ATI Talks About DirectX 10

DirectX 10 and Unified Architecture

Published: 12th July 2006 | Source: ATI Technologies | Author: Matt Kemp

ATI Talk DirectX 10 and their Next Gen

ATI have given us an insight into DirectX 10 and their next-gen hardware. We attended a quick briefing where they gave us a run through with some reasons for the implementation of the hardware that will be running the hardware on Microsoft's next API. I'm going to try to give this a quick run-through and give you some idea of what to expect with the shiny new technology.

When reading this I would like to make sure that this is a presentation by ATI and the briefing is also by ATI. I will try my best to sum it all up but please remember that this is only the way ATI look at the whole thing. At this time I have not been able to get a comment out of nVidia on their lookout for DX10. I will try to get this in due course but please do bear this in mind.

DirectX 9 - Drawbacks

DirectX 9 comes with its prices. The GPU has to render object in the game such as guns, dust, smoke, people etc. Each of these objects comes with its own overhead from the way DX 9 handles the data

Here's a couple of slides from ATI to explain:

Therefore each object comes inherent in the DirectX 9 API with an overhead. Developers have been very clever at making this work by many and varied ways but when it comes down to it they are constrained by the API and the overhead it brings with it.

DirectX 10

DirectX 10 solves this by working towards general processing units. The new Geometry Shader can manipulate Vertexes and many other types of objects. This means that it has more ways to process, access and move data. This extra level of manipulation adds a lot of headroom for developers to introduce new features into games and to utilise the GPU for more than just rendering of a scene.

This is the bit where it all gets a bit technical. ATI have made this slide so I'll let them show you:

There you can see exactly what kind of advantage the new API gives. The overhead for each small object is reduced thus making the process faster and more slimlined. This balances out the API/Driver vs Game application balance. On DirectX 9 this is split API + driver vs Game Application 60%/40%. with the new API this could be balanced out 20% API + driver and 80% Game application. ATI have said that this will not mean that the game will be executed 80% of the time, but rather developers could be able to put more into the game.

Unified Architecture

Now here's where ATI step in. They have worked closely with Microsoft on this version of their DirectX. The API is very much targeted towards a unified architecture and way of working. In a traditional GPU you have one set of pipelines working whilst the other set sits there waiting for the "right" type of outputs. Once again ATI's slide shows this succinctly.

Put this way it is very hard to ignore this argument. The worry is of course is can ATI's card push through all of the things that the various single-application shaders do on their own. This is yet to be seen but we will come to this point a bit later.

ATI say that this will mean that they can fully load up all shader pipelines with all of the data without waiting for each separate unit to do their own thing. This means both Vertex shading and Pixel shading going through these multi-purpose units.

Pixels and Geometry

According to ATI, upcoming games are going to be both Geometry and Pixel compute intensive. This means that things like HDR, depth of field and motion blur will increase dramatically. We are already seeing this with the Tech demo's from Valve for Day of Defeat: Source and the gorgeous looking Crisis with its realistic depth of field will be able to be computed on the GPU. This frees up the CPU and also gives the GPU extra tasks that it can theoretically do.

This is things like processing Physics (I'll get to that later), Morphing, Sorting Image post-processing and lots of other things. Potentially DX10 and Unified

Shader will mean that developers can use the general purpose CPU to compute AI and other things that have sometimes been lacking in modern games.