A full article that presents every aspect of implementing billboarded grass fields in games. It uses a vertex shaders for animating the grass in the wind.

Here’s the full article for free (also the source for the image). Or you could buy the great book “GPU Gems 1″ which also contains the article.
http://http.developer.nvidia.com/GPUGems/gpugems_ch07.html

An implementation of the grass rendering by Nvidia:
http://developer.nvidia.com/object/nature_scene.html

A scene graph is a tree structure that tries to structure the objects in a scene accordingly to transformations, textures, materials and much more instead of just the geometrical representation of objects like for example a quadtree does. All games does contain a scene graph in some way, in the most simple form it could just be a root node and all other rendered objects as child nodes to the root node.

Here’s a list of useful links concerning scene graphs. Most links are borrowed from a post on gamedev.net but copied to this post so that I could remove broken links and include new ones.

• Wikipedia Entry for Scene Graphs
• Game Engine Architecture – Book Except (Scene Graphs)
• Understanding and Implementing Scene Graphs
• Scene graph & moving objects
• Terrain and scene graphs
• Scenegraph Management

• Scenegraphs: Past, Present and Future
• Game Object Structure: Scene Graphs
• Game Object Structure: Scene Graphs Revisited
• The GDC 2003 Game Object Structure Roundtable (scene graph section)
• Scene Graph/Renderer interface
• Scene Graph. DAG or Tree With Mesh List?
• Design Patterns used in the OpenSceneGraph
• API-agnostic vertex storage and conversion to API-usable storage
• Some UML class diagrams
• Nvidia implementation of a scene graph dedicated for good shader support

• SG integration
• Material/Shader implmentation
• Shader system implementation
• YASIT
• Shader Engine Design Decisions

• Optimized View Frustum Culling Algorithms for Bounding Boxes
• Optimized View Frustum Culling Algorithms
• Efficient View Frustum Culling

Most of this list was copied from the following gamedev.net forum thread.
http://www.gamedev.net/community/forums/topic.asp?topic_id=349829

A method that doesn’t rely on mathematical formulas from the reality but instead only tries to mimic it’s look. The good result is possible by a large number of sprites that looks like clouds which are encapsulated in a defined bounding mesh. It’s said to use a light-curve instead of an light scattering algorithm.

Link to more details from the author (he says a demo should be available soon).
http://www.gamedev.net/community/forums/topic.asp?topic_id=511184

This technique for shadow mapping does the reverse when comparing depths. Instead of the normal case of comparing depths in light space, this method suggest that the comparison should be done in eye space. This requires the depth buffer from the lights’ view and from the camera’s view at the time of the comparison. This method is probably most useful when doing deferred lightning.

Link to the paper “Forward Shadow Mapping”
http://www.cs.unc.edu/~zhangh/shadow.html