This demo shows off several 2D particle effects. The effects include: fire,
rain, smoke, and trail.
The fire travels from the emitter origin upwards. As the article ages, the
particle shrinks and the color turns from orange to blue.
The rain travels towards the mouse position at different velocities based on
the size of the particle.
The smoke travels according to the velocity and acceleration values, and the
colors changes according to it’s position (orange glow near the bottom and gray
near the top).
The trail follows the mouse position. Each particle shrinks and rotates as the
particles accelerate away from the spawn position.
September 20, 2011