axmol/core/renderer/backend/ProgramState.h

/****************************************************************************
 Copyright (c) 2018-2019 Xiamen Yaji Software Co., Ltd.
 Copyright (c) 2021-2022 Bytedance Inc.

 https://axmolengine.github.io/

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
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 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

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#pragma once

#include <vector>
#include <string>
#include <unordered_map>
#include <cstdint>
#include <functional>
#include "platform/CCPlatformMacros.h"
#include "base/CCRef.h"
#include "base/CCEventListenerCustom.h"
#include "renderer/backend/Types.h"
#include "renderer/backend/Program.h"
#include "renderer/backend/VertexLayout.h"

#ifdef AX_USE_METAL
struct XXH32_state_s;
#endif

NS_AX_BACKEND_BEGIN

class TextureBackend;
class VertexLayout;

/**
 * @addtogroup _backend
 * @{
 */

/**
 * Store texture information.
 */
struct AX_DLL TextureInfo
{
    TextureInfo(std::vector<int>&& _slots, std::vector<backend::TextureBackend*>&& _textures);
    TextureInfo(std::vector<int>&& _slots,
                std::vector<int>&& _indexs,
                std::vector<backend::TextureBackend*>&& _textures);
    TextureInfo() = default;
    TextureInfo(const TextureInfo&);
    TextureInfo(TextureInfo&& rhs);

    ~TextureInfo();

    TextureInfo& operator=(const TextureInfo& other) noexcept;
    TextureInfo& operator=(TextureInfo&& other) noexcept;

    void assign(const TextureInfo& other);
    void assign(TextureInfo&& other);

    void retainTextures();
    void releaseTextures();

    std::vector<int> slots;
    std::vector<int> indexs;
    std::vector<backend::TextureBackend*> textures;
#if AX_ENABLE_CACHE_TEXTURE_DATA
    int location = -1;
#endif
};

/**
 * A program state object can create or reuse a program.
 * Each program state object keep its own unifroms and textures data.
 */
class AX_DLL ProgramState : public Ref
{
public:
    using UniformCallback = std::function<void(ProgramState*, const UniformLocation&)>;

    /**
     * @param program Specifies the program.
     */
    ProgramState(Program* program);

    /// destructor
    virtual ~ProgramState();

    /**
     * Deep clone ProgramState
     */
    ProgramState* clone() const;

    /**
     * Get the program object.
     */
    backend::Program* getProgram() const { return _program; }

    /**
     * Specify the value of a uniform variable for the current program state object.
     * @param uniformLocation Specifies the uniform location.
     * @param data Specifies the new values to be used for the specified uniform variable.
     * @param size Specifies the uniform data size.
     */
    void setUniform(const backend::UniformLocation& uniformLocation, const void* data, std::size_t size);

    /**
     * Get uniform location in given uniform name.
     * @param uniform Specifies the uniform name.
     * @return Uniform location.
     * @see `backend::UniformLocation getUniformLocation(backend::Uniform name) const`
     */
    backend::UniformLocation getUniformLocation(std::string_view uniform) const;

    /**
     * Get uniform location in a more efficient way by the given built-in uniform name.
     * @param uniform Specifies the engin built-in uniform name.
     * @return Uniform location.
     * @see `backend::UniformLocation getUniformLocation(backend::Uniform name) const`
     */
    backend::UniformLocation getUniformLocation(backend::Uniform name) const;

    /**
     * Get an attribute location by the actual attribute name.
     * @param name Specifies the attribute name.
     * @return Attribute location.
     * @see `int getAttributeLocation(std::string_view name) const`
     */
    inline int getAttributeLocation(std::string_view name) const { return _program->getAttributeLocation(name); }

    /**
     * Get an attribute location by the engine built-in attribute name.
     * @param name Specifies the built-in attribute name.
     * @return Attribute location.
     * @see `int getAttributeLocation(std::string_view name) const`
     */
    inline int getAttributeLocation(Attribute name) const { return _program->getAttributeLocation(name); }

    /**
     * A callback to update unifrom.
     * @param uniformLocation Specifies the uniform location.
     * @param unifromCallback Specifies a callback function to update the uniform.
     */
    void setCallbackUniform(const backend::UniformLocation&, const UniformCallback&);

    /**
     * Get the uniform callback function.
     * @return Uniform callback funciton.
     */
    inline const std::unordered_map<UniformLocation, UniformCallback, UniformLocation>& getCallbackUniforms() const
    {
        return _callbackUniforms;
    }

    /**
     * Set texture.
     * @param uniformLocation Specifies texture location.
     * @param texture Specifies a pointer to backend texture.
     */
    void setTexture(backend::TextureBackend* texture);

    /**
     * Set texture.
     * @param uniformLocation Specifies texture location.
     * @param slot Specifies texture slot selector.
     * @param texture Specifies a pointer to backend texture.
     */
    void setTexture(const backend::UniformLocation& uniformLocation, int slot, backend::TextureBackend* texture);

    /**
     * Set texture.
     * @param uniformLocation Specifies texture location.
     * @param slot Specifies texture slot selector.
     * @param index Specifies texture index selector
     * @param texture Specifies a pointer to backend texture.
     */
    void setTexture(const backend::UniformLocation& uniformLocation,
                    int slot,
                    int index,
                    backend::TextureBackend* texture);

    /**
     * Set textures in array.
     * @param uniformLocation Specifies texture location.
     * @param slots Specifies texture slot selector.
     * @param textures Specifies a vector of backend texture object.
     */
    void setTextureArray(const backend::UniformLocation& uniformLocation,
                         std::vector<int> slots,
                         std::vector<backend::TextureBackend*> textures);

    /**
     * Get vertex texture informations
     * @return Vertex texture informations. Key is the texture location, Value store the texture informations
     */
    inline const std::unordered_map<int, TextureInfo>& getVertexTextureInfos() const { return _vertexTextureInfos; }

    /**
     * Get fragment texture informations
     * @return Fragment texture informations. Key is the texture location, Value store the texture informations
     */
    inline const std::unordered_map<int, TextureInfo>& getFragmentTextureInfos() const { return _fragmentTextureInfos; }

    /**
     * Get vertex uniform buffer. The buffer store all the vertex uniform's data.
     * @param[out] buffer Specifies the pointer points to a vertex uniform storage.
     * @param[out] size Specifies the size of the buffer in bytes.
     */
    void getVertexUniformBuffer(char** buffer, std::size_t& size) const;

    /**
     * Get fragment uniform buffer. The buffer store all the fragment uniform's data for metal.
     * @param[out] buffer Specifies the pointer points to a fragment uniform storage.
     * @param[out] size Specifies the size of the buffer in bytes.
     */
    void getFragmentUniformBuffer(char** buffer, std::size_t& size) const;

    /**
     * An abstract base class that can be extended to support custom material auto bindings.
     *
     * Implementing a custom auto binding resolver allows the set of built-in parameter auto
     * bindings to be extended or overridden. Any parameter auto binding that is set on a
     * material will be forwarded to any custom auto binding resolvers, in the order in which
     * they are registered. If a registered resolver returns true (specifying that it handles
     * the specified autoBinding), no further code will be executed for that autoBinding.
     * This allows auto binding resolvers to not only implement new/custom binding strings,
     * but it also lets them override existing/built-in ones. For this reason, you should
     * ensure that you ONLY return true if you explicitly handle a custom auto binding; return
     * false otherwise.
     *
     * Note that the custom resolver is called only once for a GLProgramState object when its
     * node binding is initially set. This occurs when a material is initially bound to a
     * Node. The resolver is NOT called each frame or each time the GLProgramState is bound.
     *
     * If no registered resolvers explicitly handle an auto binding, the binding will attempt
     * to be resolved using the internal/built-in resolver, which is able to handle any
     * auto bindings found in the GLProgramState::AutoBinding enumeration.
     *
     * When an instance of a class that extends AutoBindingResolver is created, it is automatically
     * registered as a custom auto binding handler. Likewise, it is automatically unregistered
     * on destruction.
     *
     * @script{ignore}
     */
    class AX_DLL AutoBindingResolver
    {
    public:
        AutoBindingResolver();
        virtual ~AutoBindingResolver();
        /**
         * Called when an unrecognized uniform variable is encountered
         * during material loading.
         *
         * Implementations of this method should do a string comparison on the passed
         * in name parameter and decide whether or not they should handle the
         * parameter. If the parameter is not handled, false should be returned so
         * that other auto binding resolvers get a chance to handle the parameter.
         * Otherwise, the parameter should be set or bound and true should be returned.
         *
         * @param programState The ProgramState
         * @param uniformName Name of the uniform
         * @param autoBinding Name of the auto binding to be resolved.
         *
         * @return True if the auto binding is handled and the associated parameter is
         *      bound, false otherwise.
         */
        virtual bool resolveAutoBinding(ProgramState*, std::string_view uniformName, std::string_view autoBinding) = 0;
    };
    /**
     * Sets a uniform auto-binding.
     *
     * This method parses the passed in autoBinding string and attempts to convert it
     * to an enumeration value. If it matches to one of the predefined strings, it will create a
     * callback to get the correct value at runtime.
     *
     * @param uniformName The name of the material parameter to store an auto-binding for.
     * @param autoBinding A string matching one of the built-in AutoBinding enum constants.
     */
    void setParameterAutoBinding(std::string_view uniformName, std::string_view autoBinding);

    inline const VertexLayout* getVertexLayout() const { return _vertexLayout; }

    /**
     * Gets uniformID, it's part of materialID for batch draw
     */
    uint32_t getUniformID() const { return _uniformID; }

    /**
     * Updates uniformID, it's part of materialID for batch draw
     * @param uniformID if not -1, will compute with uniform buffer by XXH32 algorithm and should call
     *        this function after any unstable uniforms set
     * @remark If your custom shader uniform not stable, you needs call this function to update uniformID for
     * render to generate a different materialID
     */
    void updateUniformID(int uniformID = -1);

    void setVertexAttrib(std::string_view name,
                         std::size_t index,
                         VertexFormat format,
                         std::size_t offset,
                         bool needToBeNormallized);
    void setVertexStride(uint32_t stride);

    void setVertexLayout(const VertexLayout& vertexLayout);

    /** Custom shader program's vertex layout maybe not setup
     * so engine specific render node(such as Sprite) should invoke this API when ProgramState changed
     */
    void validateSharedVertexLayout(std::function <void(Program*)> fnValidate);

protected:

    void ensureVertexLayoutMutable();

    /**
     * Set the vertex uniform data.
     * @param location Specifies the uniform location.
     * @param data Specifies the new values to be used for the specified uniform variable.
     * @param size Specifies the uniform data size.
     */
    void setVertexUniform(int location, const void* data, std::size_t size, std::size_t offset);

    /**
     * Set the fargment uniform data.
     * @param location Specifies the uniform location.
     * @param data Specifies the new values to be used for the specified uniform variable.
     * @param size Specifies the uniform data size.
     */
    void setFragmentUniform(int location, const void* data, std::size_t size);

    /**
     * Set texture.
     * @param location Specifies the location of texture.
     * @param slot Specifies slot selector of texture.
     * @param texture Specifies the texture to set in given location.
     * @param textureInfo Specifies the texture information to update.
     */
    void setTexture(int location,
                    int slot,
                    int index,
                    backend::TextureBackend* texture,
                    std::unordered_map<int, TextureInfo>& textureInfo);

    /**
     * Set textures in array.
     * @param location Specifies the location of texture.
     * @param slots Specifies slot selector of texture.
     * @param textures Specifies the texture to set in given location.
     * @param textureInfo Specifies the texture information to update.
     */
    void setTextureArray(int location,
                         std::vector<int> slots,
                         std::vector<backend::TextureBackend*> textures,
                         std::unordered_map<int, TextureInfo>& textureInfo);

    /**
     * Reset uniform informations when EGL context lost
     */
    void resetUniforms();

    /// Initialize.
    bool init(Program* program);

#ifdef AX_USE_METAL
    /**
     * float3 etc in Metal has both sizeof and alignment same as float4, convert it before fill into uniform buffer
     * @param uniformInfo Specifies the uniform information.
     * @param srcData Specifies the new values to be used for the specified uniform variable.
     * @param srcSize Specifies the uniform data size.
     * @param uniformBuffer Specifies the uniform buffer to update.
     */
    void convertAndCopyUniformData(const backend::UniformInfo& uniformInfo,
                                   const void* srcData,
                                   std::size_t srcSize,
                                   void* buffer);
#endif
    /**
     * Applies the specified custom auto-binding.
     *
     * @param uniformName Name of the shader uniform.
     * @param autoBinding Name of the auto binding.
     */
    void applyAutoBinding(std::string_view, std::string_view);

    backend::Program* _program = nullptr;
    std::unordered_map<UniformLocation, UniformCallback, UniformLocation> _callbackUniforms;
    char* _vertexUniformBuffer             = nullptr;
    char* _fragmentUniformBuffer           = nullptr;
    std::size_t _vertexUniformBufferSize   = 0;
    std::size_t _fragmentUniformBufferSize = 0;

    std::unordered_map<int, TextureInfo> _vertexTextureInfos;
    std::unordered_map<int, TextureInfo> _fragmentTextureInfos;

    std::unordered_map<std::string, std::string> _autoBindings;

    static std::vector<AutoBindingResolver*> _customAutoBindingResolvers;
    VertexLayout* _vertexLayout = nullptr;
    bool _ownVertexLayout = false;

    uint32_t _uniformID = 0;
#ifdef AX_USE_METAL
    struct XXH32_state_s* _uniformHashState = nullptr;
#endif

#if AX_ENABLE_CACHE_TEXTURE_DATA
    EventListenerCustom* _backToForegroundListener = nullptr;
#endif
};

// end of _backend group
/// @}
NS_AX_BACKEND_END