Can I Use A Grayscale Image With The OpenGL GlTexImage2D Function?
Answer : Change it to GL_LUMINANCE. See https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glTexImage2D.xhtml 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);