mirror of
https://gitlab.com/libeigen/eigen.git
synced 2026-04-10 11:34:33 +08:00
3036eeca0a
release of tvmet (inactive for 2 years and developer unreachable) as the basis for eigen2, because it provides seemingly good expression template mechanisms, we want that, and it would take years to reinvent that wheel. We'll see. So this commit imports the last tvmet release.
104 lines
1.8 KiB
C++
104 lines
1.8 KiB
C++
#include <iostream>
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#include <cmath>
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#include <tvmet/Vector.h>
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using namespace std;
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using namespace tvmet;
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typedef Vector<double,3> vector3d;
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void reflect(vector3d& reflection, const vector3d& ray, const vector3d& surfaceNormal)
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{
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// The surface normal must be unit length to use this equation.
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reflection = ray - 2 * dot(ray,surfaceNormal) * surfaceNormal;
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// expression printing
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// cout << (ray - 2 * dot(ray,surfaceNormal) * surfaceNormal) << endl;
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}
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int main()
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{
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vector3d x, y, z;
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// y will be the incident ray
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y[0] = 1;
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y[1] = 0;
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y[2] = -1;
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// z is the surface normal
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z[0] = 0;
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z[1] = 0;
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z[2] = 1;
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reflect(x, y, z);
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cout << "Reflected ray is: [ " << x[0] << " " << x[1] << " " << x[2]
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<< " ]" << endl;
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}
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/*****************************************************************************************
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gcc 3.2.0 produce this code (i586) using tvmet 1.3.0:
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_Z7reflectRN5tvmet6VectorIdLj3EEERKS1_S4_:
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.LFB2757:
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.L8:
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.L18:
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.L22:
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.L28:
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.L32:
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.L38:
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.L44:
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.L48:
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pushl %ebp
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.LCFI0:
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movl %esp, %ebp
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.LCFI1:
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leal -32(%ebp), %eax
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pushl %ebx
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.LCFI2:
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subl $52, %esp
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.LCFI3:
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movl 16(%ebp), %edx
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movl %eax, -24(%ebp)
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movl 12(%ebp), %ecx
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leal -36(%ebp), %eax
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movl %eax, -20(%ebp)
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movl 8(%ebp), %ebx
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leal -24(%ebp), %eax
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fldl 8(%edx)
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fldl 16(%edx)
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fmull 16(%ecx)
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fxch %st(1)
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movl %eax, -12(%ebp)
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leal -52(%ebp), %eax
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fmull 8(%ecx)
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movl %eax, -48(%ebp)
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leal -12(%ebp), %eax
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fldl (%edx)
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fmull (%ecx)
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fxch %st(1)
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movl %eax, -44(%ebp)
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faddp %st, %st(2)
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faddp %st, %st(1)
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fadd %st(0), %st
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fld %st(0)
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fstl -32(%ebp)
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fxch %st(1)
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fmull (%edx)
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fsubrl (%ecx)
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fstpl (%ebx)
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fld %st(0)
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fmull 8(%edx)
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fsubrl 8(%ecx)
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fstpl 8(%ebx)
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fmull 16(%edx)
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fsubrl 16(%ecx)
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fstpl 16(%ebx)
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addl $52, %esp
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popl %ebx
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popl %ebp
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ret
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*****************************************************************************************/
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