GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 5.6 |
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glEvalPoint2(3gl) |
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glEvalPoint1, glEvalPoint2 − generate and evaluate a single point in a mesh
void
glEvalPoint1( GLint i )
void glEvalPoint2( GLint i,
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GLint j ) |
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i |
Specifies the integer value for grid domain variable $i$. | ||
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j |
Specifies the integer value for grid domain variable $j$ (- glEvalPoint2 only). |
glMapGrid and glEvalMesh are used in tandem to efficiently generate and evaluate a series of evenly spaced map domain values. glEvalPoint can be used to evaluate a single grid point in the same gridspace that is traversed by glEvalMesh. Calling glEvalPoint1 is equivalent to calling
glEvalCoord1( i$^cdot^DELTA u ~+~ u sub 1$ );
where
$DELTA u ~=~ ( u sub 2 - u sub 1 ) ^/^ n$
and $n$, $u sub 1$, and $u sub 2$ are the arguments to the most recent glMapGrid1 command. The one absolute numeric requirement is that if $i~=~n$, then the value computed from $i ^cdot^ DELTA u ~+~ u sub 1$ is exactly $u sub 2$.
In the two-dimensional case, glEvalPoint2, let
$DELTA u ~=~ mark ( u sub 2 - u sub 1 ) ^/^ n$
$DELTA v ~=~ mark ( v sub 2 - v sub 1 ) ^/^ m,$
where $n$, $u sub 1$, $u sub 2$, $m$, $v sub 1$, and $v sub 2$ are the arguments to the most recent glMapGrid2 command. Then the glEvalPoint2 command is equivalent to calling
glEvalCoord2( i$^cdot^DELTA u ~+~ u sub 1$, j$^cdot^DELTA v ~+~ v sub 1$ );
The only absolute numeric requirements are that if $i~=~n$, then the value computed from $i ^cdot^DELTA u ~+~ u sub 1$ is exactly $u sub 2$, and if $j~=~m$, then the value computed from $i ^cdot^DELTA v ~+~ v sub 1$ is exactly $v sub 2$.
glGet
with argument GL_MAP1_GRID_DOMAIN
glGet with argument GL_MAP2_GRID_DOMAIN
glGet with argument GL_MAP1_GRID_SEGMENTS
glGet with argument GL_MAP2_GRID_SEGMENTS
glEvalCoord(3G), glEvalMesh(3G), glMap1(3G), glMap2(3G), glMapGrid(3G)
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glEvalPoint2(3gl) | |