Author : Thierry Tremblay
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is needed through the computations. Just before rendering, we can compute the missing vector.
The texture plane
A texture plane contains the three needed components:
- The U vector. This vector determines the U axis orientation of the texture space. It is NOT necessarily a unit vector, and as such it also provides a scaling factor for the U axis.
- The O vector. This is a translation to apply and represent the origin of texture space. It is used to align a texture on a polygon.
- The V / U scale factor. Since we are not keeping the V vector anymore, we need this to defines the scaling of the V axis.
Algorithm
Here is the algorithm to find textures coordinates:
- transform U and O from object->world->view space
- compute the missing V vector (V = U * N * scaleVU)
- compute P and Q
- compute the factors needed for 1 / W, S and T
All of this is in the FTTexturePlane class. Take a look for more details. The W vector is M,N,O, the S vector is J1,J2,J3 and the T vector is K1,K2,K3.
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