Add `etcpak` library for faster ETC/ETC2/S3TC imports.

- `etc` module was renamed to `etcpak` and modified to use the new library.
- PKM importer is removed in the process, it's obsolete.
- Old library `etc2comp` is removed.
- S3TC compression no longer done via `squish` (but decompression still is).
- Slight modifications to etcpak sources for MinGW compatibility,
  to fix LLVM `-Wc++11-narrowing` errors, and to allow using vendored or
  system libpng.

Co-authored-by: Rémi Verschelde <rverschelde@gmail.com>

3 files changed, 0 insertions, 82 deletions

diff --git a/modules/squish/image_compress_squish.cpp b/modules/squish/image_compress_squish.cpp
index cce08034df..fb0c7aba1d 100644
--- a/modules/squish/image_compress_squish.cpp
+++ b/modules/squish/image_compress_squish.cpp
@@ -76,83 +76,3 @@ void image_decompress_squish(Image *p_image) {
 		p_image->convert_ra_rgba8_to_rg();
 	}
 }
-
-void image_compress_squish(Image *p_image, float p_lossy_quality, Image::UsedChannels p_channels) {
-	if (p_image->get_format() >= Image::FORMAT_DXT1) {
-		return; //do not compress, already compressed
-	}
-
-	int w = p_image->get_width();
-	int h = p_image->get_height();
-
-	if (p_image->get_format() <= Image::FORMAT_RGBA8) {
-		int squish_comp = squish::kColourRangeFit;
-
-		if (p_lossy_quality > 0.85) {
-			squish_comp = squish::kColourIterativeClusterFit;
-		} else if (p_lossy_quality > 0.75) {
-			squish_comp = squish::kColourClusterFit;
-		}
-
-		Image::Format target_format = Image::FORMAT_RGBA8;
-
-		p_image->convert(Image::FORMAT_RGBA8); //still uses RGBA to convert
-
-		switch (p_channels) {
-			case Image::USED_CHANNELS_L: {
-				target_format = Image::FORMAT_DXT1;
-				squish_comp |= squish::kDxt1;
-			} break;
-			case Image::USED_CHANNELS_LA: {
-				target_format = Image::FORMAT_DXT5;
-				squish_comp |= squish::kDxt5;
-			} break;
-			case Image::USED_CHANNELS_R: {
-				target_format = Image::FORMAT_RGTC_R;
-				squish_comp |= squish::kBc4;
-			} break;
-			case Image::USED_CHANNELS_RG: {
-				target_format = Image::FORMAT_RGTC_RG;
-				squish_comp |= squish::kBc5;
-			} break;
-			case Image::USED_CHANNELS_RGB: {
-				target_format = Image::FORMAT_DXT1;
-				squish_comp |= squish::kDxt1;
-			} break;
-			case Image::USED_CHANNELS_RGBA: {
-				//TODO, should convert both, then measure which one does a better job
-				target_format = Image::FORMAT_DXT5;
-				squish_comp |= squish::kDxt5;
-
-			} break;
-			default: {
-				ERR_PRINT("Unknown image format, defaulting to RGBA8");
-				break;
-			}
-		}
-
-		Vector<uint8_t> data;
-		int target_size = Image::get_image_data_size(w, h, target_format, p_image->has_mipmaps());
-		int mm_count = p_image->has_mipmaps() ? Image::get_image_required_mipmaps(w, h, target_format) : 0;
-		data.resize(target_size);
-		int shift = Image::get_format_pixel_rshift(target_format);
-
-		const uint8_t *rb = p_image->get_data().ptr();
-		uint8_t *wb = data.ptrw();
-
-		int dst_ofs = 0;
-
-		for (int i = 0; i <= mm_count; i++) {
-			int bw = w % 4 != 0 ? w + (4 - w % 4) : w;
-			int bh = h % 4 != 0 ? h + (4 - h % 4) : h;
-
-			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, bw) * MAX(4, bh)) >> shift;
-			w = MAX(w / 2, 1);
-			h = MAX(h / 2, 1);
-		}
-
-		p_image->create(p_image->get_width(), p_image->get_height(), p_image->has_mipmaps(), target_format, data);
-	}
-}
diff --git a/modules/squish/image_compress_squish.h b/modules/squish/image_compress_squish.h
index 301d30fcf1..ebc5a41887 100644
--- a/modules/squish/image_compress_squish.h
+++ b/modules/squish/image_compress_squish.h
@@ -33,7 +33,6 @@
 
 #include "core/io/image.h"
 
-void image_compress_squish(Image *p_image, float p_lossy_quality, Image::UsedChannels p_channels);
 void image_decompress_squish(Image *p_image);
 
 #endif // IMAGE_COMPRESS_SQUISH_H
diff --git a/modules/squish/register_types.cpp b/modules/squish/register_types.cpp
index 451e9d8e93..c51cdc9521 100644
--- a/modules/squish/register_types.cpp
+++ b/modules/squish/register_types.cpp
@@ -32,7 +32,6 @@
 #include "image_compress_squish.h"
 
 void register_squish_types() {
-	Image::set_compress_bc_func(image_compress_squish);
 	Image::_image_decompress_bc = image_decompress_squish;
 }