Murk 1998 DirectX 1.0

Author: moonwho101

bin/Murk.exe

@@ -629,34 +629,6 @@ void handle_mouse(int x, int y) {
 	}
 }
 
-// Adjust mouse coordinates for isometric projection
-// mx,my = mouse position
-// px,py = reference point (e.g., tile origin)
-// type   = axis selector (0 = slope +0.5, 1 = slope -0.5)
-
-void mouse_adjust_shear(int mx, int my, int px, int py, int type) {
-	// Relative mouse offset
-	int dx = mx - px;
-	int dy = my - py;
-
-	// Use integer-safe math (avoid truncation surprises)
-	int val;
-
-	if (type == 1) {
-		// Project onto axis with slope -0.5
-		// v = dy - dx/2
-		val = dy - (dx >> 1); // use bitshift for exact /2
-		calcmousex = px - val;
-		calcmousey = py + (val >> 1);
-	} else {
-		// Project onto axis with slope +0.5
-		// u = dy + dx/2
-		val = dy + (dx >> 1);
-		calcmousex = px + val;
-		calcmousey = py + (val >> 1);
-	}
-}
-
 ///////////////////////////////////////////////////////////
 //
 ///////////////////////////////////////////////////////////
@@ -670,11 +642,10 @@ void mouse_adjust(int mx, int my, int px, int py, int type) {
 	// find the intsersction of two lines to adjust the mouse
 	// to work on the 3d grid ... holy moly
 
+	// intersection of y = -1/2x + b and y = x/2,  x=b
+
 	newmx = mx - px;
 	newmy = my - py;
-	b = (int)(newmy + (.5 * newmx));
-	calcmousex = (b) + px;
-	calcmousey = (b / 2) + py;
 
 	if (type == 1) {
 		// new one
@@ -694,6 +665,34 @@ void mouse_adjust(int mx, int my, int px, int py, int type) {
 //
 ///////////////////////////////////////////////////////////
 
+// Adjust mouse coordinates for isometric projection
+// mx,my = mouse position
+// px,py = reference point (e.g., tile origin)
+// type   = axis selector (0 = slope +0.5, 1 = slope -0.5)
+
+void mouse_adjust_shear(int mx, int my, int px, int py, int type) {
+	// Relative mouse offset
+	int dx = mx - px;
+	int dy = my - py;
+
+	// Use integer-safe math (avoid truncation surprises)
+	int val;
+
+	if (type == 1) {
+		// Project onto axis with slope -0.5
+		// v = dy - dx/2
+		val = dy - (dx >> 1); // use bitshift for exact /2
+		calcmousex = px - val;
+		calcmousey = py + (val >> 1);
+	} else {
+		// Project onto axis with slope +0.5
+		// u = dy + dx/2
+		val = dy + (dx >> 1);
+		calcmousex = px + val;
+		calcmousey = py + (val >> 1);
+	}
+}
+
 void OnRButtonDown(LPARAM lParam) {
 
 	UINT x1 = LOWORD(lParam);