Strategies and Techniques for Real-Time Shaders

2. Strategies and Techniques for Real-Time Shaders Neil Hazzard Software Engineer Autodesk, Media and Entertainment

3. Overview • Recap from GDC 2005 • What’s new in 3ds max 8 • Scene Effects • Extending effects with MAXscript • Tips • Lots of Demos…

4. Quick Recap from GDC 2005 • 3ds max supports HLSL Effect files • Dynamic UI creation based on Semantic and Annotations in the file • Automatic update of changed file and bitmaps • Based on Parser Technology • Two Formats supported. 3ds max and DxSAS 0.8 • MAXScript extendible • GDC 2005 session available • http://sparks.autodesk.com/downloads

5. What’s new in 3ds max 8 • New Annotation “ColorChannel” specifies whether a Map Channel contains color information. • int texcoord1 : Texcoord • < • int Texcoord = 1; • int MapChannel = 10; • bool ColorChannel = true; • >; • #define support - _3DSMAX_, 3DSMAX, MAX & _MAX_ Easier support for max specific code, by using #ifdef _MAX_ • Use of DiffuseMap semantic to provide better Material Editor sample slot rendering • Scene Effects

6. Scene Effects • Effects that work at the scene level • Pre Effects – runs before any geometry is drawn • Useful for background images • Post Effects – runs after all geometry is drawn • Any “post production” work – blur, glow etc.. • Environment Effects – special type that process the scene for use in per object rendering • Ideal for Shadow Maps or CubeMaps generation • Only work with the DirectX 9 Shader Material

7. Using Scene Effects - 1/4 • Scene effects use a ParamID of 0x003 • Tells the system to use the correct parser • Uses bool PreShader = true; to help the parser with usage. • Post effects receive the render target containing the scene in a texture parameter called SceneMap. • Pre Effects simply render into the current active render target. • Load the scene effects using the Scene Effect Loader Utility

8. Using Scene Effects - 2/4 • Example of the post_output.fx file #include "quad.fxh“ //helper file for drawing quads string ParamID = "0x003"; //tells the system what parser //Macro to define the Scene texture and sampler DECLARE_QUAD_TEX(SceneMap,SceneSampler,"X8R8G8B8") //Simple pixel shader that simply outputs the input scene data float4 OutputPS(VertexOutput IN) : COLOR { float4 texCol = float4(tex2D(SceneSampler, IN.UV).xyz,1); // Do anything else here return texCol; }

9. Using Scene Effects - 3/4 • Environment Effects • Run before the main scene output starts • Should run in conjunction with object based shaders • Object shaders can then use specific transforms setup by the environment stage • An Example is light transforms for Shadow maps • Use multiple techniques, one for environment pass and another for final pass. Have a naming convention so the parser can set them dynamically • Can create maps that would be used by objects based effects

10. Using Scene Effects – 4/4 • Developers can write their own scene parsers • Node sorting and filtering can be implemented • The utility simply sorts based on the GBuffer ID and filters non DirectX 9 Shader materials • New interfaces – see RTMax.h • IDxSceneManager, IValidateNodeCallback and IDxSceneTransformManager

11. Extending with MAXScript Scripted Material Auto Generated UI

12. Extending with MAXScript • Scripted Material • plugin material StandardFX name:"StandardFX" classID:#(692421,413582) extends:DirectX_9_Shader replaceUI:true version:1 (…) • Parameters use the name defined in the effect file • You could still use “showproperties meditmaterials[1]” to list the names • Simply use the delegate keyword to set the value • The texture used by effects is actually a bitmap type

13. Extending with MAXScript • On Create Handler (Scripted_StandardFX.ms) on create do ( -- setup initial material effectfile = GetDir #maxroot effectfile = effectfile + "\\maps\\fx\\StandardFX.fx" delegate.effectfile = effectfile ambientlock = true )

14. Extending with MAXScript • Button Handler (Scripted_StandardFX.ms) on b_topDiffuseClr pressed do ( b = selectbitmap caption: "Top Diffuse Map" if b != undefined then ( delegate.g_TopTexture = b b_topDiffuseClr.text = b.filename topdiffuseMap = b --defined as type:#bitmap ) )

15. Extending with MAXScript • Generates custom and sophisticated UIs • Allows data validation and Access control • E.g. power of two textures, or textures no greater than a certain size. • Can provide workarounds for the UI widgets generated by the parsers • Scriptable values instead of UI generated can drive delegate values • E.g. UV clamping etc..

16. Things to remember • Annotations are case sensitive • The three built in parsers are very different, don’t mix up your annotations • Type verses ResourceType • name verses ResourceName • 3ds max is Z-up • You soon find this out with cubemaps!! • Swap YZ around to make it work • Currently only camera based matrixes are support at the object level. • Use Scripted materials • Good to work around “Auto UI” look and feel • Data management/validation

17. Resources • http://sparks.autodesk.com • Sample parsers available and documentation • http://developer.nvidia.com • http://www.ati.com/developer • msdn.microsoft.com/directx • Ben Cloward • http://www.monitorstudios.com/bcloward/resources.html • neil.hazzard@autodesk.com