Question

Why is glTexSubImage2D() suddenly causing GL_INVALID_OPERATION?

I’m trying to upgrade my hopelessly outdated augmented reality app from iOS4.x to iOS5.x, but I’m having difficulties. I run iOS5.0. Last week I ran iOS4.3. My device is an iPhone4.

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Here is a snippet from my captureOutput:didOutputSampleBuffer:fromConnection: code

uint8_t *baseAddress = /* pointer to camera buffer */
GLuint texture = /* the texture name */
glBindTexture(GL_TEXTURE_2D, texture);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 480, 360, GL_BGRA, GL_UNSIGNED_BYTE, baseAddress);
/* now glGetError(); -> returns 0x0502 GL_INVALID_OPERATION on iOS5.0, works fine on iOS4.x */

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Here is a snippet from my setup code

GLuint texture = /* the texture name */
glGenTextures(1, &texture);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); 
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); 
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 512, 512, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);

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For simplicity I have inserted hardcoded values here. In my actual code I obtain these values with CVPixelBufferGetWidth/Height/BaseAddress. The EAGLContext is initialized with kEAGLRenderingAPIOpenGLES2.

Answer 1

Ah.. I fixed it immediately after posting this question. Had to change GL_RGBA into GL_BRGA.

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 512, 512, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);

Hope it helps someone.

BTW. If you want to write AR apps then consider using CVOpenGLESTextureCache instead of using glTexSubImage2d. It’s supposed to be faster.