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Editorial Team
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Asked: 2026-06-10T09:24:57+00:00

I’ve recently succeeded at making a small test app with a GL_TEXTURE_RECTANGLE. Now I’m

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I’ve recently succeeded at making a small test app with a GL_TEXTURE_RECTANGLE. Now I’m trying to integrate it into my larger project, but when I call glBindTexture(GL_TEXTURE_RECTANGLE, _tex_id[0]) inside the render function, it’s causing the GL_INVALID_OPERATION​ error. The texture image sometimes shows for a fraction of a second, then turns black and stays black.

I am trying to do this by using two sets of vertex and fragment shaders, one set for the 3D scene, and one set for the 2D overlay, but I’ve never tried this before so I don’t know if that’s what’s causing the error, or if I should be going about this a different way. The shaders are all compiling and linking fine.

Any insight would be much appreciated, and if it would help to see some code, let me know and I’ll post some of it (although I think it may be too much for anyone to reasonably look through).

Edit: gDEBugger breaks at the call to glBindTexture(), and when clicking on the breakpoint, the properties window shows a picture of one of my other textures (one that’s being loaded by the 3D scene’s shaders), it shows that it’s trying to load texture number 1, but I know this number is already being used to draw the same 3D scene’s texture shown in the properties window… why would glGenTextures() be giving me overlapping texture id numbers? Is this normal or maybe part of the problem?

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1 Answer

  1. Editorial Team

    The black texture was due to me not forwarding some vertex shader inputs (normals) through to the fragment shader, even though I’m not using normals for anything in the 2D overlay shaders. As soon as I added outputs for all the inputs, and forwarded them along to the fragment shader, the texture was no longer black, but it was still disappearing after a fraction of a second. This was because I was calling glBindTexture(GL_TEXTURE_RECTANGLE, 0) at the end of the render function with the hopes that it would clean up some state… this was clearly the wrong thing to do, because removing that call caused the 2D texture to stay on-screen. Furthermore, calling glBindTexture() with the GL_TEXTURE_RECTANGLE target seems to work during the texture setup stage, but during rendering the GL_TEXTURE_RECTANGLE target was causing the GL_INVALID_OPERATION​ error. Changing the target to GL_TEXTURE_2D only in the render function made the error go away, and everything seems to work nicely now.

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