<blockquote>
<p>what hardware do standard graphics pipelines have access to which general purpose GPU programming APIs dont give access to?</p>
</blockquote>
<p>Every part of the <a href="https://www.khronos.org/opengl/wiki/Rendering_Pipeline_Overview" rel="nofollow noreferrer">graphics pipeline and architecture</a> that isn't a shader. This includes but is not limited to:</p>
<ul>
<li>The rasterizer</li>
<li>The post T&amp;L cache</li>
<li>Any vertex buffer fetching/decompressing logic</li>
<li>ROPs, which do read/modify&amp;test/write operation with the framebuffer, such as:
<ul>
<li>blending</li>
<li>depth/stencil testing</li>
<li>write masking</li>
</ul>
</li>
<li>All of the hardware buffers and pipelines between various stages</li>
</ul>
<p>None of these are accessible by shader logic. They're hard-wired parts of the graphics pipeline.</p>

CC BY-SA 4.0
2022-04-10T16:27:09.290Z
2022-04-10T16:27:09.290Z
Nicol Bolas
<p>Suppose that someone implemented rendering for a video game using entirely GPGPU apis, like compute shaders or CUDA.</p>
<p>Would it be possible to achieve the same performance as standard graphics pipelines on common modern GPUs? If not, then what hardware do standard graphics pipelines have access to which general purpose GPU programming APIs dont give access to?</p>

CC BY-SA 4.0
2022-04-11T12:15:35.167Z
FTR, I saw a couple of renderers done in OpenCL (I think one was used for an emulator).
Dan M.
<rendering><shader><compute-shader><hardware><cuda>
On modern GPUs, what hardware do vertex/pixel shaders have access to that compute shaders don't?
while1fork
# On modern GPUs, what hardware do vertex/pixel shaders have access to that compute shaders don't?

(Asked by: username_0 on 2022-04-10)

Suppose that someone implemented rendering for a video game using entirely GPGPU apis, like compute shaders or CUDA.

Would it be possible to achieve the same performance as standard graphics pipelines on common modern GPUs? If not, then what hardware do standard graphics pipelines have access to which general purpose GPU programming APIs dont give access to?

**Tags:** rendering, shader, compute-shader, hardware, cuda

> **Comments:**
> **username_1**: FTR, I saw a couple of renderers done in OpenCL (I think one was used for an emulator).  

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## 1 answers

### Answer by username_2 on 2022-04-10. Score: 2 | Accepted answer

> what hardware do standard graphics pipelines have access to which general purpose GPU programming APIs dont give access to?

Every part of the [graphics pipeline and architecture](https://www.khronos.org/opengl/wiki/Rendering_Pipeline_Overview) that isn't a shader. This includes but is not limited to:

* The rasterizer
* The post T&L cache
* Any vertex buffer fetching/decompressing logic
* ROPs, which do read/modify&test/write operation with the framebuffer, such as:
  + blending
  + depth/stencil testing
  + write masking
* All of the hardware buffers and pipelines between various stages

None of these are accessible by shader logic. They're hard-wired parts of the graphics pipeline.


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