Why does my translation matrix needs to be transposed?

Question

I\'m working on a small graphics engine using OpenGL and I\'m having some issues with my translation matrix. I\'m using OpenGL 3.3, GLSL and C++. The situation is this: I ha

Answer 1

You cannot swap matrices in a matrix multiplication, so A*B is different from B*A. You have to transpose B before swapping the matrices.

A * B = t(B) * A

try

void DisplayObject::updateMatrices()
{
    modelMatrix = identityMatrix();
    modelMatrix = translateMatrix( xPos, yPos, zPos ) * modelMatrix;

    /* update modelview-projection matrix */
    mvpMatrix = modelMatrix * (*projMatrix);
}