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

Overview

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

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

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

Scene Effects

 Effects that work at the scene level 

Pre Effects

drawn – runs before any geometry is    Useful for background images

Post Effects

drawn  – runs after all geometry is 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

Using Scene Effects - 1/4

    Scene effects use a ParamID of 0x003   Tells the system to use the correct parser Uses bool usage.

PreShader = true; to help the parser with 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

Using Scene Effects - 2/4

 Example of the post_output.fx file #include string "quad.fxh“ ParamID = "0x003"; //helper file for drawing quads //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;

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

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

Extending with MAXScript

Scripted Material Auto Generated UI

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

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

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 )

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..

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

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

 [email protected]