SCI32: Fix unnecessary palette updates

Some games load palettes that include color 255, but this is
hardcoded to white in SSCI, so just ignore it during merges since
it is ignored when the hardware palette is updated anyway.

1 files changed, 6 insertions, 3 deletions

diff --git a/engines/sci/graphics/palette32.cpp b/engines/sci/graphics/palette32.cpp
index 1260a962f0..2a98c237b0 100644
--- a/engines/sci/graphics/palette32.cpp
+++ b/engines/sci/graphics/palette32.cpp
@@ -128,8 +128,8 @@ GfxPalette32::GfxPalette32(ResourceManager *resMan)
 	_version(1),
 	_needsUpdate(false),
 	_currentPalette(),
-	_sourcePalette(_currentPalette),
-	_nextPalette(_currentPalette),
+	_sourcePalette(),
+	_nextPalette(),
 	// Clut
 	_clutTable(nullptr),
 	// Palette varying
@@ -162,7 +162,10 @@ GfxPalette32::~GfxPalette32() {
 }
 
 inline void mergePaletteInternal(Palette *const to, const Palette *const from) {
-	for (int i = 0, len = ARRAYSIZE(to->colors); i < len; ++i) {
+	// The last color is always white, so it is not copied.
+	// (Some palettes try to set the last color, which causes
+	// churning in the palettes when they are merged)
+	for (int i = 0, len = ARRAYSIZE(to->colors) - 1; i < len; ++i) {
 		if (from->colors[i].used) {
 			to->colors[i] = from->colors[i];
 		}