| '''OpenGL extension NV.gpu_multicast |
| |
| This module customises the behaviour of the |
| OpenGL.raw.GL.NV.gpu_multicast to provide a more |
| Python-friendly API |
| |
| Overview (from the spec) |
| |
| This extension enables novel multi-GPU rendering techniques by providing application control |
| over a group of linked GPUs with identical hardware configuration. |
| |
| Multi-GPU rendering techniques fall into two categories: implicit and explicit. Existing |
| explicit approaches like WGL_NV_gpu_affinity have two main drawbacks: CPU overhead and |
| application complexity. An application must manage one context per GPU and multi-pump the API |
| stream. Implicit multi-GPU rendering techniques avoid these issues by broadcasting rendering |
| from one context to multiple GPUs. Common implicit approaches include alternate-frame |
| rendering (AFR), split-frame rendering (SFR) and multi-GPU anti-aliasing. They each have |
| drawbacks. AFR scales nicely but interacts poorly with inter-frame dependencies. SFR can |
| improve latency but has challenges with offscreen rendering and scaling of vertex processing. |
| With multi-GPU anti-aliasing, each GPU renders the same content with alternate sample |
| positions and the driver blends the result to improve quality. This also has issues with |
| offscreen rendering and can conflict with other anti-aliasing techniques. |
| |
| These issues with implicit multi-GPU rendering all have the same root cause: the driver lacks |
| adequate knowledge to accelerate every application. To resolve this, NV_gpu_multicast |
| provides fine-grained, explicit application control over multiple GPUs with a single context. |
| |
| Key points: |
| |
| - One context controls multiple GPUs. Every GPU in the linked group can access every object. |
| |
| - Rendering is broadcast. Each draw is repeated across all GPUs in the linked group. |
| |
| - Each GPU gets its own instance of all framebuffers, allowing individualized output for each |
| GPU. Input data can be customized for each GPU using buffers created with the storage flag, |
| PER_GPU_STORAGE_BIT_NV and a new API, MulticastBufferSubDataNV. |
| |
| - New interfaces provide mechanisms to transfer textures and buffers from one GPU to another. |
| |
| The official definition of this extension is available here: |
| http://www.opengl.org/registry/specs/NV/gpu_multicast.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.NV.gpu_multicast import * |
| from OpenGL.raw.GL.NV.gpu_multicast import _EXTENSION_NAME |
|
|
| def glInitGpuMulticastNV(): |
| '''Return boolean indicating whether this extension is available''' |
| from OpenGL import extensions |
| return extensions.hasGLExtension( _EXTENSION_NAME ) |
|
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| |
