texture-cube.cpp

Go to the documentation of this file.

/*
 * 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/texture-cube.hpp>
#include <cmath>
 
namespace gl {
 
cube_map_layout texture_cube::infer_cube_map_layout(std::uint16_t w, std::uint16_t h) noexcept
{
    if (h == w * 6)
    {
        return cube_map_layout::column;
    }
    else if (w == h * 6)
    {
        return cube_map_layout::row;
    }
    else if (w == (h / 4) * 3)
    {
        return cube_map_layout::vertical_cross;
    }
    else if (h == (w / 4) * 3)
    {
        return cube_map_layout::horizontal_cross;
    }
    else if (w == h * 2)
    {
        return cube_map_layout::equirectangular;
    }
    else if (w == h)
    {
        return cube_map_layout::spherical;
    }
    
    return {};
}
 
std::uint16_t texture_cube::infer_cube_map_face_size(cube_map_layout layout, std::uint16_t w, std::uint16_t h) noexcept
{
    switch (layout)
    {
        case cube_map_layout::column:
        case cube_map_layout::spherical:
            return w;
        
        case cube_map_layout::row:
            return h;
        
        case cube_map_layout::vertical_cross:
            return h / 4;
        
        case cube_map_layout::horizontal_cross:
        case cube_map_layout::equirectangular:
            return w / 4;
        
        default:
            return 0;
    }
}
 
texture_cube::texture_cube(std::uint16_t width, std::uint16_t height, gl::pixel_type type, gl::pixel_format format, gl::transfer_function transfer_function, const std::byte* data):
    texture(width, height, true, type, format, transfer_function, data)
{
    resized();
}
 
void texture_cube::resize(std::uint16_t width, std::uint16_t height, gl::pixel_type type, gl::pixel_format format, gl::transfer_function transfer_function, const std::byte* data)
{
    texture::resize(width, height, type, format, transfer_function, data);
    resized();
}
 
void texture_cube::resize(std::uint16_t width, std::uint16_t height, const std::byte* data)
{
    texture::resize(width, height, get_pixel_type(), get_pixel_format(), get_transfer_function(), data);
    resized();
}
 
void texture_cube::set_wrapping(gl::texture_wrapping wrap_s, texture_wrapping wrap_t, texture_wrapping wrap_r)
{
    texture::set_wrapping(wrap_s, wrap_t, wrap_r);
}
 
void texture_cube::resized()
{
    const auto w = get_width();
    const auto h = get_height();
    const auto layout = infer_cube_map_layout(w, h);
    m_face_size = infer_cube_map_face_size(layout, w, h);
    m_mip_count = 1 + static_cast<std::uint16_t>(std::log2(m_face_size));
}
 
} // namespace gl