From 6d072a321b05693fefdbe0f9db1db0b8b76324f1 Mon Sep 17 00:00:00 2001
From: Sven Hesse
Date: Sat, 27 Dec 2008 22:47:34 +0000
Subject: Adding support for specifying an index that will be ignored when
 building the PaletteLUT (for transparent values that should never be found)

svn-id: r35584
---
 graphics/dither.cpp | 15 +++++++++++----
 graphics/dither.h   |  7 ++++++-
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/graphics/dither.cpp b/graphics/dither.cpp
index ff58961a17..7a92441571 100644
--- a/graphics/dither.cpp
+++ b/graphics/dither.cpp
@@ -54,9 +54,13 @@ PaletteLUT::PaletteLUT(byte depth, PaletteFormat format) {
 	memset(_gots, 1, _dim1);
 }
 
-void PaletteLUT::setPalette(const byte *palette, PaletteFormat format, byte depth) {
+void PaletteLUT::setPalette(const byte *palette, PaletteFormat format,
+		byte depth, int transp) {
+
 	assert((depth > 1) && (depth < 9));
 
+	_transp = transp;
+
 	int shift = 8 - depth;
 
 	// Checking for the table's and the palette's pixel format
@@ -113,6 +117,10 @@ void PaletteLUT::build(int d1) {
 
 			// Going over every palette entry, searching for the closest
 			for (int c = 0; c < 256; c++, p += 3) {
+				// Ignore the transparent color
+				if (c == _transp)
+					continue;
+
 				uint32 di = SQR(d1 - p[0]) + SQR(j - p[1]) + SQR(k - p[2]);
 				if (di < d) {
 					d = di;
@@ -165,7 +173,7 @@ bool PaletteLUT::save(Common::WriteStream &stream) {
 		buildNext();
 
 	stream.writeUint32BE(MKID_BE('PLUT')); // Magic
-	stream.writeUint32BE(0);               // Version
+	stream.writeUint32BE(kVersion);
 	stream.writeByte(_depth1);
 	if (stream.write(_realPal, 768) != 768)
 		return false;
@@ -193,8 +201,7 @@ bool PaletteLUT::load(Common::SeekableReadStream &stream) {
 	if (stream.readUint32BE() != MKID_BE('PLUT'))
 		return false;
 
-	// Version
-	if (stream.readUint32BE() != 0)
+	if (stream.readUint32BE() != kVersion)
 		return false;
 
 	byte depth1 = stream.readByte();
diff --git a/graphics/dither.h b/graphics/dither.h
index 270cc8c5c2..e6d606cdd4 100644
--- a/graphics/dither.h
+++ b/graphics/dither.h
@@ -71,8 +71,9 @@ public:
 	 *  @param palette The palette, plain 256 * 3 color components.
 	 *  @param format The format the palette is in.
 	 *  @param depth The number of significant bits in each color component.
+	 *  @param transp An index that's seen as transparent and therefore ignored.
 	 */
-	void setPalette(const byte *palette, PaletteFormat format, byte depth);
+	void setPalette(const byte *palette, PaletteFormat format, byte depth, int transp = -1);
 
 	/** Build the next slice.
 	 *
@@ -111,6 +112,8 @@ public:
 	bool load(Common::SeekableReadStream &stream);
 
 private:
+	static const uint32 kVersion = 1;
+
 	byte _depth1; //!< The table's depth for one dimension.
 	byte _depth2; //!< The table's depth for two dimensions.
 	byte _shift;  //!< Amount to shift to adjust for the table's depth.
@@ -119,6 +122,8 @@ private:
 	uint32 _dim2; //!< The table's entry offset for two dimensions.
 	uint32 _dim3; //!< The table's entry offset for three dimensions.
 
+	int _transp;  //!< The transparent palette index.
+
 	PaletteFormat _format; //!< The table's palette format.
 	byte _lutPal[768];     //!< The palette used for looking up a color.
 	byte _realPal[768];    //!< The original palette.
-- 
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