material.cpp

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/*
 * Copyright (C) 2023  Christopher J. Howard
 *
 * This file is part of Antkeeper source code.
 *
 * Antkeeper source code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Antkeeper source code is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#include <engine/render/material.hpp>
#include <engine/render/material-variable.hpp>
#include <engine/resources/resource-loader.hpp>
#include <engine/resources/resource-manager.hpp>
#include <engine/render/material-flags.hpp>
#include <engine/utility/json.hpp>
#include <engine/utility/hash/hash-combine.hpp>
#include <utility>
#include <type_traits>
#include <string>
 
namespace render {
 
material::material(const material& other)
{
    *this = other;
}
 
material& material::operator=(const material& other)
{
    two_sided = other.two_sided;
    blend_mode = other.blend_mode;
    shadow_mode = other.shadow_mode;
    flags = other.flags;
    shader_template = other.shader_template;
    
    variable_map.clear();
    for (const auto& [key, value]: other.variable_map)
    {
        if (value)
        {
            variable_map.emplace(key, value->clone());
        }
    }
    
    m_hash = other.m_hash;
    
    return *this;
}
 
void material::set_two_sided(bool two_sided) noexcept
{
    this->two_sided = two_sided;
    
    rehash();
}
 
void material::set_blend_mode(material_blend_mode mode) noexcept
{
    blend_mode = mode;
    
    rehash();
}
 
void material::set_shadow_mode(material_shadow_mode mode) noexcept
{
    shadow_mode = mode;
    
    rehash();
}
 
void material::set_flags(std::uint32_t flags) noexcept
{
    this->flags = flags;
    
    rehash();
}
 
void material::set_shader_template(std::shared_ptr<gl::shader_template> shader_template)
{
    this->shader_template = shader_template;
    
    rehash();
}
 
void material::set_variable(hash::fnv1a32_t key, std::shared_ptr<material_variable_base> value)
{
    variable_map[key] = std::move(value);
}
 
std::shared_ptr<material_variable_base> material::get_variable(hash::fnv1a32_t key) const
{
    if (auto i = variable_map.find(key); i != variable_map.end())
    {
        return i->second;
    }
    
    return nullptr;
}
 
void material::rehash() noexcept
{
    m_hash = 0;
    if (shader_template)
    {
        m_hash = shader_template->hash();
    }
    
    m_hash = hash_combine(m_hash, std::hash<bool>{}(two_sided));
    m_hash = hash_combine(m_hash, std::hash<material_blend_mode>{}(blend_mode));
    m_hash = hash_combine(m_hash, std::hash<material_shadow_mode>{}(shadow_mode));
    m_hash = hash_combine(m_hash, std::hash<std::uint32_t>{}(flags));
}
 
} // namespace render
 
template <typename T>
static bool read_value(T* value, const nlohmann::json& json, const std::string& name)
{
    if (auto element = json.find(name); element != json.end())
    {
        *value = element.value().get<T>();
        return true;
    }
    
    return false;
}
 
static bool load_texture_1d_property(resource_manager& resource_manager, render::material& material, hash::fnv1a32_t key, const nlohmann::json& json)
{
    // If JSON element is an array
    if (json.is_array())
    {
        // Create variable
        auto variable = std::make_shared<render::matvar_texture_1d>(json.size());
        
        // Load textures
        std::size_t i = 0;
        for (const auto& element: json)
        {
            variable->set(i, resource_manager.load<gl::texture_1d>(element.get<std::string>()));
            ++i;
        }
        
        material.set_variable(key, variable);
    }
    else
    {
        // Create variable
        auto variable = std::make_shared<render::matvar_texture_1d>(json.size());
        
        // Load texture
        variable->set(resource_manager.load<gl::texture_1d>(json.get<std::string>()));
        
        material.set_variable(key, variable);
    }
    
    return true;
}
 
static bool load_texture_2d_property(resource_manager& resource_manager, render::material& material, hash::fnv1a32_t key, const nlohmann::json& json)
{
    // If JSON element is an array
    if (json.is_array())
    {
        // Create variable
        auto variable = std::make_shared<render::matvar_texture_2d>(json.size());
        
        // Load textures
        std::size_t i = 0;
        for (const auto& element: json)
        {
            variable->set(i, resource_manager.load<gl::texture_2d>(element.get<std::string>()));
            ++i;
        }
        
        material.set_variable(key, variable);
    }
    else
    {
        // Create variable
        auto variable = std::make_shared<render::matvar_texture_2d>(json.size());
        
        // Load texture
        variable->set(resource_manager.load<gl::texture_2d>(json.get<std::string>()));
        
        material.set_variable(key, variable);
    }
    
    return true;
}
 
static bool load_texture_3d_property(resource_manager& resource_manager, render::material& material, hash::fnv1a32_t key, const nlohmann::json& json)
{
    // If JSON element is an array
    if (json.is_array())
    {
        // Create variable
        auto variable = std::make_shared<render::matvar_texture_3d>(json.size());
        
        // Load textures
        std::size_t i = 0;
        for (const auto& element: json)
        {
            variable->set(i, resource_manager.load<gl::texture_3d>(element.get<std::string>()));
            ++i;
        }
        
        material.set_variable(key, variable);
    }
    else
    {
        // Create variable
        auto variable = std::make_shared<render::matvar_texture_3d>(json.size());
        
        // Load texture
        variable->set(resource_manager.load<gl::texture_3d>(json.get<std::string>()));
        
        material.set_variable(key, variable);
    }
    
    return true;
}
 
static bool load_texture_cube_property(resource_manager& resource_manager, render::material& material, hash::fnv1a32_t key, const nlohmann::json& json)
{
    // If JSON element is an array
    if (json.is_array())
    {
        // Create variable
        auto variable = std::make_shared<render::matvar_texture_cube>(json.size());
        
        // Load textures
        std::size_t i = 0;
        for (const auto& element: json)
        {
            variable->set(i, resource_manager.load<gl::texture_cube>(element.get<std::string>()));
            ++i;
        }
        
        material.set_variable(key, variable);
    }
    else
    {
        // Create variable
        auto variable = std::make_shared<render::matvar_texture_cube>(json.size());
        
        // Load texture
        variable->set(resource_manager.load<gl::texture_cube>(json.get<std::string>()));
        
        material.set_variable(key, variable);
    }
    
    return true;
}
 
template <typename T>
static bool load_scalar_property(render::material& material, hash::fnv1a32_t key, const nlohmann::json& json)
{
    // If JSON element is an array
    if (json.is_array())
    {
        // Create variable
        auto variable = std::make_shared<render::material_variable<T>>(json.size());
        
        // Set variable values
        std::size_t i = 0;
        for (const auto& element: json)
        {
            variable->set(i, element.get<T>());
        }
        
        material.set_variable(key, variable);
    }
    else
    {
        material.set_variable(key, std::make_shared<render::material_variable<T>>(1, json.get<T>()));
    }
    
    return true;
}
 
template <typename T>
static bool load_vector_property(render::material& material, hash::fnv1a32_t key, std::size_t vector_size, const nlohmann::json& json)
{
    // If JSON element is an array of arrays
    if (json.is_array() && json.begin().value().is_array())
    {
        // Create variable
        auto variable = std::make_shared<render::material_variable<T>>(json.size());
        
        // For each vector in the array
        std::size_t i = 0;
        for (const auto& vector_element: json)
        {
            // Read vector elements
            T value;
            std::size_t j = 0;
            for (const auto& value_element: vector_element)
                value[j++] = value_element.get<typename T::element_type>();
            
            variable->set(i, value);
            
            ++i;
        }
        
        material.set_variable(key, variable);
    }
    else
    {
        // Read vector elements
        T value;
        std::size_t i = 0;
        for (const auto& value_element: json)
            value[i++] = value_element.get<typename T::element_type>();
        
        material.set_variable(key, std::make_shared<render::material_variable<T>>(1, value));
    }
    
    return true;
}
 
template <typename T>
static bool load_matrix_property(render::material& material, hash::fnv1a32_t key, std::size_t column_count, std::size_t row_count, const nlohmann::json& json)
{
    // If JSON element is an array of arrays of arrays
    if (json.is_array() && json.begin().value().is_array())
    {
        if (json.begin().value().begin().value().is_array())
        {
            // Create variable
            auto variable = std::make_shared<render::material_variable<T>>(json.size());
            
            // For each matrix in the array
            std::size_t i = 0;
            for (const auto& matrix_element: json)
            {
                // Read vector elements
                T value;
                std::size_t j = 0;
                for (const auto& column_element: matrix_element)
                {
                    std::size_t k = 0;
                    for (const auto& row_element: column_element)
                    {
                        value[j][k] = row_element.get<typename T::element_type>();
                        ++k;
                    }
                    
                    ++j;
                }
                
                // Set matrix value
                variable->set(i, value);
                
                ++i;
            }
            
            material.set_variable(key, variable);
            
            return true;
        }
        else
        {
            // Read matrix elements
            T value;
            std::size_t i = 0;
            for (const auto& column_element: json)
            {
                std::size_t j = 0;
                for (const auto& row_element: column_element)
                {
                    value[i][j] = row_element.get<typename T::element_type>();
                    ++j;
                }
                
                ++i;
            }
            
            material.set_variable(key, std::make_shared<render::material_variable<T>>(1, value));
            
            return true;
        }
    }
    
    return false;
}
 
template <>
std::unique_ptr<render::material> resource_loader<render::material>::load(::resource_manager& resource_manager, deserialize_context& ctx)
{
    auto material = std::make_unique<render::material>();
    
    // Load JSON data
    auto json = resource_loader<nlohmann::json>::load(resource_manager, ctx);
    
    // Read two sided
    bool two_sided = false;
    read_value(&two_sided, *json, "two_sided");
    material->set_two_sided(two_sided);
    
    // Read blend mode
    std::string blend_mode;
    read_value(&blend_mode, *json, "blend_mode");
    if (blend_mode == "opaque")
    {
        material->set_blend_mode(render::material_blend_mode::opaque);
    }
    else if (blend_mode == "masked")
    {
        material->set_blend_mode(render::material_blend_mode::masked);
    }
    else if (blend_mode == "translucent")
    {
        material->set_blend_mode(render::material_blend_mode::translucent);
    }
    
    // Read shadow mode
    std::string shadow_mode;
    read_value(&shadow_mode, *json, "shadow_mode");
    if (shadow_mode == "opaque")
    {
        material->set_shadow_mode(render::material_shadow_mode::opaque);
    }
    else if (shadow_mode == "none")
    {
        material->set_shadow_mode(render::material_shadow_mode::none);
    }
    
    // Init material flags
    std::uint32_t flags = 0;
    
    // Read depth mode
    std::string depth_mode;
    read_value(&depth_mode, *json, "depth_mode");
    if (depth_mode == "in_front")
        flags |= MATERIAL_FLAG_X_RAY;
    
    // Read decal mode
    std::string decal_mode;
    read_value(&decal_mode, *json, "decal_mode");
    if (decal_mode == "decal")
        flags |= MATERIAL_FLAG_DECAL;
    else if (decal_mode == "surface")
        flags |= MATERIAL_FLAG_DECAL_SURFACE;
    
    // Set material flags
    material->set_flags(flags);
    
    // Read shader template filename
    std::string shader_template_filename;
    if (read_value(&shader_template_filename, *json, "shader_template"))
    {
        // Loader shader template
        material->set_shader_template(resource_manager.load<gl::shader_template>(shader_template_filename));
    }
    
    // Read material variables
    if (auto variables_element = json->find("variables"); variables_element != json->end())
    {
        for (const auto& variable_element: variables_element.value())
        {
            // Read variable name
            std::string name;
            if (!read_value(&name, variable_element, "name"))
            {
                // Ignore nameless properties
                continue;
            }
            
            // Read variable type
            std::string type;
            if (!read_value(&type, variable_element, "type"))
            {
                // Ignore typeless properties
                continue;
            }
            
            // Find value element
            auto value_element = variable_element.find("value");
            if (value_element == variable_element.end())
            {
                // Ignore valueless properties
                continue;
            }
            
            // Hash variable name
            const hash::fnv1a32_t key = hash::fnv1a32<char>(name);
            
            if (type == "texture_1d")
            {
                load_texture_1d_property(resource_manager, *material, key, value_element.value());
            }
            else if (type == "texture_2d")
            {
                load_texture_2d_property(resource_manager, *material, key, value_element.value());
            }
            else if (type == "texture_3d")
            {
                load_texture_3d_property(resource_manager, *material, key, value_element.value());
            }
            else if (type == "texture_cube")
            {
                load_texture_cube_property(resource_manager, *material, key, value_element.value());
            }
            // If variable type is a matrix
            else if (type[type.size() - 2] == 'x' &&
                std::isdigit(type[type.size() - 3]) &&
                std::isdigit(type.back()))
            {
                std::size_t columns = std::stoul(type.substr(type.size() - 3, 1));
                std::size_t rows = std::stoul(type.substr(type.size() - 1, 1));
                
                if (type.find("float") != std::string::npos)
                {
                    if (columns == 2 && rows == 2)
                        load_matrix_property<math::fmat2>(*material, key, columns, rows, value_element.value());
                    else if (columns == 3 && rows == 3)
                        load_matrix_property<math::fmat3>(*material, key, columns, rows, value_element.value());
                    else if (columns == 4 && rows == 4)
                        load_matrix_property<math::fmat4>(*material, key, columns, rows, value_element.value());
                }
            }
            // If variable type is a vector
            else if (std::isdigit(type.back()))
            {
                std::size_t size = std::stoul(type.substr(type.size() - 1, 1));
                
                if (type.find("float") != std::string::npos)
                {
                    if (size == 2)
                        load_vector_property<math::fvec2>(*material, key, size, value_element.value());
                    else if (size == 3)
                        load_vector_property<math::fvec3>(*material, key, size, value_element.value());
                    else if (size == 4)
                        load_vector_property<math::fvec4>(*material, key, size, value_element.value());
                }
                else if (type.find("uint") != std::string::npos)
                {
                    if (size == 2)
                        load_vector_property<math::uvec2>(*material, key, size, value_element.value());
                    else if (size == 3)
                        load_vector_property<math::uvec3>(*material, key, size, value_element.value());
                    else if (size == 4)
                        load_vector_property<math::uvec4>(*material, key, size, value_element.value());
                }
                else if (type.find("int") != std::string::npos)
                {
                    if (size == 2)
                        load_vector_property<math::ivec2>(*material, key, size, value_element.value());
                    else if (size == 3)
                        load_vector_property<math::ivec3>(*material, key, size, value_element.value());
                    else if (size == 4)
                        load_vector_property<math::ivec4>(*material, key, size, value_element.value());
                }
                else if (type.find("bool") != std::string::npos)
                {
                    if (size == 2)
                        load_vector_property<math::bvec2>(*material, key, size, value_element.value());
                    else if (size == 3)
                        load_vector_property<math::bvec3>(*material, key, size, value_element.value());
                    else if (size == 4)
                        load_vector_property<math::bvec4>(*material, key, size, value_element.value());
                }
            }
            // If variable type is a scalar
            else
            {
                if (type.find("float") != std::string::npos)
                    load_scalar_property<float>(*material, key, value_element.value());
                else if (type.find("uint") != std::string::npos)
                    load_scalar_property<unsigned int>(*material, key, value_element.value());
                else if (type.find("int") != std::string::npos)
                    load_scalar_property<int>(*material, key, value_element.value());
                else if (type.find("bool") != std::string::npos)
                    load_scalar_property<bool>(*material, key, value_element.value());
            }
        }
    }
    
    return material;
}