From 130cfded751571069d16caff42baa709146ee501 Mon Sep 17 00:00:00 2001
From: Johannes Schickel
Date: Wed, 5 Mar 2008 17:38:12 +0000
Subject: Implement inventory scrolling for HoF.

svn-id: r31043
---
 engines/kyra/screen_v2.cpp | 77 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 73 insertions(+), 4 deletions(-)

(limited to 'engines/kyra/screen_v2.cpp')

diff --git a/engines/kyra/screen_v2.cpp b/engines/kyra/screen_v2.cpp
index 2bec373266..ab46dce6f3 100644
--- a/engines/kyra/screen_v2.cpp
+++ b/engines/kyra/screen_v2.cpp
@@ -84,12 +84,81 @@ void Screen_v2::generateGrayOverlay(const uint8 *srcPal, uint8 *grayOverlay, int
 		grayOverlay[i] = findLeastDifferentColor(tmpPal + 3 * i, srcPal, lastColor);
 }
 
-void Screen_v2::applyGrayOverlay(int x, int y, int w, int h, int pageNum, const uint8 *grayOverlay) {
+uint8 *Screen_v2::generateOverlay(const uint8 *palette, uint8 *buffer, int startColor, int fac) {
+	if (!palette || !buffer)
+		return buffer;
+
+	fac = MIN(0xFF, fac);
+
+	byte col1, col2, col3;
+	col1 = palette[startColor * 3 + 0];
+	col2 = palette[startColor * 3 + 1];
+	col3 = palette[startColor * 3 + 2];
+	*buffer = 0;
+
+	uint8 *dst = buffer + 1;
+	for (int i = 1; i != 255; ++i) {
+		byte procCol1, procCol2, procCol3;
+		const uint8 *src = palette + i*3;
+		const int factor = (fac >> 1) & 0xFF;
+		byte col;
+		
+		col = *src++;
+		col -= ((((col - col1) * factor) << 1) >> 8) & 0xFF;
+		procCol1 = col;
+
+		col = *src++;
+		col -= ((((col - col2) * factor) << 1) >> 8) & 0xFF;
+		procCol2 = col;
+
+		col = *src++;
+		col -= ((((col - col3) * factor) << 1) >> 8) & 0xFF;
+		procCol3 = col;
+
+		uint16 minValue = 0xFFFF;
+		uint8 colorNumber = startColor;
+		const uint8 *pal = palette + 3;
+		for (int count = 0xFF, cur = 1; count > 0; --count, ++cur) {
+			pal += 3;
+			if (cur != i) {
+				uint16 value = 0;
+				pal -= 3;
+				col = *pal++ - procCol1;
+				col *= col;
+				value += col;
+
+				col = *pal++ - procCol2;
+				col *= col;
+				value += col;
+
+				col = *pal++ - procCol3;
+				col *= col;
+				value += col;
+
+				if (value == 0) {
+					colorNumber = i;
+					break;
+				} else if (value < minValue) {
+					minValue = value;
+					colorNumber = cur;
+				}
+			}
+		}
+
+		*dst++ = colorNumber;
+	}
+
+	return buffer;
+}
+
+void Screen_v2::applyOverlay(int x, int y, int w, int h, int pageNum, const uint8 *overlay) {
 	uint8 * dst = getPagePtr(pageNum) + y * 320 + x;
 	while (h--) {
-		for (int wi = 0; wi < 320; wi++)
-			dst[wi] = grayOverlay[dst[wi]];
-		dst += 320;
+		for (int wi = 0; wi < w; ++wi) {
+			uint8 index = *dst;
+			*dst++ = overlay[index];
+		}
+		dst += 320 - w;
 	}
 }
 
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