fglConvolutionFilter1DEXT(3G)
fglConvolutionFilter1DEXT - define a one-dimensional convolution filter
As shipped in IRIX 6.5.5. Unchanged since IRIX 6.5.
NAME fglConvolutionFilter1DEXT - define a one-dimensional convolution filter FORTRAN SPECIFICATION SUBROUTINE fglConvolutionFilter1DEXT( INTEGER*4 target, INTEGER*4 internalformat, INTEGER*4 width, INTEGER*4 format, INTEGER*4 type, CHARACTER*8 image ) PARAMETERS target Must be GL_CONVOLUTION_1D_EXT. internalformat The internal format of the convolution filter kernel. The allowable values are GL_ALPHA, GL_LUMINANCE, GL_LUMINANCE_ALPHA, GL_INTENSITY_EXT, GL_RGB, and GL_RGBA. width The width of the pixel array referenced by image. format The format of the pixel data in image. The allowable values are GL_RGBA, GL_ABGR_EXT, GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA, GL_RGB, GL_LUMINANCE, GL_LUMINANCE_ALPHA and GL_YCRCB_422_SGIX are accepted. type The type of the pixel data in image. 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_EXT, GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT, GL_UNSIGNED_INT_8_8_8_8_EXT, and GL_UNSIGNED_INT_10_10_10_2_EXT. image Pointer to a one-dimensional array of pixel data that is processed to build the convolution filter kernel. DESCRIPTION fglConvolutionFilter1DEXT 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 fglDrawPixels 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_EXT parameters and biased by the four 1D GL_CONVOLUTION_FILTER_BIAS_EXT parameters. (The scale and bias parameters are set by fglConvolutionParameterEXT using the GL_CONVOLUTION_1D_EXT target and the names GL_CONVOLUTION_FILTER_SCALE_EXT and GL_CONVOLUTION_FILTER_BIAS_EXT. 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_EXT 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_EXT parameters and biased by their corresponding GL_POST_CONVOLUTION_c_BIAS_EXT parameters (where c takes on the values RED, GREEN, BLUE, and ALPHA). These parameters are set by fglPixelTransfer. ERRORS GL_INVALID_ENUM is generated if target is not GL_CONVOLUTION_1D_EXT. 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 fglGetConvolutionParameterEXT using target GL_CONVOLUTION_1D_EXT and name GL_MAX_CONVOLUTION_WIDTH_EXT. 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 fglConvolutionFilter1DEXT is executed between the execution of fglBegin and the corresponding execution of fglEnd. If type is set to GL_UNSIGNED_BYTE_3_3_2_EXT, GL_UNSIGNED_SHORT_4_4_4_4_EXT, GL_UNSIGNED_SHORT_5_5_5_1_EXT, GL_UNSIGNED_INT_8_8_8_8_EXT, or GL_UNSIGNED_INT_10_10_10_2_EXT and the EXT_packed_pixels extension is not supported then a GL_INVALID_ENUM error is generated. ASSOCIATED GETS fglGetConvolutionParameterEXT, fglGetConvolutionFilterEXT MACHINE DEPENDENCIES fglConvolutionFilter1DEXT is not supported on RealityEngine, RealityEngine2, and VTX systems. SEE ALSO fglConvolutionFilter2DEXT, fglSeparableFilter2DEXT, fglConvolutionParameterEXT, fglEnable with parameter GL_CONVOLUTION_1D_EXT, fglPixelTransfer.