About Particles Example

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Learning Objectives

This openFrameworks example is designed to illustrate and explore particle systems and some of their behaviours for interactivity such as attraction and repulsion.

In this example, pay attention to the following code:

• Use of ofSetVerticalSync to synchronize the redraw of the screen to the vertical refresh of your screen

• p.assign(num, demoParticle()); which creates a vector with the length of num, of type demoParticle to store reference to all the particles

• void ofApp::resetParticles which resets the particle system and the mode of behaviour along with the attraction points which are randomly generated

• void ofApp::update to update the the particles, along with modifying the attraction points to create some natural movement.

• ofSignedNoise for natural random motion to create attraction points for the particle system that are more organic

• void ofApp::draw() to ask the particles to draw, and draw the attraction points of area and colors

• Switching of particle modes in the keyPressed method based on key input, which is then applied and updated in update method.

Expected Behavior

When launching this app, you should see:

• A black screen with colored particles that will swarm and be attracted towards the mouse as the initial particle system state is PARTICLE_MODE_ATTRACT
• Instructions for keys that will affect the particle mode including PARTICLE_MODE_ATTRACT, PARTICLE_MODE_REPEL,PARTICLE_MODE_NEAREST_POINTS and PARTICLE_MODE_NOISE

Instructions for use:

• Press the 1 key to change the particle system mode to PARTICLE_MODE_ATTRACT
• Press the 2 key to change the particle system mode to PARTICLE_MODE_REPEL
• Press the 3 key to change the particle system mode to PARTICLE_MODE_NEAREST_POINTS
• Press the 4 key to change the particle system mode to PARTICLE_MODE_NOISE
• Press the spacebar to reset the particle systems and mode to its original state

Other classes used in this file

This Example uses "demoParticle" for the particle system.