1. Pixel shaders: programming the GPU By: Venkata Nanda Kishore

2. What is a Shader? Set of Software Instructions Degree of Flexibility Traits of an entity

5. Vertex Shaders

6. Geometric ShadersBut the name remained as it was!

7. GRAPHICS PIPELINE Geometric Shaders Rasteriser VertexShaders Pixel Shaders

8. Effect of Shaders Replaced hard coded effects Gives a programmable alternative Fixed Function PipelineProgrammable Function Pipeline 3.Parallel Programming

9. Programming Shaders HLSL (Direct 3d) GLSL (OpenGl) Cg(Nvidia + Microsoft)

10. Cg What is Cg? Is it similar to C? Is it the right question? Can we use it as a general programming language?

11. Background of Cg Use of Assembly level language What is assembly level? What is high level,low level and middle level? How easy is it?

12. Example of assembly level language fib: movedx, [esp+8] cmpedx, 0 ja @f moveax, 0 ret @@: cmpedx, 2 ja @f moveax, 1 ret @@: push ebx movebx, 1 movecx, 1 @@: lea eax, [ebx+ecx] cmpedx, 3 jbe @f movebx, ecx movecx, eax decedx jmp@b @@: pop ebx ret

13. Advantage of Cg Portable Easy Optimize the code

14. Games that Use Cg HIT MAN : Blood Money BATTLE FIELD 2 FAR CRY RACER And many more

15. Syntax and Semantics(1) Data Types: int, float, half, fixed, bool, sampler* Operators: Arithmetic and logical operators as in C Additional: arithmetic operations for vector and matrix operrations

16. Syntax and Semantics(2) Functions and Control Structures: Similar to C Standard Cg Library: Specialised GPU programming tasks Eg. Texture Mapping functions tex1D and tex2D Cg Runtime Library:Can be used with OpenGl or DirectX

17. Example Shader structVertIn //Input vertex { float4 pos : POSITION; float4 color : COLOR0; }; // output vertex structVertOut { float4 pos : POSITION; float4 color : COLOR0; }; // vertex shader main entry VertOutmain(VertIn IN, uniform float4x4 modelViewProj) { VertOut OUT; OUT.pos= mul(modelViewProj, IN.pos); //position OUT.color= IN.color; // copy input color to output OUT.color.z= 1.0f; // blue component of color = 1.0f return OUT; }

18. Loading Pixel Shaders in OpenGL 1.Loading extensions: glEnable(GL_FRAGMENT_PROGRAM_ARB); 2.Create Shader Number: glGenProgramsARB(1, &shader_num); glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, shader_num);

19. Actually Loading the Shader glProgramStringARB(GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB, strlen(program_string), program_string); glDisable(GL_FRAGMENT_PROGRAM_ARB); http://joshbeam.com/articles/cg_pixel_shaders_in_opengl/

20. Examples https://support.steampowered.com/kb_article.php?ref=4360-TPJL-2065 Gives what games need what version of pixel shaders http://www.nvidia.com/object/feature_pixelshader.html http://www.toymaker.info/Games/html/pixel_shaders.html

21. Free Book! http://http.developer.nvidia.com/CgTutorial/cg_tutorial_chapter01.html