logo GGG Myself

Àlex
Méndez
Feliu

logo IMA

Fast Photorealistic Techniques to Simulate Global Illumination in Videogames and Virtual Environments

Abstract

To compute global illumination solutions for rendering virtual scenes, physically accurate methods based on radiosity or ray-tracing are usually employed. These methods, though powerful and capable of generating images with high realism, are very costly. In this thesis, some techniques to simulate and/or accelerate the computation of global illumination are studied. The obscurances technique is based on the supposition that the more occluded is a point in the scene, the darker it will appear. It is computed by analyzing the geometric environment of the point and gives a value for the indirect illumination for the point that is, though not physically accurate, visually realistic. This technique is enhanced and improved in real-time environments as videogames. It is also applied to raytracing frameworks to generate realistic images. In this last context, sequences of frames for animation of lights and cameras are dramatically accelerated by reusing information between frames.

Images and videos

Obscurances in videogames images

Without obscurances or direct light Only Obscurances
Only direct light Obscurances and direct light
Without obscurances or direct light Only Obscurances
Only direct light Obscurances and direct light

Obscurances in videogames videos

Obscurances with Color Bleeding video
3 cubes demo video. Presented at EUROGRAPHICS 2003 Video and Slide Show.

GPU Obscurances with Depth Peeling

We take advantadge of GPU graphic cards to accelerate the computation of indirect illumination of 3d scenes.

Obscurances for Ray-Tracing

Kitchen with one light Kitchen with daylight
Kitchen vase closeup Kitchen closeup
Aircraft cabin Another illumination
Another view Stairs

Light animation with obscurances

Reuse of hits: videos

Reuse of hits: comparing images (frame 24, small)


Middle frame without reuse.


Middle frame with Havran et Al. (biased) reuse. Note the noise for specular materials as the vase.


Middle frame with unbiased reuse.

Comparing images (frame 24, big, with noise)


Middle frame without reuse.


Middle frame with Havran et Al. (biased) reuse. Note the noise for specular materials as the vase.


Middle frame with unbiased reuse.

Frame Array: Simultaneous light and camera animation