Shader Model 4.0

Posted on:September 06 2005

Now that everybody is talking about Windows Vista, lots of people are asking what Shader Model 4.0 is all about. Here's my short summary:

Unification of shaders: no more differences bettween pixel & vertex shaders
Geometry shaders: create vertices on the gpu
Resource virtualisation: A little bit like virtual memory on the gpu

No responsibility is taken for the correctness of this information. But looks like SM4 is a step further on the way to more freedom for us programmers. :)

Comments:

In the far future we will probably write software renderers again - executed as a shader on the GPU.

oli

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2005-09-07 18:50:00

far far future.

lxguy

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2005-09-07 22:16:00

But why would you want to

Robo

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2005-09-08 19:15:00

You'll have full control over the rendering process.

oli

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2005-09-09 00:23:00

@oli, How would you have more control by using a higher level language?

TSM

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2005-09-09 03:04:00

First, I do not talk about shaders how they exist today! It's just my opinion that rendering might be done by software again - executed by a GPU, with a lot of specialized functions for graphics processing (in far future) Fixed functionality is great to do things fast, but when it comes to flexibility it can be a nightmare. The functions of today's GPUs are great for graphics in general, but you could hardly to use them in a ray tracer for example.
Regarding the higher level language: You are right. As long as the shaders cover the same parts of the rendering pipeline a language improvement doesn't give you more control. But with 'Geometry shaders' the Shader Model 4.0 introduces a new kind of shaders (which give you more control)

oli

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2005-09-09 07:03:00

lillium carkapades

iksu

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2006-03-31 16:33:00

You can take away a lot of calculations from the CPU and use the GPU for them, which is incredibly fast because the GPU is made to do more complex calculations (it has assembly functions for matrix multiplication, for christ's sakes, which means it can do 20+ cpu math operations in one step). The more complex the architecture on the GPU, the more benefits like this that can be utilized. I've tried doing normal calculations for lighting on the cpu and on the gpu, and i can say that my program runs 6 times as fast doing the lighting calculations on the GPU instead. So that means the calculations are probably done hella amounts faster.

sean

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2006-07-14 23:21:00

Just a theory, but more of a hopefully than a theory, I would think SM4 is going to be used for Advanced Shadows, more or less better graphical control and representation of shadows, especially with that Floating Point Textures at 64-bits. Just like Light in SM3 made everything look better Id think Shadows would too under the right median. Course just a theory, just like I hope G80 comes out soon too...