glColor4us function
Sets the current color.
Syntax
void WINAPI glColor4us(
GLushort red,
GLushort green,
GLushort blue,
GLushort alpha
);
Parameters
-
red
-
The new red value for the current color.
-
green
-
The new green value for the current color.
-
blue
-
The new blue value for the current color.
-
alpha
-
The new alpha value for the current color.
Return value
This function does not return a value.
Remarks
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 [0,1] before the current color is updated. However, color components are clamped to this range before they are interpolated or written into a color buffer.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows 2000 Professional [desktop apps only] |
| Minimum supported server |
Windows 2000 Server [desktop apps only] |
| Header |
|
| Library |
|
| DLL |
|