tailieunhanh - Microsoft XNA Game Studio Creator’s Guide- P4

Microsoft XNA Game Studio Creator’s Guide- P4:The release of the XNA platform and specifically the ability for anyone to write Xbox 360 console games was truly a major progression in the game-programming world. Before XNA, it was simply too complicated and costly for a student, software hobbyist, or independent game developer to gain access to a decent development kit for a major console platform. | 68 MICROSOFT X N A GAME STUDIO CREATOR S GUIDE This chapter has shown how to draw 3D graphics. The vertices and primitive surfaces drawn with these simple shapes are the foundation for all 3D game graphics. Even fiery effects and 3D models begin with vertices and primitive surfaces. Chapter 5 review exercises To get the most from this chapter try out these chapter review exercises 1. Implement the step-by-step examples presented in this chapter if you have not already done so. 2. Using primitive objects create the face of a cat with ears and whiskers. 3. Use line and triangle primitives to create a small house with a roof and fence around it. You can use triangle strips triangle lists line strips and line lists. Shaders CHAPTER 6 XNA uses shader-based rendering to convert vertex data into pixel output. This method achieves high performance because shaders per- form graphics processing at breakneck speed on your graphics card. Whether you use your own shader or XNA s BasicEffect shader you must use some type of shader to draw 3D graphics from your XNA code. The shader also gives you the power to customize the way your vertices are displayed. Shaders can be used to manipulate all vertex properties for example color position and texture . The ability to provide additional vertex processing through the shader makes it possible to use them for implementing lighting blending effects such as transparency and multitexturing. For some effects such as point sprites for fire multitexturing and custom lighting you will need to write your own shader to implement the effect. RAPHICS PIPELINE In discussions about shaders you will often hear references to the graphics pipeline. The graphics pipeline refers to the process of converting vertex and primitive input into pixel output. Vertex and pixel shaders of course play a key role in this processing. The vertex shader applies transformations to the vertex inputs. When the transformed vertices are passed to the shader the output .