In the past decade, modern GPUs have provided increasing programmability with vertex, geometry and fragment shaders. However, many classical problems have not been efficiently solved using the current graphics pipeline where some stages are still fixed functions on chip. In particular, multi-fragment effects, especially order-independent transparency, require programmability of the blending stage, that makes it difficult to be solved in a single geometry pass. In this paper we present FreePipe, a system for programmable parallel rendering that can run entirely on current graphics hardware and has performance comparable with the traditional graphics pipeline. Within this framework, two schemes for the efficient rendering of multi-fragment effects in a single geometry pass have been developed by exploiting CUDA atomic operations. Both schemes have achieved significant speedups compared to the state-of-the-art methods that are based on traditional graphics pipelines.

This paper proposes a novel approach to animation realistic interactions between tree branches and raindrops in a physically-based way. A new elastic model using a three-prism structures is presented to flexibly bend and twist tree branches naturally in the first time. Various distinct forms of interactions when or after raindrops hitting on tree branches can be well simulated using a new efficient technique specially designed for liquid motion on non-rigid objects with hydrophilic surfaces. Experimental results indicate that our approach can be used to simulate the interactions between tree branches and raindrops efficiently and realistically.

Modern GPUs provide gradually increasing programmability on vertex shader, geometry shader and fragment shader in the past decade. However, many classical problems such as order-independent transparency (OIT), occlusion culling have not yet been efficiently solved using the traditional graphics pipeline. The main reason is that the behavior of the current stage of the pipeline is hard to be determined due to the unpredictable future data. Since the rasterization and blending stage are still largely fixed functions on chip, previous improvements on these problems always require hardware modifications thus remain on the theoretical level. In this paper we propose CUDA Renderer, a fully programmable graphics pipeline using compute unified device architecture (CUDA) [NVIDIA 2008] which can completely run on current graphics hardware. Our experimental results have demonstrated significant speedup to traditional graphics pipeline especially on OIT. We believe many other problems can also benefit from this flexible architecture.