---
name: "glGetMap"
section: "3x"
platform: "linux"
package: "xlibmesa-gl-dev"
version: "4.3.0.dfsg.1-14sarge7"
release: "Debian 3.1 (Sarge)"
platforms: ["linux"]
url: "https://new.carta.tech/glGetMap"
---

# glGetMap(3x)

return evaluator parameters

## NAME

**glGetMapdv, glGetMapfv, glGetMapiv** - return evaluator parameters

## C SPECIFICATION

void **glGetMapdv**( GLenum *target*,

```
	GLenum query,
	GLdouble *v )
```

void **glGetMapfv**( GLenum *target*,

```
	GLenum query,
	GLfloat *v )
```

void **glGetMapiv**( GLenum *target*,

```
	GLenum query,
	GLint *v )
```

delim $$

## PARAMETERS

- *target*

  Specifies the symbolic name of a map. Accepted values are **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. Symbolic names **GL\_COEFF**, **GL\_ORDER**, and **GL\_DOMAIN** are accepted.

- *v*

  Returns the requested data.

## DESCRIPTION

**glMap1** and **glMap2** define evaluators. **glGetMap** returns evaluator parameters. *target* chooses 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 the **glMap1** and **glMap2** reference pages.

*query* can assume the following values:

- **GL\_COEFF**

  *v* returns the control points for the evaluator function. One-dimensional evaluators return $order$ control points, and two-dimensional evaluators return $uorder ~times~ vorder$ 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. The GL returns two-dimensional control points 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**

  *v* returns the order of the evaluator function. One-dimensional evaluators return a single value, $order$. The initial value is 1. Two-dimensional evaluators return two values, $uorder$ and $vorder$. The initial value is 1,1.

- **GL\_DOMAIN**

  *v* 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.

## NOTES

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

## ERRORS

**GL\_INVALID\_ENUM** is generated if either *target* or *query* is not an accepted value.

**GL\_INVALID\_OPERATION** is generated if **glGetMap** is executed between the execution of **glBegin** and the corresponding execution of **glEnd**.

## SEE ALSO

**glEvalCoord(3G)**, **glMap1(3G)**, **glMap2(3G)**