[Scummvm-git-logs] scummvm master -> 9f1528e32f78cd4725d44025bf606647a78a7b08

[criezy]

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Summary:
9f1528e32f SDL: Fix incorrect handling of dirty rect with negative shake offset in SDL1


Commit: 9f1528e32f78cd4725d44025bf606647a78a7b08
    https://github.com/scummvm/scummvm/commit/9f1528e32f78cd4725d44025bf606647a78a7b08
Author: Thierry Crozat (criezy at scummvm.org)
Date: 2023-03-06T22:16:49Z

Commit Message:
SDL: Fix incorrect handling of dirty rect with negative shake offset in SDL1

Instead of shifting the destination to the left, if was moving the source to
the right, which had the effect of shifting the dirty rect. So part of the
surface that should have been copied to the screen was not, and instead it
was copying part of the surface that did not need to be copied.

Changed paths:
    backends/graphics/surfacesdl/surfacesdl-graphics.cpp


diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
index 3656092838f..c3b14b76795 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
@@ -1333,29 +1333,31 @@ void SurfaceSdlGraphicsManager::internUpdateScreen() {
 			int src_y = r->y;
 			int dst_x = r->x;
 			int dst_y = r->y;
-			int dst_w = 0;
-			int dst_h = 0;
+			int dst_w = r->w;
+			int dst_h = r->h;
 #ifdef USE_ASPECT
 			int orig_dst_y = 0;
 #endif
-			if (_currentShakeXOffset >= 0)
-				dst_x += _currentShakeXOffset;
-			else
-				src_x += -_currentShakeXOffset;
+			dst_x += _currentShakeXOffset;
+			if (dst_x < 0) {
+				src_x -= dst_x;
+				dst_w += dst_x;
+				dst_x = 0;
+			}
 
-			if (_currentShakeYOffset >= 0)
-				dst_y += _currentShakeYOffset;
-			else
-				src_y += -_currentShakeYOffset;
+			dst_y += _currentShakeYOffset;
+			if (dst_y < 0) {
+				src_y -= dst_y;
+				dst_h += dst_y;
+				dst_y = 0;
+			}
 
-			if (dst_x < width && dst_y < height) {
-				dst_w = r->w;
+			if (dst_x < width && dst_y < height && dst_w > 0 && dst_h > 0) {
 				if (dst_w > width - dst_x)
 					dst_w = width - dst_x;
 				if (dst_w > width - src_x)
 					dst_w = width - src_x;
 
-				dst_h = r->h;
 				if (dst_h > height - dst_y)
 					dst_h = height - dst_y;
 				if (dst_h > height - src_y)
@@ -1371,17 +1373,17 @@ void SurfaceSdlGraphicsManager::internUpdateScreen() {
 					dst_y = real2Aspect(dst_y);
 
 				_scaler->scale((byte *)srcSurf->pixels + (src_x + _maxExtraPixels) * bpp + (src_y + _maxExtraPixels) * srcPitch, srcPitch,
-					(byte *)_hwScreen->pixels + dst_x * bpp + dst_y * dstPitch, dstPitch, dst_w, dst_h, src_x, src_y);
-			}
+						(byte *)_hwScreen->pixels + dst_x * bpp + dst_y * dstPitch, dstPitch, dst_w, dst_h, src_x, src_y);
 
-			r->x = dst_x;
-			r->y = dst_y;
-			r->w = dst_w * scale1;
-			r->h = dst_h * scale1;
+				r->x = dst_x;
+				r->y = dst_y;
+				r->w = dst_w * scale1;
+				r->h = dst_h * scale1;
 
 #ifdef USE_ASPECT
-			if (_videoMode.aspectRatioCorrection && orig_dst_y < height && !_overlayInGUI)
-				r->h = stretch200To240((uint8 *) _hwScreen->pixels, dstPitch, r->w, r->h, r->x, r->y, orig_dst_y * scale1, _videoMode.filtering, convertSDLPixelFormat(_hwScreen->format));
+				if (_videoMode.aspectRatioCorrection && orig_dst_y < height && !_overlayInGUI)
+					r->h = stretch200To240((uint8 *) _hwScreen->pixels, dstPitch, r->w, r->h, r->x, r->y, orig_dst_y * scale1, _videoMode.filtering, 	convertSDLPixelFormat(_hwScreen->format));
+			}
 #endif
 		}
 		SDL_UnlockSurface(srcSurf);