Xbox One X: Graphics Enhancements in the June 2017 XDK

The June 2017 XDK is the first release with graphics driver support for Xbox One X hardware. Developers can expect performance to improve by orders of magnitude on Xbox One X with few or no code changes. Please see the Xfest 2017 Graphics presentations and Updating your Xbox One title to take advantage of Xbox One X for more details.

• Support for Xbox One X hardware features
• Xbox Hang Investigation Tool (XHIT) improvements
• Breaking changes

Support for Xbox One X hardware features

This section lists the Xbox One X graphics features that Direct3D now supports.

Delta Color Compression
Delta Color Compression (DCC) is a new form of render target compression that reduces bandwidth.

Important DCC functionality is not yet complete. Validation is missing in some places, and some functionality (such as subrect copies and clears) are not yet implemented. While you use DCC, please send feedback to your DAM so that we can better prioritize fixes and future enhancements.

Direct3D support of this feature is as follows:

• Direct3D 12.x supports DCC with the new D3D12XBOX_RESOURCE_FLAG_ALLOW_DCC resource flag and the new D3D12XBOX_DCC_OPTIONS structure.
• Direct3D 11.x (fast semantics only) supports DCC with the new D3D11X_RESOURCE_MISC_ALLOW_DCC resource misc flag.

Native reads of compressed textures
Native reads of compressed textures allow titles to read DCC compressed render targets, non-expanded fmask surfaces, and compressed depth with HTile as a SRV without a decompression operation.

Note Texture-compatible compressed depth surfaces cannot support stencil.

Direct3D support of this feature is as follows:

• Direct3D 12.x supports native reads of compressed textures when the resource is created with the D3D12XBOX_RESOURCE_FLAG_FORCE_TEXTURE_COMPATIBILITY flag.
• Direct3D 11.x supports reads from DCC and compressed depth when the resource is created with the D3D11X_RESOURCE_MISC_FORCE_TEXTURE_COMPATIBILITY flag. Reads from non-expanded fmask are not yet supported in D3D11.x.

Out-of-order rasterization
Out-of-order rasterization enables different primitives within the same draw to be processed out of order.

Direct3D support of this feature is as follows:

• In Direct3D 12.x, drivers can enable this feature automatically when provably correct. You can also force it by calling the CreateGraphicsPipelineStateX or CreateDerivedGraphicsPipelineStateX function with the D3D12XBOX_PIXEL_SHADER_OPTION_OUT_OF_ORDER_RASTERIZATION flag.
• In Direct3D 11.x, titles must explicitly enable this feature by calling the SetScanConverterModeControl function with “EnableOutOfOrderRasterization & OutOfOrderRasterizationWaterMark”.

Draw balancing
Draw balancing is a hardware feature which analyzes the draw within the work distributor (WD) and changes the alternation rates to get more even usage. By doing so, it helps obtain peak vertex/triangle rate.

Direct3D support of this feature is as follows:

• Direct3D 12.x automatically enables draw balancing when permitted.
• In Direct3D 11.x, titles must explicitly opt-in to this feature by calling the ID3D11DeviceContextX::SetDrawBalancing method. In addition, your title must guarantee correctness.

Additional memory on Xbox One X hardware
  Extra memory on Xbox One X hardware is exposed.

Xbox Hang Investigation Tool (XHIT) improvements

Xbox Hang Investigation Tool (XHIT) has been improved for all Xbox One hardware. We’ve upgraded bucketization inside .xhit files, collected various extra information, and improved integration with PIX for better GPU hang diagnosing.

Breaking changes

The following breaking changes have been made to graphics for Xbox One X. For more information about changes that you will need to make when moving your existing graphics code from Xbox One/Xbox One S to Xbox One X hardware, see Updating your Xbox One title to take advantage of Xbox One X.

• ESRAM support is deprecated on Xbox One X hardware, although it is still available on Xbox One/Xbox One S hardware. To determine which console type your title is running on, call the GetConsoleType function.
  The following APIs will fail on Xbox One X hardware:
  
  • D3DMapEsramMemory
  • D3DUnmapEsramMemory
  • D3D11X_RESOURCE_MISC_ESRAM_RESIDENT
  • XGComputeOptimalDepthStencilTileModes takes two new parameters, TiledResource and TextureCompatible, needed for Xbox One X support.