glColor

The GL stores both a current single-valued color index and a current four-valued RGBA color. glColor sets a new four-valued RGBA color. glColor has two major variants: glColor3 and glColor4 . glColor3 variants specify new red, green, and blue values explicitly and set the current alpha value to 1.0 (full intensity) implicitly. glColor4 variants specify all four color components explicitly.

glColor3b , glColor4b , glColor3s , glColor4s , glColor3i , and glColor4i take three or four signed byte, short, or long integers as arguments. When v is appended to the name, the color commands can take a pointer to an array of such values.

Current color values are stored in floating-point format, with unspecified mantissa and exponent sizes. Unsigned integer color components, when specified, are linearly mapped to floating-point values such that the largest representable value maps to 1.0 (full intensity), and 0 maps to 0.0 (zero intensity). Signed integer color components, when specified, are linearly mapped to floating-point values such that the most positive representable value maps to 1.0, and the most negative representable value maps to $-1.0$ . (Note that this mapping does not convert 0 precisely to 0.0.) Floating-point values are mapped directly.

Neither floating-point nor signed integer values are clamped to the range $\left[0,1\right]$ before the current color is updated. However, color components are clamped to this range before they are interpolated or written into a color buffer.

The initial value for the current color is (1, 1, 1, 1).

The current color can be updated at any time. In particular, glColor can be called between a call to glBegin and the corresponding call to glEnd .

glGet with argument GL_CURRENT_COLOR

glGet with argument GL_RGBA_MODE

glColorPointer , glIndex , glSecondaryColor

Copyright 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/ .