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Renus

Managing vertex and tex coord data in IB

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Assume you would like to render a simple cube with different textures at each of its 6 faces. AN index buffer approach would be fine since it reduces the vertex data by factor 3. The VB format would be something like XYZ | TEX1. But this way I have to share the tex coord for each vertex - thats not what I want since one vertex has different tex coords for the three textures. I just found two ways to go, both with huge disadvantages: 1) dont use IB, just have the data in VB. This way I have to specify each vertex three times for the three different tex coords. What a waste! Surely not the way to go. 2) Use a Vertex Shader which defines that the vertex data comes from a first VB of format XYZ and that the tex coords data comes from a second VB of format TEX1. Now I can index them - but not independantly, so again I have to pass much more data than necessary. Do you know a better way? DX-Demo&3D code and docu avoid touching it, hopefully not for good reasons. Thank you for any help! - thomas

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