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Editorial Team
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Asked: 2026-05-31T18:51:41+00:00

I ran my app through Instruments today and noticed that an excessively high amount

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I ran my app through Instruments today and noticed that an excessively high amount of time was being spent in the “glgConvertTo_32” function. I read elsewhere that this is because Apple uses “GL_BGRA and GL_UNSIGNED_INT_8_8_8_8_REV” for it’s texture format, and my code uses GL_RGBA.

I’m using glTexture2D as follows:

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData);

Neither GL_BGRA nor GL_UNSIGNED_INT_8_8_8_8_REV are available in the GL headers for iPhone, however. Is there another reason for the high volume of calls to that function, or is there possibly a different texture format I should be using?

EDIT:
I should mention that I’m using OpenGL ES 2.0.

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1 Answer

  1. Editorial Team

    I don’t know if my problem/solution is really related to yours. But your unanswered question was the first result google found while investigating my problem.

    Although I use OpenGL ES 1.1 and don’t use Textures I also noticed that my app
    spends about 23% of time in the function glgConvertTo_32().

    After changing the value of kEAGLDrawablePropertyColorFormat from kEAGLColorFormatRGBA8 to kEAGLColorFormatRGB565 in eaglLayer.drawableProperties the function glgConvertTo_32() is not called anymore. The app feels faster and I don’t see a visual difference.

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