Main.tscn

[gd_scene load_steps=5 format=2]

[ext_resource path="res://Main.gd" type="Script" id=1]
[ext_resource path="res://ship.png" type="Texture" id=2]

[sub_resource type="Shader" id=1]
code = "shader_type particles;

const float PI = 3.14159265358979323846;

uniform vec2 target = vec2(0.0, 0.0);
uniform float speed = 150.0;

float rand_from_seed(in uint seed) {
  int k;
  int s = int(seed);
  if (s == 0)
    s = 305420679;
  k = s / 127773;
  s = 16807 * (s - k * 127773) - 2836 * k;
  if (s < 0)
    s += 2147483647;
  seed = uint(s);
  return float(seed % uint(65536)) / 65535.0;
}

uint hash(uint x) {
  x = ((x >> uint(16)) ^ x) * uint(73244475);
  x = ((x >> uint(16)) ^ x) * uint(73244475);
  x = (x >> uint(16)) ^ x;
  return x;
}

mat2 rotate(float a) {
  float s = sin(-a);
  float c = cos(a);
  return mat2(vec2(c, -s), vec2(s, c));
}

float short_angle_dist (float from, float to) {
	float diff = mod(to - from, 2.0 * PI);
	return mod (2.0 * diff, 2.0 * PI) - diff;
}

float mix_angle(float from, float to, float weight) {
  return from + short_angle_dist(from, to) * weight;
}

void vertex() {
  if (RESTART) {
    uint alt_seed1 = hash(NUMBER + uint(1) + RANDOM_SEED);
    uint alt_seed2 = hash(NUMBER + uint(27) + RANDOM_SEED);
    uint alt_seed3 = hash(NUMBER + uint(43) + RANDOM_SEED);
    uint alt_seed4 = hash(NUMBER + uint(111) + RANDOM_SEED);
    CUSTOM.x = rand_from_seed(alt_seed1) * 2.0 * PI; // initial angle
    CUSTOM.y = rand_from_seed(alt_seed2) * 30.0 - 15.0; // random speed modifier
    CUSTOM.z = 0.2 + rand_from_seed(alt_seed3) * 1.8; // random proximity
    mat2 r = rotate(CUSTOM.x);
    TRANSFORM[0].xy = vec2(r[0]);
    TRANSFORM[1].xy = vec2(r[1]);
    TRANSFORM[3].xy = target;
 } else {
    float a = target.x - TRANSFORM[3].x;
	float b = target.y - TRANSFORM[3].y;	
	CUSTOM.x = mix_angle(CUSTOM.x , atan(b, a) , CUSTOM.z * DELTA);
	mat2 r = rotate(CUSTOM.x);
    TRANSFORM[0].xy = vec2(r[0]);
    TRANSFORM[1].xy = vec2(r[1]);
	TRANSFORM[3].xy += vec2((speed + CUSTOM.y) * DELTA * cos(CUSTOM.x), (speed + CUSTOM.y) * DELTA * sin(CUSTOM.x));
  }
}"

[sub_resource type="ShaderMaterial" id=2]
shader = SubResource( 1 )
shader_param/target = Vector2( 0, 0 )
shader_param/speed = 150.0

[node name="ShipTest" type="Node2D"]
script = ExtResource( 1 )

[node name="Planet" type="Polygon2D" parent="."]
position = Vector2( 531.505, 280.968 )
color = Color( 0.776471, 0.152941, 0.152941, 1 )
polygon = PoolVector2Array( 2, -24.5, 23.5, -19.5, 30, -5, 24.5, 19.5, 4, 28, -16, 24.5, -27, 9, -20.5, -15.5 )

[node name="Ships" type="Particles2D" parent="."]
emitting = false
amount = 100
lifetime = 600.0
explosiveness = 1.0
process_material = SubResource( 2 )
texture = ExtResource( 2 )