OpenGL: binding.. Texture.. graphics card.

http://stackoverflow.com/questions/11217121/how-to-manage-memory-with-texture-in-opengl



In response to your new code, I'm updating my answer with a more specific answer. You're dealing with OpenGL textures in the wrong way entirely The output of glGenTextures is a GLuint[] and not a String or char[]. For every texture you generate with glGenTextures, OpenGL gives you back a handle (as an unsigned integer) to a texture. This handle stores the state you give it with glTexParameteri as well a chunk of memory on the graphics card if you give it data with glTexImage[1/2/3]D. It's up to you to store the handle and send it new data when you want to update it. If you overwrite the handle or forget about it, the data still stays on the graphics card but you can't access it. You're also telling OpenGL to generate 3 textures when you only need 1.

Seeing as texture_data is of a fixed size, you can update the texture with glTexSubImage2D instead of glTexImage2D. Here is your code modified to avoid the memory leak from this issue:


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texture_data = new GLubyte[width*height];
GLuint texname; //handle to a texture
glGenTextures(1, &texname); //Gen a new texture and store the handle in texname

//These settings stick with the texture that's bound. You only need to set them
//once.
glBindTexture(GL_TEXTURE_2D, texname);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

//allocate memory on the graphics card for the texture. It's fine if
//texture_data doesn't have any data in it, the texture will just appear black
//until you update it.
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB,
    GL_UNSIGNED_BYTE, texture_data);

...

//bind the texture again when you want to update it.
glBindTexture(GL_TEXTURE_2D, texname);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, 0, GL_RGB,
    GL_UNSIGNED_BYTE, texture_data);

...

//When you're done using the texture, delete it. This will set texname to 0 and
//delete all of the graphics card memory associated with the texture. If you
//don't call this method, the texture will stay in graphics card memory until you
//close the application.
glDeleteTextures(1, &texname);