code is basically the position of the virtual camera in the scene minus the vertex position after multiplication by the gl_ModelViewMatrix? If this is the case, could I extract this value from the ModelView Matrix itself, perhaps?
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