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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/vertex-buffer.hpp"
- #include <stdexcept>
- #include <glad/glad.h>
-
- namespace gl {
-
- static constexpr GLenum buffer_usage_lut[] =
- {
- GL_STREAM_DRAW,
- GL_STREAM_READ,
- GL_STREAM_COPY,
- GL_STATIC_DRAW,
- GL_STATIC_READ,
- GL_STATIC_COPY,
- GL_DYNAMIC_DRAW,
- GL_DYNAMIC_READ,
- GL_DYNAMIC_COPY
- };
-
- vertex_buffer::vertex_buffer(std::size_t size, const void* data, buffer_usage usage):
- gl_buffer_id(0),
- size(size),
- usage(usage)
- {
- GLenum gl_usage = buffer_usage_lut[static_cast<std::size_t>(usage)];
- glGenBuffers(1, &gl_buffer_id);
- glBindBuffer(GL_ARRAY_BUFFER, gl_buffer_id);
- glBufferData(GL_ARRAY_BUFFER, static_cast<GLsizeiptr>(size), data, gl_usage);
- }
-
- vertex_buffer::vertex_buffer():
- vertex_buffer(0, nullptr, buffer_usage::static_draw)
- {}
-
- vertex_buffer::~vertex_buffer()
- {
- glDeleteBuffers(1, &gl_buffer_id);
- }
-
- void vertex_buffer::repurpose(buffer_usage usage, std::size_t size, const void* data)
- {
- this->size = size;
- this->usage = usage;
-
- GLenum gl_usage = buffer_usage_lut[static_cast<std::size_t>(usage)];
- glBindBuffer(GL_ARRAY_BUFFER, gl_buffer_id);
- glBufferData(GL_ARRAY_BUFFER, static_cast<GLsizeiptr>(size), data, gl_usage);
- }
-
- void vertex_buffer::resize(std::size_t size, const void* data)
- {
- repurpose(usage, size, data);
- }
-
- void vertex_buffer::write(std::size_t offset, std::size_t size, const void* data)
- {
- // Abort empty write operations
- if (!size)
- return;
-
- // Bounds check
- if (offset + size > this->size)
- throw std::out_of_range("Vertex buffer write operation exceeded buffer bounds.");
-
- glBindBuffer(GL_ARRAY_BUFFER, gl_buffer_id);
- glBufferSubData(GL_ARRAY_BUFFER, static_cast<GLintptr>(offset), static_cast<GLsizeiptr>(size), data);
- }
-
- void vertex_buffer::read(std::size_t offset, std::size_t size, void* data) const
- {
- // Abort empty read operations
- if (!size)
- return;
-
- // Bounds check
- if (offset + size > this->size)
- throw std::out_of_range("Vertex buffer read operation exceeded buffer bounds.");
-
- glBindBuffer(GL_ARRAY_BUFFER, gl_buffer_id);
- glGetBufferSubData(GL_ARRAY_BUFFER, static_cast<GLintptr>(offset), static_cast<GLsizeiptr>(size), data);
- }
-
- } // namespace gl
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