godot/drivers/png/resource_saver_png.cpp

/*************************************************************************/
/*  resource_saver_png.cpp                                               */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "resource_saver_png.h"

#include "core/image.h"
#include "globals.h"
#include "os/file_access.h"
#include "scene/resources/texture.h"

#include <png.h>

static void _write_png_data(png_structp png_ptr, png_bytep data, png_size_t p_length) {

	FileAccess *f = (FileAccess *)png_get_io_ptr(png_ptr);
	f->store_buffer((const uint8_t *)data, p_length);
}

Error ResourceSaverPNG::save(const String &p_path, const RES &p_resource, uint32_t p_flags) {

	Ref<ImageTexture> texture = p_resource;

	ERR_FAIL_COND_V(!texture.is_valid(), ERR_INVALID_PARAMETER);
	ERR_EXPLAIN("Can't save empty texture as PNG");
	ERR_FAIL_COND_V(!texture->get_width() || !texture->get_height(), ERR_INVALID_PARAMETER);

	Image img = texture->get_data();

	Error err = save_image(p_path, img);

	if (err == OK) {

		bool global_filter = Globals::get_singleton()->get("image_loader/filter");
		bool global_mipmaps = Globals::get_singleton()->get("image_loader/gen_mipmaps");
		bool global_repeat = Globals::get_singleton()->get("image_loader/repeat");

		String text;

		if (global_filter != bool(texture->get_flags() & Texture::FLAG_FILTER)) {
			text += bool(texture->get_flags() & Texture::FLAG_FILTER) ? "filter=true\n" : "filter=false\n";
		}
		if (global_mipmaps != bool(texture->get_flags() & Texture::FLAG_MIPMAPS)) {
			text += bool(texture->get_flags() & Texture::FLAG_MIPMAPS) ? "gen_mipmaps=true\n" : "gen_mipmaps=false\n";
		}
		if (global_repeat != bool(texture->get_flags() & Texture::FLAG_REPEAT)) {
			text += bool(texture->get_flags() & Texture::FLAG_REPEAT) ? "repeat=true\n" : "repeat=false\n";
		}
		if (bool(texture->get_flags() & Texture::FLAG_ANISOTROPIC_FILTER)) {
			text += "anisotropic=true\n";
		}
		if (bool(texture->get_flags() & Texture::FLAG_CONVERT_TO_LINEAR)) {
			text += "tolinear=true\n";
		}
		if (bool(texture->get_flags() & Texture::FLAG_MIRRORED_REPEAT)) {
			text += "mirroredrepeat=true\n";
		}

		if (text != "" || FileAccess::exists(p_path + ".flags")) {

			FileAccess *f = FileAccess::open(p_path + ".flags", FileAccess::WRITE);
			if (f) {

				f->store_string(text);
				memdelete(f);
			}
		}
	}

	return err;
};

Error ResourceSaverPNG::save_image(const String &p_path, Image &p_img) {

	if (p_img.get_format() > Image::FORMAT_INDEXED_ALPHA)
		p_img.decompress();

	ERR_FAIL_COND_V(p_img.get_format() > Image::FORMAT_INDEXED_ALPHA, ERR_INVALID_PARAMETER);

	png_structp png_ptr;
	png_infop info_ptr;
	png_bytep *row_pointers;

	/* initialize stuff */
	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);

	ERR_FAIL_COND_V(!png_ptr, ERR_CANT_CREATE);

	info_ptr = png_create_info_struct(png_ptr);

	ERR_FAIL_COND_V(!info_ptr, ERR_CANT_CREATE);

	if (setjmp(png_jmpbuf(png_ptr))) {
		ERR_FAIL_V(ERR_CANT_OPEN);
	}
	//change this
	Error err;
	FileAccess *f = FileAccess::open(p_path, FileAccess::WRITE, &err);
	if (err) {
		ERR_FAIL_V(err);
	}

	png_set_write_fn(png_ptr, f, _write_png_data, NULL);

	/* write header */
	if (setjmp(png_jmpbuf(png_ptr))) {
		ERR_FAIL_V(ERR_CANT_OPEN);
	}

	int pngf = 0;
	int cs = 0;

	switch (p_img.get_format()) {

		case Image::FORMAT_GRAYSCALE: {

			pngf = PNG_COLOR_TYPE_GRAY;
			cs = 1;
		} break;
		case Image::FORMAT_GRAYSCALE_ALPHA: {

			pngf = PNG_COLOR_TYPE_GRAY_ALPHA;
			cs = 2;
		} break;
		case Image::FORMAT_RGB: {

			pngf = PNG_COLOR_TYPE_RGB;
			cs = 3;
		} break;
		case Image::FORMAT_RGBA: {

			pngf = PNG_COLOR_TYPE_RGB_ALPHA;
			cs = 4;
		} break;
		default: {

			if (p_img.detect_alpha()) {

				p_img.convert(Image::FORMAT_RGBA);
				pngf = PNG_COLOR_TYPE_RGB_ALPHA;
				cs = 4;
			} else {

				p_img.convert(Image::FORMAT_RGB);
				pngf = PNG_COLOR_TYPE_RGB;
				cs = 3;
			}
		}
	}

	int w = p_img.get_width();
	int h = p_img.get_height();
	png_set_IHDR(png_ptr, info_ptr, w, h,
			8, pngf, PNG_INTERLACE_NONE,
			PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);

	png_write_info(png_ptr, info_ptr);

	/* write bytes */
	if (setjmp(png_jmpbuf(png_ptr))) {
		memdelete(f);
		ERR_FAIL_V(ERR_CANT_OPEN);
	}

	DVector<uint8_t>::Read r = p_img.get_data().read();

	row_pointers = (png_bytep *)memalloc(sizeof(png_bytep) * h);
	for (int i = 0; i < h; i++) {

		row_pointers[i] = (png_bytep)&r[i * w * cs];
	}
	png_write_image(png_ptr, row_pointers);

	memfree(row_pointers);

	/* end write */
	if (setjmp(png_jmpbuf(png_ptr))) {

		memdelete(f);
		ERR_FAIL_V(ERR_CANT_OPEN);
	}

	png_write_end(png_ptr, NULL);
	memdelete(f);

	/* cleanup heap allocation */
	png_destroy_write_struct(&png_ptr, &info_ptr);

	return OK;
}

bool ResourceSaverPNG::recognize(const RES &p_resource) const {

	return (p_resource.is_valid() && p_resource->is_type("ImageTexture"));
}
void ResourceSaverPNG::get_recognized_extensions(const RES &p_resource, List<String> *p_extensions) const {

	if (p_resource->cast_to<Texture>()) {
		p_extensions->push_back("png");
	}
}

ResourceSaverPNG::ResourceSaverPNG() {

	Image::save_png_func = &save_image;
};