Pipeline.h

// Copyright 2022 ShenMian
// License(Apache-2.0)
 
#pragma once
 
#include "PipelineLayout.h"
#include "VertexFormat.h"
#include "Viewport.hpp"
#include <memory>
 
class Program;
class VertexBuffer;
 
enum class PolygonMode
{
    Fill,     
    Wireframe 
};
 
enum class CullMode
{
    Disabled, 
    Front,    
    Back,     
};
 
enum class CompareOp
{
    AlwaysPass,
    NeverPass,
    Less,
    Equal,
    LessEqual,
    Greater,
    NotEqual,
    GreaterEqual,
};
 
struct RasterizerDescriptor
{
    PolygonMode polygonMode = PolygonMode::Fill;
    CullMode    cullMode    = CullMode::Disabled;
    float       lineWidth   = 1.0f;
};
 
struct DepthDescriptor
{
    bool      enableTest  = true;
    bool      enableWrite = true;
    CompareOp compareOp   = CompareOp::Less;
};
 
class Pipeline
{
public:
    struct Descriptor
    {
        PipelineLayout           layout;
        VertexFormat             vertexFormat;
        std::shared_ptr<Program> program;
        std::vector<Viewport>    viewports;
 
        RasterizerDescriptor rasterizer;
        DepthDescriptor      depth;
    };
 
    [[nodiscard]] static std::shared_ptr<Pipeline> create(const Descriptor& desc);
 
    virtual void bind() = 0;
 
protected:
    Pipeline(const Descriptor& desc);
    virtual ~Pipeline() = default;
 
    Descriptor desc;
};