red and blue switching
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I'm using SDL/OpenGL (as a lot of people should know by now [smile]). The textures for my quads are getting there red and blue values switched when they load, though. Any ideas why? Thanks. I really have no idea where the problem might lay - I'm using IMG_Load (sdl_image.h) to load the images, and they are saved in bitmap format (made in MS Paint, no less). Thanks.
Its the way the SDL loads the images, to get around it just specifiy GL_BGR/GL_BGR_EXT as the image format
I suppose you are using a RGB texture, right?
OpenGL by default uses a 32 bit alignment and unpack from the MSB (most significant bit!)(in practice GL 'inverts' red and blue)
Simply tell OpenGL just before TexImage what you want; what you want should be
glPixelStorei(GL_UNPACK_ROW_LENGTH, width_of_your_image); // you know this
glPixelStorei(GL_UNPACK_ALIGNMENT, 1); // 1 byte alignment
glPixelStorei(GL_UNPACK_LSB_FIRST, 1); // 1==TRUE
I've not the code here but I will make the corrections if something I wrote is not correct. But it should work; you have a lot of parameters to play with.
For the same reason if you try to read back the buffer in an RGB array and get a crash (like me:) ) you know the reason now (in this case you must specify PACK attributes)(or use RGBA).
OpenGL by default uses a 32 bit alignment and unpack from the MSB (most significant bit!)(in practice GL 'inverts' red and blue)
Simply tell OpenGL just before TexImage what you want; what you want should be
glPixelStorei(GL_UNPACK_ROW_LENGTH, width_of_your_image); // you know this
glPixelStorei(GL_UNPACK_ALIGNMENT, 1); // 1 byte alignment
glPixelStorei(GL_UNPACK_LSB_FIRST, 1); // 1==TRUE
I've not the code here but I will make the corrections if something I wrote is not correct. But it should work; you have a lot of parameters to play with.
For the same reason if you try to read back the buffer in an RGB array and get a crash (like me:) ) you know the reason now (in this case you must specify PACK attributes)(or use RGBA).
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