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Update content.en-GB.md

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closes https://github.com/Pomax/BezierInfo-2/issues/319
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Pomax
2021-08-26 09:30:57 -07:00
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docs/chapters/decasteljau/content.en-GB.md
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@@ -23,23 +23,23 @@ To see this in action, move the slider for the following sketch to changes which
### How to implement de Casteljau's algorithm ### How to implement de Casteljau's algorithm
Let's just use the algorithm we just specified, and implement that: Let's just use the algorithm we just specified, and implement that as a function that can take a list of curve-defining points, and a `t` value, and draws the associated point on the curve for that `t` value:
``` ```
function drawCurve(points[], t): function drawCurvePoint(points[], t):
if(points.length==1): if(points.length==1):
draw(points[0]) draw(points[0])
else: else:
newpoints=array(points.size-1) newpoints=array(points.size-1)
for(i=0; i<newpoints.length; i++): for(i=0; i<newpoints.length; i++):
newpoints[i] = (1-t) * points[i] + t * points[i+1] newpoints[i] = (1-t) * points[i] + t * points[i+1]
drawCurve(newpoints, t) drawCurvePoint(newpoints, t)
``` ```
And done, that's the algorithm implemented. Except usually you don't get the luxury of overloading the "+" operator, so let's also give the code for when you need to work with `x` and `y` values: And done, that's the algorithm implemented. Although: usually you don't get the luxury of overloading the "+" operator, so let's also give the code for when you need to work with `x` and `y` values separately:
``` ```
function drawCurve(points[], t): function drawCurvePoint(points[], t):
if(points.length==1): if(points.length==1):
draw(points[0]) draw(points[0])
else: else:
@@ -48,7 +48,7 @@ function drawCurve(points[], t):
x = (1-t) * points[i].x + t * points[i+1].x x = (1-t) * points[i].x + t * points[i+1].x
y = (1-t) * points[i].y + t * points[i+1].y y = (1-t) * points[i].y + t * points[i+1].y
newpoints[i] = new point(x,y) newpoints[i] = new point(x,y)
drawCurve(newpoints, t) drawCurvePoint(newpoints, t)
``` ```
So what does this do? This draws a point, if the passed list of points is only 1 point long. Otherwise it will create a new list of points that sit at the <i>t</i> ratios (i.e. the "markers" outlined in the above algorithm), and then call the draw function for this new list. So what does this do? This draws a point, if the passed list of points is only 1 point long. Otherwise it will create a new list of points that sit at the <i>t</i> ratios (i.e. the "markers" outlined in the above algorithm), and then call the draw function for this new list.