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mikealexander

OpenGL newbie has a problem w/ tga.

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I hate to bother everyone with this, but I haven't been able to fix it by myself after several hours at it (like, 12). I have been working on tga loading code to load textures for an opengl scene. Everything appears to be alright, at least up to the actual image data. But when I go to texture an object in my scene, the square remains white... I was wondering if somebody could take a look through my code to see if they can find my screw-up? you can get the files here: PELoadTGA.cpp PELoadTGA.h Just as a forewarning, the code is probably a bit ugly, and there may be some incorrect naming conventions and such, but I'm sure you can figure it out. also, before anyone suggests I use code thats already out there, I'm trying to do this my own way (somewhat) so I can learn how it all works. Thanks for the help, and God bless! Mike (Im using dev-cpp if that matters)

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If the image appears to load correct, but the texturing is wrong, why show the image loading code which appears to work and not the texturing code which appears to not work?

Check the usual things like unsuported texture size (possible power of two limits) and filtering mode (default minification filter requires a complete mipmap set).

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Square remaining white usually means the data wasn't uploaded correctly, or you haven't enabled GL_TEXTURE_2D (or you have fog cranked up on white, or light.. but I doubt that's your problem).

Hope that helps,
~Zix

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Use GLAUX or something similar to load a simple BMP and use it with the same texturing code you use - if that doesn't work you probably texture incorrectly(and TGA loading might actually work).

If that does work, write a TGA saving routine, and then look at what you actually loaded.

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Thanks for the replies. I am reusing the code I have for a working bitmap loader, and so I know it isn't the texturing thats the problem. And I've been using iostream.h and debugging to watch all the variables throughout execution. The stuff seems to be right up until I actually loop through to load the image data.

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Does the fact that you call CleanupImage(); at the end of the loading procedure before I see any OpenGL upload code mean anything? This seems to be the problem... the rest of your code looks fine.

~Zix

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nope, never mind. I thought I commented out something needed, but I didn't, thats all good.

zix99 That part of the code is fine I think (if not logically, trial and error proves it)

Seroja - I tried your suggestion. The tga file that came out was corrupted in some way. So either I messed up that code too or the problem is with the actual loading.

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hang on a sec mikealexander:

don't dismiss zix99's observation so quickly:

tell me you are not deleting the texture as soon as you load it.

the code you presented loads the texture then promptly deletes it
with CleanupImage()!

Or are you magically hiding the gl code that must upload the texture to video memory before you use CleanupImage().

I expected to see something like:

//maybe Generate OpenGL texture IDs
glGenTextures(1, &ID);
//maybe Bind the texture to a texture object
glBindTexture(GL_TEXTURE_2D, ID);

// but definitely load up with
gluBuild2DMipmaps(..,..,..,..,ucImgData)
//and/or
GL_TEXTURE_2D.(..,..,..,..,ucImgData)

// before you delete ucImgData!

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