skia / external / github.com / KhronosGroup / OpenGL-Registry / f06072fd879297ac9979d28fa7c61e78e069866d / . / extensions / SGIX / SGIX_complex_polar.txt

XXX - Not complete yet!!! | |

Name | |

SGIX_complex_polar | |

Name Strings | |

GL_SGIX_complex_polar | |

Version | |

$Date: 1996/06/12 03:45:06 $ $Revision: 1.2 $ | |

Number | |

?? | |

Dependencies | |

SGIX_complex is required | |

Overview | |

This extension generates the magnitude and phase of a complex input | |

source. Computing the spectrum (magnitude) and the phase of a | |

fourier transform (a typical complex input source) is useful | |

for signal and image processing applications. | |

Issues | |

- this extension is somewhat of hack to work around the problem | |

of generating only 1 component from an input that has 2 components: | |

real and imaginary. This extension is really computing 2 operations | |

that, for generality, should be defined as atomic operations. | |

New Procedures and Functions | |

None | |

New Tokens | |

Accepted by the <cap> parameter of Enable, Disable, and IsEnabled, by the | |

<pname> parameter of GetBooleanv, GetIntegerv, GetFloatv, and GetDoublev: | |

COMPLEX_POLAR_EXT 0x???? | |

Additions to Chapter 2 of the 1.0 Specification (OpenGL Operation) | |

None | |

Additions to Chapter 3 of the 1.0 Specification (Rasterization) | |

****On RedTail we'll be implementing this through texture LUTs. However, | |

the more natural fit would be to do it as a post blending operation. | |

Thus, I'm unclear as to what chapter this description will fall in: | |

The specification of generating the magnitude and phase of a fourier | |

signal is added to the GL Specification in section X.X.X. The resulting | |

fragment will be: | |

C_real' = SQRT((Cs_real * Cs_real) + (Cd_imaginary * Cd_imaginary)) | |

C_imaginary' = arctan(Cs_real / Cs_imaginary) | |

where Cs_real and Cs_imaginary are the source fragment real and imaginary | |

subcomponents and C_real' and C_imaginary' are the result fragment | |

subcomponents. | |

In all cases the above equation is evaluated separately for each | |

color component. | |

Additions to Chapter 4 of the 1.0 Specification (Per-Fragment Operations | |

and the Frame Buffer) | |

None | |

Additions to Chapter 5 of the GL Specification (Special Functions) | |

None | |

Additions to Chapter 6 of the GL Specification (State and State Requests) | |

None | |

Additions to the GLX Specification | |

None | |

GLX Protocol | |

None | |

Errors | |

None | |

New State | |

Get Value Get Command Type Initial Value Attribute | |

--------- ----------- ---- ------------- --------- | |

COMPLEX_POLAR_EXT IsEnabled B False color-buffer | |

New Implementation Dependent State | |

None |