XXX - Not complete yet!!!
Name
SGI_complex_type
Name Strings
GL_SGI_complex_type
Version
$Date: 1996/11/15 20:52:37 $ $Revision: 1.5 $
Number
88
Dependencies
SGI_complex is required
EXT_texture3D affects the definition of this extension
EXT_subtexture affects the definition of this extension
EXT_convolution affects the definition of this extension
EXT_histogram affects the definition of this extension
SGI_color_table affects the definition of this extension
SGIS_texture4D affects the definition of this extension
Overview
This extension defines complex pixel types which can be used
as the type parameter in any OpenGL command which accepts
a pixel image parameter (e.g. DrawPixels, ReadPixels, etc).
New Procedures and Functions
None
New Tokens
Accepted by the parameter of DrawPixels, ReadPixels,
TexImage1D, TexImage2D, TexImage3DEXT, TexImage4DSGIS, TexSubImage1DEXT,
TexSubImage2DEXT, TexSubImage3DEXT, TexSubImage4DSGIS, GetTexImage,
ColorTableSGI, GetColorTableSGI, ConvolutionFilter1DEXT,
ConvolutionFilter2DEXT, ConvolutionFilter3DEXT, GetConvolutionFilterEXT,
SeparableFilter2DEXT, SeparableFilter3DEXT, GetSeparableFilterEXT,
GetHistogramEXT, and GetMinmaxEXT:
COMPLEX_UNSIGNED_BYTE_SGI 0x81BD
COMPLEX_BYTE_SGI 0x81BE
COMPLEX_UNSIGNED_SHORT_SGI 0x81BF
COMPLEX_SHORT_SGI 0x81C0
COMPLEX_UNSIGNED_INT_SGI 0x81C1
COMPLEX_INT_SGI 0x81C2
COMPLEX_FLOAT_SGI 0x81C3
Additions to Chapter 2 of the 1.0 Specification (OpenGL Operation)
None
Additions to Chapter 3 of the 1.0 Specification (Rasterization)
The seven tokens defined by this extension are added to Table 3.4:
Parameter Corresponding Special
Token Value GL Data Type Interpretation
---------------- ------------- --------------
UNSIGNED_BYTE ubyte No
BYTE byte No
UNSIGNED_SHORT ushort No
SHORT short No
UNSIGNED_INT uint No
INT int No
FLOAT float No
BITMAP ubyte Yes
UNSIGNED_BYTE_3_3_2_EXT ubyte Yes
UNSIGNED_SHORT_4_4_4_4_EXT ushort Yes
UNSIGNED_SHORT_5_5_5_1_EXT ushort Yes
UNSIGNED_INT_8_8_8_8_EXT uint Yes
UNSIGNED_INT_10_10_10_2_EXT uint Yes
COMPLEX_UNSIGNED_BYTE_SGI ubyte No
COMPLEX_BYTE_SGI byte No
COMPLEX_UNSIGNED_SHORT_SGI ushort No
COMPLEX_SHORT_SGI short No
COMPLEX_UNSIGNED_INT_SGI uint No
COMPLEX_INT_SGI int No
COMPLEX_FLOAT_SGI float No
Table 3.4: DrawPixels and ReadPixels parameter values and the
corresponding GL data types. Refer to table 2.2 for definitions of
GL data types. Special interpretations are described near the end
of section 3.6.3.
[Section 3.6.3 of the GL Specification (Rasterization of Pixel
Rectangles) has the following paragraphs added immediately before
the discussion of the Bitmap type:]
Calling DrawPixels with a of COMPLEX_UNSIGNED_BYTE_SGI,
COMPLEX_BYTE_SGI, COMPLEX_UNSIGNED_SHORT_SGI, COMPLEX_SHORT_SGI,
COMPLEX_UNSIGNED_INT_SGI, COMPLEX_INT_SGI, or COMPLEX_FLOAT_SGI is a
special case in which the elements in each group are actually pairs of
real and imaginary parts of a single complex element. The number of
elements is fixed by the parameter and the underlying type of
each of the constituent parts of the complex element (subcomponent) is
indicated by the parameter in the obvious way. Complex components
are placed with the real part first in memory and the imaginary part
second. For the purposes of determining the location of an element in a
row, the element size should be considered twice the size of the GL type
corresponding to the subcomponent type. e.g., if is not FLOAT, final conversion consists of
masking the index with the value given in Table 4.6; if the is
FLOAT, then the integer index is converted to a GL float data value.
For a component, each component is first clamped to [0,1]. Then,
the appropriate conversion formula from Table 4.7 is applied to the
component.
Parameter Index Mask
---------------- ----------
UNSIGNED_BYTE 2**8 - 1
BITMAP 1
BYTE 2**7 - 1
UNSIGNED_SHORT 2**16 - 1
SHORT 2**15 - 1
UNSIGNED_INT 2**32 - 1
INT 2**31 - 1
Table 4.6: Index masks used by ReadPixels. Floating point data
are not masked.
GL Data Component/Subcomponent
Parameter Type Conversion Formula
--------- ------- ------------------
UNSIGNED_BYTE ubyte c = ((2**8)-1)*f
BYTE byte c = (((2**8)-1)*f-1)/2
UNSIGNED_SHORT ushort c = ((2**16)-1)*f
SHORT short c = (((2**16)-1)*f-1)/2
UNSIGNED_INT uint c = ((2**32)-1)*f
INT int c = (((2**32)-1)*f-1)/2
FLOAT float c = f
UNSIGNED_BYTE_3_3_2_EXT ubyte c = ((2**N)-1)*f
UNSIGNED_SHORT_4_4_4_4_EXT ushort c = ((2**N)-1)*f
UNSIGNED_SHORT_5_5_5_1_EXT ushort c = ((2**N)-1)*f
UNSIGNED_INT_8_8_8_8_EXT uint c = ((2**N)-1)*f
UNSIGNED_INT_10_10_10_2_EXT uint c = ((2**N)-1)*f
COMPLEX_UNSIGNED_BYTE ubyte cs = ((2**8)-1)*fs
COMPLEX_BYTE byte cs = (((2**8)-1)*fs-1)/2
COMPLEX_UNSIGNED_SHORT ushort cs = ((2**16)-1)*fs
COMPLEX_SHORT short cs = (((2**16)-1)*fs-1)/2
COMPLEX_UNSIGNED_INT uint cs = ((2**32)-1)*fs
COMPLEX_INT int cs = (((2**32)-1)*fs-1)/2
COMPLEX_FLOAT float cs = fs
Table 4.7: Reversed component conversions - used when component data
are being returned to client memory. Color, normal, and depth
components are converted from the internal floating-point
representation (f) to a datum of the specified GL data type (c) using
the equations in this table. All arithmetic is done in the internal
floating point format. These conversions apply to component data
returned by GL query commands and to components of pixel data returned
to client memory. The equations remain the same even if the
implemented ranges of the GL data types are greater than the minimum
required ranges. (Refer to table 2.2.) Equations with N as the
exponent are performed for each bitfield of the packed data type,
with N set to the number of bits in the bitfield.
Placement in Client Memory
Groups of elements are placed in memory just as they are taken from memory
for DrawPixels. That is, the ith group of the jth row (corresponding to
the ith pixel in the jth row) is placed in memory must where the ith group
of the jth row would be taken from for DrawPixels. See Unpacking under
section 3.6.3. The only difference is that the storage mode parameters
whose names begin with PACK_ are used instead of those whose names begin
with UNPACK_. If the parameter is complex then both the real
and imaginary parts are written to memory and the element size should be
considered twice the size of the size of the subcomponent type. If the
parameter is not complex, then only the real part is placed in
memory.
[End of changes to Section 4.3.2]
If this extension is supported, all commands that return pixel data
also return packed pixel data. These commands are ReadPixels,
GetTexImage, GetHistogramEXT, GetMinmaxEXT, GetConvolutionFilterEXT,
GetSeparableFilterEXT, and GetColorTableSGI.
Additions to Chapter 5 of the 1.0 Specification (Special Functions)
None
Additions to Chapter 6 of the 1.0 Specification (State and State Requests)
None
Additions to the GLX Specification
None
GLX Protocol
None
Dependencies on EXT_texture3D
If EXT_texture3D is not implemented, then the references to
TexImage3DEXT in this file are invalid, and should be ignored.
Dependencies on EXT_subtexture
If EXT_subtexture is not implemented, then the references to
TexSubImage1DEXT, TexSubImage2DEXT, and TexSubImage3DEXT in this file
are invalid, and should be ignored.
Dependencies on EXT_histogram
If EXT_histogram is not implemented, then the references to
GetHistogramEXT and GetMinmaxEXT in this file are invalid, and should be
ignored.
Dependencies on EXT_convolution
If EXT_convolution is not implemented, then the references to
ConvolutionFilter1DEXT, ConvolutionFilter2DEXT, ConvolutionFilter3DEXT,
GetConvolutionFilterEXT, SeparableFilter2DEXT, SeparableFilter3DEXT, and
GetSeparableFilterEXT in this file are invalid, and should be ignored.
Dependencies on SGI_color_table
If SGI_color_table is not implemented, then the references to
ColorTableSGI and GetColorTableSGI in this file are invalid, and should
be ignored.
Dependencies on SGIS_texture4D
If SGIS_texture4D is not implemented, then the references to
TexImage4DSGIS and TexSubImage4DSGIS in this file are invalid, and should
be ignored.
Errors
None
New State
None
New Implementation Dependent State
None