glTexImage2D shows black texture on iPhone6, but works on simulator and on an iPhone4

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Created Jul ’15

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glTexImage2D shows black texture on iPhone6, but works on simulator and on an iPhone4.

There are no errors with glGetError on device or on simulator after each step. Image height/width are powers of 2.

Here's a 2x2 texture which reproduces the problem. Any hints on debugging this ?

GLubyte pixels[4*3] = { 255, 0, 0, 0, 255, 0 , 0, 0, 255, 255, 255, 0 };

glPixelStorei ( GL_UNPACK_ALIGNMENT, 1 );

glGenTextures ( 1, &m_textureID );

glBindTexture ( GL_TEXTURE_2D, m_textureID );

glTexImage2D ( GL_TEXTURE_2D, 0, GL_RGB, 3, 2, 0, GL_RGB, GL_UNSIGNED_BYTE, pixels );

glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);

glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

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Answer 1

Jul ’15

glTexImage2D ( GL_TEXTURE_2D, 0, GL_RGB, 3, 2, 0, GL_RGB, GL_UNSIGNED_BYTE, pixels );

You're creating a 3x2 image. That should be:

glTexImage2D ( GL_TEXTURE_2D, 0, GL_RGB, 2, 2, 0, GL_RGB, GL_UNSIGNED_BYTE, pixels );

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Answer 2

Jul ’15

Yea, doesn't solve the prob though.

The frame capture discussed here could be used to debug the black texture rendering..

http://blog.manbolo.com/2012/11/20/using-xcode-opengl-es-frame-capture

along with high level overview of states in the state machine

Couple tools for xcode -

and theory of list of matrices and their stack looks useful.

http://content.gpwiki.org/index.php/OpenGL:Tutorials:Theory

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