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OpenGL Index Buffer question

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Hi, Currently I'm creating an Index Buffer in OpenGL via GL_ELEMENT_ARRAY_BUFFER_ARB in a call to glBufferDataARB(). When I get ready to render my geometry, I call the following: glDrawElements( GL_TRIANGLES, num_indices, GL_INT, 0 ); The above *should* work, I think, however it doesn't. If I change GL_INT to GL_UNSIGNED_INT, it seems to render. My index array is an array of 'int', not 'unsigned int', so I don't know why OpenGL treats these differently (since fundamentally they are the same size anyway). Could someone explain? Thank you.

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