The compiler uses the NEON processor for all kinds of things. Time to start optimizing. There is still plenty of speed we can pick up here. Can you choose the eight control points so that the curve becomes a circle? The first thing to understand is that this is exactly the same function that UIBezierPath uses.

If key 2 is pressed again, then the subdivided control polygon should be drawn. The first thing to understand is that this is exactly the same function that UIBezierPath uses. That gets us to 6. Accelerate is optimized for big matrices. P0 through P3 are the control points. The easiest way to navigate this output is by searching for. This method should be activated when key 2 is pressed on the keyboard.

There is still plenty of speed we can pick up here. I mean, everyone knows that Accelerate uses the fancy vector hardware and that means super-duper fast.

You will construct a curve segment for each adjacent pair. Function calls can be expensive.

Introduction to Fast Bezier (and Trying the Accelerate.framework)

But day-to-day multiplication is often not one of them. It may even be slower than the simplest possible non-Accelerate implementation.

bezier curve homework

Back to the assembler, note that there are only two calls to powf. Let be the the set of input points. If you called addCurveToPoint: Each time the key is pressed the subdivision level is increased by 1 until it reaches the maximum.


For instance if you want to calculate intersections, or you want to draw text along the curve like in CurvyText from iOS: To accomplish this task, you need to write supporting code to convert your input data control points into a format that is expected by gluNurbsCurve.

In fairness, we should try removing the powf calls in the Accelerate function. The end point would be P3 and the control points would be P1 and P2. For little tiny things, the cost of the function call dwarfs what you might save otherwise. So we have to call it twice per point. I can feel the speed already.

CS Lecture Page

You can then look for blx to find the places you make function calls. Time to start optimizing.

bezier curve homework

On my iPhone 4, in Debug mode, with points, this takes over 20 seconds to run. We got rid of a lot of function calls both calls to Bezier and calls to powfand we replaced a very expensive squaring function with a very cheap one using vmul.

P0 through P3 are the control points. You need to supply a list of control pointa list of b-spline knots and order of the b-spline to the gluNurbsCurve function.


Assignment 1: Arbitrary-degree Bezier Curves

Which brings us to the next point. Still 10x slower then hand-coded. You can get the full test code in BezierPerf.

bezier curve homework

In this assignment, you should use the formula given to you in class to generate a large number of points to approximate the B-spline curve. The title of the window should be your full name and your GatorLink ID in parentheses. But in release mode, the Bezier function is gone entirely.

Justify your answer and write it to the ReadMe. Control polygon should be drawn first without subdivision. This is one of the big reasons that hand-calculation can be so much faster than Accelerate.

This just calls Bezier twice. Finally, the strangest thing you need to cueve is that this function is not linear for t. First, you can take a look at the code by editing the Scheme and setting the Build Configuration to Debug. After that this method should be deactivated and not drawn on the screen.