geomerative

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COPYRIGHT

Copyright 2006-2008 Ricard Marxer [email protected]

This product includes software developed by the Solution Engineering, Inc. (http://www.seisw.com/).

This product includes software developed by the The Apache Software Foundation (http://www.apache.org/).

INSTALL

Unzip the geomerative-XX.zip in the Processing libraries directory. The result shoul look like this: /path/to/processing/libraries/geomerative/library/geomerative.jar

USAGE

In the Processing IDE Sketch > Import Library > geomerative

DOCUMENTATION

The documentation is in the documentation folder. Just open the index.html with any web browser.

MINI-TUTORIAL

This geometry library consists of three main classes:

RShape - Contains subshapes formed of commands (move,lines,beziers,...) RPolygon - Contains contours formed of points RMesh - Contains strips formed of vertices

There are several uses of the library:

• Draw shapes with holes, in order to do so, we create a new shape and add commands to it. Once the shape is created we can:

  • draw it using draw(g) (note the use of g in order to draw the shape to the main PGraphics object)
  • convert it to a polygon using toPolygon()
  • acces its subshapes' commands or the points of these commands, accesing its attribute subshapes and the RSubshape methods

• Draw polygons with holes, in order to do so, we create a new polygon and add points (addPoint(x,y)) or contours (addContour()) to it. Once the polygon is created we can:

  • draw it using draw(g)
  • convert it to a mesh using toMesh()
  • acces its contours' points, accesing its attribute contours and the RContour methods
  • do binary operations over two polygons, using the methods diff(), union(), xor() and intersection()

EXAMPLE

/// Example to draw a simple shape with a hole /// Converting the shape to a mesh in the setup() avoids having to tesselate it for each frame, therefore the use of RMesh import geomerative.*;

RPolygon p; RShape s; RMesh m; int t = 0;

void setup(){ size(100,100,P3D); framerate(34); background(255); fill(0); //noFill(); stroke(255,0,0);

s = new RShape();

s.addMoveTo(-30,250); s.addLineTo(30,150); s.addArcTo(50,75,100,30); s.addBezierTo(130,90,75,100,90,150); s.addLineTo(130,250); s.addBezierTo(80,200,70,200,-30,250);

s.addMoveTo(60,120); s.addBezierTo(75,110,85,130,75,140); s.addBezierTo(70,150,65,140,60,120);

p = s.toPolygon(100); m = p.toMesh(); }

void draw(){ scale(0.25); translate(200,50); background(255);

rotateY(PI/65*t); fill(0); m.draw(g);

rotateY(PI/64*t); noFill(); p.draw(g); t++; } /// End of example

/// Example calculating the difference of two polygons /// Note the use of predefined polygons (createStar(), createCircle(), createRing(),...) import geomerative.*;

RMesh m; RPolygon p = RPolygon.createStar(120,70,6); RPolygon p2 = RPolygon.createStar(60,50,30);

float t=0;

void setup(){ size(400,400,P3D); framerate(24); //smooth(); noStroke(); fill(0);

p=p.diff(p2); m = p.toMesh(); }

void draw(){ background(255); translate(width/2,height/2);

rotateX(t/39); m.draw(g);

rotateY(-t/5); scale(0.3); m.draw(g);

t++; } /// End of example

KNOWN ISSUES

• Under certain renderers there's a big loss of precision, resulting in really ugly renderings of fonts and polygons in general.
• When we decrease the font size we get bad results, bad shapes. This must have to do with the font fixed point arithmetics, haven't studied any of that yet.