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- /*
- * Copyright (C) 2021 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 "gl/shader-object.hpp"
- #include <glad/glad.h>
- #include <stdexcept>
-
- namespace gl {
-
- static constexpr GLenum gl_shader_type_lut[] =
- {
- GL_VERTEX_SHADER,
- GL_FRAGMENT_SHADER,
- GL_GEOMETRY_SHADER
- };
-
- shader_object::shader_object(shader_stage stage):
- gl_shader_id(0),
- stage(stage),
- compiled(false)
- {
- // Look up OpenGL shader type enumeration that corresponds to the given stage
- GLenum gl_shader_type = gl_shader_type_lut[static_cast<std::size_t>(stage)];
-
- // Create an OpenGL shader object
- gl_shader_id = glCreateShader(gl_shader_type);
-
- // Handle OpenGL errors
- if (!gl_shader_id)
- {
- throw std::runtime_error("An error occurred while creating an OpenGL shader object.");
- }
- }
-
- shader_object::~shader_object()
- {
- // Flags the OpenGL shader object for deletion
- glDeleteShader(gl_shader_id);
- }
-
- void shader_object::source(const char* buffer, std::size_t size)
- {
- // Replace OpenGL shader object source code
- GLint gl_length = size;
- glShaderSource(gl_shader_id, 1, &buffer, &gl_length);
-
- // Handle OpenGL errors
- switch (glGetError())
- {
- case GL_INVALID_VALUE:
- throw std::runtime_error("Shader object handle is not a value generated by OpenGL.");
- break;
-
- case GL_INVALID_OPERATION:
- throw std::runtime_error("Shader object handle is not a shader object.");
- break;
- }
- }
-
- bool shader_object::compile()
- {
- // Compile OpenGL shader object
- glCompileShader(gl_shader_id);
-
- // Handle OpenGL errors
- switch (glGetError())
- {
- case GL_INVALID_VALUE:
- throw std::runtime_error("Shader object handle is not a value generated by OpenGL.");
- break;
-
- case GL_INVALID_OPERATION:
- throw std::runtime_error("Shader object handle is not a shader object.");
- break;
- }
-
- // Get OpenGL shader object compilation status
- GLint gl_compile_status;
- glGetShaderiv(gl_shader_id, GL_COMPILE_STATUS, &gl_compile_status);
- compiled = (gl_compile_status == GL_TRUE);
-
- // Get OpenGL shader object info log length
- GLint gl_info_log_length;
- glGetShaderiv(gl_shader_id, GL_INFO_LOG_LENGTH, &gl_info_log_length);
-
- if (gl_info_log_length > 0)
- {
- // Resize string to accommodate OpenGL shader object info log
- info_log.resize(gl_info_log_length);
-
- // Read OpenGL shader object info log into string
- glGetShaderInfoLog(gl_shader_id, gl_info_log_length, &gl_info_log_length, info_log.data());
-
- // Remove redundant null terminator from string
- info_log.pop_back();
- }
- else
- {
- // Empty info log
- info_log.clear();
- }
-
- // Return compilation status
- return compiled;
- }
-
- } // namespace gl
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