Thursday, April 26, 2012

Brigade 2 development shots

I've just received some jaw-dropping Matrix-like debug screenshots from Brigade developer Jeroen van Schijndel, showing a glimpse of an in-development ultra-efficient BVH acceleration structure. The screenshots visualize the bounding volumes (nested axis-aligned bounding boxes against which rays are tested before they are tested for intersection with the primitives that are contained in these AABBs) in the "Streets of Asia" scene that was shown in previous posts.  Brigade also gained a dazzling 30% increase in performance yesterday.

Wednesday, April 25, 2012

Real-time photorealistic path tracing: Urban Sprawl 2

Urban Sprawl 2 from Stonemason is a very detailed 3d city model, so it was a no-brainer to test this scene with Brigade. Since the scene rendered much more smoothly than expected, I also threw in a high poly Transformer model to make it a bit more challenging (the materials on the Transformer model still need some tweaking). Surprisingly, Brigade doesn't break a sweat. All the eye candy inherent to path tracing is present:  glossy and specular reflection, refraction, global illumination with diffuse color bleeding, ambient occlusion (under the cars) and depth of field. With Brigade performing so great, there's a lot of headroom left for dynamic objects like cars and animated characters (which will be shown in another post). For example, a photorealistic GTA or real-time photorealistic urban planning with dynamic day-night cycle are some of the possibilities. 

A plethora of screenshots (some of them have already been shown in previous posts) for thy viewing pleasure:

6 minute video of a real-time rendered fly-through

Tuesday, April 24, 2012

720p video of the Streets of Asia

Path traced in real-time at 1280x720 resolution with Brigade on 2 Geforce GTX 580s:

7 minute video (watch in 720p):

And one screenshot of an upcoming demo:

Incoherent ray tracing without acceleration structures

Just stumbled upon a very interesting paper by the author of the Voxelium blog, whose impressive research on hybrid voxel/triangle ray tracing I've blogged about in the past (see and 

This guy has invented a new algorithm for tracing incoherent rays that doesn't need an acceleration structure at all, which means no time consuming updates or rebuilds of the acceleration structure. This would also immediately solve the problem of ray tracing huge dynamic scenes. The research was inspired by a recent algorithm proposed by Keller and Wachter (toxie on ompf), which was in turn inspired by a method described in a patent of Caustic Graphics iirc. 
Excerpt of the abstract:  
We present a new ray traversal method based on this principle, which ef´Čüciently handles incoherent rays, and takes advantage of the SSE and AVX instruction sets of the CPU. Our algorithm offers notable performance improvements over similar existing solutions, and it is competitive with powerful static ray tracers

Monday, April 23, 2012

Real-time photorealistic GPU path tracing: normal mapped Streets of Asia

I've upgraded the Streets of asia scene with some normal mapping to add an extra layer of realism. The scene truly comes alive now and is downright gorgeous. It's a joy to fly through the environment and see the real-time photorealistic lighting infuse every object with spirit. The screenshots below rendered instantly, thanks to a  healthy speed bump in Brigade's code:


I'll make a very high quality video (720p) of the above scene for an upcoming blogpost and will also show more of this huge modern city ("Urban Sprawl 2: The Big City" by Stonemason):