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zqueezy

OpenGL OpenGL-Multitexture

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zqueezy    122
hey folks, do you know weather mutlitexturing allows for multiple texture matrices to be set? can i switch the texture matrix between those calls? glLoadIdentity(); glTranslatef(1.0f, 1.0f, 0.5f); glMultiTexCoord2fARB(GL_TEXTURE0_ARB, s0, t0); glMatrixMode(GL_TEXTURE); glLoadIdentity(); glScalef(2.0f, 2.0f, 2.0f); glMultiTexCoord4fARB(GL_TEXTURE1_ARB, s1, t1, r1, q1); will there be different texture matrices in the shader? I tried to implement a modelloader for 3ds and the texture-coodinates are always between 0..1 and the textures gets scaled. or is it better to have different texture-coordinate-arrays to look up with modified texcoords? thanx zqueezy

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dpadam450    2357
Then in your loader change the texture coordinates. Texture coords are supposed to be from 0 to 1. What does "textured gets scaled" mean. It goes from 512x512 to 1024x1024??? If so that doesnt make any sense, but regardless of texture size, it will still map the same texture coordinates.

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zqueezy    122
the texture in 3ds has options like u-scale, v-scale for tiling and/or mirroring also.
i could preprocess the texture coordinates in opengl or i give the scling to a shader but each different texture-layer can have different u,v-scaling (and also translation) so i don't know if its wise to give so much data per texture to the shader...

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zqueezy    122
for example a plane (quad) has the texture coordinates (1.0, 0.0)... stuff
in 3ds max there's tiling on for texture layer 1. let's say 4x4 so that actually the texture coordinates for the quad need to be (4.0,0.0)...
but for texture layer 2 there's no tiling (1.0, 0.0) and I need the original texture coordinates...
I'd like to use glDrawElements for the final rendering but when I specify glTexCoordPointer and use the index-list given for gldrawelements, then I'd need two texture-arrays of course that's not the problem but the indices mean that both arrays need to have the same size to work correctly and if my model has multiple materials (which each have 2-4 texture layers) I'd need to store many many different texture-coord arrays of the same size (!!!) lot of them unneeded.

is it bad to have so many texture-coord arrays or is the performance overhead almost equal zero?
thanx

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