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glColorTable.3gl
Langue: en
Version: 383635 (fedora - 01/12/10)
Section: 3 (Bibliothèques de fonctions)
NAME
glColorTable - define a color lookup tableC SPECIFICATION
void glColorTable( GLenum target,GLenum internalformat, GLsizei width, GLenum format, GLenum type, const GLvoid *table )
PARAMETERS
- target
- Must be one of GL_COLOR_TABLE, GL_POST_CONVOLUTION_COLOR_TABLE, GL_POST_COLOR_MATRIX_COLOR_TABLE, GL_PROXY_COLOR_TABLE, GL_PROXY_POST_CONVOLUTION_COLOR_TABLE, or GL_PROXY_POST_COLOR_MATRIX_COLOR_TABLE.
- internalformat
- The internal of the color table. The allowable values are GL_ALPHA, GL_ALPHA4, GL_ALPHA8, GL_ALPHA12, GL_ALPHA16, GL_LUMINANCE, GL_LUMINANCE4, GL_LUMINANCE8, GL_LUMINANCE12, GL_LUMINANCE16, GL_LUMINANCE_ALPHA, GL_LUMINANCE4_ALPHA4, GL_LUMINANCE6_ALPHA2, GL_LUMINANCE8_ALPHA8, GL_LUMINANCE12_ALPHA4, GL_LUMINANCE12_ALPHA12, GL_LUMINANCE16_ALPHA16, GL_INTENSITY, GL_INTENSITY4, GL_INTENSITY8, GL_INTENSITY12, GL_INTENSITY16, GL_R3_G3_B2, GL_RGB, GL_RGB4, GL_RGB5, GL_RGB8, GL_RGB10, GL_RGB12, GL_RGB16, GL_RGBA, GL_RGBA2, GL_RGBA4, GL_RGB5_A1, GL_RGBA8, GL_RGB10_A2, GL_RGBA12, and GL_RGBA16.
- width
- The number of entries in the color lookup table specified by table.
- format
- The of the pixel data in table. The allowable values are GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_LUMINANCE, GL_LUMINANCE_ALPHA, GL_RGB, GL_BGR, GL_RGBA, and GL_BGRA.
- type
- The type of the pixel data in table. The allowable values are GL_UNSIGNED_BYTE, GL_BYTE, GL_UNSIGNED_SHORT, GL_SHORT, GL_UNSIGNED_INT, GL_INT, GL_FLOAT, GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_5_6_5_REV, GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV, GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV, GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV, GL_UNSIGNED_INT_10_10_10_2, and GL_UNSIGNED_INT_2_10_10_10_REV.
- table
- Pointer to a one-dimensional array of pixel data that is processed to build the color table.
DESCRIPTION
glColorTable may be used in two ways: to test the actual size and color resolution of a lookup table given a particular set of parameters, or to load the contents of a color lookup table. Use the targets GL_PROXY_* for the first case and the other targets for the second case. If target is GL_COLOR_TABLE, GL_POST_CONVOLUTION_COLOR_TABLE, or GL_POST_COLOR_MATRIX_COLOR_TABLE, glColorTable builds a color lookup table from an array of pixels. The pixel array specified by width, format, type, and table is extracted from memory and processed just as if glDrawPixels were called, but processing stops after the final expansion to RGBA is completed. The four scale parameters and the four bias parameters that are defined for the table are then used to scale and bias the R, G, B, and A components of each pixel. (Use glColorTableParameter to set these scale and bias parameters.) Next, the R, G, B, and A values are clamped to the range [0, 1]. Each pixel is then converted to the internal specified by internalformat. This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal (red, green, blue, alpha, luminance, and intensity). The mapping is as follows: | ||||||
Internal Format | Red | Green | Blue | Alpha | Luminance | Intensity |
| ||||||
GL_ALPHA | A | |||||
GL_LUMINANCE | R | |||||
GL_LUMINANCE_ALPHA | A | R | ||||
GL_INTENSITY | R | |||||
GL_RGB | R | G | B | |||
GL_RGBA | R | G | B | A | ||
|
| |
Representation | Meaning |
| |
r | Table index computed from R |
g | Table index computed from G |
b | Table index computed from B |
a | Table index computed from A |
L[i] | Luminance value at table index i |
I[i] | Intensity value at table index i |
R[i] | Red value at table index i |
G[i] | Green value at table index i |
B[i] | Blue value at table index i |
A[i] | Alpha value at table index i |
|
| ||||
Resulting Texture Components | ||||
Table Internal Format | R | G | B | A |
| ||||
GL_ALPHA | R | G | B | A[a] |
GL_LUMINANCE | L[r] | L[g] | L[b] | At |
GL_LUMINANCE_ALPHA | L[r] | L[g] | L[b] | A[a] |
GL_INTENSITY | I[r] | I[g] | I[b] | I[a] |
GL_RGB | R[r] | G[g] | B[b] | A |
GL_RGBA | R[r] | G[g] | B[b] | A[a] |
|
NOTES
glColorTable is present only if GL_ARB_imaging is returned when glGetString is called with an argument of GL_EXTENSIONS. If target is set to GL_COLOR_TABLE, GL_POST_CONVOLUTION_COLOR_TABLE, or GL_POST_COLOR_MATRIX_COLOR_TABLE, then width must be a power of two or a GL_INVALID_VALUE error is generated.ERRORS
GL_INVALID_ENUM is generated if target is not one of the allowable values. GL_INVALID_ENUM is generated if internalformat is not one of the allowable values. GL_INVALID_VALUE is generated if width is less than zero. GL_INVALID_ENUM is generated if format is not one of the allowable values. GL_INVALID_ENUM is generated if type is not one of the allowable values. GL_TABLE_TOO_LARGE is generated if the requested color table is too large to be supported by the implementation, and target is not a GL_PROXY_* target. GL_INVALID_OPERATION is generated if glColorTable is executed between the execution of glBegin and the corresponding execution of glEnd.ASSOCIATED GETS
glGetColorTableParameterSEE ALSO
glColorSubTable(3G), glColorTableParameter(3G), glCopyColorTable(3G), glCopyColorSubTable(3G), glGetColorTable(3G)Contenus ©2006-2024 Benjamin Poulain
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