/*************************************************************************/
/*  image_etc.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 "image_etc.h"
#include "image.h"
#include "os/copymem.h"
#include "print_string.h"
#include "rg_etc1.h"
static void _decompress_etc(Image *p_img) {

	ERR_FAIL_COND(p_img->get_format() != Image::FORMAT_ETC);

	int imgw = p_img->get_width();
	int imgh = p_img->get_height();
	DVector<uint8_t> src = p_img->get_data();
	DVector<uint8_t> dst;

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

	int mmc = p_img->get_mipmaps();

	for (int i = 0; i <= mmc; i++) {

		dst.resize(dst.size() + imgw * imgh * 3);
		const uint8_t *srcbr = &r[p_img->get_mipmap_offset(i)];
		DVector<uint8_t>::Write w = dst.write();

		uint8_t *wptr = &w[dst.size() - imgw * imgh * 3];

		int bw = MAX(imgw / 4, 1);
		int bh = MAX(imgh / 4, 1);

		for (int y = 0; y < bh; y++) {

			for (int x = 0; x < bw; x++) {

				uint8_t block[4 * 4 * 4];

				rg_etc1::unpack_etc1_block(srcbr, (unsigned int *)block);
				srcbr += 8;

				int maxx = MIN(imgw, 4);
				int maxy = MIN(imgh, 4);

				for (int yy = 0; yy < maxy; yy++) {

					for (int xx = 0; xx < maxx; xx++) {

						uint32_t src_ofs = (yy * 4 + xx) * 4;
						uint32_t dst_ofs = ((y * 4 + yy) * imgw + x * 4 + xx) * 3;
						wptr[dst_ofs + 0] = block[src_ofs + 0];
						wptr[dst_ofs + 1] = block[src_ofs + 1];
						wptr[dst_ofs + 2] = block[src_ofs + 2];
					}
				}
			}
		}

		imgw = MAX(1, imgw / 2);
		imgh = MAX(1, imgh / 2);
	}

	r = DVector<uint8_t>::Read();
	//print_line("Re Creating ETC into regular image: w "+itos(p_img->get_width())+" h "+itos(p_img->get_height())+" mm "+itos(p_img->get_mipmaps()));
	*p_img = Image(p_img->get_width(), p_img->get_height(), p_img->get_mipmaps(), Image::FORMAT_RGB, dst);
	if (p_img->get_mipmaps())
		p_img->generate_mipmaps(-1, true);
}

static void _compress_etc(Image *p_img) {

	Image img = *p_img;

	int imgw = img.get_width(), imgh = img.get_height();

	ERR_FAIL_COND(next_power_of_2(imgw) != imgw || next_power_of_2(imgh) != imgh);

	if (img.get_format() != Image::FORMAT_RGB)
		img.convert(Image::FORMAT_RGB);

	int mmc = img.get_mipmaps();
	if (mmc == 0)
		img.generate_mipmaps(); // force mipmaps, so it works on most hardware

	DVector<uint8_t> res_data;
	DVector<uint8_t> dst_data;
	DVector<uint8_t>::Read r = img.get_data().read();

	int mc = 0;

	rg_etc1::etc1_pack_params pp;
	pp.m_quality = rg_etc1::cLowQuality;
	for (int i = 0; i <= mmc; i++) {

		int bw = MAX(imgw / 4, 1);
		int bh = MAX(imgh / 4, 1);
		const uint8_t *src = &r[img.get_mipmap_offset(i)];
		int mmsize = MAX(bw, 1) * MAX(bh, 1) * 8;
		dst_data.resize(dst_data.size() + mmsize);
		DVector<uint8_t>::Write w = dst_data.write();
		uint8_t *dst = &w[dst_data.size() - mmsize];

		//		print_line("bh: "+itos(bh)+" bw: "+itos(bw));

		for (int y = 0; y < bh; y++) {

			for (int x = 0; x < bw; x++) {

				//				print_line("x: "+itos(x)+" y: "+itos(y));

				uint8_t block[4 * 4 * 4];
				zeromem(block, 4 * 4 * 4);
				uint8_t cblock[8];

				int maxy = MIN(imgh, 4);
				int maxx = MIN(imgw, 4);

				for (int yy = 0; yy < maxy; yy++) {

					for (int xx = 0; xx < maxx; xx++) {

						uint32_t dst_ofs = (yy * 4 + xx) * 4;
						uint32_t src_ofs = ((y * 4 + yy) * imgw + x * 4 + xx) * 3;
						block[dst_ofs + 0] = src[src_ofs + 0];
						block[dst_ofs + 1] = src[src_ofs + 1];
						block[dst_ofs + 2] = src[src_ofs + 2];
						block[dst_ofs + 3] = 255;
					}
				}

				rg_etc1::pack_etc1_block(cblock, (const unsigned int *)block, pp);
				for (int j = 0; j < 8; j++) {

					dst[j] = cblock[j];
				}

				dst += 8;
			}
		}

		imgw = MAX(1, imgw / 2);
		imgh = MAX(1, imgh / 2);
		mc++;
	}

	*p_img = Image(p_img->get_width(), p_img->get_height(), mc - 1, Image::FORMAT_ETC, dst_data);
}

void _register_etc1_compress_func() {

	rg_etc1::pack_etc1_block_init();
	Image::_image_compress_etc_func = _compress_etc;
	Image::_image_decompress_etc = _decompress_etc;
}