gllinewidth(3g) [xfree86 man page]
GLLINEWIDTH(3G) GLLINEWIDTH(3G) NAME
glLineWidth - specify the width of rasterized lines C SPECIFICATION
void glLineWidth( GLfloat width ) PARAMETERS
width Specifies the width of rasterized lines. The initial value is 1. DESCRIPTION
glLineWidth specifies the rasterized width of both aliased and antialiased lines. Using a line width other than 1 has different effects, depending on whether line antialiasing is enabled. To enable and disable line antialiasing, call glEnable and glDisable with argument GL_LINE_SMOOTH. Line antialiasing is initially disabled. If line antialiasing is disabled, the actual width is determined by rounding the supplied width to the nearest integer. (If the rounding results in the value 0, it is as if the line width were 1.) If |/x|>=|/y|, i pixels are filled in each column that is rasterized, where i is the rounded value of width. Otherwise, i pixels are filled in each row that is rasterized. If antialiasing is enabled, line rasterization produces a fragment for each pixel square that intersects the region lying within the rec- tangle having width equal to the current line width, length equal to the actual length of the line, and centered on the mathematical line segment. The coverage value for each fragment is the window coordinate area of the intersection of the rectangular region with the corre- sponding pixel square. This value is saved and used in the final rasterization step. Not all widths can be supported when line antialiasing is enabled. If an unsupported width is requested, the nearest supported width is used. Only width 1 is guaranteed to be supported; others depend on the implementation. Likewise, there is a range for aliased line widths as well. To query the range of supported widths and the size difference between supported widths within the range, call glGet with argu- ments GL_ALIASED_LINE_WIDTH_RANGE, GL_SMOOTH_LINE_WIDTH_RANGE, GL_SMOOTH_LINE_WIDTH_GRANULARITY. NOTES
The line width specified by glLineWidth is always returned when GL_LINE_WIDTH is queried. Clamping and rounding for aliased and antialiased lines have no effect on the specified value. Nonantialiased line width may be clamped to an implementation-dependent maximum. Call glGet with GL_ALIASED_LINE_WIDTH_RANGE to determine the maximum width. ERRORS
GL_INVALID_VALUE is generated if width is less than or equal to 0. GL_INVALID_OPERATION is generated if glLineWidth is executed between the execution of glBegin and the corresponding execution of glEnd. ASSOCIATED GETS
glGet with argument GL_LINE_WIDTH glGet with argument GL_ALIASED_LINE_WIDTH_RANGE glGet with argument GL_SMOOTH_LINE_WIDTH_RANGE glGet with argument GL_SMOOTH_LINE_WIDTH_GRANULARITY glIsEnabled with argument GL_LINE_SMOOTH SEE ALSO
glEnable(3G) GLLINEWIDTH(3G)
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GLPOINTSIZE(3G) GLPOINTSIZE(3G) NAME
glPointSize - specify the diameter of rasterized points C SPECIFICATION
void glPointSize( GLfloat size ) PARAMETERS
size Specifies the diameter of rasterized points. The initial value is 1. DESCRIPTION
glPointSize specifies the rasterized diameter of both aliased and antialiased points. Using a point size other than 1 has different effects, depending on whether point antialiasing is enabled. To enable and disable point antialiasing, call glEnable and glDisable with argument GL_POINT_SMOOTH. Point antialiasing is initially disabled. If point antialiasing is disabled, the actual size is determined by rounding the supplied size to the nearest integer. (If the rounding results in the value 0, it is as if the point size were 1.) If the rounded size is odd, then the center point ( x , y ) of the pixel fragment that represents the point is computed as (xw + .5, yw + .5) where w subscripts indicate window coordinates. All pixels that lie within the square grid of the rounded size centered at ( x , y ) make up the fragment. If the size is even, the center point is (xw + .5, yw + .5) and the rasterized fragment's centers are the half-integer window coordinates within the square of the rounded size centered at ( x , y ). All pixel fragments produced in rasterizing a nonantialiased point are assigned the same associated data, that of the vertex corresponding to the point. If antialiasing is enabled, then point rasterization produces a fragment for each pixel square that intersects the region lying within the circle having diameter equal to the current point size and centered at the point's ( xw , yw). The coverage value for each fragment is the window coordinate area of the intersection of the circular region with the corresponding pixel square. This value is saved and used in the final rasterization step. The data associated with each fragment is the data associated with the point being rasterized. Not all sizes are supported when point antialiasing is enabled. If an unsupported size is requested, the nearest supported size is used. Only size 1 is guaranteed to be supported; others depend on the implementation. To query the range of supported sizes and the size differ- ence between supported sizes within the range, call glGet with arguments GL_SMOOTH_POINT_SIZE_RANGE and GL_SMOOTH_POINT_SIZE_GRANULARITY. For aliased points, query the supported range with glGet with arguments GL_ALIASED_POINT_SIZE_RANGE and NOTES
The point size specified by glPointSize is always returned when GL_POINT_SIZE is queried. Clamping and rounding for aliased and antialiased points have no effect on the specified value. A non-antialiased point size may be clamped to an implementation-dependent maximum. Although this maximum cannot be queried, it must be no less than the maximum value for antialiased points, rounded to the nearest integer value. GL_POINT_SIZE_RANGE and GL_POINT_SIZE_GRANULARITY are deprecated in GL versions 1.2 and greater. Their functionality has been replaced by GL_SMOOTH_POINT_SIZE_RANGE and GL_SMOOTH_POINT_SIZE_GRANULARITY. ERRORS
GL_INVALID_VALUE is generated if size is less than or equal to 0. GL_INVALID_OPERATION is generated if glPointSize is executed between the execution of glBegin and the corresponding execution of glEnd. ASSOCIATED GETS
glGet with argument GL_POINT_SIZE glGet with argument GL_ALIASED_POINT_SIZE_RANGE glGet with argument GL_SMOOTH_POINT_SIZE_RANGE glGet with argument GL_SMOOTH_POINT_SIZE_GRANULARITY glIsEnabled with argument GL_POINT_SMOOTH SEE ALSO
glEnable GLPOINTSIZE(3G)