kc3-lang/angle/src/compiler/translator/tree_util/DriverUniform.h

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• Hash : 665ddccd
  Author :
  Date : 2021-12-09T23:06:39
  

  Vulkan: Emulate dithering
  
  Dithering in OpenGL is vaguely defined, to the extent that no dithering
  is also a valid dithering algorithm.  Dithering is enabled by default,
  but emulating it has a non-negligible cost.  Similarly to some other
  GLES drivers, ANGLE enables dithering only on low-bit formats where
  visual banding is particularly common; namely RGBA4444, RGBA5551 and
  RGB565.
  
  Dithering is emulated in the fragment shader and is controlled by a spec
  constant.  Every 2 bits of the spec constant correspond to one
  attachment, with the value indicating:
  
  - 00: No dithering
  - 01: Dither for RGBA4444
  - 10: Dither for RGBA5551
  - 11: Dither for RGB565
  
  The translator appends code to the shader that, based on the format
  specified by the specialization constant, adds dithering to each color
  attachment output.  A 2x2 Bayer matrix is used for dithering, indexed by
  gl_FragCoord.xy % 2.
  
  Bug: angleproject:6755
  Change-Id: Ib45da5938e299b6626bff921119d63e7357dd353
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3374261
  Reviewed-by: Tim Van Patten <timvp@google.com>
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
  

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• src/compiler/translator/tree_util/DriverUniform.h

• //
  // Copyright 2020 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  // DriverUniform.h: Add code to support driver uniforms
  //
  
  #ifndef COMPILER_TRANSLATOR_TREEUTIL_DRIVERUNIFORM_H_
  #define COMPILER_TRANSLATOR_TREEUTIL_DRIVERUNIFORM_H_
  
  #include "common/angleutils.h"
  #include "compiler/translator/Types.h"
  
  namespace sh
  {
  
  class TCompiler;
  class TIntermBlock;
  class TIntermNode;
  class TSymbolTable;
  class TIntermTyped;
  class TIntermSwizzle;
  class TIntermBinary;
  
  enum class DriverUniformMode
  {
      // Define the driver uniforms as an interface block. Used by the
      // Vulkan and Metal/SPIR-V backends.
      InterfaceBlock,
  
      // Define the driver uniforms as a structure. Used by the
      // direct-to-MSL Metal backend.
      Structure
  };
  
  class DriverUniform
  {
    public:
      DriverUniform(DriverUniformMode mode)
          : mMode(mode), mDriverUniforms(nullptr), mEmulatedDepthRangeType(nullptr)
      {}
      virtual ~DriverUniform() = default;
  
      bool addComputeDriverUniformsToShader(TIntermBlock *root, TSymbolTable *symbolTable);
      bool addGraphicsDriverUniformsToShader(TIntermBlock *root, TSymbolTable *symbolTable);
  
      TIntermTyped *getViewportRef() const;
      TIntermTyped *getAbcBufferOffsets() const;
      TIntermTyped *getXfbVerticesPerInstance() const;
      TIntermTyped *getXfbBufferOffsets() const;
      TIntermTyped *getClipDistancesEnabled() const;
      TIntermTyped *getDepthRangeRef() const;
      TIntermTyped *getDepthRangeReservedFieldRef() const;
      TIntermTyped *getNumSamplesRef() const;
  
      virtual TIntermTyped *getFlipXYRef() const { return nullptr; }
      virtual TIntermTyped *getNegFlipXYRef() const { return nullptr; }
      virtual TIntermTyped *getPreRotationMatrixRef() const { return nullptr; }
      virtual TIntermTyped *getFragRotationMatrixRef() const { return nullptr; }
      virtual TIntermTyped *getHalfRenderAreaRef() const { return nullptr; }
      virtual TIntermTyped *getNegFlipYRef() const { return nullptr; }
      virtual TIntermTyped *getDitherRef() const { return nullptr; }
  
      const TVariable *getDriverUniformsVariable() const { return mDriverUniforms; }
  
    protected:
      TIntermTyped *createDriverUniformRef(const char *fieldName) const;
      virtual TFieldList *createUniformFields(TSymbolTable *symbolTable);
      TType *createEmulatedDepthRangeType(TSymbolTable *symbolTable);
  
      const DriverUniformMode mMode;
      const TVariable *mDriverUniforms;
      TType *mEmulatedDepthRangeType;
  };
  
  class DriverUniformExtended : public DriverUniform
  {
    public:
      DriverUniformExtended(DriverUniformMode mode) : DriverUniform(mode) {}
      virtual ~DriverUniformExtended() override {}
  
      TIntermTyped *getFlipXYRef() const override;
      TIntermTyped *getNegFlipXYRef() const override;
      TIntermTyped *getPreRotationMatrixRef() const override;
      TIntermTyped *getFragRotationMatrixRef() const override;
      TIntermTyped *getHalfRenderAreaRef() const override;
      TIntermTyped *getNegFlipYRef() const override;
      TIntermTyped *getDitherRef() const override;
  
    protected:
      virtual TFieldList *createUniformFields(TSymbolTable *symbolTable) override;
  };
  
  }  // namespace sh
  
  #endif  // COMPILER_TRANSLATOR_TREEUTIL_DRIVERUNIFORM_H_
  

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