41 lines
763 B
Ruby
41 lines
763 B
Ruby
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# A = old position, c = center of ball, v = current moving vector
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def reflection_vector(ax,ay,cx,cy,xv,yv)
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# Bouncing of resulting point: R
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rx = ax + xv
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ry = ay + yv
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ux = rx - cx
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uy = ry - cy
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r = (-ux*cx + ux*ax -uy*cy + uy*ay).to_f / ( ux * ux + uy * uy).to_f
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fx = cx + r * ux
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fy = cy + r * uy
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afx = fx - ax
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afy = fy - ay
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gx = ax + 2 * afx
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gy = ay + 2 * afy
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rgx = gx - rx
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rgy = gy - ry
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return rgx,rgy
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end
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# x,y further away than r allows?
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def bouncing?(x,y,cx,cy,r)
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# d(cx,cy,x,y) > r?
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d = Math.sqrt((x - cx)*(x-cx) + ( y - cy)*( y - cy))
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d > r
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end
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# if the speed vector is higher than the radius, we are done (2x radius would be still okay actually)
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def too_fast?(vx,vy,r)
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d = Math.sqrt(vx*vx+vy*vy)
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d > r
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end
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