glConvolutionFilter1D(3G) OpenGL Reference glConvolutionFilter1D(3G)
glConvolutionFilter1D - define a one-dimensional convolution filter
void glConvolutionFilter1D( GLenum target,
GLenum internalformat,
GLsizei width,
GLenum format,
GLenum type,
const GLvoid *image )
target Must be GL_CONVOLUTION_1D.
internalformat The internal format of the convolution filter kernel.
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, or
GL_RGBA16.
width The width of the pixel array referenced by image.
format The format of the pixel data in image. The allowable
values are GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB,
GL_BGR, GL_RGBA, GL_BGRA, GL_ABGR_EXT, GL_LUMINANCE, and
GL_LUMINANCE_ALPHA.
type The type of the pixel data in image. Symbolic constants
GL_UNSIGNED_BYTE, GL_BYTE, GL_BITMAP, 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 are accepted.
image Pointer to a one-dimensional array of pixel data that is
processed to build the convolution filter kernel.
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glConvolutionFilter1D(3G) OpenGL Reference glConvolutionFilter1D(3G)
glConvolutionFilter1D builds a one-dimensional convolution filter kernel
from an array of pixels.
The pixel array specified by width, format, type, and image is extracted
from memory and processed just as if glDrawPixels were called, but
processing stops after the final expansion to RGBA is completed.
The R, G, B, and A components of each pixel are next scaled by the four
1D GL_CONVOLUTION_FILTER_SCALE parameters and biased by the four 1D
GL_CONVOLUTION_FILTER_BIAS parameters. (The scale and bias parameters
are set by glConvolutionParameter using the GL_CONVOLUTION_1D target and
the names GL_CONVOLUTION_FILTER_SCALE and GL_CONVOLUTION_FILTER_BIAS.
The parameters themselves are vectors of four values that are applied to
red, green, blue, and alpha, in that order.) The R, G, B, and A values
are not clamped to [0,1] at any time during this process.
Each pixel is then converted to the internal format 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 format
(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
_______________________________________________________________________
The red, green, blue, alpha, luminance, and/or intensity components of
the resulting pixels are stored in floating-point rather than integer
format. They form a one-dimensional filter kernel image indexed with
coordinate i such that i starts at 0 and increases from left to right.
Kernel location i is derived from the ith pixel, counting from 0.
Note that after a convolution is performed, the resulting color
components are also scaled by their corresponding
GL_POST_CONVOLUTION_c_SCALE parameters and biased by their corresponding
GL_POST_CONVOLUTION_c_BIAS parameters (where c takes on the values RED,
GREEN, BLUE, and ALPHA). These parameters are set by glPixelTransfer.
glConvolutionFilter1D is present only if GL_ARB_imaging is returned when
glGetString is called with an argument of GL_EXTENSIONS.
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glConvolutionFilter1D(3G) OpenGL Reference glConvolutionFilter1D(3G)
GL_ABGR_EXT is valid only if the EXT_abgr extension is supported.
GL_INVALID_ENUM is generated if target is not GL_CONVOLUTION_1D.
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 or greater than
the maximum supported value. This value may be queried with
glGetConvolutionParameter using target GL_CONVOLUTION_1D and name
GL_MAX_CONVOLUTION_WIDTH.
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_INVALID_OPERATION is generated if glConvolutionFilter1D is executed
between the execution of glBegin and the corresponding execution of
glEnd.
GL_INVALID_OPERATION is generated if format is one of
GL_UNSIGNED_BYTE_3_3_2, GL_UNSIGNED_BYTE_2_3_3_REV,
GL_UNSIGNED_SHORT_5_6_5, or GL_UNSIGNED_SHORT_5_6_5_REV and type is not
GL_RGB.
GL_INVALID_OPERATION is generated if format is one of
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, or GL_UNSIGNED_INT_2_10_10_10_REV and type is
not GL_RGBA, GL_BGRA or GL_ABGR_EXT.
glGetConvolutionParameter, glGetConvolutionFilter
glConvolutionFilter2D, glSeparableFilter2D, glConvolutionParameter,
glPixelTransfer
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