PVRTC: Move compress func to `modules/pvr`, drop obsolete PVRTexTool code

The code we had for PVRTexTool doesn't work as it's not compatible with current
PVRTexTool CLI options, and likely hasn't been for years.

Instead, we have our own vendored pvrtccompressor thirdparty library which all
users have thus de-facto been using. This commit moves the compress code to
`modules/pvr` where it belongs.

There's no proper compress function for PVRTC 2-bit format, that's a bug that
will need to be fixed (currently it's compressed as 4-bit format even if you
use Image::FORMAT_PVRTC2).

Fixes #28669.

4 files changed, 126 insertions, 49 deletions

diff --git a/modules/pvr/image_compress_pvrtc.cpp b/modules/pvr/image_compress_pvrtc.cpp
new file mode 100644
index 0000000000..4cb0083556
--- /dev/null
+++ b/modules/pvr/image_compress_pvrtc.cpp
@@ -0,0 +1,86 @@
+/*************************************************************************/
+/*  image_compress_pvrtc.cpp                                             */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "image_compress_pvrtc.h"
+
+#include "core/io/image.h"
+#include "core/object/reference.h"
+
+#include <PvrTcEncoder.h>
+#include <RgbaBitmap.h>
+
+static void _compress_pvrtc4(Image *p_img) {
+	Ref<Image> img = p_img->duplicate();
+
+	bool make_mipmaps = false;
+	if (!img->is_size_po2() || img->get_width() != img->get_height()) {
+		make_mipmaps = img->has_mipmaps();
+		img->resize_to_po2(true);
+	}
+	img->convert(Image::FORMAT_RGBA8);
+	if (!img->has_mipmaps() && make_mipmaps) {
+		img->generate_mipmaps();
+	}
+
+	bool use_alpha = img->detect_alpha();
+
+	Ref<Image> new_img;
+	new_img.instance();
+	new_img->create(img->get_width(), img->get_height(), img->has_mipmaps(), use_alpha ? Image::FORMAT_PVRTC4A : Image::FORMAT_PVRTC4);
+
+	Vector<uint8_t> data = new_img->get_data();
+	{
+		uint8_t *wr = data.ptrw();
+		const uint8_t *r = img->get_data().ptr();
+
+		for (int i = 0; i <= new_img->get_mipmap_count(); i++) {
+			int ofs, size, w, h;
+			img->get_mipmap_offset_size_and_dimensions(i, ofs, size, w, h);
+			Javelin::RgbaBitmap bm(w, h);
+			void *dst = (void *)bm.GetData();
+			copymem(dst, &r[ofs], size);
+			Javelin::ColorRgba<unsigned char> *dp = bm.GetData();
+			for (int j = 0; j < size / 4; j++) {
+				// Red and blue colors are swapped.
+				SWAP(dp[j].r, dp[j].b);
+			}
+			new_img->get_mipmap_offset_size_and_dimensions(i, ofs, size, w, h);
+			Javelin::PvrTcEncoder::EncodeRgba4Bpp(&wr[ofs], bm);
+		}
+	}
+
+	p_img->create(new_img->get_width(), new_img->get_height(), new_img->has_mipmaps(), new_img->get_format(), data);
+}
+
+void _register_pvrtc_compress_func() {
+	// FIXME: We claim to support PVRTC2 but use the same method as for PVRTC4.
+	Image::_image_compress_pvrtc2_func = _compress_pvrtc4;
+	Image::_image_compress_pvrtc4_func = _compress_pvrtc4;
+}
diff --git a/modules/pvr/image_compress_pvrtc.h b/modules/pvr/image_compress_pvrtc.h
new file mode 100644
index 0000000000..fde65f4bbe
--- /dev/null
+++ b/modules/pvr/image_compress_pvrtc.h
@@ -0,0 +1,36 @@
+/*************************************************************************/
+/*  image_compress_pvrtc.h                                               */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef IMAGE_COMPRESS_PVRTC_H
+#define IMAGE_COMPRESS_PVRTC_H
+
+void _register_pvrtc_compress_func();
+
+#endif // IMAGE_COMPRESS_PVRTC_H
diff --git a/modules/pvr/register_types.cpp b/modules/pvr/register_types.cpp
index 1eb697bba3..9bfc334d76 100644
--- a/modules/pvr/register_types.cpp
+++ b/modules/pvr/register_types.cpp
@@ -30,6 +30,7 @@
 
 #include "register_types.h"
 
+#include "image_compress_pvrtc.h"
 #include "texture_loader_pvr.h"
 
 static Ref<ResourceFormatPVR> resource_loader_pvr;
@@ -37,6 +38,8 @@ static Ref<ResourceFormatPVR> resource_loader_pvr;
 void register_pvr_types() {
 	resource_loader_pvr.instance();
 	ResourceLoader::add_resource_format_loader(resource_loader_pvr);
+
+	_register_pvrtc_compress_func();
 }
 
 void unregister_pvr_types() {
diff --git a/modules/pvr/texture_loader_pvr.cpp b/modules/pvr/texture_loader_pvr.cpp
index 0923714387..46101262c8 100644
--- a/modules/pvr/texture_loader_pvr.cpp
+++ b/modules/pvr/texture_loader_pvr.cpp
@@ -29,11 +29,8 @@
 /*************************************************************************/
 
 #include "texture_loader_pvr.h"
-#include "PvrTcEncoder.h"
-#include "RgbaBitmap.h"
+
 #include "core/os/file_access.h"
-#include <string.h>
-#include <new>
 
 static void _pvrtc_decompress(Image *p_img);
 
@@ -183,53 +180,8 @@ String ResourceFormatPVR::get_resource_type(const String &p_path) const {
 	return "";
 }
 
-static void _compress_pvrtc4(Image *p_img) {
-	Ref<Image> img = p_img->duplicate();
-
-	bool make_mipmaps = false;
-	if (!img->is_size_po2() || img->get_width() != img->get_height()) {
-		make_mipmaps = img->has_mipmaps();
-		img->resize_to_po2(true);
-	}
-	img->convert(Image::FORMAT_RGBA8);
-	if (!img->has_mipmaps() && make_mipmaps) {
-		img->generate_mipmaps();
-	}
-
-	bool use_alpha = img->detect_alpha();
-
-	Ref<Image> new_img;
-	new_img.instance();
-	new_img->create(img->get_width(), img->get_height(), img->has_mipmaps(), use_alpha ? Image::FORMAT_PVRTC4A : Image::FORMAT_PVRTC4);
-
-	Vector<uint8_t> data = new_img->get_data();
-	{
-		uint8_t *wr = data.ptrw();
-		const uint8_t *r = img->get_data().ptr();
-
-		for (int i = 0; i <= new_img->get_mipmap_count(); i++) {
-			int ofs, size, w, h;
-			img->get_mipmap_offset_size_and_dimensions(i, ofs, size, w, h);
-			Javelin::RgbaBitmap bm(w, h);
-			void *dst = (void *)bm.GetData();
-			copymem(dst, &r[ofs], size);
-			Javelin::ColorRgba<unsigned char> *dp = bm.GetData();
-			for (int j = 0; j < size / 4; j++) {
-				/* red and blue colors are swapped.  */
-				SWAP(dp[j].r, dp[j].b);
-			}
-			new_img->get_mipmap_offset_size_and_dimensions(i, ofs, size, w, h);
-			Javelin::PvrTcEncoder::EncodeRgba4Bpp(&wr[ofs], bm);
-		}
-	}
-
-	p_img->create(new_img->get_width(), new_img->get_height(), new_img->has_mipmaps(), new_img->get_format(), data);
-}
-
 ResourceFormatPVR::ResourceFormatPVR() {
 	Image::_image_decompress_pvrtc = _pvrtc_decompress;
-	Image::_image_compress_pvrtc4_func = _compress_pvrtc4;
-	Image::_image_compress_pvrtc2_func = _compress_pvrtc4;
 }
 
 /////////////////////////////////////////////////////////