| '''OpenGL extension APPLE.float_pixels |
| |
| This module customises the behaviour of the |
| OpenGL.raw.GL.APPLE.float_pixels to provide a more |
| Python-friendly API |
| |
| Overview (from the spec) |
| |
| This extensions adds texture types, texture internal formats and |
| color buffers composed of both 32 bit and 16 floating point numbers. |
| 16 bit floats (half float) are very similar to the IEEE |
| single-precision floating-point standard, except that it has only 5 |
| exponent bits and 10 mantissa bits. All floating point numbers are |
| clamped to the limits of the range representable by their respective |
| format. |
| |
| Specifically, APPLE_float_pixels adds four pieces of functionality |
| to OpenGL. First, it provides an HALF_APPLE texture type allowing |
| clients to pass textures in the half float format. Second, it adds |
| 12 additional sized internal formats to allow OpenGL to process and |
| maintain texture data in the requested format if possible. Next, it |
| provides the COLOR_FLOAT_APPLE pixel format to allow creation of |
| floating point and half float color buffers. Lastly, it provides an |
| additional query to allow clients to verify that they have a |
| floating point color buffer. |
| |
| The HALF_APPLE texture type allows clients to use source textures |
| composed of half float color components. This constant is use in |
| the type parameter in DrawPixels, ReadPixels and texturing commands |
| with a corresponding GL half data type, which corresponds to a 16 |
| bit half float, and has no special interpretation. |
| |
| Clients can use the 12 additional (6 floating point and 6 half |
| float) sized internal texture formats to specify the mapping of R, |
| G, B and A values to texture components, as they would with any |
| other sized internal texture format. Note, as is the standard |
| practice with OpenGL, implementations should map the sized internal |
| texture R, G, B and A values to internal components with memory |
| allocations as close as possible to those specified in the sized |
| internal format. |
| |
| Floating point color buffers are created by specifying the |
| appropriate color floating point pixel format attribute for the |
| windowing system API in use by the client. Both 128 bit and 64 bit |
| floating point color buffers can be supported, the former with full |
| 32 bit floating point components and the latter with 16 bit half |
| float components. |
| |
| Additionally, clients can query to see if they have a floating point |
| color buffer using GetBooleanv with COLOR_FLOAT_APPLE as the get |
| value. The number of bits per color buffer component can be |
| determined in the usual manner. |
| |
| The official definition of this extension is available here: |
| http://www.opengl.org/registry/specs/APPLE/float_pixels.txt |
| ''' |
| from OpenGL import platform, constant, arrays |
| from OpenGL import extensions, wrapper |
| import ctypes |
| from OpenGL.raw.GL import _types, _glgets |
| from OpenGL.raw.GL.APPLE.float_pixels import * |
| from OpenGL.raw.GL.APPLE.float_pixels import _EXTENSION_NAME |
|
|
| def glInitFloatPixelsAPPLE(): |
| '''Return boolean indicating whether this extension is available''' |
| from OpenGL import extensions |
| return extensions.hasGLExtension( _EXTENSION_NAME ) |
|
|
|
|
| |
