CODEWITHSUNDEEP
iphone
catskytw
catskytw

Reputation: 1

How to make the matrix caculating faster?

Hello guys: I have to project many points before drawing them on a frame. my codes are blow:

-(Coordination*)xyWorldToDev:(Coordination*)pt isIphoneYAxis:(BOOL)isIphoneYAxis{
    CGPoint tmpPoint=CGPointApplyAffineTransform(CGPointMake(pt.x,pt.y),worldToDevMatrix);
    Coordination *resultPoint=[[[Coordination alloc]initWithXY:tmpPoint.x withY:(isIphoneYAxis)?(sscy-tmpPoint.y):tmpPoint.y]autorelease];
    return resultPoint; }

-(Coordination*)xyDevTo3D:(Coordination*)cPt{
    double x=0.0,y=0.0;
    double divide=1+m_cView3DPara.v*cPt.y;
    x=(m_cView3DPara.a*cPt.x+m_cView3DPara.b*cPt.y+m_cView3DPara.e)/divide;
    y=(m_cView3DPara.d*cPt.y+m_cView3DPara.f)/divide;
    return [[[Coordination alloc]initWithXY:x withY:sscy-y]autorelease];
}
-(Coordination*)transformWorldTo3D:(Coordination*)pt{
    return [self xyDevTo3D:[self xyWorldToDev:pt isIphoneYAxis:NO]];
}

Therefore,the method "-(Coordination*)transformWorldTo3D:(Coordination*)pt " is called hundreds times because projecting.

But i found it is very very SLOW while calling transformWorldTo3D! Is there another way to accelerate it? Or using another framework which could caculate the projecting value faster?

Upvotes: 0

Views: 108

Answers (1)

David Gelhar
David Gelhar

Reputation: 27900

Object allocations are expensive (relative to arithmetic operations); and it appears that you're doing 2 alloc-init-autorelease sequences for every point.

My first suggestion would be to try to do some of this work with CGPoints and avoid the allocations.

(Actually, that's my second suggestion: my first is to profile the code to see where the time is being spent.)

Upvotes: 2

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