Fireflies following Lissajous curves for GameMaker (GML)

// Firefly by @PixelChipCode
// This code controls the movement and glow behavior of a firefly in GameMaker.
// The firefly follows a Lissajous curve, which creates smooth, looping movement patterns
// based on sine waves for both the x and y positions. Random values are assigned
// to the amplitude, frequency, and phase shift of the curve to make each firefly's movement unique.
// Additionally, the firefly exhibits a soft, glowing effect that fades in and out in cycles.
// This glow is controlled by a timer, and each firefly's glow intensity and speed of fading
// are randomized for a more natural and organic feel.

// Create event

// Store the origin position based on the spawn location (mouse)
origin_x = x;  // Set the initial x position to mouse_x when spawned
origin_y = y;  // Set the initial y position to mouse_y when spawned

// Initialize Lissajous curve variables with random values
amplitude_x = irandom_range(80, 150);
amplitude_y = irandom_range(40, 100);
frequency_x = irandom_range(2, 4);
frequency_y = irandom_range(1, 3);
phase_shift = random_range(0, 2 * pi);
speed = random_range(0.001, 0.003);
time = 0;

// Glow variables
glow_timer = 0;                           // Timer for the glow effect
glow_duration = irandom_range(60, 120);    // Random duration of the glow cycle (in frames)
glow_intensity = 0;                       // Intensity of the glow (0 = off, 1 = full glow)
glow_speed = random_range(0.01, 0.03);    // How fast the glow fades in/out

color = random_range(40,60);

// Step event

// Update time and calculate position based on the Lissajous curve
time += speed;

// Set x and y relative to the original spawn location (origin_x, origin_y)
x = origin_x + amplitude_x * sin(frequency_x * time + phase_shift);
y = origin_y + amplitude_y * sin(frequency_y * time);

// Handle glow effect
glow_timer += 1;  // Increment the glow timer

if (glow_timer < glow_duration / 2) {
    // Fade in glow (first half of the glow cycle)
    glow_intensity = min(glow_intensity + glow_speed, 1);
} else {
    // Fade out glow (second half of the glow cycle)
    glow_intensity = max(glow_intensity - glow_speed, 0);
}

// Reset timer when the full glow cycle is complete
if (glow_timer >= glow_duration) {
    glow_timer = 0;
    glow_duration = irandom_range(60, 120);  // Set a new random duration for the next cycle
}

// Draw event

// Set additive blending for the glow effect
gpu_set_blendmode(bm_add);

// Set the glow color to a more yellowy-green hue
var glow_color = make_color_hsv(color, 255, 255);  // Shifted hue to 65 for a more yellowy tone
draw_set_color(glow_color);
draw_set_alpha(glow_intensity);  // Use the glow intensity to control the alpha

// Draw the glowing firefly as a circle
draw_circle(x, y,  2 * glow_intensity, false);  // The size increases slightly with glow intensity

// Reset blend mode to normal
gpu_set_blendmode(bm_normal);

// Reset color and alpha to default
draw_set_color(c_white);
draw_set_alpha(1);


/////obj_firefly_spawner

//step event
if(mouse_check_button(mb_left)) {
    var firefly = instance_create_layer(mouse_x, mouse_y, "Instances", obj_firefly);
    // Set the origin manually, if needed
    firefly.origin_x = mouse_x;
    firefly.origin_y = mouse_y;
}

if(keyboard_check_pressed(ord("R"))){
    game_restart();
}