glClear — clear buffers to preset values
void glClear(
GLbitfield mask)
;
mask
Bitwise OR of masks that indicate the buffers to be cleared. The three masks are GL_COLOR_BUFFER_BIT
, GL_DEPTH_BUFFER_BIT
, and GL_STENCIL_BUFFER_BIT
.
glClear
sets the bitplane area of the window to values previously selected by glClearColor
, glClearDepth
, and glClearStencil
. Multiple color buffers can be cleared simultaneously by selecting more than one buffer at a time using glDrawBuffer.
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
.
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.
glGet with argument GL_DEPTH_CLEAR_VALUE
glGet with argument GL_COLOR_CLEAR_VALUE
glGet with argument GL_STENCIL_CLEAR_VALUE
open.gl - Depth and Stencil Buffers
open.gl - Geometry Shaders
opengl-tutorial.org - Tutorial 4 : A Colored Cube
glClearColor
, glClearDepth
, glClearStencil
, glColorMask, glDepthMask, glDrawBuffer, glScissor, glStencilMask
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