游戏引擎中实时广域流体渲染研究和应用

【作者】 吴磊；

【导师】 陈雷霆；

【作者基本信息】 电子科技大学 ， 计算机应用技术， 2008， 硕士

【摘要】 近年来,随着游戏和虚拟现实技术的不断发展,对于实时渲染的真实感、场景的复杂度不断提出更高的要求。与此同时,计算机的图形硬件处理能力也有了巨大的发展,尤其是支持可编程渲染管线GPU的推出使得PC机的图形处理能力获得了质的飞跃。这使得用户对于渲染的真实感和实时性的要求不断提高。而对覆盖有流体的地形表面进行有效地处理能够大大地提高视觉真实感。水面模拟就是其中一个重要部分。但是,目前已有的水面渲染算法普遍存在计算量庞大,耗时久,实时性不强等缺点。本文首先系统地分析和总结了现在的一些水面渲染技术。在此基础上,结合最新图形加速硬件特征,以渲染效果和渲染效率达到良好平衡为目的,对目前典型的水面模拟算法进行合理优化。该优化以两个主线进行:一是通过多张高度场纹理图混合简化实时水面网格模型的计算量,以及利用GPU强大的并行计算能力求解波动方程。二是针对网格顶点光照计算优化,基本策略是将以前放置在CPU上完成的复杂计算通过GPU的相关硬件特性进行替换,如环境纹理映射等,较为真实地模拟了水面上发生的折射和反射等光学现象。该算法最终有效地运用到游戏引擎的实时渲染系统中,实验证明该算法可行。另一方面,对水面漂浮物体与水面的交互运动模拟也是目前研究的一个热点和难点。漂浮物体在水面浮力作用下其运动状态变化比较复杂。目前有两种计算方式,一种是将浮力计算指定在刚体外表面的一些特殊点上,并假设小区域表面面积归结到这些点上;另一种是在刚体中填入一些规则几何体,然后分别计算它们的浮力。这两种方法都存在一个问题,就是对外形复杂的刚体很难模拟准确,同时还需要大量额外计算,不适合实时系统。在本文中,提出利用几何分解法对浮力计算进行简化的思路,大大提高了算法的效率,并在实验中获得了良好的效果。最后,本文对实验中存在的不足进行了分析,并提出了需要继续完善的几个方面。同时,对广域流体实时渲染的发展进行了展望。更多还原

【Abstract】 In recent years, with the development of the PC game and virtual environment systems, people need to increase the quality of real-time rendering and the complexness of rendering scene. The capability of the computer’s graphics hardware also has huge development, especially when the programmable render pipeline appeared. So the render systems should have more actual feelings and real-time. The rendering of the land covered with large liquid can improve the customer’s feeling. So the simulation about water has the very large importance. But the current arithmetic has a lot of disadvantages, such as needing large amount of compute and time’s limit, which make the arithmetic hard to put into the real-time render system.Firstly, this paper analyses and summarizes some current arithmetic of water rendering. On this condition, for making the balance between the rendering effect and efficiency, author optimizes the typical arithmetic with the new capability of the graphics hardware. The author focuses the two aspects about optimizing the arithmetic. One is reducing the amount of compute about the mesh by using the mulriple texture blending and resolving the wave equation on the GPU. The anther one is simplifying the calculating about the light model. By using the graphics hardware’s capability such as environment texture mapping, it can simulate the light’s refracting and reflecting efficiently.Simulating the rigid body floating on the water also is the hotspot. The movement of the floating rigid body is very complex. Presently, there are two computing methods: the first is that embedding some regular bodies into the rigid body and computing buoyancy respectively; the second is that labeling some especial points on the body’s surface and computing the area delegated by each point. Neither of the methods adapt to the real-time system, because they can not simulate the body with complicate surface, and need large additional data. The author simplifies the arithmetic by decomposing the rigid body, which improves efficiency remarkably.At last, this paper analyses the deficiencies to be improved on in the experiment and makes the expectation about the development of real-time liquid rendering.更多还原