Hi! I'm trying to build my own 3D engine using D3D9 and I'm having a problem involving matrix stacks and lights. I want to make a light stay at a fixed location in my world, but it moves as I move :(( ... If I don't use a matrix stack I achieve this effect, but as soon as I switch back to the matrix stack the light moves along with me :(. I found some explanations at www.opengl.org about matrix stacks and lights but the rules do not seem to aply to D3D as I can't notice any difference. I've searched the net and found nothing envolving matrix stacks and lights under D3D. Does anyone have any experience with this topic?! Please help. I don't want code ... only an idee will do ... at least the mathematical explanation for matrix stacks and light positions ... I'll try to understand myself ... but I need somekind of a starting point ... than k u :)

Cross post. Closed.