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<STRONG>NAME</STRONG>
<STRONG>glMapGrid1d,</STRONG> <STRONG>glMapGrid1f,</STRONG> <STRONG>glMapGrid2d,</STRONG> <STRONG>glMapGrid2f</STRONG> - define
a one- or two-dimensional mesh
<STRONG>C</STRONG> <STRONG>SPECIFICATION</STRONG>
void <STRONG>glMapGrid1d</STRONG>( GLint <EM>un</EM>,
GLdouble <EM>u1</EM>,
GLdouble <EM>u2</EM> )
void <STRONG>glMapGrid1f</STRONG>( GLint <EM>un</EM>,
GLfloat <EM>u1</EM>,
GLfloat <EM>u2</EM> )
void <STRONG>glMapGrid2d</STRONG>( GLint <EM>un</EM>,
GLdouble <EM>u1</EM>,
GLdouble <EM>u2</EM>,
GLint <EM>vn</EM>,
GLdouble <EM>v1</EM>,
GLdouble <EM>v2</EM> )
void <STRONG>glMapGrid2f</STRONG>( GLint <EM>un</EM>,
GLfloat <EM>u1</EM>,
GLfloat <EM>u2</EM>,
GLint <EM>vn</EM>,
GLfloat <EM>v1</EM>,
GLfloat <EM>v2</EM> )
<STRONG>PARAMETERS</STRONG>
<EM>un</EM> Specifies the number of partitions in the grid range
interval [<EM>u1</EM>, <EM>u2</EM>]. Must be positive.
<EM>u1</EM>, <EM>u2</EM>
Specify the mappings for integer grid domain values i=0
and i=un.
<EM>vn</EM> Specifies the number of partitions in the grid range
interval [<EM>v1</EM>, <EM>v2</EM>]
(<STRONG>glMapGrid2</STRONG> only).
<EM>v1</EM>, <EM>v2</EM>
Specify the mappings for integer grid domain values j=0
and j=vn
(<STRONG>glMapGrid2</STRONG> only).
<STRONG>DESCRIPTION</STRONG>
<STRONG>glMapGrid</STRONG> and <STRONG>glEvalMesh</STRONG> are used together to efficiently
generate and evaluate a series of evenly-spaced map domain
values. <STRONG>glEvalMesh</STRONG> steps through the integer domain of a
one- or two-dimensional grid, whose range is the domain of
the evaluation maps specified by <STRONG>glMap1</STRONG> and <STRONG>glMap2</STRONG>.
<STRONG>glMapGrid1</STRONG> and <STRONG>glMapGrid2</STRONG> specify the linear grid mappings
between the i (or i and j) integer grid coordinates, to the
u (or u and v) floating-point evaluation map coordinates.
See <STRONG>glMap1</STRONG> and <STRONG>glMap2</STRONG> for details of how u and v coordinates
are evaluated.
<STRONG>glMapGrid1</STRONG> specifies a single linear mapping such that
integer grid coordinate 0 maps exactly to <EM>u1</EM>, and integer
grid coordinate <EM>un</EM> maps exactly to <EM>u2</EM>. All other integer
grid coordinates i are mapped so that
u = i(u2-u1)/un + u1
<STRONG>glMapGrid2</STRONG> specifies two such linear mappings. One maps
integer grid coordinate i=0 exactly to <EM>u1</EM>, and integer grid
coordinate i=un exactly to <EM>u2</EM>. The other maps integer grid
coordinate j=0 exactly to <EM>v1</EM>, and integer grid coordinate
j=vn exactly to <EM>v2</EM>. Other integer grid coordinates i and j
are mapped such that
u = i(u2-u1)/un + u1
v = j(v2-v1)/vn + v1
The mappings specified by <STRONG>glMapGrid</STRONG> are used identically by
<STRONG>glEvalMesh</STRONG> and <STRONG>glEvalPoint</STRONG>.
<STRONG>ERRORS</STRONG>
<STRONG>GL_INVALID_VALUE</STRONG> is generated if either <EM>un</EM> or <EM>vn</EM> is not
positive.
<STRONG>GL_INVALID_OPERATION</STRONG> is generated if <STRONG>glMapGrid</STRONG> is executed
between the execution of <STRONG>glBegin</STRONG> and the corresponding
execution of <STRONG>glEnd</STRONG>.
<STRONG>ASSOCIATED</STRONG> <STRONG>GETS</STRONG>
<STRONG>glGet</STRONG> with argument <STRONG>GL_MAP1_GRID_DOMAIN</STRONG>
<STRONG>glGet</STRONG> with argument <STRONG>GL_MAP2_GRID_DOMAIN</STRONG>
<STRONG>glGet</STRONG> with argument <STRONG>GL_MAP1_GRID_SEGMENTS</STRONG>
<STRONG>glGet</STRONG> with argument <STRONG>GL_MAP2_GRID_SEGMENTS</STRONG>
<STRONG>SEE</STRONG> <STRONG>ALSO</STRONG>
<STRONG>glEvalCoord</STRONG>, <STRONG>glEvalMesh</STRONG>, <STRONG>glEvalPoint</STRONG>, <STRONG>glMap1</STRONG>, <STRONG>glMap2</STRONG>
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