BasisUniversal: Fix texture decompression

[BlueCube3310]

BasisU requires providing an image's pixel count for transcoding textures to uncompressed formats. Previously it would always be given the compressed block count, and thus decompression would always fail.

This is a difficult bug to reproduce, since it only happens on hardware which doesn't support any compressed formats.

MRP: BasisuDecompressed.zip
Testing requires applying the diff posted below.

[fire]

There's no reproduction project but the code uses the enumeration to check if it's compressed and switch on the result. Seems correct, but I can't test it on hardware.

uint32_t mip_block_or_pixel_count = image_format >= Image::FORMAT_DXT1 ? basisu_level.m_total_blocks : basisu_level.m_orig_width * basisu_level.m_orig_height;

[BlueCube3310]

It's possible to force disable transcoding to all compressed formats with this diff:

diff --git a/modules/basis_universal/image_compress_basisu.cpp b/modules/basis_universal/image_compress_basisu.cpp
index 72e7977eef..9321923739 100644
--- a/modules/basis_universal/image_compress_basisu.cpp
+++ b/modules/basis_universal/image_compress_basisu.cpp
@@ -153,10 +153,10 @@ Ref<Image> basis_universal_unpacker_ptr(const uint8_t *p_data, int p_size) {
 	Image::Format image_format = Image::FORMAT_MAX;
 
 	// Get supported compression formats.
-	bool bptc_supported = RS::get_singleton()->has_os_feature("bptc");
-	bool astc_supported = RS::get_singleton()->has_os_feature("astc");
-	bool s3tc_supported = RS::get_singleton()->has_os_feature("s3tc");
-	bool etc2_supported = RS::get_singleton()->has_os_feature("etc2");
+	bool bptc_supported = false; // RS::get_singleton()->has_os_feature("bptc");
+	bool astc_supported = false; // RS::get_singleton()->has_os_feature("astc");
+	bool s3tc_supported = false; // RS::get_singleton()->has_os_feature("s3tc");
+	bool etc2_supported = false; // RS::get_singleton()->has_os_feature("etc2");
 
 	bool needs_ra_rg_swap = false;

[akien-mga]

Thanks!