Mat4 array GLSL issues

Hey all.

I’m currently trying to upload an array of mat4 to a GLSL shader problem. I’m however having quiet a bit of difficulty finding out what I’m doing wrong (If it’s not a driver bug).

Silly test GLSL code:

// Attributes
in vec4 m_kColor;

out vec4 FRAGDATA0;

uniform mat4 akTest[4];

// Shader code
void main()
        vec4 kTest = m_kColor;
        for (int i = 0; i < 4; i++)
                kTest = akTest[i] * kTest;

        FRAGDATA0 = kTest;

Silly test CPU program:

int loc0 = pkTest->GetUniformLocation("akTest[0]"); // <-- Returns 0
int loc1 = pkTest->GetUniformLocation("akTest[1]"); // <-- Returns 1 (Should be 4)
int loc2 = pkTest->GetUniformLocation("akTest[2]"); // <-- Returns 2  (Should be 8)
int loc3 = pkTest->GetUniformLocation("akTest[3]"); // <-- Returns 3  (Should be 12)

As you can see from the above test code I’m not getting the matrix locations I would expect. Afaik a matrix in a GLSL shader takes up 4 128bit registers. When trying to upload the matrices using glUniformMatrix4fv(m_iLocation, 4, GL_FALSE, akMatrices);

That’s the right call. m_iLocation should be the return value of glGetUniformLocation() on “akTest”.

As for the rest, looks like you’re presuming that “location” should be an offset in floats, but I don’t understand why you think it should be. It’s just an abstract handle AFAIK.

You might post a short test program that illustrates your problem.

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