glEvalPoint

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 where

and $\mathit{n}$ , ${\mathit{u}}_1$ , and ${\mathit{u}}_2$ are the arguments to the most recent glMapGrid1 command. The one absolute numeric requirement is that if $\mathit{i}=\mathit{n}$ , then the value computed from $\mathit{i}\mathit{u}+{\mathit{u}}_1$ is exactly ${\mathit{u}}_2$ .

In the two-dimensional case, glEvalPoint2 , let

where $\mathit{n}$ , ${\mathit{u}}_1$ , ${\mathit{u}}_2$ , $\mathit{m}$ , ${\mathit{v}}_1$ , and ${\mathit{v}}_2$ are the arguments to the most recent glMapGrid2 command. Then the glEvalPoint2 command is equivalent to calling The only absolute numeric requirements are that if $\mathit{i}=\mathit{n}$ , then the value computed from $\mathit{i}\mathit{u}+{\mathit{u}}_1$ is exactly ${\mathit{u}}_2$ , and if $\mathit{j}=\mathit{m}$ , then the value computed from $\mathit{j}\mathit{v}+{\mathit{v}}_1$ is exactly ${\mathit{v}}_2$ .

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 , glEvalMesh , glMap1 , glMap2 , glMapGrid

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