Flow Field Particle System (GML)

By @pixelchipcode

Flow Field Particle System (GML)

Creates a particle system that moves according to a dynamic flow field. Each particle is influenced by perlin-like 3D noise, creating swirling, organic patterns. Here's a breakdown of what each part does:

Create Event:
Initializes particle_count particles with randomized properties like position, speed, direction, color, and size.
Sets up a flow field grid that influences particle movement.
Uses a custom simple_noise_3d function for dynamic noise to simulate complex flow patterns.

Step Event:
Updates the flow field with changing noise over time, making the movement dynamic and ever-changing.
Updates each particle's direction based on the flow field and smoothly transitions to new positions.
Gradually changes each particle's hue over time for a continuous, colorful effect.

Draw Event:
Draws all particles onto a surface with a semi-transparent black rectangle to create a fading trail effect.
The result is a glowing, dynamic flow of particles that are influenced by a constantly shifting flow field.
Feel free to tweak the particle_count, flow_field_resolution, and color properties to see how different settings change the visuals. This setup is great for learning about flow fields, noise, and creating visually engaging effects.

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/// Create Event
function simple_noise_3d(x, y, z) {
    return (sin(x * 10 + noise_seed) * sin(y * 10 + noise_seed) * sin(z * 10 + noise_seed)) * 0.5 + 0.5;
}

particle_count = 10000;
particles = array_create(particle_count);
flow_field_resolution = 22;
flow_field_width = ceil(room_width / flow_field_resolution);
flow_field_height = ceil(room_height / flow_field_resolution);
flow_field = array_create(flow_field_width * flow_field_height);
for (var i = 0; i < particle_count; i++) {
    particles[i] = {
        x: random(room_width),
        y: random(room_height),
        speed: random_range(0.5, 2),
        direction: random(360),
        color: make_color_hsv(255, 200, 255),
        size: random_range(0.3, 1)
    };
}
time = 0;
time_speed = 0.002;
surface = -1;
noise_seed = random(10000);

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/// Step Event
time += time_speed;
// Update flow field
for (var i = 0; i < array_length(flow_field); i++) {
    flow_field[i] = simple_noise_3d((i % flow_field_width) * 0.1, (i div flow_field_width) * 0.1, time) * 360;
}
// Update particles
for (var i = 0; i < particle_count; i++) {
    var p = particles[i];
    var index = floor(p.x / flow_field_resolution) + floor(p.y / flow_field_resolution) * flow_field_width;

    // Update particle direction and position
    p.direction = lerp(p.direction, flow_field[index], 0.1);
    p.x = (p.x + lengthdir_x(p.speed, p.direction) + room_width) % room_width;
    p.y = (p.y + lengthdir_y(p.speed, p.direction) + room_height) % room_height;

    // Slowly change particle color over time
    var hue = color_get_hue(p.color);
    hue = (hue + 0.1) % 255;
    p.color = make_color_hsv(hue, 200, 255);
}

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/// Draw Event
if (!surface_exists(surface)) {
    surface = surface_create(room_width, room_height);
}
surface_set_target(surface);
// Draw a semi-transparent black rectangle to create trail effect
draw_set_alpha(0.1);
draw_rectangle_color(0, 0, room_width, room_height, c_black, c_black, c_black, c_black, false);
draw_set_alpha(1);
gpu_set_blendmode(bm_add);
for (var i = 0; i < particle_count; i++) {
    var p = particles[i];
    draw_circle_color(p.x, p.y, p.size, p.color, p.color, false);
}
gpu_set_blendmode(bm_normal);
surface_reset_target();
draw_surface(surface, 0, 0);