Real-Time Painterly Rendering of Terrains

We present a non-photo realistic, real-time painterly rendering technique for terrains. The painterly appearance and the impression of terrains is created by effectively rendering several brush strokes. The strokes have fixed locations on the surfaces of the terrain during animation to enable frame to frame coherency. The strokes are rendered as alpha blended sprites in two-dimensions and are oriented along the slope of terrain analogous to the way artists paint on canvas. By exploiting the regular nature of terrain data, we create pre-decided rendering depth orders for primitives for any camera orientation. With this, we avoid the necessity of sorting the primitives of sprites required for alpha blending. We use DirectX10/SM4.0 based shaders to render strokes to improve performance. Being distributed on terrain, strokes get cluttered when they are closely located on screen. We follow a level of detail scheme that maintains a uniform stroke density in screen space. Various styles can be achieved with different stroke variations. Phong shading the rendered output in real-time is possible for more varied styles. We achieve painterly rendering in real-time with a combination of object space positioning and image space rendering of strokes. We illustrate our method with images and performance results.