- /*
- * 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/gl/shader-template.hpp>
- #include <algorithm>
- #include <engine/gl/shader-object.hpp>
- #include <engine/gl/shader-program.hpp>
- #include <engine/resources/resource-loader.hpp>
- #include <engine/resources/resource-manager.hpp>
- #include <engine/utility/text-file.hpp>
- #include <engine/utility/hash/hash-combine.hpp>
- #include <sstream>
- #include <unordered_set>
-
- namespace gl {
-
- shader_template::shader_template(const text_file& source_code):
- m_template_source{source_code}
- {
- find_directives();
- rehash();
- }
-
- shader_template::shader_template(text_file&& source_code):
- m_template_source{source_code}
- {
- find_directives();
- rehash();
- }
-
- shader_template::shader_template(text_file&& source_code, std::vector<std::shared_ptr<text_file>>&& include_files):
- m_template_source{source_code},
- m_include_files{include_files}
- {
- find_directives();
- rehash();
- }
-
- void shader_template::source(const text_file& source_code)
- {
- m_template_source = source_code;
- m_include_files.clear();
- find_directives();
- rehash();
- }
-
- void shader_template::source(text_file&& source_code)
- {
- m_template_source = source_code;
- m_include_files.clear();
- find_directives();
- rehash();
- }
-
- std::string shader_template::configure(gl::shader_stage stage, const dictionary_type& definitions) const
- {
- replace_stage_directives(stage);
- replace_define_directives(definitions);
-
- // Join vector of source lines into single string
- std::string string;
- for (const auto& line: m_template_source.lines)
- {
- string += line;
- string += '\n';
- }
-
- return string;
- }
-
- std::unique_ptr<gl::shader_object> shader_template::compile(gl::shader_stage stage, const dictionary_type& definitions) const
- {
- // Generate shader object source
- const std::string object_source = configure(stage, definitions);
-
- // Create shader object
- std::unique_ptr<gl::shader_object> object = std::make_unique<gl::shader_object>(stage);
-
- // Set shader object source
- object->source(object_source);
-
- // Compile shader object
- object->compile();
-
- return object;
- }
-
- std::unique_ptr<gl::shader_program> shader_template::build(const dictionary_type& definitions) const
- {
- std::unique_ptr<gl::shader_object> vertex_object;
- std::unique_ptr<gl::shader_object> fragment_object;
- std::unique_ptr<gl::shader_object> geometry_object;
-
- // Create shader program
- std::unique_ptr<gl::shader_program> program = std::make_unique<gl::shader_program>();
-
- if (has_vertex_directive())
- {
- // Compile vertex shader object and attach to shader program
- vertex_object = compile(gl::shader_stage::vertex, definitions);
- program->attach(*vertex_object);
- }
-
- if (has_fragment_directive())
- {
- // Compile fragment shader object and attach to shader program
- fragment_object = compile(gl::shader_stage::fragment, definitions);
- program->attach(*fragment_object);
- }
-
- if (has_geometry_directive())
- {
- // Compile geometry shader object and attach to shader program
- geometry_object = compile(gl::shader_stage::geometry, definitions);
- program->attach(*geometry_object);
- }
-
- // Link attached shader objects into shader program
- program->link();
-
- // Detach all attached shader objects
- program->detach_all();
-
- return program;
- }
-
- void shader_template::find_directives()
- {
- // Reset directives
- m_vertex_directives.clear();
- m_fragment_directives.clear();
- m_geometry_directives.clear();
- m_define_directives.clear();
-
- // Parse directives
- for (std::size_t i = 0; i < m_template_source.lines.size(); ++i)
- {
- std::istringstream line_stream(m_template_source.lines[i]);
- std::string token;
-
- // Detect `#pragma` directives
- if (line_stream >> token && token == "#pragma")
- {
- if (line_stream >> token)
- {
- // Map line numbers of supported directives
- if (token == "define")
- {
- if (line_stream >> token)
- {
- m_define_directives.insert({token, i});
- }
- }
- else if (token == "vertex")
- {
- m_vertex_directives.insert(i);
- }
- else if (token == "fragment")
- {
- m_fragment_directives.insert(i);
- }
- else if (token == "geometry")
- {
- m_geometry_directives.insert(i);
- }
- }
- }
- }
- }
-
- void shader_template::rehash()
- {
- m_hash = 0;
- for (const auto& line: m_template_source.lines)
- {
- m_hash = hash_combine(m_hash, std::hash<std::string>{}(line));
- }
- }
-
- void shader_template::replace_stage_directives(gl::shader_stage stage) const
- {
- // Determine stage directives according to the shader stage being generated
- const char* vertex_directive = (stage == gl::shader_stage::vertex) ? "#define __VERTEX__" : "/* #undef __VERTEX__ */";
- const char* fragment_directive = (stage == gl::shader_stage::fragment) ? "#define __FRAGMENT__" : "/* #undef __FRAGMENT__ */";
- const char* geometry_directive = (stage == gl::shader_stage::geometry) ? "#define __GEOMETRY__" : "/* #undef __GEOMETRY__ */";
-
- // Handle `#pragma <stage>` directives
- for (const auto directive_line: m_vertex_directives)
- {
- m_template_source.lines[directive_line] = vertex_directive;
- }
- for (const auto directive_line: m_fragment_directives)
- {
- m_template_source.lines[directive_line] = fragment_directive;
- }
- for (const auto directive_line: m_geometry_directives)
- {
- m_template_source.lines[directive_line] = geometry_directive;
- }
- }
-
- void shader_template::replace_define_directives(const dictionary_type& definitions) const
- {
- // For each `#pragma define <key>` directive
- for (const auto& define_directive: m_define_directives)
- {
- // Get a reference to the directive line
- std::string& line = m_template_source.lines[define_directive.second];
-
- // Check if the corresponding definition was given by the configuration
- auto definitions_it = definitions.find(define_directive.first);
- if (definitions_it != definitions.end())
- {
- // Definition found, replace `#pragma define <key>` with `#define <key>` or `#define <key> <value>`
- line = "#define " + define_directive.first;
- if (!definitions_it->second.empty())
- {
- line += " " + definitions_it->second;
- }
- }
- else
- {
- // Definition not found, replace `#pragma define <key>` with the comment `/* #undef <key> */`.
- line = "/* #undef " + define_directive.first + " */";
- }
- }
- }
-
- bool shader_template::has_define_directive(const std::string& key) const
- {
- return (m_define_directives.find(key) != m_define_directives.end());
- }
-
- } // namespace gl
-
- /**
- * Scans a text file for the presence of a `#pragma once` directive.
- *
- * @param source Text file to scan.
- *
- * @return `true` if the file contains a `#pragma once` directive, `false` otherwise.
- */
- static bool has_pragma_once(const text_file& source)
- {
- for (const auto& line: source.lines)
- {
- std::istringstream line_stream(line);
- std::string token;
-
- // If line contains a `#pragma once` directive
- if (line_stream >> token && token == "#pragma")
- {
- if (line_stream >> token && token == "once")
- {
- return true;
- }
- }
- }
-
- return false;
- }
-
- /**
- * Handles `#pragma include` directives by loading the specified text files and inserting them in place.
- */
- static void handle_includes(std::vector<std::shared_ptr<text_file>>& include_files, text_file& source, std::unordered_set<std::filesystem::path>& include_once, resource_manager& resource_manager)
- {
- // For each line in the source
- for (std::size_t i = 0; i < source.lines.size(); ++i)
- {
- std::string token;
- std::istringstream line_stream(source.lines[i]);
-
- // If line contains a `#pragma include` directive
- if (line_stream >> token && token == "#pragma" &&
- line_stream >> token && token == "include")
- {
- // If third token is enclosed in quotes or angled brackets
- if (line_stream >> token && token.size() > 2 &&
- ((token.front() == '\"' && token.back() == '\"') ||
- (token.front() == '<' && token.back() == '>')))
- {
- // Extract include path
- const std::filesystem::path path = token.substr(1, token.length() - 2);
-
- // Skip pre-included files that contain a `#pragma once` directive
- if (include_once.contains(path))
- {
- source.lines[i] = "/* #pragma exclude " + token + " */";
- continue;
- }
-
- // Load include file
- auto include_file = resource_manager.load<text_file>(path);
- if (!include_file)
- {
- source.lines[i] = "#error file not found: " + path.string();
- continue;
- }
- else
- {
- include_files.emplace_back(include_file);
- }
-
- // If file has `#pragma once` directive
- if (has_pragma_once(*include_file))
- {
- // Add file to set of files to include once
- include_once.insert(path);
- }
-
- // Create a copy of the include file
- text_file include_file_copy = *include_file;
-
- // Handle `#pragma include` directives inside include file
- handle_includes(include_files, include_file_copy, include_once, resource_manager);
-
- // Replace #pragma include directive with include file contents
- source.lines.erase(source.lines.begin() + i);
- source.lines.insert(source.lines.begin() + i, include_file_copy.lines.begin(), include_file_copy.lines.end());
- i += include_file_copy.lines.size() - 1;
- }
- else
- {
- source.lines[i] = "#error malformed include directive: \"" + source.lines[i] + "\"";
- }
- }
- }
- }
-
- template <>
- std::unique_ptr<gl::shader_template> resource_loader<gl::shader_template>::load(::resource_manager& resource_manager, deserialize_context& ctx)
- {
- // Load shader template source file
- const auto source_file = resource_loader<text_file>::load(resource_manager, ctx);
-
- // Make a copy of the shader template source file
- text_file source_file_copy = *source_file;
-
- std::vector<std::shared_ptr<text_file>> include_files;
-
- // Handle `#pragma include` directives
- std::unordered_set<std::filesystem::path> include_once;
- include_once.insert(ctx.path());
- handle_includes(include_files, source_file_copy, include_once, resource_manager);
-
- // Construct shader template
- return std::make_unique<gl::shader_template>(std::move(source_file_copy), std::move(include_files));
- }
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