Research On GPU Based Real Time Rendering Of Fire Volume

The research on Fire Simulation and Real Time Rendering is one of the most difficult and hot research area in Computer Graphics and Virtual Reality,and it is also one of the core techniques in digital cultural industry.This technique has broad promising application in many areas such as movie and video animation,interactive entertainment and simulation of security areas.Both realistic result and real time performance is required in these applications.Lots of work has been done by our predecessors,However,there is also a gap between the research and its application.In order to meet the requirements in applications,we carry out a deep research on real time rendering of fire volume,which consist of three aspects:the representation and processing of large time-varying fire volume,accelerated rendering based on graphic hardware and realistic rendering of fire.The main results of our research are listed as follows:1.A data compression method of large time-varying volume data based on principle component analysis is proposed.The representation of processing of volume data is the base of real time rendering of realistic flames.There are two main features in the data of computational fluid dynamics.In one aspect,the size of the data is too large to save all the volume data on GPU memory,and another,the data is time-varying,which has a strong relevance in frames.In order to analysis and process these large data,we first split the long time series data into segments uniform and then compress the segmented data by principle component analysis.The real time rendering of PCA-based compressed data make full advantage of the parallel working mechanism of CPU and GPU.The data of the next segment will be uploaded to GPU memory whereas the GPU is rendering current segment.Our rendering algorithm make full use of the bandwidth between the system memory and GPU memory,the decompression of data is very fast and it can also be executed parallel,which can use the parallel acceleration of graphic hardware.2.We propose a hybrid polygon and volume rendering technique based on Raycasting method of GPU.Large scale volume data such as smoke need to be visualized in virtual scene real time,the application of which is widespread in disaster simulation,however, conventional method cannot process the occlusion and clipping of volume real-time in the hybrid rendering of both polygon and volume data,which also cause the wrong clip of fragment in the endoscope rendering.We proposed a novel GPU based hybrid rendering algorithm,which treat the volume as participate media,and the result of polygon rendering is used as the restriction of volume integral region.We expand the clipping to volume rendering and integrate the hybrid rendering seamlessly. Experimental result demonstrates that our algorithm can render the large volume data in the virtual scene and endoscope real-time.3.In order to meet the special high dynamic property of fire data,a GPU based high dynamic range fire volume rendering algorithm is proposed.The reason why the rendering of flame is more difficult than other participate media is that flame can emits light.The lights emitted by flame exceeds the display range of computer,so it is hard to render fire with the algorithm of traditional low dynamic range rendering.Our method make use of Physical optics and radiosity,the temperature of fire volume is used as the source of rendering data.Based on the ability of off screen rendering of GPU,we first render the flame to a high dynamic range texture,then the texture picture will be transform to low dynamic range on GPU, ultimately we achieve the aim of real time rendering of realistic flame.