GLCONVOLUTIONFILTER1D(3G)GLCONVOLUTIONFILTER1D(3G)NAMEglConvolutionFilter1D - define a one-dimensional convolution filter
C SPECIFICATION
void glConvolutionFilter1D( GLenum target,
GLenum internalformat,
GLsizei width,
GLenum format,
GLenum type,
const GLvoid *image )
PARAMETERS
target Must be GL_CONVOLUTION_1D.
internalformat
The internal of the convolution filter kernel. The allowable
values are GL_ALPHA, GL_LUMINANCE, GL_LUMINANCE_ALPHA,
GL_INTENSITY, GL_RGB, and GL_RGBA.
width The width of the pixel array referenced by image.
format The of the pixel data in image. 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.
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.
DESCRIPTIONglConvolutionFilter1D 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 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
------------------------------------------------------------------------
The red, green, blue, alpha, luminance, and/or intensity components of
the resulting pixels are stored in floating-point rather than integer
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.
NOTESglConvolutionFilter1D is present only if GL_ARB_imaging is returned
when glGetString is called with an argument of GL_EXTENSIONS.
ERRORS
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 neither GL_RGBA nor GL_BGRA.
ASSOCIATED GETS
glGetConvolutionParameter, glGetConvolutionFilter
SEE ALSOglConvolutionFilter2D(3G), glSeparableFilter2D(3G),
glConvolutionParameter(3G), glPixelTransfer(3G)
March 1, 2011
