godot/core/io/image_loader.cpp

/*************************************************************************/
/*  image_loader.cpp                                                     */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* included in all copies or substantial portions of the Software.       */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/*************************************************************************/

#include "image_loader.h"

#include "core/print_string.h"

bool ImageFormatLoader::recognize(const String &p_extension) const {
	List<String> extensions;
	get_recognized_extensions(&extensions);
	for (List<String>::Element *E = extensions.front(); E; E = E->next()) {
		if (E->get().nocasecmp_to(p_extension) == 0) {
			return true;
		}
	}

	return false;
}

Error ImageLoader::load_image(String p_file, Ref<Image> p_image, FileAccess *p_custom, bool p_force_linear, float p_scale) {
	ERR_FAIL_COND_V_MSG(p_image.is_null(), ERR_INVALID_PARAMETER, "It's not a reference to a valid Image object.");

	FileAccess *f = p_custom;
	if (!f) {
		Error err;
		f = FileAccess::open(p_file, FileAccess::READ, &err);
		if (!f) {
			ERR_PRINT("Error opening file '" + p_file + "'.");
			return err;
		}
	}

	String extension = p_file.get_extension();

	for (int i = 0; i < loader.size(); i++) {
		if (!loader[i]->recognize(extension)) {
			continue;
		}
		Error err = loader[i]->load_image(p_image, f, p_force_linear, p_scale);
		if (err != OK) {
			ERR_PRINT("Error loading image: " + p_file);
		}

		if (err != ERR_FILE_UNRECOGNIZED) {
			if (!p_custom) {
				memdelete(f);
			}

			return err;
		}
	}

	if (!p_custom) {
		memdelete(f);
	}

	return ERR_FILE_UNRECOGNIZED;
}

void ImageLoader::get_recognized_extensions(List<String> *p_extensions) {
	for (int i = 0; i < loader.size(); i++) {
		loader[i]->get_recognized_extensions(p_extensions);
	}
}

ImageFormatLoader *ImageLoader::recognize(const String &p_extension) {
	for (int i = 0; i < loader.size(); i++) {
		if (loader[i]->recognize(p_extension)) {
			return loader[i];
		}
	}

	return nullptr;
}

Vector<ImageFormatLoader *> ImageLoader::loader;

void ImageLoader::add_image_format_loader(ImageFormatLoader *p_loader) {
	loader.push_back(p_loader);
}

void ImageLoader::remove_image_format_loader(ImageFormatLoader *p_loader) {
	loader.erase(p_loader);
}

const Vector<ImageFormatLoader *> &ImageLoader::get_image_format_loaders() {
	return loader;
}

void ImageLoader::cleanup() {
	while (loader.size()) {
		remove_image_format_loader(loader[0]);
	}
}

/////////////////

RES ResourceFormatLoaderImage::load(const String &p_path, const String &p_original_path, Error *r_error, bool p_no_subresource_cache) {
	FileAccess *f = FileAccess::open(p_path, FileAccess::READ);
	if (!f) {
		if (r_error) {
			*r_error = ERR_CANT_OPEN;
		}
		return RES();
	}

	uint8_t header[4] = { 0, 0, 0, 0 };
	f->get_buffer(header, 4);

	bool unrecognized = header[0] != 'G' || header[1] != 'D' || header[2] != 'I' || header[3] != 'M';
	if (unrecognized) {
		memdelete(f);
		if (r_error) {
			*r_error = ERR_FILE_UNRECOGNIZED;
		}
		ERR_FAIL_V(RES());
	}

	String extension = f->get_pascal_string();

	int idx = -1;

	for (int i = 0; i < ImageLoader::loader.size(); i++) {
		if (ImageLoader::loader[i]->recognize(extension)) {
			idx = i;
			break;
		}
	}

	if (idx == -1) {
		memdelete(f);
		if (r_error) {
			*r_error = ERR_FILE_UNRECOGNIZED;
		}
		ERR_FAIL_V(RES());
	}

	Ref<Image> image;
	image.instance();

	Error err = ImageLoader::loader[idx]->load_image(image, f, false, 1.0);

	memdelete(f);

	if (err != OK) {
		if (r_error) {
			*r_error = err;
		}
		return RES();
	}

	if (r_error) {
		*r_error = OK;
	}

	return image;
}

void ResourceFormatLoaderImage::get_recognized_extensions(List<String> *p_extensions) const {
	p_extensions->push_back("image");
}

bool ResourceFormatLoaderImage::handles_type(const String &p_type) const {
	return p_type == "Image";
}

String ResourceFormatLoaderImage::get_resource_type(const String &p_path) const {
	return p_path.get_extension().to_lower() == "image" ? "Image" : String();
}