From d840165a324b5c218ca3a4882f030986855c8383 Mon Sep 17 00:00:00 2001
From: "K. S. Ernest (iFire) Lee" <ernest.lee@chibifire.com>
Date: Tue, 6 Apr 2021 22:05:56 -0700
Subject: Add `etcpak` library for faster ETC/ETC2/S3TC imports.
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- `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>
---
 thirdparty/etcpak/ProcessCommon.hpp | 50 +++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 thirdparty/etcpak/ProcessCommon.hpp

(limited to 'thirdparty/etcpak/ProcessCommon.hpp')

diff --git a/thirdparty/etcpak/ProcessCommon.hpp b/thirdparty/etcpak/ProcessCommon.hpp
new file mode 100644
index 0000000000..657d68888f
--- /dev/null
+++ b/thirdparty/etcpak/ProcessCommon.hpp
@@ -0,0 +1,50 @@
+#ifndef __PROCESSCOMMON_HPP__
+#define __PROCESSCOMMON_HPP__
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+
+template<class T>
+static size_t GetLeastError( const T* err, size_t num )
+{
+    size_t idx = 0;
+    for( size_t i=1; i<num; i++ )
+    {
+        if( err[i] < err[idx] )
+        {
+            idx = i;
+        }
+    }
+    return idx;
+}
+
+static uint64_t FixByteOrder( uint64_t d )
+{
+    return ( ( d & 0x00000000FFFFFFFF ) ) |
+           ( ( d & 0xFF00000000000000 ) >> 24 ) |
+           ( ( d & 0x000000FF00000000 ) << 24 ) |
+           ( ( d & 0x00FF000000000000 ) >> 8 ) |
+           ( ( d & 0x0000FF0000000000 ) << 8 );
+}
+
+template<class T, class S>
+static uint64_t EncodeSelectors( uint64_t d, const T terr[2][8], const S tsel[16][8], const uint32_t* id )
+{
+    size_t tidx[2];
+    tidx[0] = GetLeastError( terr[0], 8 );
+    tidx[1] = GetLeastError( terr[1], 8 );
+
+    d |= tidx[0] << 26;
+    d |= tidx[1] << 29;
+    for( int i=0; i<16; i++ )
+    {
+        uint64_t t = tsel[i][tidx[id[i]%2]];
+        d |= ( t & 0x1 ) << ( i + 32 );
+        d |= ( t & 0x2 ) << ( i + 47 );
+    }
+
+    return d;
+}
+
+#endif
-- 
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