1. High Performance in Broad Reach Games Chas. Boyd
Principal Program Manager
Microsoft Corporation

2. High Performance in Broad Reach Games
The more polished the game, the larger the revenue opportunity. This talk covers techniques to give your app a professsional appeal using modern features for a fluid experience. Learn how to expand your audience by leveraging capabilities across the entire range of Windows8 PCs, including languages, tools, and APIs for high-performance graphics.

3. Agenda
Windows 8 hardware diversity A unified 3D API to access the power of the GPU Designing for the Broadest Reach Optimizing Performance Tile-based rendering optimizations Recommendations

4. 3 Presentations Today Step by Step through Game Development
How to set up the game
How to code it
How to optimize it <- You are here

5. Windows 8 PC Hardware Diversity

6. GPU Hardware Evolution
Year Version Defining Feature
1996 DirectX3 Hardware rasterization
1997 DirectX5 2 Shading options to choose from
1998 DirectX6 Multi-texture operations
1999 DirectX7 Vertex Processing in hardware
2000 DirectX8 Programmable Shaders: Vertex and Pixel
2001 DirectX8.1 Longer shaders
2002 DirectX9 High Level Shading Language, 32 instr
2003 DirectX9c 1000s of instructions per shader
2006 DirectX10 Geometry shader, Consistent shader models
2009 DirectX11 Compute Shader, Tessellation

7. After
Before DirectX

8. DirectX9 Hardware Vertex shaders Pixel shaders 8 Textures
4 Render Targets
Cube maps
Volume textures
Anisotropic filtering
Antialiasing
HDR rendering
Texture compression

9. DirectX 10 Hardware Vertex shaders Geometry shaders Pixel shaders
8 Textures
4 Render Targets
Cube maps
Volume textures
Anisotropic filtering
Antialiasing
HDR rendering
Texture compression
Geometry shaders
Stream out
128 Textures per shader
8 Render Targets
Integers in shaders
Vertex textures
Shader sampling
Constant buffers
Alpha-to-coverage
Basic DirectCompute
Async resource creation

10. DirectX 11 Hardware Vertex shaders Pixel shaders 8 Textures
4 Render Targets
Cube maps
Volume textures
Anisotropic filtering
Antialiasing
HDR rendering
Texture compression
Geometry shaders
Stream out
128 Textures per shader
8 Render Targets
Integers in shaders
Vertex textures
Shader sampling
Constant buffers
Alpha-to-coverage
Basic DirectCompute
Async resource creation
Full DirectCompute
Random access writes
Tessellation shaders
New compression formats
Shader linkage

11. Feature Levels
Direct3D 11 provides a uniform interface to access hardware capabilities
Feature Levels map to hardware capabilities
Feature_Level_9  DirectX 9 Hardware
Feature_Level_10  DirectX 10 Hardware
Feature_Level_11  DirectX 11 Hardware

12. Select Feature Levels to Support
D3D_FEATURE_LEVEL featureLevels[] = {
D3D_FEATURE_LEVEL_11_1,
D3D_FEATURE_LEVEL_11_0,
D3D_FEATURE_LEVEL_10_1,
D3D_FEATURE_LEVEL_10_0,
D3D_FEATURE_LEVEL_9_3,
D3D_FEATURE_LEVEL_9_1 };
UINT creationFlags = D3D11_CREATE_DEVICE_BGRA_SUPPORT;
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

13. Create the Device and Context
ComPtr<ID3D11Device> device;
ComPtr<ID3D11DeviceContext> context;
D3D11CreateDevice(
nullptr, // use the default adapter
D3D_DRIVER_TYPE_HARDWARE,
0, // use 0 unless a software device
creationFlags, // defined above
featureLevels, // what app will support
ARRAYSIZE(featureLevels),
D3D11_SDK_VERSION, // should always be D3D11_SDK_VERSION
&device, // created device
&m_featureLevel, // feature level of the device
&context // corresponding immediate context );
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

14. Development Strategy Develop on DirectX 11 hardware
Target Feature_Level_9 and scale up
Include calibration code in game to dynamically configure for current hardware
Be aware of Feature Level differences
Test by restricting Feature Level
Test on multiple PCs

15. DirectX Control Panel

16. Chapter 1/4
Balancing Act

17. Features vs Performance
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

18. Opposing Directions
Prune features and image quality to meet performance goals on low-end hardware
Add features and image quality to differentiate your app on high-end hardware

19. Development Strategy Develop on DirectX 11 hardware
Target Feature_Level_9 and scale up
Include calibration code in game to dynamically configure for current hardware
Adjust to maintain performance
Be aware of Feature Level differences
Test by restricting Feature Level
Test on multiple PCs

20. Differentiation Increase Visual Quality Higher resolution textures
Use bump maps

21. Texture Quality Control
Balance visual quality with performance
Scale back on size via mipmap levels
Use block-compressed
texture formats
Loader code skips mip levels
1024 x 1024
512 x 512
256 x 256

22. Optimization Techniques
Tune Anisotropic filter quality
Simple scalar value
MultiSampling AntiAliasing (MSAA)
Reduce sample count to maintain frame rate
Render to a lower resolution and scale up for final image
For best image quality, do not scale 2D text
Geometry
Feature_Level_11 – use tessellation for more polygon count control
Consider lower-resolution (lower vertex count) meshes

23. Basic Performance Checks
Be sure you are not setting state and loading data that doesn’t change every frame
Set breakpoint in the render code
We’ve seen some apps drawing twice per frame
Make sure that the game loop routines are still in the right order
Check to see if you are CPU bound, or GPU bound.
If GPU, check to see if you are fill-rate or vertex bound.

24. Use PIX PIX is a profiler mode for Visual Studio 11
You can use it to step-through DirectX API calls
And display:
event history
pixel history
DX rendering pipeline
the DX object table, and
call stacks

25. Chapter 3/4
More Optimizations

26. More Optimizations Pure performance helps low-end hardware
But if image quality is not impacted, high-end hardware benefits too
Minimum Precision is a new capability in Windows 8 HLSL

27. Minimum Precision
Reduce the number of bits of precision in shader calculations
Hints to the graphics driver where optimizations can be done
Specifies minimum rather than actual precision
min16float
min12int
min16int

28. Minimum Precision HLSL Code Sample
static const float brightThreshold = 0.5f;
Texture2D sourceTexture : register(t0);
float4 DownScale3x3BrightPass(QuadVertexShaderOutput input) : SV_TARGET {
float3 brightColor = 0;
// Gather 16 adjacent pixels (each bilinear sample reads a 2x2 region)
brightColor = sourceTexture.Sample(linearSampler, input.tex, int2(-1,-1)).rgb;
brightColor += sourceTexture.Sample(linearSampler, input.tex, int2( 1,-1)).rgb;
brightColor += sourceTexture.Sample(linearSampler, input.tex, int2(-1, 1)).rgb;
brightColor += sourceTexture.Sample(linearSampler, input.tex, int2( 1, 1)).rgb;
brightColor /= 4.0f;
// Brightness thresholding
brightColor = max(0, brightColor - brightThreshold);
return float4(brightColor, 1.0f); }
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

29. Minimum Precision HLSL Code Sample
static const min16float brightThreshold = (min16float)0.5;
Texture2D<min16float4> sourceTexture : register(t0);
float4 DownScale3x3BrightPass(QuadVertexShaderOutput input) : SV_TARGET {
min16float3 brightColor = 0;
// Gather 16 adjacent pixels (each bilinear sample reads a 2x2 region)
brightColor = sourceTexture.Sample(linearSampler, input.tex, int2(-1,-1)).rgb;
brightColor += sourceTexture.Sample(linearSampler, input.tex, int2( 1,-1)).rgb;
brightColor += sourceTexture.Sample(linearSampler, input.tex, int2(-1, 1)).rgb;
brightColor += sourceTexture.Sample(linearSampler, input.tex, int2( 1, 1)).rgb;
brightColor /= (min16float)4.0;
// Brightness thresholding
brightColor = max(0, brightColor - brightThreshold);
return float4(brightColor, 1.0f); }
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

30. Chapter 2/4
Tile –Based Rendering

31. Typical Rendering Command stream sent to GPU Command Stream
CommandBuffer1
Command1
Command2
Command3
Command4
Command5
Command6
CommandBuffer2
CommandBuffer3
Command Stream

32. Tile Based Rendering Display the final image
Send Command Stream to GPU
Execute Command Stream for Tile 1
Execute Command Stream for Tile 2
Execute Command Stream for Tile 3
Execute Command Stream for Tile 4
CommandBuffer1
Command1
Command2
Command3
Command4
Command5
Command6
CommandBuffer2
CommandBuffer3
Buffered Commands
Execute Command Stream for Tile 5
Execute Command Stream for Tile 6
Display the final image

33. Tile-based Rendering Strategies
Avoid mid-scene flushes
Avoid swapping back and forth between RenderTargets
Use scissors when updating small portions of a RenderTarget
Use DISCARD and NO_OVERWRITE when possible

34. Tile-based Rendering Optimizations
GPUs with a tile-based rendering architecture can get a performance boost with a special flag:
m_swapChain->Present(1, 0); // present the image on the display
ComPtr<ID3D11View> view;
m_renderTargetView.As(&view); // get the view on the RT
m_d3dContext->DiscardView(view.Get()); // release the view

35. Chapter 4/4
Recommendations

36. Conclusion
Windows 8
Runs on the broadest graphics hardware diversity ever
Designed for graphics hardware acceleration
Direct3D 11 is the 3D API to access the power of the GPU
You can get Great Graphics Performance leveraging the GPU AND hit the broadest markets

37. Strategy Recap for Indie Devs
Design for Feature_Level_9
Adjust at runtime for actual Feature Level
Use advanced features to differentiate when available
Dynamically calibrate for smooth performance
Use new Direct3D 11 features to better utilize hardware
Minimum precision
Tile-based rendering optimizations

38. Time to Act
Biggest opportunity. Ever. Windows 8 Consumer Preview is now available. Check out the store. Go build great games.

39. Q & A

40. 4/20/2017 8:42 AM
© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.