From 2fe886f3a5257b625d2d7798ed2cd242eeb7f154 Mon Sep 17 00:00:00 2001
From: BlueCube3310 <53150244+BlueCube3310@users.noreply.github.com>
Date: Wed, 6 Dec 2023 19:56:55 +0100
Subject: [PATCH] Fix squish RGTC_R decompression corruption

(cherry picked from commit 433a2a6ea2bbaa06943db00de390c9aee14870c4)
---
 thirdparty/squish/colourblock.cpp     |  17 +++-
 thirdparty/squish/colourblock.h       |   1 +
 thirdparty/squish/godot-changes.patch | 109 ++++++++++++++++++++++++++
 thirdparty/squish/squish.cpp          |   4 +-
 4 files changed, 127 insertions(+), 4 deletions(-)

diff --git a/thirdparty/squish/colourblock.cpp b/thirdparty/squish/colourblock.cpp
index 3d87adaa779..f14c9362bd5 100644
--- a/thirdparty/squish/colourblock.cpp
+++ b/thirdparty/squish/colourblock.cpp
@@ -24,9 +24,9 @@
    -------------------------------------------------------------------------- */
 
 #include "colourblock.h"
-// -- Godot start --
+// -- GODOT start --
 #include "alpha.h"
-// -- Godot end --
+// -- GODOT end --
 
 namespace squish {
 
@@ -214,7 +214,18 @@ void DecompressColour( u8* rgba, void const* block, bool isDxt1 )
     }
 }
 
-// -- Godot start --
+// -- GODOT start --
+void DecompressColourBc4( u8* rgba, void const* block)
+{
+    DecompressAlphaDxt5(rgba,block);
+    for ( int i = 0; i < 16; ++i ) {
+        rgba[i*4] = rgba[i*4 + 3];
+		rgba[i*4 + 1] = 0;
+		rgba[i*4 + 2] = 0;
+        rgba[i*4 + 3] = 255;
+    }
+}
+
 void DecompressColourBc5( u8* rgba, void const* block)
 {
     void const* rblock = block;
diff --git a/thirdparty/squish/colourblock.h b/thirdparty/squish/colourblock.h
index 3cb9b7e3b93..e1eb9e4917a 100644
--- a/thirdparty/squish/colourblock.h
+++ b/thirdparty/squish/colourblock.h
@@ -36,6 +36,7 @@ void WriteColourBlock4( Vec3::Arg start, Vec3::Arg end, u8 const* indices, void*
 
 void DecompressColour( u8* rgba, void const* block, bool isDxt1 );
 // -- GODOT start --
+void DecompressColourBc4( u8* rgba, void const* block );
 void DecompressColourBc5( u8* rgba, void const* block );
 // -- GODOT end --
 
diff --git a/thirdparty/squish/godot-changes.patch b/thirdparty/squish/godot-changes.patch
index ef7bafb4b4e..555fbc51d0e 100644
--- a/thirdparty/squish/godot-changes.patch
+++ b/thirdparty/squish/godot-changes.patch
@@ -100,3 +100,112 @@ index 1d22a64ad..fd11a147d 100644
  
      // decompress alpha separately if necessary
      if( ( flags & kDxt3 ) != 0 )
+
+diff --git a/thirdparty/squish/colourblock.cpp b/thirdparty/squish/colourblock.cpp
+index 49401358bc..f14c9362bd 100644
+--- a/thirdparty/squish/colourblock.cpp
++++ b/thirdparty/squish/colourblock.cpp
+@@ -24,9 +24,9 @@
+    -------------------------------------------------------------------------- */
+ 
+ #include "colourblock.h"
+-// -- Godot start --
++// -- GODOT start --
+ #include "alpha.h"
+-// -- Godot end --
++// -- GODOT end --
+ 
+ namespace squish {
+ 
+diff --git a/thirdparty/squish/godot-changes.patch b/thirdparty/squish/godot-changes.patch
+index ef7bafb4b4..655a8cffc2 100644
+--- a/thirdparty/squish/godot-changes.patch
++++ b/thirdparty/squish/godot-changes.patch
+@@ -1,22 +1,33 @@
+ diff --git a/thirdparty/squish/colourblock.cpp b/thirdparty/squish/colourblock.cpp
+-index af8b98036..3d87adaa7 100644
++index af8b980365..f14c9362bd 100644
+ --- a/thirdparty/squish/colourblock.cpp
+ +++ b/thirdparty/squish/colourblock.cpp
+ @@ -24,6 +24,9 @@
+     -------------------------------------------------------------------------- */
+  
+  #include "colourblock.h"
+-+// -- Godot start --
+++// -- GODOT start --
+ +#include "alpha.h"
+-+// -- Godot end --
+++// -- GODOT end --
+  
+  namespace squish {
+  
+-@@ -211,4 +214,23 @@ void DecompressColour( u8* rgba, void const* block, bool isDxt1 )
++@@ -211,4 +214,34 @@ void DecompressColour( u8* rgba, void const* block, bool isDxt1 )
+      }
+  }
+  
+-+// -- Godot start --
+++// -- GODOT start --
+++void DecompressColourBc4( u8* rgba, void const* block)
+++{
+++    DecompressAlphaDxt5(rgba,block);
+++    for ( int i = 0; i < 16; ++i ) {
+++        rgba[i*4] = rgba[i*4 + 3];
+++		rgba[i*4 + 1] = 0;
+++		rgba[i*4 + 2] = 0;
+++        rgba[i*4 + 3] = 255;
+++    }
+++}
+++
+ +void DecompressColourBc5( u8* rgba, void const* block)
+ +{
+ +    void const* rblock = block;
+@@ -37,21 +48,22 @@ index af8b98036..3d87adaa7 100644
+ +
+  } // namespace squish
+ diff --git a/thirdparty/squish/colourblock.h b/thirdparty/squish/colourblock.h
+-index fee2cd7c5..3cb9b7e3b 100644
++index fee2cd7c5d..e1eb9e4917 100644
+ --- a/thirdparty/squish/colourblock.h
+ +++ b/thirdparty/squish/colourblock.h
+-@@ -35,6 +35,9 @@ void WriteColourBlock3( Vec3::Arg start, Vec3::Arg end, u8 const* indices, void*
++@@ -35,6 +35,10 @@ void WriteColourBlock3( Vec3::Arg start, Vec3::Arg end, u8 const* indices, void*
+  void WriteColourBlock4( Vec3::Arg start, Vec3::Arg end, u8 const* indices, void* block );
+  
+  void DecompressColour( u8* rgba, void const* block, bool isDxt1 );
+ +// -- GODOT start --
+++void DecompressColourBc4( u8* rgba, void const* block );
+ +void DecompressColourBc5( u8* rgba, void const* block );
+ +// -- GODOT end --
+  
+  } // namespace squish
+  
+ diff --git a/thirdparty/squish/config.h b/thirdparty/squish/config.h
+-index 92edefe96..05f8d7259 100644
++index 92edefe966..05f8d72598 100644
+ --- a/thirdparty/squish/config.h
+ +++ b/thirdparty/squish/config.h
+ @@ -32,6 +32,26 @@
+@@ -82,17 +94,19 @@ index 92edefe96..05f8d7259 100644
+  #define SQUISH_USE_SSE 0
+  #endif
+ diff --git a/thirdparty/squish/squish.cpp b/thirdparty/squish/squish.cpp
+-index 1d22a64ad..fd11a147d 100644
++index 1d22a64ad6..086ba11cd0 100644
+ --- a/thirdparty/squish/squish.cpp
+ +++ b/thirdparty/squish/squish.cpp
+-@@ -135,7 +135,13 @@ void Decompress( u8* rgba, void const* block, int flags )
++@@ -135,7 +135,15 @@ void Decompress( u8* rgba, void const* block, int flags )
+          colourBlock = reinterpret_cast< u8 const* >( block ) + 8;
+  
+      // decompress colour
+ -    DecompressColour( rgba, colourBlock, ( flags & kDxt1 ) != 0 );
+ +    // -- GODOT start --
+ +    //DecompressColour( rgba, colourBlock, ( flags & kDxt1 ) != 0 );
+-+    if(( flags & ( kBc5 ) ) != 0)
+++    if(( flags & ( kBc4 ) ) != 0)
+++        DecompressColourBc4( rgba, colourBlock);
+++	else if(( flags & ( kBc5 ) ) != 0)
+ +        DecompressColourBc5( rgba, colourBlock);
+ +    else
+ +        DecompressColour( rgba, colourBlock, ( flags & kDxt1 ) != 0 );
\ No newline at end of file
diff --git a/thirdparty/squish/squish.cpp b/thirdparty/squish/squish.cpp
index fd11a147de6..1de1da3e529 100644
--- a/thirdparty/squish/squish.cpp
+++ b/thirdparty/squish/squish.cpp
@@ -137,7 +137,9 @@ void Decompress( u8* rgba, void const* block, int flags )
     // decompress colour
     // -- GODOT start --
     //DecompressColour( rgba, colourBlock, ( flags & kDxt1 ) != 0 );
-    if(( flags & ( kBc5 ) ) != 0)
+    if(( flags & ( kBc4 ) ) != 0)
+        DecompressColourBc4( rgba, colourBlock);
+    else if(( flags & ( kBc5 ) ) != 0)
         DecompressColourBc5( rgba, colourBlock);
     else
         DecompressColour( rgba, colourBlock, ( flags & kDxt1 ) != 0 );