godot/modules/squish/image_compress_squish.cpp

/*************************************************************************/
/*  image_compress_squish.cpp                                            */
/*************************************************************************/
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/*                           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_compress_squish.h"

#include "print_string.h"

#if defined(__SSE2__)
#define SQUISH_USE_SSE 2
#elif defined(__SSE__)
#define SQUISH_USE_SSE 1
#endif

#include <squish.h>

void image_decompress_squish(Image *p_image) {
	int w = p_image->get_width();
	int h = p_image->get_height();

	Image::Format target_format = Image::FORMAT_RGBA;
	DVector<uint8_t> data;
	int mm_count = p_image->get_mipmaps();
	int target_size = Image::get_image_data_size(w, h, target_format, mm_count);

	data.resize(target_size);

	DVector<uint8_t>::Read rb = p_image->get_data().read();
	DVector<uint8_t>::Write wb = data.write();

	int squish_flags = Image::FORMAT_MAX;
	if (p_image->get_format() == Image::FORMAT_BC1) {
		squish_flags = squish::kDxt1;
	} else if (p_image->get_format() == Image::FORMAT_BC2) {
		squish_flags = squish::kDxt3;
	} else if (p_image->get_format() == Image::FORMAT_BC3) {
		squish_flags = squish::kDxt5;
	} else if (p_image->get_format() == Image::FORMAT_BC4) {
		squish_flags = squish::kBc4;
	} else if (p_image->get_format() == Image::FORMAT_BC5) {
		squish_flags = squish::kBc5;
	} else {
		ERR_FAIL_COND(true);
		return;
	}

	int dst_ofs = 0;

	for (int i = 0; i <= mm_count; i++) {
		int src_ofs = 0, mipmap_size = 0, mipmap_w = 0, mipmap_h = 0;
		p_image->get_mipmap_offset_size_and_dimensions(i, src_ofs, mipmap_size, mipmap_w, mipmap_h);
		squish::DecompressImage(&wb[dst_ofs], mipmap_w, mipmap_h, &rb[src_ofs], squish_flags);
	}

	*p_image = Image(p_image->get_width(), p_image->get_height(), p_image->get_mipmaps(), target_format, data);
}

void image_compress_squish(Image *p_image) {

	int w = p_image->get_width();
	int h = p_image->get_height();

	if (p_image->get_mipmaps() == 0) {
		ERR_FAIL_COND(!w || w % 4 != 0);
		ERR_FAIL_COND(!h || h % 4 != 0);
	} else {
		ERR_FAIL_COND(!w || w != next_power_of_2(w));
		ERR_FAIL_COND(!h || h != next_power_of_2(h));
	};

	if (p_image->get_format() >= Image::FORMAT_BC1)
		return; //do not compress, already compressed

	int shift = 0;
	int squish_comp = squish::kColourRangeFit;
	Image::Format target_format;

	if (p_image->get_format() == Image::FORMAT_GRAYSCALE_ALPHA) {
		//compressed normalmap
		target_format = Image::FORMAT_BC3;
		squish_comp |= squish::kDxt5;
	} else if (p_image->detect_alpha() != Image::ALPHA_NONE) {

		target_format = Image::FORMAT_BC2;
		squish_comp |= squish::kDxt3;
	} else {
		target_format = Image::FORMAT_BC1;
		shift = 1;
		squish_comp |= squish::kDxt1;
	}

	p_image->convert(Image::FORMAT_RGBA); //always expects rgba

	int mm_count = p_image->get_mipmaps();

	DVector<uint8_t> data;
	int target_size = Image::get_image_data_size(w, h, target_format, mm_count);
	data.resize(target_size);

	DVector<uint8_t>::Read rb = p_image->get_data().read();
	DVector<uint8_t>::Write wb = data.write();

	int dst_ofs = 0;

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

		int src_ofs = p_image->get_mipmap_offset(i);
		squish::CompressImage(&rb[src_ofs], w, h, &wb[dst_ofs], squish_comp);
		dst_ofs += (MAX(4, w) * MAX(4, h)) >> shift;
		w >>= 1;
		h >>= 1;
	}

	rb = DVector<uint8_t>::Read();
	wb = DVector<uint8_t>::Write();

	p_image->create(p_image->get_width(), p_image->get_height(), p_image->get_mipmaps(), target_format, data);
}