I'm working on the terrain rendering technique which involves displacement mapping. I have a couple of textures that are, logically, the mip-map of the terrain. Now, I have to update them all, from the biggest to the smallest, and to do so I do the following: device->GetRenderTarget(0, &oldRT); device->GetDepthStencilSurface(&oldDSS); device->BeginScene(); for (i = 0; i < levels - 1; i++) { // // Set the current texture as displacement map device->SetTexture(D3DVERTEXSAMPLER0, level.displacement); // // Set the next texture as render target and the depth surface as NULL device->SetRenderTarget(0, level.displacement); device-&gt;SetDepthStencilSurface(NULL); // // Render a 2D quad that updates the texture (no Clear) } device-&gt;EndScene(); device-&gt;SetRenderTarget(0, oldRT); device-&gt;SetDepthStencilSurface(oldDSS); This is achieved in the Update function that is called before Render function. However, when I move through the world (so the Update is called), the terrain disappears until I stop moving; then the terrain appears again, like nothing had happened. I don't know why this happens, can anyone help me? My updating textures are 32bit floating point if this is of any importance.

I've moved that code before the rendering, so now I only have one BeginScene / EndScene, but I still encounter that problem. Can anybody help me?