From 344d97b0916387639ac4eaaf5e7bc96acffdc1b9 Mon Sep 17 00:00:00 2001
From: Vasiliy Makarov <drmoriarty.0@gmail.com>
Date: Wed, 16 Sep 2020 18:11:11 +0300
Subject: [PATCH] Fix import logic for VRAM compressed texture formats

Compressed stream texture now saves right image dimensions for every compression format.
Also it allows to compressor resize image on it's side to make it more optimized.
So ETC1 format becames smaller then before. Pvrtc format always saves square texture.
---
 editor/import/resource_importer_texture.cpp | 53 ++++++++++++++-------
 1 file changed, 36 insertions(+), 17 deletions(-)

diff --git a/editor/import/resource_importer_texture.cpp b/editor/import/resource_importer_texture.cpp
index 88547280ceac..976328e98e8e 100644
--- a/editor/import/resource_importer_texture.cpp
+++ b/editor/import/resource_importer_texture.cpp
@@ -227,21 +227,8 @@ void ResourceImporterTexture::_save_stex(const Ref<Image> &p_image, const String
 	f->store_8('S');
 	f->store_8('T'); //godot streamable texture
 
-	bool resize_to_po2 = false;
-
-	if (p_compress_mode == COMPRESS_VIDEO_RAM && p_force_po2_for_compressed && (p_mipmaps || p_texture_flags & Texture::FLAG_REPEAT)) {
-		resize_to_po2 = true;
-		f->store_16(next_power_of_2(p_image->get_width()));
-		f->store_16(p_image->get_width());
-		f->store_16(next_power_of_2(p_image->get_height()));
-		f->store_16(p_image->get_height());
-	} else {
-		f->store_16(p_image->get_width());
-		f->store_16(0);
-		f->store_16(p_image->get_height());
-		f->store_16(0);
-	}
-	f->store_32(p_texture_flags);
+	int orig_width = p_image->get_width();
+	int orig_height = p_image->get_height();
 
 	uint32_t format = 0;
 
@@ -263,6 +250,12 @@ void ResourceImporterTexture::_save_stex(const Ref<Image> &p_image, const String
 	switch (p_compress_mode) {
 		case COMPRESS_LOSSLESS: {
 
+			f->store_16(orig_width);
+			f->store_16(0);
+			f->store_16(orig_height);
+			f->store_16(0);
+			f->store_32(p_texture_flags);
+
 			Ref<Image> image = p_image->duplicate();
 			if (p_mipmaps) {
 				image->generate_mipmaps();
@@ -292,6 +285,13 @@ void ResourceImporterTexture::_save_stex(const Ref<Image> &p_image, const String
 
 		} break;
 		case COMPRESS_LOSSY: {
+
+			f->store_16(orig_width);
+			f->store_16(0);
+			f->store_16(orig_height);
+			f->store_16(0);
+			f->store_32(p_texture_flags);
+
 			Ref<Image> image = p_image->duplicate();
 			if (p_mipmaps) {
 				image->generate_mipmaps();
@@ -322,9 +322,15 @@ void ResourceImporterTexture::_save_stex(const Ref<Image> &p_image, const String
 		case COMPRESS_VIDEO_RAM: {
 
 			Ref<Image> image = p_image->duplicate();
-			if (resize_to_po2) {
-				image->resize_to_po2();
+
+			if (p_force_po2_for_compressed || p_mipmaps || p_texture_flags & Texture::FLAG_REPEAT) {
+				if (p_vram_compression == Image::COMPRESS_PVRTC4 || p_vram_compression == Image::COMPRESS_ETC) {
+					// we don't need to resize image there, because encoder will resize it by more proper way
+				} else {
+					image->resize_to_po2();
+				}
 			}
+
 			if (p_mipmaps) {
 				image->generate_mipmaps(p_force_normal);
 			}
@@ -342,6 +348,13 @@ void ResourceImporterTexture::_save_stex(const Ref<Image> &p_image, const String
 				image->compress(p_vram_compression, csource, p_lossy_quality);
 			}
 
+			// save image dimensions after compressing, because the compressor can resize it
+			f->store_16(image->get_width());
+			f->store_16(orig_width);
+			f->store_16(image->get_height());
+			f->store_16(orig_height);
+			f->store_32(p_texture_flags);
+
 			format |= image->get_format();
 
 			f->store_32(format);
@@ -353,6 +366,12 @@ void ResourceImporterTexture::_save_stex(const Ref<Image> &p_image, const String
 		} break;
 		case COMPRESS_UNCOMPRESSED: {
 
+			f->store_16(orig_width);
+			f->store_16(0);
+			f->store_16(orig_height);
+			f->store_16(0);
+			f->store_32(p_texture_flags);
+
 			Ref<Image> image = p_image->duplicate();
 			if (p_mipmaps) {
 				image->generate_mipmaps();