attractor

src/main.zig

@@ -79,6 +79,11 @@ const Particle = struct {
     pub fn applyGravity(self : *Self,val : f32) void {
         self.velocity.a.y += val;
     }
+    pub fn applyForce(self : *Self,vec : pr.Vec) void {
+        self.velocity.a.x += vec.a.x;
+        self.velocity.a.y += vec.a.y;
+        self.velocity.a.z += vec.a.z;
+    }
 };
 
 const Emitter = struct
@@ -118,12 +123,16 @@ const Emitter = struct
     {
         var posx : i32 = 0;
         var posy : i32 = 0;
+        const att : Attractor = .{.vec = .{.a=.{.x=200,.y=200,.z=0}}};
 
+        att.draw();
         for (self.particles) |*p| {
             if(p.show == 1)
             {
                 p.update();
-                p.applyGravity(2);
+                p.applyGravity(0);
+                p.applyForce(att.attract(p.*));
+
                 posx = @intFromFloat(screenWidth / 2 + p.position.a.x);
                 posy = @intFromFloat(screenHeight / 2 + p.position.a.y);
                 //rl.drawRectangle(posx,posy,2,2,rl.Color{.r=p.position.a.color.r,.g=p.position.a.color.g,.b=p.position.a.color.b,.a=255});
@@ -133,6 +142,22 @@ const Emitter = struct
         }
     }
 };
+const Attractor = struct
+{
+    vec : pr.Vec,
+    pub fn attract(self:Attractor,particle : Particle) pr.Vec
+    {
+        var vec = self.vec.sub(particle.position);
+        vec.a.x /= 100;
+        vec.a.y /= 100;
+        vec.a.z /= 100;
+        return vec;
+    }
+    pub fn draw(self:Attractor) void
+    {
+        rl.drawRectangle(@intFromFloat(self.vec.a.x),@intFromFloat(self.vec.a.y),10,10,rl.Color{.r=10,.g=10,.b=120,.a=255});
+    }
+};
 fn ItoF(x:i32) f32
 {
     return @as(f32,@floatFromInt(x));

src/primitives.zig

@@ -24,6 +24,18 @@ pub const Vec = struct {
         self.a.y = self.a.y + m1.a.y;
         self.a.z = self.a.z + m1.a.z;
     }
+    pub fn self_sub(self:*Self,m1:Self) void {
+        self.a.x = self.a.x - m1.a.x;
+        self.a.y = self.a.y - m1.a.y;
+        self.a.z = self.a.z - m1.a.z;
+    }
+    pub fn sub(self:Self,m1:Self) Vec {
+        var vec : Vec = undefined;
+        vec.a.x = self.a.x - m1.a.x;
+        vec.a.y = self.a.y - m1.a.y;
+        vec.a.z = self.a.z - m1.a.z;
+        return vec;
+    }
 };
 pub const Vec2 = struct {
     a: Point = .{ .x = 0, .y = 0, .z = 0},