mirror of
https://github.com/TorqueGameEngines/Torque3D.git
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94 lines
2.9 KiB
C++
94 lines
2.9 KiB
C++
//-----------------------------------------------------------------------------
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// Copyright (c) 2012 GarageGames, LLC
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to
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// deal in the Software without restriction, including without limitation the
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// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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// sell copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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// IN THE SOFTWARE.
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//-----------------------------------------------------------------------------
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#include "platform/platform.h"
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#include "math/mSphere.h"
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#include "math/mMatrix.h"
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bool SphereF::intersectsRay( const Point3F &start, const Point3F &end ) const
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{
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MatrixF worldToObj( true );
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worldToObj.setPosition( center );
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worldToObj.inverse();
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VectorF dir = end - start;
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dir.normalize();
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Point3F tmpStart = start;
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worldToObj.mulP( tmpStart );
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//Compute A, B and C coefficients
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F32 a = mDot(dir, dir);
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F32 b = 2 * mDot(dir, tmpStart);
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F32 c = mDot(tmpStart, tmpStart) - (radius * radius);
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//Find discriminant
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F32 disc = b * b - 4 * a * c;
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// if discriminant is negative there are no real roots, so return
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// false as ray misses sphere
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if ( disc < 0 )
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return false;
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// compute q as described above
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F32 distSqrt = mSqrt( disc );
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F32 q;
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if ( b < 0 )
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q = (-b - distSqrt)/2.0;
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else
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q = (-b + distSqrt)/2.0;
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// compute t0 and t1
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F32 t0 = q / a;
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F32 t1 = c / q;
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// make sure t0 is smaller than t1
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if ( t0 > t1 )
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{
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// if t0 is bigger than t1 swap them around
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F32 temp = t0;
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t0 = t1;
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t1 = temp;
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}
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// This function doesn't use it
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// but t would be the interpolant
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// value for getting the exact
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// intersection point, by interpolating
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// start to end by t.
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F32 t = 0;
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TORQUE_UNUSED(t);
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// if t1 is less than zero, the object is in the ray's negative direction
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// and consequently the ray misses the sphere
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if ( t1 < 0 )
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return false;
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// if t0 is less than zero, the intersection point is at t1
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if ( t0 < 0 ) // t = t1;
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return true;
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else // else the intersection point is at t0
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return true; // t = t0;
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}
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