How to Program a Shotgun Blast Effect Using Threejs in a 3D Game

This code is a part of a 3D zombie attack game and implements a shotgun blast effect using the Three.js library. It was developed by Shane Brumback with 3D Interactive. Instead of using a particle system, this solution uses spheres to simulate the spread of the shot.

The fireShotGunSpheres() function generates 20 spheres and adds them to the scene. The sphere's position is set relative to the camera's position, so that the spheres appear always in front of the camera. Each sphere has a SphereGeometry of 0.05 units and a MeshBasicMaterial of yellow color. The spheres are added to an array called shotGunSpheres.

The animateShotGunParticles() function animates the spheres by looping through each sphere in the shotGunSpheres array, calculating the distance between the sphere and the starting position (the position of the shotgun object), and translating the sphere accordingly. If the distance is less than 10 units, the sphere is moved in a random direction on the x and y axis and down the -z axis. If the distance is less than 1 unit, the sphere is set to be invisible. If the distance is greater than or equal to 10 units, the sphere is removed from the scene and spliced from the shotGunSpheres array.

This code can be modified to suit the desired look for the shotgun blast effect. For example, the size and number of spheres, the distance the spheres move, and the color of the spheres can be changed to achieve a different look.