Volume visualization using advanced graphics hardware shaders

Graphics hardware based volume visualization techniques have been the active research topic over the last decade. With the more powerful computation ability, the availability of large texture memory, and the high programmability, modern graphics hardware has been playing a more and more important role in volume visualization. In the first part of the thesis, we focus on the graphics hardware acceleration techniques. Particularly, we develop a fast X-Ray volume rendering technique using point-convolution. An X-ray image is generated by convolving the voxel projection in the rendering buffer with a reconstruction kernel. Our technique allows users to interactively view large datasets at their original resolutions on standard PC hardware. Later, an acceleration technique for slice based volume rendering (SBVR) is examined. By means of the early z-culling feature from the modern graphics hardware, we can properly set up the z-buffer from isosurfaces to gain significant improvement in rendering speed for SBVR. The high programmability of the graphics processing unit (GPU) incurs a great deal of research work on exploring this advanced graphics hardware feature. In the second part of the thesis, we first revisit the texture splat for flow visualization. We develop a texture splat vertex shader to achieve fast animated flow visualization. Furthermore, we develop a new rendering shader of the implicit flow. By careful tracking and encoding of the advection parameters into a three-dimensional texture, we achieve high appearance control and flow representation in real time rendering. Finally, we present an indirect shader synthesizer to combine different shader rendering effects to create a highly informative image to visualize the investigating data. One or more different shaders are associated with the voxels or geometries. The shader is resolved at run time to be selected for rendering. Our indirect shader synthesizer provides a novel method to control the appearance of the rendering over multi-shaders.