1 files changed, 44 insertions, 0 deletions
diff --git a/lib/systems.odin b/lib/systems.odin
new file mode 100644
index 0000000..288bd01
--- /dev/null
+++ b/lib/systems.odin
@@ -0,0 +1,44 @@
+package djup
+
+DELTA: f32 : 1.0 / 60.0
+
+@(export = true)
+sim_tick :: proc "c" (cur, next: ^Snapshot) {
+	if cur == nil || next == nil {
+		return
+	}
+	context = next.ctx^
+
+	next.tick = cur.tick + 1
+	copy(next.metadata, cur.metadata)
+
+	player_input_system(cur, next)
+	ball_movement_system(cur, next)
+}
+
+player_input_system :: proc(cur, next: ^Snapshot) {
+	for &e, id in soa_zip(m = cur.metadata, input = cur.player_inputs, ball = cur.balls) {
+		if e.m < {.Exists, .PlayerInput, .Ball} {
+			continue
+		}
+
+		PLAYER_ACCELERATION :: 1500
+		PLAYER_DRAG :: 2
+
+		acc :=
+			vec2_normal(e.input.direction) * PLAYER_ACCELERATION + e.ball.velocity * -PLAYER_DRAG
+		e.ball.velocity += acc * DELTA
+		next.player_inputs[id] = e.input
+	}
+}
+
+ball_movement_system :: proc(cur, next: ^Snapshot) {
+	for &e, id in soa_zip(m = cur.metadata, ball = cur.balls) {
+		if e.m < {.Exists, .Ball} {
+			continue
+		}
+
+		next.balls[id].position = e.ball.velocity * DELTA
+		next.balls[id].velocity = e.ball.velocity
+	}
+}