游戏物理引擎开发

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  2012-10-23
  This matrix is called a “skew-symmetric” matrix, and an important result about crossproducts is that the cross product is equivalent tomultiplication by the correspondingskew-symmetric matrix
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  2012-10-23
  THE BENEFIT OF PESSIMISTIC COLLISION DETECTION
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  2012-10-17
  fifteen axes
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  2012-10-17
  distance < oneProject + twoProject
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  2012-10-15
  MULTI-RESOLUTION MAPS
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  2012-10-14
  Bounding volume hierarchies are used extensively to reduce the number of objectsthat need to be drawn.
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  2012-10-12
  Again we need to change the basis of the tensor at each frame before applying this function.
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  2012-10-11
  Order is crucial for both transformations and matrix multiplication:the matrix AB is a transformation that would result from first doing B and then doingA. In other words, the order of the transformations is the opposite of the orderof the matrices in the multiplication
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  2012-10-09
  For an aircraft these rotations are about the three axes: pitch is a rotation aboutthe X axis, yaw is about the Y axis, and roll is about the Z axis (assuming an aircraft islooking down the Z axis, with the Y axis up).
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  2012-10-08
  Let the start time be the current simulation time and the end time be the end ofthe current update request.
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  2012-10-08
  We can work out whatthe velocity would be if only the force acted on it, by simply multiplying the force bythe frame duration. If the actual velocity of the object is less than or equal to this value(or even slightly above it, if we acknowledge that rounding errors can creep in), we know that the particle was stationary at the previous frame.
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  2012-10-03
  This is the same as the scalar product, replacing the cosine with the sine. In factwe can write
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  2012-10-02
  If you so desire, you can easily convince yourself that equations 2.3 and 2.4 areequivalent by using Pythagoras’s theorem and constructing a right-angled trianglewhere each vector is the hypotenuse. I’ll leave this as an exercise for the skeptical.
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  2012-10-02
  In other words, to subtract vector b from vector a we first go forward along a,and then go backward along b.
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  2012-10-02
  In other words we multiply a vector by a scalar by multiplying all the components of the vector by the scalar.
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  2012-10-02
  Because it is very difficult to make things truly rigid in a physics engine, it isdifficult to make really firm objects in a mass-aggregate system.