graphicsPipeline.h

//
// Copyright 2020 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_IMAGING_HGI_GRAPHICS_PIPELINE_H
#define PXR_IMAGING_HGI_GRAPHICS_PIPELINE_H

#include "pxr/pxr.h"
#include "pxr/imaging/hgi/api.h"
#include "pxr/imaging/hgi/attachmentDesc.h"
#include "pxr/imaging/hgi/enums.h"
#include "pxr/imaging/hgi/handle.h"
#include "pxr/imaging/hgi/resourceBindings.h"
#include "pxr/imaging/hgi/shaderProgram.h"
#include "pxr/imaging/hgi/types.h"

#include "pxr/base/gf/vec2f.h"

#include <string>
#include <vector>

PXR_NAMESPACE_OPEN_SCOPE


struct HgiVertexAttributeDesc
{
    HGI_API
    HgiVertexAttributeDesc();

    HgiFormat format;
    uint32_t offset;
    uint32_t shaderBindLocation;
};
using HgiVertexAttributeDescVector = std::vector<HgiVertexAttributeDesc>;

HGI_API
bool operator==(
    const HgiVertexAttributeDesc& lhs,
    const HgiVertexAttributeDesc& rhs);

HGI_API
bool operator!=(
    const HgiVertexAttributeDesc& lhs,
    const HgiVertexAttributeDesc& rhs);


struct HgiVertexBufferDesc
{
    HGI_API
    HgiVertexBufferDesc();

    uint32_t bindingIndex;
    HgiVertexAttributeDescVector vertexAttributes;
    HgiVertexBufferStepFunction vertexStepFunction;
    uint32_t vertexStride;
};
using HgiVertexBufferDescVector = std::vector<HgiVertexBufferDesc>;

HGI_API
bool operator==(
    const HgiVertexBufferDesc& lhs,
    const HgiVertexBufferDesc& rhs);

HGI_API
inline bool operator!=(
    const HgiVertexBufferDesc& lhs,
    const HgiVertexBufferDesc& rhs);


struct HgiMultiSampleState
{
    HGI_API
    HgiMultiSampleState();

    bool multiSampleEnable;
    bool alphaToCoverageEnable;
    bool alphaToOneEnable;
    HgiSampleCount sampleCount;
};

HGI_API
bool operator==(
    const HgiMultiSampleState& lhs,
    const HgiMultiSampleState& rhs);

HGI_API
bool operator!=(
    const HgiMultiSampleState& lhs,
    const HgiMultiSampleState& rhs);


struct HgiRasterizationState
{
    HGI_API
    HgiRasterizationState();

    HgiPolygonMode polygonMode;
    float lineWidth;
    HgiCullMode cullMode;
    HgiWinding winding;
    bool rasterizerEnabled;
    bool depthClampEnabled;
    GfVec2f depthRange;
    bool conservativeRaster;
    size_t numClipDistances;
};

HGI_API
bool operator==(
    const HgiRasterizationState& lhs,
    const HgiRasterizationState& rhs);

HGI_API
bool operator!=(
    const HgiRasterizationState& lhs,
    const HgiRasterizationState& rhs);

//.   The reference value used by the stencil test function.</li>
struct HgiStencilState
{
    HGI_API
    HgiStencilState();

    HgiCompareFunction compareFn;
    uint32_t referenceValue;
    HgiStencilOp stencilFailOp;
    HgiStencilOp depthFailOp;
    HgiStencilOp depthStencilPassOp;
    uint32_t readMask;
    uint32_t writeMask;
};

HGI_API
bool operator==(
    const HgiStencilState& lhs,
    const HgiStencilState& rhs);

HGI_API
bool operator!=(
    const HgiStencilState& lhs,
    const HgiStencilState& rhs);

struct HgiDepthStencilState
{
    HGI_API
    HgiDepthStencilState();

    bool depthTestEnabled;
    bool depthWriteEnabled;
    HgiCompareFunction depthCompareFn;

    bool depthBiasEnabled;
    float depthBiasConstantFactor;
    float depthBiasSlopeFactor;

    bool stencilTestEnabled;
    HgiStencilState stencilFront;
    HgiStencilState stencilBack;
};

HGI_API
bool operator==(
    const HgiDepthStencilState& lhs,
    const HgiDepthStencilState& rhs);

HGI_API
bool operator!=(
    const HgiDepthStencilState& lhs,
    const HgiDepthStencilState& rhs);

struct HgiGraphicsShaderConstantsDesc {
    HGI_API
    HgiGraphicsShaderConstantsDesc();

    uint32_t byteSize;
    HgiShaderStage stageUsage;
};

HGI_API
bool operator==(
    const HgiGraphicsShaderConstantsDesc& lhs,
    const HgiGraphicsShaderConstantsDesc& rhs);

HGI_API
bool operator!=(
    const HgiGraphicsShaderConstantsDesc& lhs,
    const HgiGraphicsShaderConstantsDesc& rhs);

struct HgiTessellationLevel
{
    HGI_API
    HgiTessellationLevel();

    float innerTessLevel[2];
    float outerTessLevel[4];
};

struct HgiTessellationState
{
    enum PatchType {
        Triangle,
        Quad,
        Isoline
    };

    enum TessFactorMode {
        Constant,
        TessControl,
        TessVertex
    };

    HGI_API
    HgiTessellationState();

    PatchType patchType;
    int primitiveIndexSize;
    TessFactorMode tessFactorMode = TessFactorMode::Constant;
    HgiTessellationLevel tessellationLevel;
};

struct HgiGraphicsPipelineDesc
{
    HGI_API
    HgiGraphicsPipelineDesc();

    std::string debugName;
    HgiPrimitiveType primitiveType;
    HgiShaderProgramHandle shaderProgram;
    HgiDepthStencilState depthState;
    HgiMultiSampleState multiSampleState;
    HgiRasterizationState rasterizationState;
    HgiVertexBufferDescVector vertexBuffers;
    HgiAttachmentDescVector colorAttachmentDescs;
    HgiAttachmentDesc depthAttachmentDesc;
    bool resolveAttachments;
    HgiGraphicsShaderConstantsDesc shaderConstantsDesc;
    HgiTessellationState tessellationState;
};

HGI_API
bool operator==(
    const HgiGraphicsPipelineDesc& lhs,
    const HgiGraphicsPipelineDesc& rhs);

HGI_API
bool operator!=(
    const HgiGraphicsPipelineDesc& lhs,
    const HgiGraphicsPipelineDesc& rhs);


class HgiGraphicsPipeline
{
public:
    HGI_API
    virtual ~HgiGraphicsPipeline();

    HGI_API
    HgiGraphicsPipelineDesc const& GetDescriptor() const;

protected:
    HGI_API
    HgiGraphicsPipeline(HgiGraphicsPipelineDesc const& desc);

    HgiGraphicsPipelineDesc _descriptor;

private:
    HgiGraphicsPipeline() = delete;
    HgiGraphicsPipeline & operator=(const HgiGraphicsPipeline&) = delete;
    HgiGraphicsPipeline(const HgiGraphicsPipeline&) = delete;
};

using HgiGraphicsPipelineHandle = HgiHandle<HgiGraphicsPipeline>;
using HgiGraphicsPipelineHandleVector = std::vector<HgiGraphicsPipelineHandle>;


PXR_NAMESPACE_CLOSE_SCOPE

#endif