Hey folks, I have a wierd situation here and everyone I have asked is stumped about exactly what’s going on. Allow me to explain:
I have a program with I want to display a cube rotating in the center of the window, all sides textured, against a background image, then on a second pass use the texturing GL_MODULATE and GL_BLEND to make a second-pass environment map.
So my display saves matricies, makes a gluOrtho2D projection matrix, and draws a poly with the background texture to screen space (with writes to the depth buffer disabled). When it switches back, renders the cube. Up until this point it works fine. However when I run the 2nd pass on the cube it looks more or less correct, but the texure is RED. Bright red. The image is still viewable (you can see it as the sphere map plays it’s coordinates about) but only the red component is being shown. The texture has been loaded properly and opengl isn’t telling me it’s had any errors.
Even more confusing, changing my texture mode to GL_REPLACE or GL_DECAl gives me the results I’d expect! This is especially wierd, I thought it would efface the texture currently on the cube, but nope. Further, if I skip drawing the background quad with the picture on it, the textures behave as I’d expect again.
The code I am using has been lifted from other maps I’ve made where I get the proper results, so I’m really at a loss. Anyone know why it might be doing this?
Any input would be appreciated.
(I’m using a geforce gtx ddr and the Xfree86 4.0 drivers… which seem to work fine)