The graphics detail settings partially work now. They only affect how

sprites are drawn, but I think that's how it should be.

1: No bells or whistles.
2: This setting adds sprite blending, e.g. the smoke at the docks or the
   display cases at the Glease Gallery.
3: This setting adds light map support, e.g. when walking under the shack
   at the docks.
4: This setting adds better scaling algorithms.

The first three settings should work fine now. In fact, the third setting
is what we used to implement. The fourth setting still needs work and
testing. I've added code for downscaling case, but frankly I'm not
convinced the result is any better than with the simpler scaler. I usually
can't even tell the difference.

Of course, my translation of the original code could very well be buggy.

svn-id: r9867

1 files changed, 54 insertions, 10 deletions

diff --git a/sword2/driver/render.cpp b/sword2/driver/render.cpp
index 1d9749e3f8..3bdc306f97 100644
--- a/sword2/driver/render.cpp
+++ b/sword2/driver/render.cpp
@@ -349,15 +349,16 @@ void UploadRect(ScummVM::Rect *r) {
 static uint16 xScale[SCALE_MAXWIDTH];
 static uint16 yScale[SCALE_MAXHEIGHT];
 
-// This is based on the "line doubling" scaler in the original sprite renderer.
-// I've made it into two separate functions because there were cases from
+// I've made the scaling two separate functions because there were cases from
 // DrawSprite() where it wasn't obvious if the sprite should grow or shrink,
 // which caused crashes.
 //
-// The functions can probably be merged later, if/when we implement a better
-// scale function for it.
+// Maybe the functions can be merged later?
+//
+// The code is based on the original DrawSprite() code, so apart from not
+// knowing if I got it right, I don't know how good the original really is.
 
-void SquashImage(byte *dst, uint16 dstPitch, uint16 dstWidth, uint16 dstHeight,byte *src, uint16 srcPitch, uint16 srcWidth, uint16 srcHeight) {
+void SquashImage(byte *dst, uint16 dstPitch, uint16 dstWidth, uint16 dstHeight, byte *src, uint16 srcPitch, uint16 srcWidth, uint16 srcHeight, byte *backbuf) {
 	int32 ince, incne, d;
 	int16 x, y;
 
@@ -403,15 +404,56 @@ void SquashImage(byte *dst, uint16 dstPitch, uint16 dstWidth, uint16 dstHeight,b
 
 	// Copy the image
 
-	for (y = 0; y < dstHeight; y++) {
-		for (x = 0; x < dstWidth; x++) {
-			dst[x] = src[yScale[y] * srcPitch + xScale[x]];
+	if (backbuf) {
+		for (y = 0; y < dstHeight; y++) {
+			for (x = 0; x < dstWidth; x++) {
+				uint8 p;
+				uint8 p1 = 0;
+				int count = 0;
+				int spriteCount = 0;
+				int red = 0;
+				int green = 0;
+				int blue = 0;
+				int i, j;
+
+				for (j = yScale[y]; j < yScale[y + 1]; j++) {
+					for (i = xScale[x]; i < xScale[x + 1]; i++) {
+						p = src[j * srcPitch + i];
+						if (p) {
+							red += palCopy[p][0];
+							green += palCopy[p][1];
+							blue += palCopy[p][2];
+							p1 = p;
+							spriteCount++;
+						} else {
+							red += palCopy[backbuf[x]][0];
+							green += palCopy[backbuf[x]][1];
+							blue += palCopy[backbuf[x]][2];
+						}
+						count++;
+					}
+				}
+				if (spriteCount == 0)
+					dst[x] = 0;
+				else if (spriteCount == 1)
+					dst[x] = p1;
+				else
+					dst[x] = QuickMatch((uint8) (red / count), (uint8) (green / count), (uint8) (blue / count));
+			}
+			dst += dstPitch;
+			backbuf += lpBackBuffer->_width;
+		}
+	} else {
+		for (y = 0; y < dstHeight; y++) {
+			for (x = 0; x < dstWidth; x++) {
+				dst[x] = src[yScale[y] * srcPitch + xScale[x]];
+			}
+			dst += dstPitch;
 		}
-		dst += dstPitch;
 	}
 }
 
-void StretchImage(byte *dst, uint16 dstPitch, uint16 dstWidth, uint16 dstHeight,byte *src, uint16 srcPitch, uint16 srcWidth, uint16 srcHeight) {
+void StretchImage(byte *dst, uint16 dstPitch, uint16 dstWidth, uint16 dstHeight, byte *src, uint16 srcPitch, uint16 srcWidth, uint16 srcHeight, byte *backbuf) {
 	int32 ince, incne, d;
 	int16 x, y, i, j, k;
 
@@ -456,6 +498,8 @@ void StretchImage(byte *dst, uint16 dstPitch, uint16 dstWidth, uint16 dstHeight,
 
 	// Copy the image
 
+	// FIXME: If backbuf != NULL the image should be anti-aliased
+
 	for (y = 0; y < srcHeight; y++) {
 		for (j = yScale[y]; j < yScale[y + 1]; j++) {
 			k = 0;