PeasyCam provides a dead-simple mouse-driven camera for Processing. It is created and maintained by Jonathan Feinberg. It is free for all uses, per the Apache 2.0 license.

To download the distribution, and to see a demo, go to the PeasyCam home page.

Example

PeasyCam camera;

void setup() {
    // PeasyCam constructor:
    // PeasyCam(PApplet parent,
    //          double lookAtX, double lookAtY, double lookAtZ, 
    //          double distance);
    camera = new PeasyCam(this, 0, 0, 0, 50);
}

That’s it. Now a mouse left-drag will rotate the camera around the subject, a right drag will zoom in and out, and a middle-drag will pan. A double-click restores the camera to its original position.

The PeasyCam is positioned on a sphere whose radius is the given distance from the look-at point. Rotations are around axes that pass through the looked-at point.

Constructors

PeasyCam(PApplet parent, double lookAtX, double lookAtY, double lookAtZ, double distance);
PeasyCam(PApplet parent, double distance); // look at 0,0,0

Methods

camera.setActive(boolean active);  // false to make this camera stop responding to mouse

// returns if camera will respond to mouse
camera.isActive();

// By default, the camera is in "free rotation" mode, but you can
// constrain it to any axis, around the look-at point:
camera.setYawRotationMode();   // like spinning a globe
camera.setPitchRotationMode(); // like a somersault
camera.setRollRotationMode();  // like a radio knob
camera.setSuppressRollRotationMode();  // Permit pitch/yaw only.
camera.setSuppressYawRotationMode();  // Permit pitch/roll only.
camera.setSuppressPitchRotationMode();  // Permit roll/yaw only.

// Then you can set it back to its default mode:
camera.setFreeRotationMode();

// reassign particular drag gestures, or set them to null
camera.setLeftDragHandler(PeasyDragHandler handler);
camera.setCenterDragHandler(PeasyDragHandler handler);
camera.setRightDragHandler(PeasyDragHandler handler);
PeasyDragHandler getPanDragHandler();
PeasyDragHandler getRotateDragHandler();
PeasyDragHandler getZoomDragHandler();

// mouse wheel zooms by default; set null, or make your own
camera.setWheelHandler(PeasyWheelHandler handler);
PeasyWheelHandler getZoomWheelHandler();

// change sensitivity of built-in mouse controls
camera.setWheelScale(double scale); // 1.0 by default
camera.setZoomScale(double scale); // 1.0 by default
camera.setRotationScale(double scale); // 1.0 by default
camera.setPanScale(double scale); // 1.0 by default
double getWheelScale();
double getZoomScale();
double getRotationScale();
double getPanScale();

// make your own!
public interface PeasyDragHandler {
	public void handleDrag(final double dx, final double dy);
}
public interface PeasyWheelHandler {
	public void handleWheel(final int delta);
}

camera.setDamping(double rotate, double zoom, double pan); // default .84,.84,.84
camera.setResetOnDoubleClick(boolean resetOnDoubleClick); // default true
camera.setPanOnScreenEdge(boolean panOnScreenEdge); //pans when mouse touches screen edge - default false
camera.setReversePan(boolean reverse); //reverses pan direction when true - default false
camera.setReverseZoom(boolean reverse); //reverses zoom direction when true - default false
camera.setReverseRotate(boolean reverse); //reverses rotate direction when true - default false
camera.setSpeedLock(boolean lock); //increases camera speed if framerate drops - default true
camera.setSpeedRate(double frameRate); //sets the SpeedLock to the target FrameRate - default 60

//lookAt sets the center of the camera - rotate around the lookAt
camera.lookAt(double x, double y, double z);
camera.lookAt(double x, double y, double z, long animationTimeInMillis);
camera.lookAt(double x, double y, double z, double distance);
camera.lookAt(double x, double y, double z, double distance, long animationTimeInMillis);

//lookThrough rotates the camera to look through a point at the lookAt
camera.lookThrough(double x, double y, double z);
camera.lookThrough(double x, double y, double z, long animationTimeInMillis);
camera.lookThrough(double x, double y, double z, double distance);
camera.lookThrough(double x, double y, double z, double distance, long animationTimeInMillis);

camera.rotateX(double angle);  // rotate around the x-axis passing through the subject
camera.rotateY(double angle);  // rotate around the y-axis passing through the subject
camera.rotateZ(double angle);  // rotate around the z-axis passing through the subject
camera.setDistance(double d);  // distance from looked-at point
camera.pan(double dx, double dy);     // move the looked-at point relative to current orientation

double camera.getDistance();  // current distance
float[] camera.getLookAt();  // float[] { x, y, z }, looked-at point

camera.setMinimumDistance(double minimumDistance);
camera.setMaximumDistance(double maximumDistance);  // clamp zooming
camera.getMinimumDistance();
camera.getMaximumDistance();
camera.setMaximumPanDistance(double maximumDistance);  // clamp panning
camera.getMaximumPanDistance();

camera.reset();
camera.reset(long animationTimeInMillis);  // reset camera to its starting settings

camera.isMoving();  // returns true or false

CameraState state = camera.getState(); // get a serializable settings object for current state
camera.setState(CameraState state);
camera.setState(CameraState state, long animationTimeInMillis); // set the camera to the given saved state

float[] rotations = camera.getRotations(); // x, y, and z rotations required to face camera in model space
camera.setRotations(double pitch, double yaw, double roll); // rotations are applied in that order
camera.setRotations(double pitch, double yaw, double roll, long animationTimeInMillis);
float[] position = camera.getPosition(); // x, y, and z coordinates of camera in model space

// Utility methods to permit the use of a Heads-Up Display
// Thanks, A.W. Martin
camera.beginHUD();
// now draw things that you want relative to the camera's position and orientation
camera.endHUD(); // always!

PeasyCam is impervious to gimbal lock, and has no known “singularities” or discontinuities in its behavior. It relies on the excellent Apache Commons Math geometry package for its rotations.

Contributors

Thanks: Gennaro Senatore, Michael Kaufmann, Oori Shalev, Jeffrey Gentes, A.W. Martin, Yiannis Chatzikonstantinou, and Donald Ephraim Curtis for bug reports and feature suggestions.