Difference between revisions of "GLAPI/glScissor"
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{{infobox feature | {{infobox feature | ||
| − | | name = glScissor | + | | name = glScissor }} |
| − | |||
| − | }} | ||
'''glScissor:''' define the scissor box | '''glScissor:''' define the scissor box | ||
| Line 8: | Line 6: | ||
== Function Definition == | == Function Definition == | ||
| − | void '''glScissor'''(GLint | + | void '''glScissor'''(GLint {{param|x}}, GLint {{param|y}}, GLsizei {{param|width}}, GLsizei {{param|height}}); |
; x, y | ; x, y | ||
: Specify the lower left corner of the scissor box. Initially (0, 0). | : Specify the lower left corner of the scissor box. Initially (0, 0). | ||
; width, height | ; width, height | ||
| − | : Specify the width and height of the scissor box. When a GL context is first attached to a window, | + | : Specify the width and height of the scissor box. When a GL context is first attached to a window, {{param|width}} and {{param|height}} are set to the dimensions of that window. |
== Description == | == Description == | ||
| − | '''glScissor''' defines a rectangle, called the scissor box, in window coordinates. The first two arguments, | + | '''glScissor''' defines a rectangle, called the scissor box, in window coordinates. The first two arguments, {{param|x}} and {{param|y}}, specify the lower left corner of the box. {{param|width}} and {{param|height}} specify the width and height of the box. |
| − | To enable and disable the scissor test, call | + | To enable and disable the scissor test, call {{apifunc|glEnable}} and {{apifunc|glDisable}} with argument {{enum|GL_SCISSOR_TEST}}. The test is initially disabled. While the test is enabled, only pixels that lie within the scissor box can be modified by drawing commands. Window coordinates have integer values at the shared corners of frame buffer pixels. {{code|glScissor(0,0,1,1)}} allows modification of only the lower left pixel in the window, and {{code|glScissor(0,0,0,0)}} doesn't allow modification of any pixels in the window. |
When the scissor test is disabled, it is as though the scissor box includes the entire window. | When the scissor test is disabled, it is as though the scissor box includes the entire window. | ||
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== Errors == | == Errors == | ||
| − | {{ | + | {{enum|GL_INVALID_VALUE}} is generated if either {{param|width}} or {{param|height}} is negative. |
== Associated Gets == | == Associated Gets == | ||
| − | + | {{apifunc|glGet}} with argument {{enum|GL_SCISSOR_BOX}} | |
| − | + | {{apifunc|glIsEnabled}} with argument {{enum|GL_SCISSOR_TEST}} | |
== See Also == | == See Also == | ||
| − | + | {{apifunc|glEnable|(GL_SCISSOR_TEST)}}, {{apifunc|glScissorArray}}, {{apifunc|glScissorIndexed}}, {{apifunc|glViewport}} | |
== Copyright == | == Copyright == | ||
| Line 41: | Line 39: | ||
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see [http://oss.sgi.com/projects/FreeB/ http://oss.sgi.com/projects/FreeB/]. | Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see [http://oss.sgi.com/projects/FreeB/ http://oss.sgi.com/projects/FreeB/]. | ||
| − | [[Category:API | + | [[Category:Core API Ref Post Fragment Shader Operations|Scissor]] |
| − | [[Category: | + | [[Category:Core API Reference|Scissor]] |
Latest revision as of 01:54, 27 September 2012
| Core in version | 4.6 | |
|---|---|---|
glScissor: define the scissor box
Function Definition
void glScissor(GLint x, GLint y, GLsizei width, GLsizei height);
- x, y
- Specify the lower left corner of the scissor box. Initially (0, 0).
- width, height
- Specify the width and height of the scissor box. When a GL context is first attached to a window, width and height are set to the dimensions of that window.
Description
glScissor defines a rectangle, called the scissor box, in window coordinates. The first two arguments, x and y, specify the lower left corner of the box. width and height specify the width and height of the box.
To enable and disable the scissor test, call glEnable and glDisable with argument GL_SCISSOR_TEST. The test is initially disabled. While the test is enabled, only pixels that lie within the scissor box can be modified by drawing commands. Window coordinates have integer values at the shared corners of frame buffer pixels. glScissor(0,0,1,1) allows modification of only the lower left pixel in the window, and glScissor(0,0,0,0) doesn't allow modification of any pixels in the window.
When the scissor test is disabled, it is as though the scissor box includes the entire window.
Errors
GL_INVALID_VALUE is generated if either width or height is negative.
Associated Gets
glGet with argument GL_SCISSOR_BOX
glIsEnabled with argument GL_SCISSOR_TEST
See Also
glEnable(GL_SCISSOR_TEST), glScissorArray, glScissorIndexed, glViewport
Copyright
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.