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Topic: moveTo for shape (Read 340 times) |
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kevinP
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moveTo for shape
« on: Jun 7th, 2004, 2:21pm » |
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Hi all,
I am trying to draw some simple polygons using side lengths and angles (somewhat like turtle graphics do).
I thought that this is not much more than converting polar coords to Cartesian, but in my simplified example below I get a diamond (or rotated square) rather than a square parallel to my X/Y axes. The vertices are being calculated relative to the central starting point.
Code:
void setup()
{
size(300,300);
}
// square
int[] side = { 100, 100, 100, 100 }; // length of sides
int[] dir = { 0, -90, -180, -270 }; // direction in deg.
void draw()
{
display();
}
void display()
{
translate(width/2, height/2);
beginShape(POLYGON);
{
for(int i=0; i<side.length; i++) {
vertex(side[i] * cos(radians(dir[i])),
side[i] * sin(radians(dir[i])));
translate(side[i] * cos(radians(dir[i])),
side[i] * sin(radians(dir[i])));
}
}
endShape();
}
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Follow-up - using this and no beginShape() works fine:
line(0,0, cos(angle), sin(angle));
translate(cos(angle), sin(angle));
But I want to be able to draw a filled polygon (using side length and angle).
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| « Last Edit: Jun 7th, 2004, 2:47pm by kevinP » |
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Kevin Pfeiffer
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TomC
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Re: moveTo for shape
« Reply #1 on: Jun 7th, 2004, 2:49pm » |
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You're only drawing one vertex per line.
line(x1,y1,x2,y2) is the equivalent of vertex(x1,y1) and vertex(x2,y2).
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| « Last Edit: Jun 7th, 2004, 2:50pm by TomC » |
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kevinP
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Re: moveTo for shape
« Reply #2 on: Jun 7th, 2004, 2:58pm » |
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I realized that I need to save my "current position" and then add that to each new X/Y calculation in order to get vertices relative to each other.
This works...
Code:
void display()
{
int xPos = 0;
int yPos = 0;
translate(width/2, height/2);
beginShape(LINE_LOOP);
{
vertex(xPos, yPos);
for(int i=0; i<side.length; i++) {
xPos += int( side[i] * cos(radians(dir[i])) );
yPos += int( side[i] * sin(radians(dir[i])) );
vertex(xPos, yPos);
println("xPos = " + xPos + " yPos = " + yPos);
}
}
endShape();
}
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| « Last Edit: Jun 7th, 2004, 3:13pm by kevinP » |
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Kevin Pfeiffer
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TomC
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Re: moveTo for shape
« Reply #3 on: Jun 7th, 2004, 3:01pm » |
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True. On second thought I think that the problem is with calling translate inside beginShape/endShape.
Quote:
Transformations such as translate(), rotate(), and scale() do not work within beginShape().
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-- http://processing.org/reference/beginShape_.html
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kevinP
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Re: moveTo for shape
« Reply #4 on: Jun 7th, 2004, 3:14pm » |
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Yes, I see. Also sorry for stepping on your reply -- I updated my previous posting which threw your answer here out of context.
-K
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Kevin Pfeiffer
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