antkeeper
/
source


								/*

								 * 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 "resource-loader.hpp"

								#include "stb/stb_image.h"

								#include "resources/image.hpp"

								#include <cstring>

								#include <stdexcept>

								#include <physfs.h>

								#include <tinyexr.h>


								template <>

								image* resource_loader<image>::load(resource_manager* resource_manager, PHYSFS_File* file, const std::filesystem::path& path)

								{

									unsigned char* buffer;

									int size;

									::image* image = nullptr;


									// Read input stream into buffer

									size = static_cast<int>(PHYSFS_fileLength(file));

									buffer = new unsigned char[size];

									PHYSFS_readBytes(file, buffer, size);


									// Select loader according to file extension

									if (path.extension() == ".exr")

									{

										// Load OpenEXR with TinyEXR

										int status = TINYEXR_SUCCESS;

										const char* error = nullptr;


										// Read EXR version

										EXRVersion exr_version;

										status = ParseEXRVersionFromMemory(&exr_version, buffer, size);

										if (status != TINYEXR_SUCCESS)

										{

											delete[] buffer;

											throw std::runtime_error("TinyEXR parse version error (" + std::to_string(status) + "): invalid EXR file");

										}


										// Check if image is multipart

										if (exr_version.multipart)

										{

											throw std::runtime_error("OpenEXR multipart images not supported");

										}


										// Read EXR header

										EXRHeader exr_header;

										InitEXRHeader(&exr_header);

										status = ParseEXRHeaderFromMemory(&exr_header, &exr_version, buffer, size, &error);

										if (status != TINYEXR_SUCCESS)

										{

											std::string error_string(error);

											FreeEXRErrorMessage(error);

											delete[] buffer;

											throw std::runtime_error("TinyEXR parse header error (" + std::to_string(status) + "): " + error_string);

										}


										// Check if image is tiled

										if (exr_header.tiled)

										{

											FreeEXRHeader(&exr_header);

											delete[] buffer;

											throw std::runtime_error("OpenEXR tiled images not supported");

										}


										// Read half channels as float

										for (int i = 0; i < exr_header.num_channels; ++i)

										{

											if (exr_header.pixel_types[i] == TINYEXR_PIXELTYPE_HALF)

											{

												exr_header.requested_pixel_types[i] = TINYEXR_PIXELTYPE_FLOAT;

											}

										}


										// Read EXR data

										EXRImage exr_image;

										InitEXRImage(&exr_image);

										status = LoadEXRImageFromMemory(&exr_image, &exr_header, buffer, size, &error);

										if (status != TINYEXR_SUCCESS)

										{

											std::string error_string(error);

											FreeEXRErrorMessage(error);

											FreeEXRHeader(&exr_header);

											delete[] buffer;

											throw std::runtime_error("TinyEXR load error (" + std::to_string(status) + "): " + error_string);

										}


										// Free file buffer

										delete[] buffer;


										// Create image

										image = new ::image();

										image->format(sizeof(float), exr_image.num_channels);

										image->resize(static_cast<unsigned int>(exr_image.width), static_cast<unsigned int>(exr_image.height));


										// Fill image pixels

										float* component = static_cast<float*>(image->get_pixels());

										for (int y = exr_image.height - 1; y >= 0; --y)

										{

											int row_offset = y * exr_image.width;


											for (int x = 0; x < exr_image.width; ++x)

											{

												int pixel_index = row_offset + x;


												for (int c = exr_image.num_channels - 1; c >= 0; --c)

												{

													*(component++) = reinterpret_cast<float**>(exr_image.images)[c][pixel_index];

												}

											}

										}


										// Free EXR data

										FreeEXRImage(&exr_image);

										FreeEXRHeader(&exr_header);

									}

									else

									{

										// Load all other formats with stb_image


										// Determine if image is in an HDR format

										bool hdr = (stbi_is_hdr_from_memory(buffer, size) != 0);


										// Set vertical flip on load in order to upload pixels correctly to OpenGL

										stbi_set_flip_vertically_on_load(true);


										// Load image data

										void* pixels = nullptr;

										int width = 0;

										int height = 0;

										int channels = 0;

										if (hdr)

										{

											pixels = stbi_loadf_from_memory(buffer, size, &width, &height, &channels, 0);

										}

										else

										{

											pixels = stbi_load_from_memory(buffer, size, &width, &height, &channels, 0);

										}


										// Free file buffer

										delete[] buffer;


										// Check if image was loaded

										if (!pixels)

										{

											throw std::runtime_error("STBI failed to load image from memory.");

										}


										// Create image

										std::size_t component_size = (hdr) ? sizeof(float) : sizeof(unsigned char);

										image = new ::image();

										image->format(component_size, channels);

										image->resize(static_cast<unsigned int>(width), static_cast<unsigned int>(height));

										std::memcpy(image->get_pixels(), pixels, image->get_size());


										// Free loaded image data

										stbi_image_free(pixels);

									}


									return image;

								}