Introduction of some graphics concepts, personal excerpts or sorting, as the entry quotes of personal articles;
Draw Call：
Simply put, the CPU calls the image programming interface, such as the glDrawElements command in OpenGL or the DrawIndexedPrimitive command in DirectX, to command the GPU to perform rendering operations;
The reason for the performance in Draw Call is generally the CPU; the reason is that before each Draw Call is called, the CPU needs to send a lot of content to the GPU, including data, status, and commands. At this stage, the CPU needs to complete a lot of work. For example, check the rendering status, etc.; once the CPU completes these preparations, the GPU can start this rendering; GPU rendering capabilities are very strong, rendering 200 or 2000 triangles is usually no difference, if there are too many Draw Calls, the CPU Will spend a lot of time on submitting Draw Call, causing CPU overload;
To minimize Draw Calls, you can use the idea of batch processing, that is, to merge many small Draw Calls into one large Draw Call; merge processing is more suitable for those static objects, such as objects that will not move. These static objects are only It needs to be merged once; dynamic objects can also be merged, but because they are constantly moving, each frame needs to be merged again and then sent to the GPU, which will have a certain impact on time and space;