shader-template.hpp

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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/>.
 */
 
#ifndef ANTKEEPER_GL_SHADER_TEMPLATE_HPP
#define ANTKEEPER_GL_SHADER_TEMPLATE_HPP
 
#include <engine/gl/shader-object.hpp>
#include <engine/gl/shader-program.hpp>
#include <engine/utility/text-file.hpp>
#include <map>
#include <memory>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
 
namespace gl {
 
class shader_template
{
public:
    using dictionary_type = std::unordered_map<std::string, std::string>;
    
    explicit shader_template(const text_file& source_code);
    explicit shader_template(text_file&& source_code);
    
    shader_template(text_file&& source_code, std::vector<std::shared_ptr<text_file>>&& include_files);
    
    constexpr shader_template() noexcept = default;
    
    void source(const text_file& source_code);
    void source(text_file&& source_code);
    
    [[nodiscard]] std::string configure(gl::shader_stage stage, const dictionary_type& definitions = {}) const;
    
    [[nodiscard]] std::unique_ptr<gl::shader_object> compile(gl::shader_stage stage, const dictionary_type& definitions = {}) const;
    
    [[nodiscard]] std::unique_ptr<gl::shader_program> build(const dictionary_type& definitions = {}) const;
    
    [[nodiscard]] inline bool has_vertex_directive() const noexcept
    {
        return !m_vertex_directives.empty();
    }
    
    [[nodiscard]] inline bool has_fragment_directive() const noexcept
    {
        return !m_fragment_directives.empty();
    }
    
    [[nodiscard]] inline bool has_geometry_directive() const noexcept
    {
        return !m_geometry_directives.empty();
    }
    
    [[nodiscard]] bool has_define_directive(const std::string& key) const;
    
    [[nodiscard]] inline constexpr std::size_t hash() const noexcept
    {
        return m_hash;
    }
    
private:
    void find_directives();
    void rehash();
    void replace_stage_directives(gl::shader_stage stage) const;
    void replace_define_directives(const dictionary_type& definitions) const;
    
    mutable text_file m_template_source;
    std::unordered_set<std::size_t> m_vertex_directives;
    std::unordered_set<std::size_t> m_fragment_directives;
    std::unordered_set<std::size_t> m_geometry_directives;
    std::multimap<std::string, std::size_t> m_define_directives;
    std::size_t m_hash{0};
    std::vector<std::shared_ptr<text_file>> m_include_files;
};
 
} // namespace gl
 
#endif // ANTKEEPER_GL_SHADER_TEMPLATE_HPP