Research And Implementation Of Natural Scene Modeling Technology Of Lake Water Area Based On Google O3D

Virtual Reality is a new and integrative information technology, which integrates many latest information technologies and gives people a strong support in building and expericing virtual world. Virtual Reality has been used in many fields, such as beauty spot landscape advertising.commerce products exhibition,flight simulation,game,virtual city and war game system etc. In virtual scene,natural environment virtualization is important application of Virtual Reality, yet dynamic water scene is a very important part. This task is a subtask of "marsh entironment visualization", which is science task. main research content is to simulate the natural scene of lakeland which is surrounding with foothill based on google03D, including dynamic water surface waves modeling,local reflection effect modeling,refraction effect modeling and particular effect of trees etc, trying to show a real virtual scene of lake water area.As above says, when designing the virtual scene, the main research target is to generate dynamic water surface, the perlin noise is adopted to generate height field used to simulate dynamic water surface, perlin noise has smoothness characteristics that is employed to simulate water surface. Vertex/pixel shader, which has great graphic processing ability, is used to speed rendering dynamic water surface and particular effect. Rendering to texture, as a technology, has been employed to generate local reflectional texture and refractional texture for partial scene. Vertex shader has a function to transform water surface plane vertex and produce local reflection texture coordinates and refraction texture coordinates, lighting calculating is performed along the normal vector in pixel shader, the1-D texture is used to reflect the Fresnel Term.The refraction and reflection is adjusted to simulate the refractional and reflectional effect with the fresnel term. In the meantime, the alpha channel in the local reflection has been taken advantage of to adjust the global reflection and the refractional and reflectional effect in order to simulate the lake which has dynamic sunshine on it. Moreover, too many trees in virtual scene are simulated by256x256pixel picture instead of real3D tree model to reduce large amounts data. instancing technology,Billboard technology and Impostor technology are used together to generate2D trees, GPU hardware is also applied to speed rendering2D trees image, finally, you can see the far trees always presenting towards screen and near the screen trees showing different size and appearance when looking with different visual angle.From the experiment, the simulation about the virtual scene of water area via Google O3D API is real-time on the commodity PC.