# Triangle Strip

Triangle Strip by Ira Greenberg.

Generate a closed ring using the vertex() function and beginShape(TRIANGLE_STRIP) mode. The outsideRadius and insideRadius variables control ring’s radii respectively.

```
int x;
int y;
float outsideRadius = 150;
float insideRadius = 100;

void setup() {
size(640, 360);
background(204);
x = width/2;
y = height/2;
}

void draw() {
background(204);

int numPoints = int(map(mouseX, 0, width, 6, 60));
float angle = 0;
float angleStep = 180.0/numPoints;

beginShape(TRIANGLE_STRIP);
for (int i = 0; i <= numPoints; i++) {
float px = x + cos(radians(angle)) * outsideRadius;
float py = y + sin(radians(angle)) * outsideRadius;
angle += angleStep;
vertex(px, py);
px = x + cos(radians(angle)) * insideRadius;
py = y + sin(radians(angle)) * insideRadius;
vertex(px, py);
angle += angleStep;
}
endShape();
}

```

## Functions Used

size()

Defines the dimension of the display window width and height in units of pixels

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vertex()

All shapes are constructed by connecting a series of vertices

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sin()

Calculates the sine of an angle

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beginShape()

Using the beginShape() and endShape() functions allow creating more complex forms

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int

Datatype for integers, numbers without a decimal point

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setup()

The setup() function is run once, when the program starts

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map()

Re-maps a number from one range to another

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cos()

Calculates the cosine of an angle

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draw()

Called directly after setup(), the draw() function continuously executes the lines of code contained inside its block until the program is stopped or noLoop() is called

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radians()

Converts a degree measurement to its corresponding value in radians

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endShape()

The endShape() function is the companion to beginShape() and may only be called after beginShape()

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background()

The background() function sets the color used for the background of the Processing window

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