Difference between revisions of "FAQ/Clipping, Culling, and Visibility Testing"

From OpenGL Wiki
< FAQ
Jump to navigation Jump to search
(change layout)
(Link to new FAQ page.)
Line 4: Line 4:
 
:When I move the viewpoint close to an object, it starts to disappear. How can I disable OpenGL's zNear clipping plane?
 
:When I move the viewpoint close to an object, it starts to disappear. How can I disable OpenGL's zNear clipping plane?
 
; [[Occlusion Query]] : How do I perform occlusion or visibility testing?
 
; [[Occlusion Query]] : How do I perform occlusion or visibility testing?
; [[Stencil Mask]] : How do I render to a nonrectangular viewport?
+
; [[FAQ/Stencil Mask]] : How do I render to a nonrectangular viewport?
 
; [[Raster Position And Clipping]] : How do I draw glBitmap() or glDrawPixels() primitives that have an initial glRasterPos() outside the window's left or bottom edge?
 
; [[Raster Position And Clipping]] : How do I draw glBitmap() or glDrawPixels() primitives that have an initial glRasterPos() outside the window's left or bottom edge?
 
; [[Scissor Test And Framebuffer Clearing]] : Why doesn't glClear() work for areas outside the scissor rectangle?
 
; [[Scissor Test And Framebuffer Clearing]] : Why doesn't glClear() work for areas outside the scissor rectangle?

Revision as of 15:44, 3 February 2015

Clipping
How do I tell if a vertex has been clipped or not?
When an OpenGL primitive moves placing one vertex outside the window, suddenly the color or texture mapping is incorrect. What's going on?
I know my geometry is inside the view volume. How can I turn off OpenGL's view-volume clipping to maximize performance?
When I move the viewpoint close to an object, it starts to disappear. How can I disable OpenGL's zNear clipping plane?
Occlusion Query
How do I perform occlusion or visibility testing?
FAQ/Stencil Mask
How do I render to a nonrectangular viewport?
Raster Position And Clipping
How do I draw glBitmap() or glDrawPixels() primitives that have an initial glRasterPos() outside the window's left or bottom edge?
Scissor Test And Framebuffer Clearing
Why doesn't glClear() work for areas outside the scissor rectangle?
Culling
How does face culling work? Why doesn't it use the surface normal?