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glEvalCoord1f function

Applies to: desktop apps only

The glEvalCoord1f function evaluates enabled one-dimensional maps.

Syntax

void WINAPI glEvalCoord1f(
  GLfloat u
);

Parameters

u

A value that is the domain coordinate u to the basis function defined in a previous glMap1 function.

Return value

This function does not return a value.

Remarks

The glEvalCoord1f function evaluates enabled one-dimensional maps at argument u. Define maps with glMap1. Enable or disable them with glEnable and glDisable.

When one of the glEvalCoord functions is issued, all currently enabled maps of the indicated dimension are evaluated. Then, for each enabled map, it is as if the corresponding OpenGL function were issued with the computed value. That is, if GL_MAP1_INDEX or GL_MAP2_INDEX is enabled, a glIndex function is simulated. If GL_MAP1_COLOR_4 or GL_MAP2_COLOR_4 is enabled, a glcolor function is simulated. If GL_MAP1_NORMAL or GL_MAP2_NORMAL is enabled, a normal vector is produced, and if any of GL_MAP1_TEXTURE_COORD_1, GL_MAP1_TEXTURE_COORD_2, GL_MAP1_TEXTURE_COORD_3, GL_MAP1_TEXTURE_COORD_4, GL_MAP2_TEXTURE_COORD_1, GL_MAP2_TEXTURE_COORD_2, GL_MAP2_TEXTURE_COORD_3, and GL_MAP2_TEXTURE_COORD_4 is enabled, then an appropriate glTexCoord function is simulated.

OpenGL uses evaluated values instead of current values for those evaluations that are enabled, and current values otherwise, for color, color index, normal, and texture coordinates. However, the evaluated values do not update the current values. Thus, if glVertex functions are interspersed with glEvalCoord functions, the color, normal, and texture coordinates associated with the glVertex functions are not affected by the values generated by the glEvalCoord functions, but only by the most recent glColor, glIndex, glNormal, and glTexCoord functions.

The following functions retrieve information related to the glEvalCoord1f function:

glIsEnabled with argument GL_MAP1_VERTEX_3

glIsEnabled with argument GL_MAP1_VERTEX_4

glIsEnabled with argument GL_MAP1_INDEX

glIsEnabled with argument GL_MAP1_COLOR_4

glIsEnabled with argument GL_MAP1_NORMAL

glIsEnabled with argument GL_MAP1_TEXTURE_COORD_1

glIsEnabled with argument GL_MAP1_TEXTURE_COORD_2

glIsEnabled with argument GL_MAP1_TEXTURE_COORD_3

glIsEnabled with argument GL_MAP1_TEXTURE_COORD_4

glIsEnabled with argument GL_MAP2_VERTEX_3

glIsEnabled with argument GL_MAP2_VERTEX_4

glIsEnabled with argument GL_MAP2_INDEX

glIsEnabled with argument GL_MAP2_COLOR_4

glIsEnabled with argument GL_MAP2_NORMAL

glIsEnabled with argument GL_MAP2_TEXTURE_COORD_1

glIsEnabled with argument GL_MAP2_TEXTURE_COORD_2

glIsEnabled with argument GL_MAP2_TEXTURE_COORD_3

glIsEnabled with argument GL_MAP2_TEXTURE_COORD_4

glIsEnabled with argument GL_AUTO_NORMAL

Requirements

Minimum supported client

Windows 2000 Professional

Minimum supported server

Windows 2000 Server

Header

Gl.h

Library

Opengl32.lib

DLL

Opengl32.dll

See also

glBegin
glColor
glDisable
glEnable
glEnd
glEvalMesh
glEvalPoint
glGetMap
glIndex
glIsEnabled
glMap1
glMap2
glMapGrid
glNormal
glTexCoord
glVertex

 

 

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Build date: 3/6/2012

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