Data commit

Task/Ray-casting-algorithm/Liberty-BASIC/ray-casting-algorithm.basic

@@ -0,0 +1,76 @@
+NoMainWin
+Global sw, sh, verts
+
+sw = 640 :   sh = 480
+WindowWidth  = sw+8 : WindowHeight = sh+31
+UpperLeftX = (DisplayWidth -sw)/2
+UpperLeftY = (DisplayHeight-sh)/2
+Open"Ray Casting Algorithm" For Graphics_nf_nsb As #g
+#g "Down; TrapClose [halt]"
+h$ = "#g"
+
+Dim xp(15),yp(15)
+#g "when leftButtonDown [halt];when mouseMove checkPoint"
+#g "when rightButtonDown [Repeat]"
+
+[Repeat]
+    #g "Cls;Fill 32 160 255; Color white;BackColor 32 160 255"
+    #g "Place 5 460;\L-click to exit"
+    #g "Place 485 460;\R-click for new polygon"
+
+    'generate polygon from random points
+    numPoints =  rand(4,15)
+    verts = numPoints
+    For i = 0 To numPoints-1
+        xp(i) = rand(20,620)
+        yp(i) = rand(40,420)
+    Next
+    Call drawPoly h$, verts, "white"
+    #g "Flush"
+    Wait
+
+[halt]
+Close #g
+End
+
+'Point In Polygon Function
+Function pnp(x, y, numSides)
+    j= numSides-1: oddNodes = 0
+    For i = 0 To numSides-1
+        If ((yp(i)<y) And (yp(j)>=y)) Or ((yp(j)<y) And (yp(i)>=y)) Then
+            f1 = y - yp(i):f2 = yp(j) - yp(i): f3 = xp(j) - xp(i)
+            If (xp(i) + f1 / f2 * f3) < x Then oddNodes = 1 - oddNodes
+        End If
+        j = i
+    Next
+    pnp = oddNodes
+End Function
+
+'draw the polygon
+Sub drawPoly h$, verts, colour$
+    #h$, "Color ";colour$
+    j = verts-1
+    For i = 0 To verts-1
+        #h$ "Line ";xp(j);" ";yp(j);" ";xp(i);" ";yp(i)
+        j = i
+    Next
+End Sub
+
+'change message and color of polygon
+Sub checkPoint h$, x, y
+    If pnp(x,y,verts) Then
+        #h$ "Color 32 160 255;BackColor 32 160 255"
+        #h$ "Place 5 0;BoxFilled 150 20;Color white"
+        #h$ "Place 7 15;\Mouse In Polygon"
+        Call drawPoly h$, verts, "red"
+    Else
+        #h$ "Color 32 160 255;BackColor 32 160 255"
+        #h$ "Place 5 0;BoxFilled 150 20;Color white"
+        #h$ "Place 7 15;\Mouse Not In Polygon"
+        Call drawPoly h$, verts, "white"
+    End If
+End Sub
+
+Function rand(loNum,hiNum)
+    rand = Int(Rnd(0)*(hiNum-loNum+1)+loNum)
+End Function