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Manual Reference Pages  - GLPOLYGONSTIPPLE (3G)

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glPolygonStipple - set the polygon stippling pattern

CONTENTS

C Specification
Parameters
Description
Errors
Associated Gets
See Also

void glPolygonStipple( const GLubyte *mask )

mask	Specifies a pointer to a 32 times 32 stipple pattern that will be unpacked from memory in the same way that  glDrawPixels unpacks pixels.

Polygon stippling, like line stippling (see  glLineStipple), masks out certain fragments produced by rasterization, creating a pattern. Stippling is independent of polygon antialiasing.

mask is a pointer to a 32 times 32 stipple pattern that is stored in memory just like the pixel data supplied to a  glDrawPixels call with height and width both equal to 32, a pixel of  GL_COLOR_INDEX, and data type of  GL_BITMAP. That is, the stipple pattern is represented as a 32 times 32 array of 1-bit color indices packed in unsigned bytes.  glPixelStore parameters like  GL_UNPACK_SWAP_BYTES and  GL_UNPACK_LSB_FIRST affect the assembling of the bits into a stipple pattern. Pixel transfer operations (shift, offset, pixel map) are not applied to the stipple image, however.

To enable and disable polygon stippling, call  glEnable and  glDisable with argument  GL_POLYGON_STIPPLE. Polygon stippling is initially disabled. If it’s enabled, a rasterized polygon fragment with window coordinates x_w and y_w is sent to the next stage of the GL if and only if the (x_w mod 32)th bit in the (y_w mod 32)th row of the stipple pattern is 1 (one). When polygon stippling is disabled, it is as if the stipple pattern consists of all 1’s.

 GL_INVALID_OPERATION is generated if  glPolygonStipple is executed between the execution of  glBegin and the corresponding execution of  glEnd.

 glGetPolygonStipple
 glIsEnabled with argument  GL_POLYGON_STIPPLE

 glDrawPixels(3G),  glLineStipple(3G),  glPixelStore(3G),  glPixelTransfer(3G)

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