OpenGL voxel engine slow

Question

I'm making a voxel engine in C++ and OpenGL (à la Minecraft) and can't get decent fps on my 3GHz with ATI X1600... I'm all out of ideas.

When I have about 12000 cubes on the screen it falls to under 20fps - pathetic.

So far the optimizations I have are: frustum culling, back face culling (via OpenGL's glEnable(GL_CULL_FACE)), the engine draws only the visible faces (except the culled ones of course) and they're in an octree.

I've tried VBO's, I don't like them and they do not significantly increase the fps.

How can Minecraft's engine be so fast... I struggle with a 10000 cubes, whereas Minecraft can easily draw much more at higher fps.

Any ideas?

Answer 1

@genpfault: I analyze the connectivity and just generate faces for the outer, visible surface. The VBO had a single cube that I glTranslate()d

I'm not an expert at OpenGL, but as far as I understand this is going to save very little time because you still have to send every cube to the card.

Instead what you should do is generate faces for all of the outer visible surface, put that in a VBO, and send it to the card and continue to render that VBO until the geometry changes. This saves you a lot of the time your card is actually waiting on your processor to send it the geometry information.