Hybrid Real-time Rendering Of Large-scale Ocean Scene

Realistic real-time simulation of large-scale ocean scene is a very challenging research topic in the field of movie, animation, virtual reality and computer games. However, nowadays various methods of ocean scene modeling and rendering bear their own advantages and disadvantages. How to combine the advantages of different methods to achieve realistic and real-time rendering has become a common concern of graphics researchers and enthusiasts. This thesis proposes a hybrid method to achieve real-time rendering of large-scale ocean scene including ocean wave, two-way coupling between ship and ocean, foam and spray.Existing rendering of ocean scene often bears the repetition in visual effect. To overcome this defect, we propose an improved method for ocean scene simulation based on Philips spectrum in Chapter Two. We increase the controllable height of wave by adjusting the exponential value of angular speed for harmonic waves in the Fourier transform of Phillips spectrum.; we achieve steeper waves by applying horizontal displacement to the vertices of sea grid to a certain amount; we use Perlin Noise to combine with the FFT method generated height map according to the distance from the point of view, reducing the repeatability of waves. To improve the realism of ocean scene, we combine the gradient field of waves and wake which results in the right normal of sea grids. Also we achieve kinds of optical properties and HDR effects of the ocean.We propose a simulation frame of controllable fluid-solid coupling for ocean scene in Chapter Three. To raise the efficiency of simulation, we make reasonable simplification for existing fluid-solid coupling methods; to achieve more realistic visual effect of ship wake, we improve the traditional two-dimensional wave equation based simulation method by using waveform control factor to achieve control on the grid data when solving the equation with uniform grid, resulting in closer visual effect of Kelvin wake.To increase the realism of detail effect for ocean scene, we achieve detail effects including foam, spray and shoal effects in Chapter Four. We propose a Gaussian-curvature-based method to simulate the foam on the sea surface; we design and realize a generation mechanism for spray based on ship speed using particle system; we also realize the wave shoaling effect based on the change of the depth of water.We demonstrate and analyze the rendering results of our techniques in Chapter Five. Experiments show that the sea surface scene rendered using the methods we proposed has achieved realism to a certain extent and perfectly fulfill the requirement of real-time rendering. Comparing to other methods, our method have made improvement for visual effect to some extent, very suitable for use in games and virtual reality.