Dolphin Emulator Ubershaders A Ridiculous Solution to an Impossible Problem. When youre playing your favorite game on Dolphin with a powerful computer, things should run fairly well. The game is running full speed, there are no graphical glitches, and you can use your favorite controller if you want. Yet, every time you go to a new area, or load a new effect, theres a very slight but noticeable stutter. You turn off the framelimiter to check and your computer can run the game at well over full speed. Whats going on The slowdown when loading new areas, effects, models, and more is commonly referred to as Shader Compilation Stuttering, by users and developers alike. This problem has been a part of Dolphin since the very beginning, but has only recently become more of a focus. When games barely ran at all, a little stutter here and there wasnt a big deal. Though emulation has improved to near perfection in many titles, the stuttering has remained the same over the years. Since the release of Dolphin 4. While some of this may be partially due to increased GPU requirements from integer math, the bigger cause was actually that the stuttering stuck out more with there now being fewer serious issues otherwise. There was some frustration and even antipathy from the developers toward shader compilation stuttering. It was something that was deemed unfixable and was garnering a lot of ill will and frustration within the community. Ironically, we hated the stuttering as much as anyone else, but the sheer insanity of the task was enough to keep most developers away. Despite this, some still privately held onto a glimmer of hope. It started out as a theory that had a chance of working. A theory that would take hundreds, if not thousands, of person hours just to see if it was possible. That hope is what fueled an arduous journey against seemingly impossible odds. A journey that would take multiple GPU engineers across two years. All in an effort to emulate the full range of the Game. Pixel Shader 5.0' title='Pixel Shader 5.0' />CubeWiis proto programmable pipeline without falling victim to this pesky stuttering. This is the dawn of the Ubershader era. The ProblemModern GPUs are incredibly flexible, but this flexibility comes at a cost they are insanely complicated. To unlock this power, developers use shaders programs that the GPU runs just like a CPU runs an application to program the GPU to perform effects and complex rendering techniques. International Harvester Cub Cadet 1000. Devs write code in a shader language from an API such as Open. GL and a shader compiler in the video driver translates that code into binaries that your PCs GPU can run. This compiling takes processing power and time to complete, so modern PC games usually get around this by compiling shaders during periods in which framerate doesnt matter, such as loadtimes. Due to the number of different PC GPUs out there, its impossible for PC games to pre compile their shaders for a specific GPU, and the only way to get shaders to run on specific PC hardware is for the video drivers to compile at some point in the game. Flipper, the Game. Cube GPU, is the largest chip on the motherboard. Image Credit Anandtech. Consoles are very different. When you know the precise hardware you are going to run the game on, and you know that the hardware will never change, you can pre compile GPU programs and just include them on the disc, giving your game faster load times and more consistent performance. This is especially important on older consoles, which may not have enough memory for or possibly even the capability to store shaders in memory. Flipper, the Game. Pixel Shader 5.0 Download' title='Pixel Shader 5.0 Download' />This is the first of a twopart article on tessellation shaders with OpenGL 4. This entry gives an overview of tessellation and walks through an example of simple. Dolphin uses a Unique ID object, or UID to represent a configuration of the emulated GPU, and these UIDs are then turned into shader code and handed to the video. This is to date the most realistic shaders pack for Minecraft PE. The light of the sun and moon shimmers beautifully when reflected on the water. Cube GPU, is the latter. While it has some fixed function parts, Flipper features a programmable TEV Texture En. Vironment unit that can be configured to perform a huge variety of effects and rendering techniques much the same way that pixel shaders do. In fact, the TEV unit has very similar capabilities to the Direct. X 8 pixel shaders of the Xbox It was so flexible and powerful that Flipper was reused as the Wii GPU redubbed Hollywood with few modifications. Unfortunately for us though, the TEV unit is designed for the game to configure and run TEV configurations immediately when an effect is needed. There is no preloading of the TEV configurations whatsoever, since the TEV unit doesnt have the memory for that. That instantaneous loading is the source of all our problems. Dolphin has to translate each FlipperHollywood configuration that a game uses into a specialized shader that current GPUs can run, and shaders have to be compiled, which takes time. But the TEV unit doesnt have the ability to store configurations, so GCWii games must configure it to render an effect the instant it is needed, without any delay or notice. To deal with this disparity, Dolphins only option is to delay the CPU thread while the GPU thread and the video driver perform the compilation essentially pausing the emulated GCWii. Usually the compilation will take place in under a frame and users will be none the wiser, but when it takes longer than a frame, the game will visibly stop until the compilation is complete. This is shader compilation stuttering. Typically a stutter only lasts a couple of frames, but on really demanding scenes with multiple compiling shaders, stutters of over a second are possible. As the first emulator to emulate a system with a highly programmable GPU at full speed, Dolphin has had to go it alone at tackling this problem. We implemented shader caching so if any configuration occurred a second time it would not stutter, but it would take hours of playing a game to build a reliable cache for it, and a GPU change, GPU driver update, or even going to a new Dolphin version would invalidate the cache and start the stuttering all over again. Maria Member Ozawa Rapidshare Thread. For years, it seemed like there was nothing more we could do about shader compilation stuttering, and many wondered if it would ever be solved. Solving an Impossible ProblemOf all of Dolphins remaining issues, shader compilation stuttering is the most complained about. Whether it be on the issue trackers, forums, social media, or IRC, this problem comes up all the time. Over the years, the reaction has shifted. At first, this stuttering was ignored as a non issue. What did it matter if there was a slight stutter here and there if games barely ran at all in the first place Things shifted in January of 2. Pathfinder Club Uniform Patch Placement. Dolphins issue tracker, and awareness spread. Over the past few years, weve had users ask many questions about shader stuttering, demand action, declare the emulator useless, and some even cuss developers out over the lack of attention to shader compilation stuttering. The truth is that we hated the stuttering as much as anyone else, and we had thought about the problem for many years. Tons of solutions had been pondered, some even attempted. It just didnt seem possible to fix without serious side effects. The Potential SolutionsGenerate All the Shaders BeforehandAs a reference, there are a mere 7. Earth. Dolphin is pretty fast at generating the shaders it needs, but compiling them is a problem. But, if we could somehow generate and compile shaders for every single configuration, that would solve the problem, right Unfortunately, this is simply not possible. There are roughly 5. TEV unit alone, and wed have to make a unique shader for each and every configuration. Vertex shaders are also used to emulate the semi programmable Hardware Transform and Lighting unit, and this raises the number of combinations even higher.