Diff: BulletVelocities.h

Revision:

4:673eb9735d44

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BulletVelocities.h	Sat Jun 08 11:24:05 2013 +0000
@@ -0,0 +1,121 @@
+/*
+ * SOURCE FILE : BulletVelocities.h
+ *
+ * Converts from set of joystick inputs to horizontal and vertical velocities.
+ *
+ */
+
+#ifndef BulletVelocitiesIncluded
+  
+  #define BulletVelocitiesIncluded
+
+  #include "Int16Pair.h"
+  
+  class BulletVelocities {
+  
+  public :
+
+    /***************/
+    /* CONSTRUCTOR */
+    /***************/
+    // Pass velocity for a horizontally moving bullet in h.
+    // Pass velocity for a vertically moving bullet in v.
+    BulletVelocities( Int16 h, Int16 v ) {
+      // Calculate velocities used on the diagonal.
+      // This is really doing hd = h * cos( 45 degrees ) and
+      // vd = v * sin( 45 degrees ).
+      Int16 hd = (Int16)floor( (double)h * 0.707 + 0.5 );
+      Int16 vd = (Int16)floor( (double)v * 0.707 + 0.5 );
+      // Initialise the table of velocities.
+      Int16Pair *ptr = pairs;
+      // No joystick contacts closed. Index 0.
+      ptr->X = 0;
+      ptr->Y = 0;
+      ptr++;
+      // Joystick up. Index 1
+      ptr->X = 0;
+      ptr->Y = -v;
+      ptr++;
+      // Joystick down. Index 2.
+      ptr->X = 0;
+      ptr->Y = v;
+      ptr++;
+      // Joystick up and down (impossible). Index 3.
+      ptr->X = 0;
+      ptr->Y = v;
+      ptr++;
+      // Joystick left. Index 4.
+      ptr->X = -h;
+      ptr->Y = 0;
+      ptr++;
+      // Joystick left and up. Index 5.
+      ptr->X = -hd;
+      ptr->Y = -vd;
+      ptr++;
+      // Joystick left and down. Index 6.
+      ptr->X = -hd;
+      ptr->Y = vd;
+      ptr++;
+      // Joystick up, down and left (impossible). Index 7.
+      ptr->X = 0;
+      ptr->Y = v;
+      ptr++;
+      // Joystick right. Index 8.
+      ptr->X = h;
+      ptr->Y = 0;
+      ptr++;
+      // Joystick right and up. Index 9.
+      ptr->X = hd;
+      ptr->Y = -vd;
+      ptr++;
+      // Joystick right and down. Index 10.
+      ptr->X = hd;
+      ptr->Y = vd;
+      ptr++;
+      // Joystick up, down and right (impossible). Index 11.
+      ptr->X = 0;
+      ptr->Y = v;
+      ptr++;
+      // Joystick left and right (impossible). Index 12.
+      ptr->X = 0;
+      ptr->Y = v;
+      ptr++;
+      // Joystick up, left and right (impossible). Index 13.
+      ptr->X = 0;
+      ptr->Y = v;
+      ptr++;
+      // Joystick down, left and right (impossible) Index 14.
+      ptr->X = 0;
+      ptr->Y = v;
+      ptr++;
+      // Joystick up, down, left and right (impossible). Index 15.
+      ptr->X = 0;
+      ptr->Y = v;
+      ptr++;
+    }
+
+    /*******************************************************/
+    /* GET VELOCITIES FOR A COMBINATION OF JOYSTICK INPUTS */
+    /*******************************************************/
+    // Pass a map containing joystick inputs where a set bit indicates a closed contact.
+    // Bits must be ordered as follows :
+    // Bit 0 = Up.
+    // Bit 1 = Down.
+    // Bit 2 = Left.
+    // Bit 3 = Right.
+    // Remaining bits are ignored.
+    const Int16Pair *GetVelocities( UInt8 joyMap ) const {
+      return pairs + ( joyMap & 0x0F );
+    }
+    
+  private :
+
+    // Horizontal and vertical velocities for each combination of joystick inputs.    
+    Int16Pair pairs[ 16 ];
+    
+  };
+  
+#endif
+
+/* END of BulletVelocities.h */
+