axmol/cocos/renderer/backend/ProgramState.h

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

 http://www.cocos2d-x.org

 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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 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 ****************************************************************************/
 
#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"

CC_BACKEND_BEGIN

class TextureBackend;
class VertexLayout;

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

 /**
  * Store texture information.
  */
struct TextureInfo
{
    TextureInfo(const std::vector<uint32_t>& _slots, const std::vector<backend::TextureBackend*> _textures);
    TextureInfo() = default;
    TextureInfo(const TextureInfo &);
    ~TextureInfo();
    TextureInfo& operator=(TextureInfo&& rhs);
    TextureInfo& operator=(const TextureInfo& rhs);

    void retainTextures();
    void releaseTextures();

    std::vector<uint32_t> slot;
    std::vector<backend::TextureBackend*> textures;
#if CC_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 ProgramState : public Ref
{
public:
    using UniformCallback = std::function<void(ProgramState*, const UniformLocation &)>;

    /**
     * @param vertexShader Specifies the vertex shader.
     * @param fragmentShader Specifies the fragment shader.
     * @see `ProgramState(ProgramType type)`
     */
    ProgramState(const std::string& vertexShader, const std::string& fragmentShader);
    
    /**
     * Create an program state object more efficient by engine built-in program type.
     * @param type Specifies the built-in program type.
     * @see `ProgramState(const std::string& vertexShader, const std::string& fragmentShader)`
     */
    ProgramState(ProgramType type);

    ///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, uint32_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(const std::string& 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(const std::string& name) const`
     */
    inline int getAttributeLocation(const std::string& 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(const std::string& 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 &);

    /**
     * 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, uint32_t slot, 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, const std::vector<uint32_t>& slots, const 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 the uniform callback function.
     * @return Uniform callback funciton.
     */
    inline const std::unordered_map<UniformLocation, UniformCallback, UniformLocation>& getCallbackUniforms() const { return _callbackUniforms; }

    /**
     * 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 CC_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 *, const std::string &uniformName, const std::string &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(const std::string &uniformName, const std::string &autoBinding);

    inline std::shared_ptr<VertexLayout> getVertexLayout() const { return _vertexLayout; }
protected:

    ProgramState();

    /**
     * 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, uint32_t size, uint32_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, uint32_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, uint32_t slot, 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, const std::vector<uint32_t>& slots, const std::vector<backend::TextureBackend*> textures, std::unordered_map<int, TextureInfo>& textureInfo);
    
    /**
     * Reset uniform informations when EGL context lost
     */
    void resetUniforms();

    ///Initialize.
    void init();
    
#ifdef CC_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, uint32_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(const std::string &, const std::string &);

    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;
    std::shared_ptr<VertexLayout> _vertexLayout = std::make_shared<VertexLayout>();

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

//end of _backend group
/// @}
CC_BACKEND_END