An attempt to implement thick line drawing.

svn-id: r29639

3 files changed, 64 insertions, 6 deletions

diff --git a/engines/scumm/he/wiz_he.cpp b/engines/scumm/he/wiz_he.cpp
index 164cfef7f8..05052fcd2a 100644
--- a/engines/scumm/he/wiz_he.cpp
+++ b/engines/scumm/he/wiz_he.cpp
@@ -1789,14 +1789,16 @@ void Wiz::fillWizLine(const WizParameters *params) {
 			int x2 = params->box2.right;
 			int y2 = params->box2.bottom;
 
+			drawProcP lineP;
+
+			lineP.imageRect = &imageRect;
+			lineP.wizd = wizd;
+			lineP.width = w;
+
 			if (params->processFlags & kWPFThickLine) {
-				debug(0, "Unsupported ThickLine (%d, %d)", params->lineUnk1, params->lineUnk2);
+				assert (params->lineUnk2 == 1); // Catch untested usage
+				Graphics::drawThickLine(x1, y1, x2, y2, params->lineUnk1, color, drawProc, &lineP);
 			} else {
-				drawProcP lineP;
-
-				lineP.imageRect = &imageRect;
-				lineP.wizd = wizd;
-				lineP.width = w;
 
 				Graphics::drawLine(x1, y1, x2, y2, color, drawProc, &lineP);
 			}
diff --git a/graphics/primitives.cpp b/graphics/primitives.cpp
index 9fdcb13b7b..85a0383ea9 100644
--- a/graphics/primitives.cpp
+++ b/graphics/primitives.cpp
@@ -64,4 +64,59 @@ void drawLine(int x0, int y0, int x1, int y1, int color, void (*plotProc)(int, i
 	}
 }
 
+
+// FIXME: This is a limited version of thick line drawing
+// it draws striped lines at some angles. Better algorithm could
+// be found here:
+//
+//   http://homepages.enterprise.net/murphy/thickline/index.html
+//
+// Feel free to replace it with better implementation
+void drawThickLine(int x0, int y0, int x1, int y1, int thickness, int color, void (*plotProc)(int, int, int, void *), void *data) {
+	const bool steep = ABS(y1 - y0) > ABS(x1 - x0);
+
+	if (steep) {
+		SWAP(x0, y0);
+		SWAP(x1, y1);
+	}
+
+	float dx = x1 - x0;
+	float dy = y1 - y0;
+	float d = sqrtf(dx * dx + dy * dy);
+
+	if (!d)
+        return;
+
+	int thickX = (int)((float)thickness * dy / d / 2);
+	int thickY = (int)((float)thickness * dx / d / 2);
+
+	const int delta_x = ABS(x1 - x0);
+	const int delta_y = ABS(y1 - y0);
+	const int delta_err = delta_y;
+	int x = x0;
+	int y = y0;
+	int err = 0;
+
+	const int x_step = (x0 < x1) ? 1 : -1;
+	const int y_step = (y0 < y1) ? 1 : -1;
+
+	if (steep)
+		drawLine(y - thickY, x + thickX, y + thickY, x - thickX, color, plotProc, data);
+	else
+		drawLine(x - thickX, y + thickY, x + thickX, y - thickY, color, plotProc, data);
+
+	while (x != x1) {
+		x += x_step;
+		err += delta_err;
+		if (2 * err > delta_x) {
+			y += y_step;
+			err -= delta_x;
+		}
+		if (steep)
+			drawLine(y - thickY, x + thickX, y + thickY, x - thickX, color, plotProc, data);
+		else
+			drawLine(x - thickX, y + thickY, x + thickX, y - thickY, color, plotProc, data);
+	}
+}
+
 }	// End of namespace Graphics
diff --git a/graphics/primitives.h b/graphics/primitives.h
index 2bc44d6644..0c96c1545a 100644
--- a/graphics/primitives.h
+++ b/graphics/primitives.h
@@ -28,6 +28,7 @@
 namespace Graphics {
 
 void drawLine(int x0, int y0, int x1, int y1, int color, void (*plotProc)(int, int, int, void *), void *data);
+void drawThickLine(int x0, int y0, int x1, int y1, int thickness, int color, void (*plotProc)(int, int, int, void *), void *data);
 
 }	// End of namespace Graphics