Procedural Rendering of Geometry-Based Grass in Real-Time

Sammanfattning: Since grass is abundant on our planet it plays an important role in the rendering of many different outdoor scenes. This study focuses on the real-time rendering of many individual grass blades with geometry. As a grass blade in real life is very thin and have a simple shape it can be represented with only a handful of vertices. The challenge is introduced when a meadow of grass is to be rendered as it can contain billions of grass blades. Two different algorithms were developed; one which use traditional vertex buffers to store and render the grass blades while the other makes use of textures. Quantitative data was generated from these algorithms. Among this data were images of the scene. These images were subjected to a questionnaire to collect qualitative information about the grass. All the generated data was then analyzed and interpreted to find advantages and disadvantages of the algorithms. The buffer-based algorithm was found to be slightly more computationally efficient compared to the texture-based algorithm. The quality of the visual result was perceived to be towards good while the realism was perceived as mediocre at best. The advantage of the texture-based algorithm is that it allows more options to handle the grass blades data when rendering. Using the terrain data to generate the grass blades was concluded to be advantageous. The realism of the grass could have been improved by using a grass blade texture as well as introducing variety in density and grass species.