- PIXEL SHADER FOR NVIDIA QUADRO K600 SOFTWARE
- PIXEL SHADER FOR NVIDIA QUADRO K600 CODE
- PIXEL SHADER FOR NVIDIA QUADRO K600 SERIES
PIXEL SHADER FOR NVIDIA QUADRO K600 CODE
For example, an if test based on only constant parameters can be fully evaluated at compile time, and the compiler can either discard all the code inside the block after the if or run it unconditionally, depending on the test's value.
The second feature is the ability to flag shader parameters as constant values the compiler can use the knowledge that a particular parameter is constant to substantially improve how well it optimizes the code. This feature is particularly handy for writing shaders that use a variable number of light parameter sets, skinning matrices, and so on. The array size must be provided to the Cg runtime before the program can be executed. The first, unsized arrays, allows the programmer to declare and use arrays without a fixed size. Two other new features in Cg 1.2 complement shader interfaces, improving both the flexibility and the efficiency of shaders. To give a sense of possible applications for shader interfaces, we then show three examples of how they can be used in Cg: (1) to choose between two methods of vector normalization, (2) to support variable numbers of lights in shaders, and (3) to describe materials and texture in a general, hierarchical manner. In this chapter, we describe the basic syntax for shader interfaces and how they are used with the Cg compiler and runtime. Applications that use this feature would no longer need to implement string-concatenation routines to synthesize Cg source code on the fly to solve this problem-avoiding an approach that is both error prone and unwieldy. As new specific implementations of these interfaces are developed, old shaders can use them without needing to be rewritten. The developer can write generic shaders, with large chunks of the functionality expressed in terms of shader object interfaces (such as a basic "light source" interface). They do so in a way that reduces the burden on the programmer without compromising performance. Shader interfaces provide a type-safe solution to this kind of problem. This approach is somewhat unwieldy, and it doesn't scale elegantly to multiple lights-especially if the number of lights is unknown ahead of time as well. Alternatively, the preprocessor could be used, and the application could use #ifdef guards so that it could manually compile a specialized version of the program, depending on which light-source model was actually being used.
PIXEL SHADER FOR NVIDIA QUADRO K600 SERIES
A very inefficient approach would be to pass a "light type" parameter into the program and have a series of if tests to determine which light-source model to use. By allowing applications to build shaders by composing the effect of modular pieces that implement well-defined bits of functionality, shader interfaces give the application greater flexibility in creating shading effects and help hide limitations of hardware profiles with no reduction in the quality or efficiency of the final compiled code that runs on the GPU.įor example, consider writing a fragment program that needs to compute a shaded color for a surface while supporting a variety of different types of light source: point light, spotlight, complex projective light source with shadow map and procedurally defined distance attenuation function, and so on.
PIXEL SHADER FOR NVIDIA QUADRO K600 SOFTWARE
Unlike object-oriented languages that provide this kind of mechanism for abstraction for developing large software systems, the motivation for adding this feature to Cg was to make it easy to construct shaders at runtime out of multiple pieces of source code. The user must provide objects that implement the interfaces used in the program to the Cg runtime, which then handles putting together the final shader code to run on the hardware. Shader interfaces provide functionality similar to Java or C# interface classes and C++ abstract base classes: they allow code to be written that makes calls to abstract interfaces, without knowing what the particular implementation of the interface will be. The release of Cg 1.2 introduced an important new feature to the Cg programming language called shader interfaces.
The CD content, including demos and content, is available on the web and for download.Ĭhapter 32. You can purchase a beautifully printed version of this book, and others in the series, at a 30% discount courtesy of InformIT and Addison-Wesley. GPU Gems GPU Gems is now available, right here, online.
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