glGetMapdv, glGetMapfv, glGetMapiv

These functions return evaluator parameters.

void glGetMapdv(
  GLenum target,
  GLenum query,
  GLdouble *v
);

void glGetMapfv(
  GLenum target,
  GLenum query,
  GLfloat *v
);

void glGetMapiv(
  GLenum target,
  GLenum query,
  GLint *v
);

Parameters

target
The symbolic name of a map. The following are accepted values: GL_MAP1_COLOR_4, GL_MAP1_INDEX, GL_MAP1_NORMAL, GL_MAP1_TEXTURE_COORD_1, GL_MAP1_TEXTURE_COORD_2, GL_MAP1_TEXTURE_COORD_3, GL_MAP1_TEXTURE_COORD_4, GL_MAP1_VERTEX_3, GL_MAP1_VERTEX_4, GL_MAP2_COLOR_4, GL_MAP2_INDEX, GL_MAP2_NORMAL, GL_MAP2_TEXTURE_COORD_1, GL_MAP2_TEXTURE_COORD_2, GL_MAP2_TEXTURE_COORD_3, GL_MAP2_TEXTURE_COORD_4, GL_MAP2_VERTEX_3, and GL_MAP2_VERTEX_4.
query
Specifies which parameter to return. The following symbolic names are accepted:
Value Meaning
GL_COEFF The v parameter returns the control points for the evaluator function. One-dimensional evaluators return order control points, and two-dimensional evaluators return uorderxvorder control points. Each control point consists of one, two, three, or four integer, single-precision floating-point, or double-precision floating-point values, depending on the type of the evaluator. Two-dimensional control points are returned in row-major order, incrementing the uorder index quickly, and the vorder index after each row. Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values.
GL_ORDER The v parameter returns the order of the evaluator function. One-dimensional evaluators return a single value, order. Two-dimensional evaluators return two values, uorder and vorder.
GL_DOMAIN The v parameter returns the linear u and v mapping parameters. One-dimensional evaluators return two values, u1 and u2, as specified by glMap1. Two-dimensional evaluators return four values (u1, u2, v1, and v2) as specified by glMap2. Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values.

v
Returns the requested data.

Remarks

The glGetMap function returns evaluator parameters. (The glMap1 and glMap2 functions define evaluators.) The target parameter specifies a map, query selects a specific parameter, and v points to storage where the values will be returned.

The acceptable values for the target parameter are described in glMap1 and glMap2.

If an error is generated, no change is made to the contents of v.

Error Codes

The following are the error codes generated and their conditions.

Error code Condition
GL_INVALID_ENUM target or query was not an accepted value.
GL_INVALID_OPERATION glGetMap was called between a call to glBegin and the corresponding call to glEnd.

Requirements

  Windows NT/2000: Requires Windows NT 3.5 or later.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in Gl.h.
  Library: Use Opengl32.lib.

See Also

glBegin, glEnd, glEvalCoord, glMap1, glMap2


  

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