I'm trying to figure out how to make a semi-transparent 2D overlay over my 3D scene, reading the OpenGL SuperBible 5th edition for reference.
It has an example which overlays the OpenGL logo over a scene (in Chapter 7) using the texture target GL_TEXTURE_RECTANGLE, and a GLSL uniform type called sampler2DRect. The texture is supposed to be displayed in the fragment shader using the texture() command.
The example in this book uses many source files and I'm having a really hard time implementing it in a simple program, so I'm wondering if anyone could point me to a simpler example of the sampler2DRect.
I have no trouble with the part about switching to an orthographic projection, rather when I try to load the texture, it just displays the surface in white. My code's getting really messy at this point, and I can't seem to pinpoint the problem, so I'd rather start over from scratch following a simpler example if one is available anywhere.
P.S. I'm using SFML 2.0rc for loading the image file, in case it matters.
error C1101: ambiguous overloaded function reference "mul(mat4, vec3)"
(0) : mat3x4 mul(mat3x1, mat1x4)
(0) : mat3 mul(mat3x1, mat1x3)
(0) : mat3x2 mul(mat3x1, mat1x2)
(0) : mat3x1 mul(mat3x1, mat1)
(0) : mat2x4 mul(mat2x1, mat1x4)
.....
This is a very wordy way to tell you that there's no such function that multiplies a mat4 with a vec3. It's then listing all of the legal variants of mul.
Your dimensions must match when you multiply matrices, what you likely want is to multiply a mat4 with a vec4. If this is for your position coordinate, then add a 1.0 as the final value of the vector:
uniform mat4 mvpMatrix;
in vec3 position;
main()
gl_Position = mvpMatrix * vec4(position, 1.0);