1GLPOINTSIZE(3G) GLPOINTSIZE(3G)
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6 glPointSize - specify the diameter of rasterized points
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10 void glPointSize( GLfloat size )
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14 size Specifies the diameter of rasterized points. The initial value
15 is 1.
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18 glPointSize specifies the rasterized diameter of both aliased and
19 antialiased points. Using a point size other than 1 has different
20 effects, depending on whether point antialiasing is enabled. To enable
21 and disable point antialiasing, call glEnable and glDisable with argu‐
22 ment GL_POINT_SMOOTH. Point antialiasing is initially disabled.
23 If point antialiasing is disabled, the actual size is determined by
25 rounding the supplied size to the nearest integer. (If the rounding
26 results in the value 0, it is as if the point size were 1.) If the
27 rounded size is odd, then the center point (x, y) of the pixel fragment
28 that represents the point is computed as
29 ( ⌊xw⌋+.5, ⌊yw⌋+.5)
31 where w subscripts indicate window coordinates. All pixels that lie
33 within the square grid of the rounded size centered at (x, y) make up
34 the fragment. If the size is even, the center point is
35 ( ⌊xw+.5⌋, ⌊yw+.5⌋)
37 and the rasterized fragment's centers are the half-integer window coor‐
39 dinates within the square of the rounded size centered at (x, y). All
40 pixel fragments produced in rasterizing a nonantialiased point are
41 assigned the same associated data, that of the vertex corresponding to
42 the point.
43 If antialiasing is enabled, then point rasterization produces a frag‐
45 ment for each pixel square that intersects the region lying within the
46 circle having diameter equal to the current point size and centered at
47 the point's (xw, yw). The coverage value for each fragment is the win‐
48 dow coordinate area of the intersection of the circular region with the
49 corresponding pixel square. This value is saved and used in the final
50 rasterization step. The data associated with each fragment is the data
51 associated with the point being rasterized.
52 Not all sizes are supported when point antialiasing is enabled. If an
54 unsupported size is requested, the nearest supported size is used.
55 Only size 1 is guaranteed to be supported; others depend on the imple‐
56 mentation. To query the range of supported sizes and the size differ‐
57 ence between supported sizes within the range, call glGet with argu‐
58 ments GL_SMOOTH_POINT_SIZE_RANGE and GL_SMOOTH_POINT_SIZE_GRANULARITY.
59 For aliased points, query the supported ranges and granularity with
60 glGet with arguments GL_ALIASED_POINT_SIZE_RANGE and
61 GL_ALIASED_POINT_SIZE_GRANULARITY.
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64 The point size specified by glPointSize is always returned when
65 GL_POINT_SIZE is queried. Clamping and rounding for aliased and
66 antialiased points have no effect on the specified value.
67 A non-antialiased point size may be clamped to an implementation-depen‐
69 dent maximum. Although this maximum cannot be queried, it must be no
70 less than the maximum value for antialiased points, rounded to the
71 nearest integer value.
72 GL_POINT_SIZE_RANGE and GL_POINT_SIZE_GRANULARITY are deprecated in GL
74 versions 1.2 and greater. Their functionality has been replaced by
75 GL_SMOOTH_POINT_SIZE_RANGE and GL_SMOOTH_POINT_SIZE_GRANULARITY.
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78 GL_INVALID_VALUE is generated if size is less than or equal to 0.
79 GL_INVALID_OPERATION is generated if glPointSize is executed between
81 the execution of glBegin and the corresponding execution of glEnd.
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84 glGet with argument GL_POINT_SIZE
85 glGet with argument GL_ALIASED_POINT_SIZE_RANGE
86 glGet with argument GL_ALIASED_POINT_SIZE_GRANULARITY
87 glGet with argument GL_SMOOTH_POINT_SIZE_RANGE
88 glGet with argument GL_SMOOTH_POINT_SIZE_GRANULARITY
89 glIsEnabled with argument GL_POINT_SMOOTH
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92 glEnable(3G)
93 GLPOINTSIZE(3G)