2.4 KiB
_glClear: clear buffers to preset values
Syntax
Parameters
- mask that indicate the buffer OR buffers to be cleared. The three masks are _GL_COLOR_BUFFER_BIT, _GL_DEPTH_BUFFER_BIT, and _GL_STENCIL_BUFFER_BIT.
Description
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_glClear sets the bitplane area of the window to values previously selected by _glClearColor, glClearDepth, and _glClearStencil.
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Multiple color buffers can be cleared simultaneously by selecting more than one buffer at a time using _glDrawBuffer.
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The pixel ownership test, the scissor test, dithering, and the buffer writemasks affect the operation of _glClear. The scissor box bounds the cleared region. Alpha function, blend function, logical operation, stenciling, texture mapping, and depth-buffering are ignored by _glClear.
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_glClear takes a single argument that is the bitwise OR of several values indicating which buffer is to be cleared. The values are as follows:
:: _GL_COLOR_BUFFER_BIT: Indicates the buffers currently enabled for color writing. :: _GL_DEPTH_BUFFER_BIT: Indicates the depth buffer. :: _GL_STENCIL_BUFFER_BIT: Indicates the stencil buffer.
- The value to which each buffer is cleared depends on the setting of the clear value for that buffer.
Notes
If a buffer is not present, then a _glClear directed at that buffer has no effect.
Error(s)
_GL_INVALID_VALUE is generated if any bit other than the three defined bits is set in mask.
Use With
_glGet with argument _GL_DEPTH_CLEAR_VALUE
_glGet with argument _GL_COLOR_CLEAR_VALUE
_glGet with argument _GL_STENCIL_CLEAR_VALUE