Strategies and Techniques Strategies and Techniques for for

Real-Time ShadersReal-Time Shaders

Neil HazzardNeil Hazzard

Software EngineerSoftware Engineer

Autodesk, Media and Autodesk, Media and EntertainmentEntertainment

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 – 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

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

Using Scene Effects - 2/4 Example of the post_output.fx file

#include "quad.fxh“ //helper file for drawing quadsstring ParamID = "0x003"; //tells the system what parser

//Macro to define the Scene texture and samplerDECLARE_QUAD_TEX(SceneMap,SceneSampler,"X8R8G8B8")

//Simple pixel shader that simply outputs the input scene datafloat4 OutputPS(VertexOutput IN) : COLOR{

float4 texCol = float4(tex2D(SceneSampler, IN.UV).xyz,1);// Do anything else herereturn 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 materialeffectfile = GetDir #maxroot effectfile = effectfile + "\\maps\\fx\\

StandardFX.fx"delegate.effectfile = effectfileambientlock = 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

neil.hazzard@autodesk.com