![]() A vertex shader works on the vertices in your scene ( predictably enough… ) and are responsible for positioning each vertex in the world. So basically shaders are little programs that run over and over again on the data in your scene. That description also glossed over about a million tiny details, but that is the gist of how the process occurs. It sounds like a horribly complex process, but the GPUs have dedicated hardware for performing exactly such operations, millions upon millions of times per second. In the end, this is the value that will be displayed on the screen. A fragment shader, unlike a vertex shader, can only return a single attribute, which is the RGBA color of the individual pixel. ![]() Once again, the fragment shader is executed once for each fragment. This is why they are called fragment shaders instead of pixel shaders, although people commonly refer to them using either expression. The results of this process are fragments, which you can think of as “prospective pixels,” and the fragment are passed in to the fragment shader. Next the results are transformed, culled, and clipped to the screen, discarding anything that is not visible, then rasterized, which is the process of converting from vector graphics to pixel graphics, something that can be drawn to the screen. The vertex shader is executed once for every vertex and a number of different values can be output from this process (these are the out attributes we saw in the shader earlier). Then this information is sent off to a vertex shader, which can then transform that vertex, do lighting calculations and more (we will see this process shortly). It all starts with the shader program, vertex buffers, texture coordinates, and so on being passed in to the graphics device. □Ī top-level view of how rendering occurs might help you understand the shader process. This is the high level description I gave in PlayStation Mobile book, it’s not plagiarism because I’m the author. ![]() To better understand the role of GL shaders, it’s good to have a basic understanding of how the modern graphics pipeline works. For more information on OpenGL in general, I also created this guide. It has all the information you should need to get up to speed with GLSL. If you want more information on working with GLSL I put together the OpenGL Shader Programming Resource Round-up back in May. When you create a SpriteBatch object in LibGDX, it automatically creates a default vertex and fragment shader for you. ![]() It’s been pretty transparent to you till this point because LibGDX mostly takes care of everything for you. In fact, every single thing rendered with OpenGL has at least a pair of shaders attached to it. GLSL standards for OpenGL Shader Language and since the move from a fixed to programmable graphics pipeline, Shader programming has become incredibly important. In this part of the LibGDX tutorial series we are going to take a look at using GLSL shaders. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |