Image Collection

I haven't made a lot of progress recently on the engine due to my internship (completed) and the start of the new school year (my last) I did make some screenshots a while back when I was working on flares and terrain texture mapping. Below a small assorted list of the things I did.

With the terrain texturing I tried to minimize stretching on steep surfaces without using the tri-planar technique, there were some difficulties and I don't have a finalized method yet. The red/green colors on the terrain indicate UV coordinates, the lines are the surface normals and the yellow text displays the vertex number in the VertexBuffer. I hope this can at least somewhat fill the major gap in between posts recently, hopefully I can do some cool stuff again soon like working on the mesh editor from my previous post.

Environment Mapping (w/ Normal Maps)

A while ago I was trying to get Environment maps (aka Cube-maps) to work with SunBurn's Deferred renderer with reasonable success. Last week I had a go at it again, this time in my own renderer, because the normal-mapping information was already available inside the shader it was relatively easier to do this time around (along with all the problems I have already solved the first time)
It was supposed to be a transparent (forward)-effect for windows etc, but somehow turned into an opaque cube-mapped deferred shader...Not sure how that happened :)

Below you can see what the shader looks like at the moment, where the first two images show the 'forward' shader and the last two use the deferred shader (which includes pointlights, specularity etc.) The forward shader will be modified so it supports alpha-mapping, what it was originally designed for anyway.

Forward shader - environment map, with normal map and simple directional light.

Forward shader - similar setup as above.

The deferred shader - with pointlight on the left and right (with very strong colors to highlight the effect)

Deferred shader - with the deferred rendertargets (LoR: color, normals,depth,lighting)

The next step is to further develop the forward rendering pass, for transparency mostly. This includes depth-sorting of the objects along with Composite Lighting that calculates approximate lighting for objects that don't support deferred shading.

Resources:

Custom Model Effect XNA Sample - Source for the cube-map processor and the basics for the environment mapping shader.
Shawn Hargraves on Cube-mapping - Some interesting bits about cube-mapping, closely tied to the XNA sample above.

A new (Deferred) Renderer [Part 1]

For a long time I have used SunBurn as my primary rendering solution. This helped a great deal while developing Needle Juice, Over Night and more recently: Project Sunburn. With no new game projects lined up with Core Engine, I have decided to experiment with my own rendering solution, based on Catalin’s Deferred Rendering sample along with information from many other sources including a Killzone 2 presentation from 2007.

The above images shows the most recent unit-test of filling the hardware DepthBuffer with the Gbuffer-depth to draw post-deferred geometry (i.e. using forward rendering for transparent surfaces) and other visuals such as vertex-lines. This is done during the final combining pass of the geometry data and lighting using the ‘DEPTH’ semantic. This fills the depth-buffer as all depth is lost after switching RenderTargets (something that can be prevented on the PC using PreserverContents, but does not work on the Xbox - this solves the problem entirely)

Some other experiments include texture projection as seen below.

Texture projection has several great uses, including Deferred Decals, light shapes and video projection on the scene's geometry (as seen in Splinter Cell: Conviction) Back while developing Over Night we used shadow-mapping in places where texture projection could have been much cheaper. A good example of this is the blue light coming from outside through the shaded window, covering most of the room as seen below. The second image uses a texture to simulate a similar effect, without having to re-draw the entire shadowmap every frame, instead simply sampling from the texture and projecting it into screen-space.

Looking back at Needle Juice, where we used a directional light with shadows to draw light coming through the windows, another place where texture projection would have been a cheaper and more elegant solution to our problem (also preventing light-leaking, which is very common with directional lighting)

Needle Juice: directional-light coming through the window, required shadow-mapping.

I will continue working on the renderer for the time to come, with such a wealth of presentations, papers and samples on deferred rendering (and graphics programming in general) it will keep me busy for a while…Until next time! :)