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var v3d=function(x,y,z)
{
this.x=(x!==undefined)?x:0;
this.y=(y!==undefined)?y:0;
this.z=(z!==undefined)?z:0;
}
v3d.prototype.l=function(){return Math.sqrt(this.x*this.x+this.y*this.y+this.z*this.z);}
v3d.prototype.n=function(){var L=this.l();this.x/=L;this.y/=L;this.z/=L;}
v3d.prototype.ms=function(s)
{
this.x*=s;this.y*=s;this.z*=s;
}
v3d.prototype.mm=function(m)
{
return new v3d(
m[0]*this.x+m[4]*this.y+m[8]*this.z,
m[1]*this.x+m[5]*this.y+m[9]*this.z,
m[2]*this.x+m[6]*this.y+m[10]*this.z
);
}
v3d.prototype.cross=function(b)
{
return new v3d(
this.y*b.z-this.z*b.y,
this.z*b.x-this.x*b.z,
this.x*b.y-this.y*b.x
);
}
function buildIdentityMatrix()
{
var m=new Float32Array(16);
for(var i=0;i<4;++i)m[i*4+i]=1.;
return m;
}
function buildProjectionMatrix2D(l,r,b,t,near,far)
{
var m=buildIdentityMatrix();
m[0]=2/(r-l);m[5]=2/(t-b);m[10]=-2/(far-near);
m[12]=-(r+l)/(r-l);m[13]=-(t+b)/(t-b);m[14]=-(far+near)/(far-near);
return m;
}
function buildProjectionMatrix3D(w,h,fov,near,far)
{
var m=new Float32Array(16);
var f=1./Math.tan(Math.PI*fov/360.);
var ar=w/h;
m[0]=f/ar;m[5]=f;m[10]=(far+near)/(near-far);
m[11]=-1.;m[14]=(2*far*near)/(near-far);
return m;
}
function buildTranslationMatrix(x,y,z)
{
var m=buildIdentityMatrix();
m[12]=x;m[13]=y;m[14]=z;
return m;
}
function buildRotationMatrix(a,x,y,z)
{
var m=buildIdentityMatrix();
//check (x,y,z) here
var c=Math.cos(a),s=Math.sin(a);
m[0]=x*x*(1-c)+c;m[4]=x*y*(1-c)-z*s;m[8]=x*z*(1-c)+y*s;
m[1]=y*x*(1-c)+z*s;m[5]=y*y*(1-c)+c;m[9]=y*z*(1-c)-x*s;
m[2]=x*z*(1-c)-y*s;m[6]=y*z*(1-c)+x*s;m[10]=z*x*(1-c)+c;
m[15]=1.;
return m;
}
function buildLookAtMatrix(e,a,u)
{
var f=new v3d(a[0]-e[0],a[1]-e[1],a[2]-e[2]);
f.n();var up=new v3d(u[0],u[1],u[2]);up.n();
var r=f.cross(up);r.n();var p=r.cross(f);
var m=buildIdentityMatrix();
m[0]=r.x;m[4]=r.y;m[8]=r.z;
m[1]=p.x;m[5]=p.y;m[9]=p.z;
m[2]=-f.x;m[6]=-f.y;m[10]=-f.z;
m=multMatrix(m,buildTranslationMatrix(-e[0],-e[1],-e[2]));
return m;
}
function multMatrix(a,b)
{
var r=new Float32Array(16);
for(var i=0;i<4;++i)
for(var j=0;j<4;++j)
for(var k=0;k<4;++k)
r[i*4+j]+=a[i*4+k]*b[k*4+j];
return r;
}
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