Can I use a grayscale image with the OpenGL glTexImage2D function?

c++ opengl textures
Nick Bolton picture Nick Bolton · Mar 25, 2009 · Viewed 17.7k times · Source

I have a texture which has only 1 channel as it's a grayscale image. When I pass the pixels in to glTexImage2D, it comes out red (obviously because channel 1 is red; RGB).

glTexImage2D(
    GL_TEXTURE_2D, 0, GL_RGBA,
    dicomImage->GetColumns(), dicomImage->GetRows(),
    0, GL_RGBA, GL_UNSIGNED_BYTE, pixelArrayPtr);

Do I change GL_RGBA? If so, what to?

Answer

ypnos picture ypnos · Mar 25, 2009

Change it to GL_LUMINANCE. See http://www.opengl.org/documentation/specs/man_pages/hardcopy/GL/html/gl/teximage2d.html

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