From 96397a5741e6495cb7f9494841ff5b815bc96bda Mon Sep 17 00:00:00 2001
From: Filippos Karapetis
Date: Sat, 15 Dec 2012 08:10:30 +0200
Subject: TINSEL: Initial version of the graphics drawing function for DW1 Mac

Still some graphical glitches remain, as clipping isn't done correctly
---
 engines/tinsel/graphics.cpp | 65 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 59 insertions(+), 6 deletions(-)

diff --git a/engines/tinsel/graphics.cpp b/engines/tinsel/graphics.cpp
index 5f200b5e2f..b23f6bc8a4 100644
--- a/engines/tinsel/graphics.cpp
+++ b/engines/tinsel/graphics.cpp
@@ -211,6 +211,59 @@ static void t0WrtNonZero(DRAWOBJECT *pObj, uint8 *srcP, uint8 *destP, bool apply
 	}
 }
 
+/**
+ * Straight rendering with transparency support, Mac variant
+ */
+static void MacDrawTiles(DRAWOBJECT *pObj, uint8 *srcP, uint8 *destP, bool applyClipping) {
+	// TODO: Finish off clipping
+
+	if (applyClipping) {
+		// Adjust the height down to skip any bottom clipping
+		pObj->height -= pObj->botClip;
+
+		// Make adjustment for the top clipping row
+		srcP += sizeof(uint16) * ((pObj->width + 3) >> 2) * (pObj->topClip >> 2);
+		pObj->height -= pObj->topClip;
+		pObj->topClip %= 4;
+	}
+
+	// Simple RLE-like scheme: the two first bytes of each data chunk determine
+	// if bytes should be repeated or copied.
+	// Example: 10 00 00 20 will repeat byte 0x0 0x10 times, and will copy 0x20
+	// bytes from the input stream afterwards
+
+	// Vertical loop
+	for (int y = 0; y < pObj->height; ++y) {
+		// Horizontal loop
+		for (int x = 0; x < pObj->width; ) {
+			byte repeatBytes = *srcP++;
+			if (repeatBytes > 0) {
+				byte fillColor = *srcP++;
+				if (fillColor > 0)	// color 0 is transparent
+					memset(destP, fillColor, repeatBytes);
+				destP += repeatBytes;
+				x += repeatBytes;
+			} else {
+				byte copyBytes = *srcP++;
+				for (int z = 0; z < copyBytes; ++z) {
+					if (*srcP > 0)	// color 0 is transparent
+						*destP = *srcP;
+					srcP++;
+					destP++;
+				}
+				// Round up to the next even number
+				if (copyBytes % 2)
+					srcP++;
+				x += copyBytes;
+			}
+		}	// horizontal loop
+
+		// Move to next line
+		destP += (SCREEN_WIDTH - pObj->width);
+	}	// vertical loop
+}
+
+
 /**
  * Straight rendering with transparency support, PSX variant supporting also 4-BIT clut data
  */
@@ -272,7 +325,7 @@ static void PsxDrawTiles(DRAWOBJECT *pObj, uint8 *srcP, uint8 *destP, bool apply
 			assert(boxBounds.bottom >= boxBounds.top);
 			assert(boxBounds.right >= boxBounds.left);
 
-			int16 indexVal = READ_16(srcP);
+			int16 indexVal = READ_LE_UINT16(srcP);
 			srcP += sizeof(uint16);
 
 			// Draw a 4x4 block based on the opcode as in index into the block list
@@ -381,7 +434,7 @@ static void WrtNonZero(DRAWOBJECT *pObj, uint8 *srcP, uint8 *destP, bool applyCl
 			assert(boxBounds.bottom >= boxBounds.top);
 			assert(boxBounds.right >= boxBounds.left);
 
-			int16 indexVal = READ_16(srcP);
+			int16 indexVal = READ_LE_UINT16(srcP);
 			srcP += sizeof(uint16);
 
 			if (indexVal >= 0) {
@@ -763,8 +816,8 @@ void DrawObject(DRAWOBJECT *pObj) {
 			byte *p = (byte *)LockMem(pObj->hBits & HANDLEMASK);
 
 			srcPtr = p + (pObj->hBits & OFFSETMASK);
-			pObj->charBase = (char *)p + READ_32(p + 0x10);
-			pObj->transOffset = READ_32(p + 0x14);
+			pObj->charBase = (char *)p + READ_LE_UINT32(p + 0x10);
+			pObj->transOffset = READ_LE_UINT32(p + 0x14);
 
 			// Decompress block indexes for Discworld PSX
 			if (TinselV1PSX) {
@@ -793,7 +846,7 @@ void DrawObject(DRAWOBJECT *pObj) {
 						psxPaletteMapper(pObj->pPal, srcPtr + sizeof(uint16), psxMapperTable);
 
 						psxFourBitClut = true;
-						psxSkipBytes = READ_32(p + sizeof(uint32) * 5) << 4; // Fetch number of bytes we have to skip
+						psxSkipBytes = READ_LE_UINT32(p + sizeof(uint32) * 5) << 4; // Fetch number of bytes we have to skip
 						switch (indexType) {
 							case 0xDD: // Normal uncompressed indexes
 								psxRLEindex = false;
@@ -852,7 +905,7 @@ void DrawObject(DRAWOBJECT *pObj) {
 			else if (TinselV1PSX)
 				PsxDrawTiles(pObj, srcPtr, destPtr, typeId == 0x41, psxFourBitClut, psxSkipBytes, psxMapperTable, true);
 			else if (TinselV1Mac)
-				{} // TODO
+				MacDrawTiles(pObj, srcPtr, destPtr, typeId == 0x41);
 			else if (TinselV1)
 				WrtNonZero(pObj, srcPtr, destPtr, typeId == 0x41);
 			else if (TinselV0)
-- 
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