Revision 2:74bc9b16fb88, committed 2015-02-25

Comitter:

maxint

Date:

Wed Feb 25 10:43:15 2015 +0000

Parent:

1:71185a0aadfc

Child:

3:441dc90d10ce

Commit message:

added methods for better bouncing experiments

Changed in this revision

--- a/Ball.cpp	Fri Feb 06 10:18:02 2015 +0000
+++ b/Ball.cpp	Wed Feb 25 10:43:15 2015 +0000
@@ -91,9 +91,37 @@
     this->unmove(); // undo move to pre-bouncing position to avoid drawing on colliding position
 
     this->vSpeed.multiply(vBounce);
+    //this->vSpeed.bounce(vBounce);
 
     // check speed w/max
     if(this->vSpeed.y>5.0) this->vSpeed.y=5;
+    if(this->vSpeed.x>5.0) this->vSpeed.x=5;
+    if(this->vSpeed.y<-5.0) this->vSpeed.y=-5;
+    if(this->vSpeed.x<-5.0) this->vSpeed.x=-5;
+}
+
+void Ball::BounceAgainst(Vector vBounce)
+{   // change the direction in a certain direction
+    this->unmove(); // undo move to pre-bouncing position to avoid drawing on colliding position
+
+    //this->vSpeed.multiply(vBounce);
+    this->vSpeed.bounce(vBounce);
+
+    // check speed w/max
+    if(this->vSpeed.y>5.0) this->vSpeed.y=5;
+    if(this->vSpeed.x>5.0) this->vSpeed.x=5;
+    if(this->vSpeed.y<-5.0) this->vSpeed.y=-5;
+    if(this->vSpeed.x<-5.0) this->vSpeed.x=-5;
+
+    if(abs(vSpeed.x)>abs(vSpeed.y))
+        vSpeed.x=vSpeed.x/abs(vSpeed.x) * abs(vSpeed.y);
+
+/*    
+    if(this->vSpeed.y>0 && this->vSpeed.y<1.0) this->vSpeed.y=1;
+    if(this->vSpeed.x>0 && this->vSpeed.x<1.0) this->vSpeed.x=1;
+    if(this->vSpeed.y<0 && this->vSpeed.y>-1.0) this->vSpeed.y=-1;
+    if(this->vSpeed.x<0 && this->vSpeed.x>-1.0) this->vSpeed.x=-1;
+*/
 }
 
 

--- a/Ball.h	Fri Feb 06 10:18:02 2015 +0000
+++ b/Ball.h	Wed Feb 25 10:43:15 2015 +0000
@@ -34,6 +34,7 @@
         Circle getBoundingCircle();
         bool collides(Rectangle r);
         void Bounce(Vector vBounce);
+        void BounceAgainst(Vector vBounce);
 
     private:
         uint16_t uColor;

--- a/Vector.cpp	Fri Feb 06 10:18:02 2015 +0000
+++ b/Vector.cpp	Wed Feb 25 10:43:15 2015 +0000
@@ -57,4 +57,49 @@
 {   // multiply the vector by means of the other vector
     x*=vMult.x;
     y*=vMult.y;
+}
+
+Vector Vector::getNormalized()
+{   // get the Unit vector (= vector normalized to length 1)
+    // see http://en.wikipedia.org/wiki/Unit_vector
+    return(Vector(x/getSize(), y/getSize()));
+}
+
+Vector Vector::getNormal()
+{   // get the normal Vector
+    // see http://stackoverflow.com/questions/14885693/how-do-you-reflect-a-vector-over-another-vector
+    // vec.leftNormal --> vx = vec.vy; vy = -vec.vx; 
+    // vec.rightNormal --> vx = -vec.vy; vy = vec.vx;
+    if(isLeft())
+        return(Vector(y, -1 * x));
+    else
+        return(Vector(-1 * y, x));
+}
+    
+void Vector::bounce(Vector vBounce)
+{   // bounce a vector against another vector
+    // see http://stackoverflow.com/questions/14885693/how-do-you-reflect-a-vector-over-another-vector
+    Vector vBounceNormalized=vBounce.getNormalized();
+    Vector vBounceNormal=vBounce.getNormal();
+    Vector vBounceNormalNormalized=vBounceNormal.getNormalized();
+
+    // 1. Find the dot product of vec1 and vec2
+    // Note: dx and dy are vx and vy divided over the length of the vector (magnitude)
+    float dpA = x * vBounceNormalized.x + y * vBounceNormalized.y;
+
+    // 2. Project vec1 over vec2
+    float prA_vx = dpA * vBounceNormalized.x;
+    float prA_vy = dpA * vBounceNormalized.y;
+
+    // 3. Find the dot product of vec1 and vec2's normal
+    float dpB = x * vBounceNormalNormalized.x + y * vBounceNormalNormalized.y;
+
+    // 4. Project vec1 over vec2's left normal
+    float prB_vx = dpB * vBounceNormalNormalized.x;
+    float prB_vy = dpB * vBounceNormalNormalized.y;
+
+    // 5. Add the first projection prA to the reverse of the second -prB
+    float new_vx = prA_vx - prB_vx;
+    float new_vy = prA_vy - prB_vy;
+    set(new_vx, new_vy);
 }
\ No newline at end of file

--- a/Vector.h	Fri Feb 06 10:18:02 2015 +0000
+++ b/Vector.h	Wed Feb 25 10:43:15 2015 +0000
@@ -9,7 +9,7 @@
         
         Vector();
         Vector(float fX, float fY);
-        void set(float dX, float fY);
+        void set(float fX, float fY);
         void set(int nX, int nY);
         float getSize();
         bool isLeft();
@@ -19,4 +19,7 @@
         void add(float fAdd);
         void add(Vector vAdd);
         void multiply(Vector vMult);
+        Vector getNormal();
+        Vector getNormalized();
+        void bounce(Vector vBounce);
 };