webgl1es2_shader_program.h

// © 2019 Joseph Cameron - All Rights Reserved

#ifndef GDK_GFX_WEBGL1ES2_SHADER_PROGRAM_H
#define GDK_GFX_WEBGL1ES2_SHADER_PROGRAM_H

#include <gdk/graphics_types.h>
#include <gdk/opengl.h>
#include <gdk/shader_program.h>
#include <gdk/webgl1es2_texture.h>
#include <jfc/shared_proxy_ptr.h>
#include <jfc/unique_handle.h>

#include <array>
#include <optional>
#include <string>
#include <unordered_map>

namespace gdk
{
    //TODO: consider a "pipeline" abstraction, which specifies all fixed options, then takes a program to specify programmable ones.
    //TODO: pipline abstraction is required to properly support blend-based transparencies, since frag order matters when blending.
    class webgl1es2_shader_program final : public shader_program
    {
    public:
        struct active_attribute_info
        {
            GLint location; 
            GLenum type; 
            //TODO this is not component count. this is number of types (vec2 is 1 not 2)
            GLint count; 
        };

        struct active_uniform_info
        {
            GLint location; 
            GLenum type; 
            GLint size; 
        };

        using active_attribute_collection_type = std::unordered_map<std::string, active_attribute_info>;
        using active_uniform_collection_type = std::unordered_map<std::string, active_uniform_info>;

        using integer2_uniform_type = std::array<GLint, 2>;
        using integer3_uniform_type = std::array<GLint, 3>;
        using integer4_uniform_type = std::array<GLint, 4>;

    public:
        std::optional<active_attribute_info> tryGetActiveAttribute(
            const std::string &aAttributeName) const;

        bool try_set_uniform(const std::string &aName, const GLfloat aValue) const;
        bool try_set_uniform(const std::string &aName, 
            const graphics_vector2_type &aValue) const;
        bool try_set_uniform(const std::string &aName, 
            const graphics_vector3_type &aValue) const;
        bool try_set_uniform(const std::string &aName, 
            const graphics_vector4_type &aValue) const;
        bool try_set_uniform(const std::string &aName, 
            const std::vector<GLfloat> &avalue) const;
        bool try_set_uniform(const std::string &aName, 
            const std::vector<graphics_vector2_type> &avalue) const; 
        bool try_set_uniform(const std::string &aName, 
            const std::vector<graphics_vector3_type> &avalue) const;
        bool try_set_uniform(const std::string &aName, 
            const std::vector<graphics_vector4_type> &avalue) const; 

        bool try_set_uniform(const std::string &aName, const GLint aValue) const;
        bool try_set_uniform(const std::string aName, const integer2_uniform_type &aValue) const;
        bool try_set_uniform(const std::string aName, const integer3_uniform_type &aValue) const;
        bool try_set_uniform(const std::string aName, const integer4_uniform_type &aValue) const;

        bool try_set_uniform(const std::string &aName, const std::vector<GLint> &aValue) const;
        bool try_set_uniform(const std::string &aName, const std::vector<integer2_uniform_type> &aValue) const;
        bool try_set_uniform(const std::string &aName, const std::vector<integer3_uniform_type> &aValue) const;
        bool try_set_uniform(const std::string &aName, const std::vector<integer4_uniform_type> &aValue) const;

        //bool try_set_uniform(const std::string &aName, const bool &aValue) const;
        //bool try_set_uniform(const std::string &aName, const boolean2_uniform_type &a) const;
        //bool try_set_uniform(const std::string &aName, const boolean3_uniform_type &a) const;
        //bool try_set_uniform(const std::string &aName, const boolean4_uniform_type &a) const;

        //bool try_set_uniform(const std::string &aName, const std::vector<bool> &aValue) const;
        //bool try_set_uniform(const std::string>&aName, const std::vector<boolean2_uniform_type> &a) const;
        //bool try_set_uniform(const std::string>&aName, const std::vector<boolean3_uniform_type> &a) const;
        //bool try_set_uniform(const std::string>&aName, const std::vector<boolean4_uniform_type> &a) const;

        /*//! assign a mat2x2 uniform from a mat2x2
        bool try_set_uniform(const std::string &aName, const graphics_mat2x2_type &avalue) const; 
        bool try_set_uniform(const std::string &aName, const std::vector<graphics_mat2x2_type> &avalue) const; 

        bool try_set_uniform(const std::string &aName, const graphics_mat3x3_type &avalue) const; 
        bool try_set_uniform(const std::string &aName, const std::vector<graphics_mat3x3_type> &avalue) const;*/

        bool try_set_uniform(const std::string &aName, const graphics_mat4x4_type &avalue) const; 
        bool try_set_uniform(const std::string &aName, const std::vector<graphics_mat4x4_type> &avalue) const; 

        //TODO: texture needs to support more than tex2d!
        bool try_set_uniform(const std::string &aName, const gdk::webgl1es2_texture &aTexture) const;

        //TODO: texture needs to support more than tex2d!
        //bool try_set_uniform(const std::string &aName, const gdk::texture &aTexture) const;

        void useProgram() const;
                
        bool operator==(const webgl1es2_shader_program &) const; 
        bool operator!=(const webgl1es2_shader_program &) const; 

        webgl1es2_shader_program(webgl1es2_shader_program &&) = default;
        webgl1es2_shader_program &operator=(webgl1es2_shader_program &&) = default;
        
        webgl1es2_shader_program(std::string aVertexSource, std::string aFragmentSource);

        static const jfc::shared_proxy_ptr<gdk::webgl1es2_shader_program> PinkShaderOfDeath;

        static const jfc::shared_proxy_ptr<gdk::webgl1es2_shader_program> AlphaCutOff;

        static const size_t MAX_TEXTURE_UNITS = 8;
    
    private:
        jfc::unique_handle<GLuint> m_VertexShaderHandle;

        jfc::unique_handle<GLuint> m_FragmentShaderHandle;

        jfc::unique_handle<GLuint> m_ProgramHandle; 

        active_attribute_collection_type m_ActiveAttributes;
        
        active_uniform_collection_type m_ActiveUniforms;
    };
}

#endif