Let's talk about the pros and cons of megatextures. Do you use them?
Hao Chen: We don't use them right now. There are two main interpretations of "megatexture." One is to store a giant texture, say 16k by 16k, and use a combination of hardware, OS, and client side streaming to allow you to map that big texture to your world.
This is cool, but we already have similar technology in places where that would be needed. For example, this is great for terrain, but we already have a very good terrain solution that uses a great LOD and paging scheme to allow us to do large and high fidelity terrain.
The other interpretation of megatexture, or the so-called sparse texture, is great for things that only have valid data in small parts of a texture. For example, if you paint a mask on terrain, then you will only have valid data where the paintbrushes touched, and everywhere else it is useless data.
Sparse textures allow us to represent these textures very efficiently without wasting precious storage and bandwidth on useless data. Another cool application of sparse texture that we are excited about is shadows. If we can render to sparse textures, then it's possible that we can render very high resolution shadows to places that need them and still be efficient.
A disadvantage of megatextures is that on a console, we typically already know exactly what the hardware is doing, and we have very very tight control of where the resources go. So we could do a lot of things [that are similar to the benefits provided by] megatextures already on consoles, that you can't do on PC. So I guess there wouldn't really be a disadvantage, it's just that the coolness of having a texture that is automatically managed is less relevant in the console than it is on the PC.
