not many, map is divided into 32x256x32 chunks, each has it's own vbo. then I'm sending only centre of each cube to the gpu instead of all the verts and cube is created in geometry shader. in the alpha channel is encoded info which faces are actually visible and since I'm planning to use deferred rendering then alpha is not much of use anyways. and I do frustum culling on chunks, 'radar' in right bottom corner shows which of them are rendered. runs pretty smooth on my laptop, we'll see if it's still smooth with lighting