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

Question

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).<

Answer 1

in the FragmentShader, you can write:

uniform sampler2D A;
vec3 result = vec3(texture(A, TexCoord).r);

in the cpp file,you can write:

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