VolumeRendering
3D Texture Coordinate Generation
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If the model coordinates are bounded by [0,1], then the texture coordinates are identical to model coordinates:
glTexCoord3f(x,y,z);
glVertex3d(x,y,z);
glVertex3d(x,y,z);
If this is not the case, OpenGL supports a texture matrix stack to transform the texture coordinates just like the transformation of vertices with the model view matrix.
Example for model coordinates x,y,z∈[−0.5,0.5] and texture coordinates s,t,r∈[0,1]:
glMatrixMode(GL_TEXTURE);
glLoadIdentity();
glTranslated(0.5,0.5,0.5);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslated(0.5,0.5,0.5);
glMatrixMode(GL_MODELVIEW);
Note: Transforming an object left, moves the object left. Transforming a texture coordinate left moves the texture coordinate left but it moves the texture visually right!
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