algorithm - How to prevent overdrawing? -

This is a difficult question to search in Google because it has other meanings in finance.

Of course, I mean there is "drawing" here .. computer graphics .. no money ..

I am interested in preventing overdrawing for both 3D drawing and 2D drawing. .
(Should I make them in two separate questions?)

I know that this can be a very comprehensive question because I did not specify which technology to use if it Very comprehensive, so maybe some of the resources I can read are some signs that will be fine.

EDIT: What do I mean by overdrawing:

• When
• When you are more attracted than the area's needs , Then a single frame will be very slow

This is a very complex subject.

The first thing to consider is to think. This will filter the objects that are not in the field of camera view, so you can just pass them on the render step.

The second thing is the z-sorting of objects that are in the camera, it is better to put them back and forth from the back so that the nearest objects can write "near-value" in depth buffers and the distant objects are not pixels. Because they will not pass the depth test. This will save your GPU's fill rate and pixel-shader work. However, note that if you have SemestersPartent Objects in the view, they should be drawn first in first-to-front order to make alpha-blending possible.

If you use some type of space division then both things may be received or which is better depending on your game. Quatry is better for large open spaces and the octiery is good for many spaces as well as for spaces.

And do not forget about the simple, which can be enabled with DirectX and SingleGL in OpenGL to prevent the face line, which the camera sees with their backs.