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openglopengl-3

"invalid enumerant" when creating 16-bit texture

I'm attempting to create a 16-bit texture to hold the height-map for my terrain patches, however both of the following are returning "invalid enumerant" errors. The CHECK_GL_ERROR() macro shows the gluErrorString as a message and breaks if glGetError returns something other than GL_NO_ERROR.

CHECK_GL_ERROR( glTexImage2D( GL_TEXTURE_2D, 0, GL_LUMINANCE16, width_, depth_, 0, GL_LUMINANCE, GL_UNSIGNED_SHORT, 0 /*data_.raw_data()*/ ) );
CHECK_GL_ERROR( glTexImage2D( GL_TEXTURE_2D, 0, GL_ALPHA16, width_, depth_, 0, GL_ALPHA, GL_UNSIGNED_SHORT, 0 /*data_.raw_data()*/ ) );

I have a created texture bound to the GL_TEXTURE_2D target, and have the same error with and without:

glPixelStorei( GL_UNPACK_ALIGNMENT, 2 );

I'm using an OpenGL 3.2 context, NVIDIA CUDA dev drivers 286.16 on a GTX 560Ti. Can anyone see what I am doing wrong?

Cheers

Solution

  • If you're using a core context, then that should be expected. There's no GL_LUMINANCE or GL_ALPHA image formats anymore.

    If you want to emulate the effect of them, you need to create a single-channel image format. So GL_R16 should be your internal format. Then set up a texture swizzle mask on the texture object, so that the single Red channel is broadcast to either RGB or Alpha, as you see fit.

    It's really better this way.