aa0ac0035a
Operations such as erasing with occlusion and drawing on the surface require reading the depth buffer. However, this is being done with minimal efficiency. Currently, to read the depth corresponding to each point of the new stroke, a ReadPixel is called to send a message to the GPU and read the depth of the corresponding pixel in the VRAM. The communication between GPU and CPU is known to be a slow operation so it is good to be avoided. Therefore, save the entire depth buffer in a cache to be read directly from the RAM. (Also the `ED_view3d_autodist_depth` and `ED_view3d_autodist_depth_seg` have been removed since they are no longer used). Reviewed By: antoniov, fclem Differential Revision: https://developer.blender.org/D10894