add money

src/engine/math.zig

@@ -380,6 +380,10 @@ pub const Rect = struct {
         };
     }
 
+    pub fn initCentered(x: f32, y: f32, width: f32, height: f32) Rect {
+        return init(x - width/2, y - height/2, width, height);
+    }
+
     pub fn clip(self: Rect, other: Rect) Rect {
         const left_edge   = @max(self.left(), other.left());
         const right_edge  = @min(self.right(), other.right());
@@ -437,7 +441,7 @@ pub const Rect = struct {
         return (lhs.left() < rhs.right() and lhs.right() > rhs.left()) and
             (lhs.top() < rhs.bottom() and lhs.bottom() > rhs.top());
     }
-    
+
     pub fn growX(self: Rect, amount: f32) Rect {
         return Rect{
             .pos = .init(self.pos.x - amount, self.pos.y),
@@ -453,7 +457,7 @@ pub const Rect = struct {
     }
 
     pub fn grow(self: Rect, amount: f32) Rect {
-        return self.growX(self.growY(amount), amount);
+        return self.growX(amount).growY(amount);
     }
 };
 

src/game.zig

@@ -55,7 +55,12 @@ const Kinetic = struct {
 
 const Player = struct {
     kinetic: Kinetic = .{},
-    last_shot_at: ?Nanoseconds = null
+    money: u32 = 0,
+    last_shot_at: ?Nanoseconds = null,
+
+    pub fn getRect(self: Player) Rect {
+        return getCenteredRect(self.kinetic.pos, 16);
+    }
 };
 
 const Bullet = struct {
@@ -88,10 +93,20 @@ const Wave = struct {
     };
 };
 
+const Pickup = struct {
+    const Kind = enum {
+        money
+    };
+
+    pos: Vec2,
+    kind: Kind,
+};
+
+const pickup_spawn_duration_s = Range.init(1, 5);
 const wave_infos = [_]Wave.Info{
     .{
         .enemies = 10,
-        .duration_s = 1,
+        .duration_s = 10,
         .starts_at_s = 0
     }
 };
@@ -105,6 +120,9 @@ player: Player = .{},
 bullets: std.ArrayList(Bullet) = .empty,
 enemies: std.ArrayList(Enemy) = .empty,
 
+pickups: std.ArrayList(Pickup) = .empty,
+next_pickup_spawn_at: Nanoseconds,
+
 wave_timer: Nanoseconds = 0,
 
 waves: std.ArrayList(Wave) = .empty,
@@ -114,16 +132,22 @@ pub fn init(gpa: Allocator, seed: u64, assets: *Assets) !Game {
     var arena = std.heap.ArenaAllocator.init(gpa);
     errdefer arena.deinit();
 
+    var rng = RNGState.init(seed);
+
+    const next_pickup_spawn_at_s = pickup_spawn_duration_s.random(rng.random());
+    const next_pickup_spawn_at: Nanoseconds = @intFromFloat(next_pickup_spawn_at_s * std.time.ns_per_s);
+
     return Game{
         .arena = arena,
         .gpa = gpa,
         .assets = assets,
+        .next_pickup_spawn_at = next_pickup_spawn_at,
         .player = .{
             .kinetic = .{
                 .pos = .init(50, 50),
             }
         },
-        .rng = RNGState.init(seed),
+        .rng = rng
     };
 }
 
@@ -132,6 +156,7 @@ pub fn deinit(self: *Game) void {
     self.bullets.deinit(self.gpa);
     self.enemies.deinit(self.gpa);
     self.waves.deinit(self.gpa);
+    self.pickups.deinit(self.gpa);
     self.spawned_waves.deinit(self.gpa);
 }
 
@@ -184,6 +209,17 @@ fn spawnEnemy(self: *Game) !void {
     });
 }
 
+fn spawnPickup(self: *Game) !void {
+    const margin = 10;
+    const spawn_area = (Rect{ .pos = .zero, .size = world_size }).grow(-margin);
+    const pos = Vec2.initRandomRect(self.rng.random(), spawn_area);
+
+    try self.pickups.append(self.gpa, Pickup{
+        .pos = pos,
+        .kind = .money
+    });
+} 
+
 pub fn tick(self: *Game, frame: *Engine.Frame) !void {
     const dt = frame.deltaTime();
 
@@ -202,7 +238,7 @@ pub fn tick(self: *Game, frame: *Engine.Frame) !void {
         try self.spawned_waves.append(self.gpa, i);
         try self.waves.append(self.gpa, .{
             .started_at = self.wave_timer,
-            .duration = wave_info.duration_s * std.time.ns_per_s,
+            .duration = @as(u64, wave_info.duration_s) * std.time.ns_per_s,
             .enemies_spawned = 0,
             .total_enemies = wave_info.enemies
         });
@@ -237,6 +273,13 @@ pub fn tick(self: *Game, frame: *Engine.Frame) !void {
         }
     }
 
+    if (self.wave_timer >= self.next_pickup_spawn_at) {
+        const next_pickup_spawn_at_s = pickup_spawn_duration_s.random(self.rng.random());
+        const next_pickup_spawn_at: Nanoseconds = @intFromFloat(next_pickup_spawn_at_s * std.time.ns_per_s);
+        self.next_pickup_spawn_at = self.wave_timer + next_pickup_spawn_at;
+        try self.spawnPickup();
+    }
+
     frame.graphics.canvas_size = world_size;
 
     if (frame.isKeyPressed(.F3)) {
@@ -306,7 +349,7 @@ pub fn tick(self: *Game, frame: *Engine.Frame) !void {
     }
 
     frame.drawRectangle(.{
-        .rect = getCenteredRect(self.player.kinetic.pos, 16),
+        .rect = self.player.getRect(),
         .color = rgb(255, 255, 255)
     });
 
@@ -342,6 +385,32 @@ pub fn tick(self: *Game, frame: *Engine.Frame) !void {
         });
     }
 
+    {
+        var index: usize = 0;
+        while (index < self.pickups.items.len) {
+            var destroy: bool = false;
+            const pickup = self.pickups.items[index];
+
+            const pickup_rect = Rect.initCentered(pickup.pos.x, pickup.pos.y, 10, 10);
+
+            if (pickup_rect.hasOverlap(self.player.getRect())) {
+                self.player.money += 1;
+                destroy = true;
+            }
+
+            frame.drawRectangle(.{
+                .rect = pickup_rect,
+                .color = rgb(20, 20, 200)
+            });
+
+            if (destroy) {
+                _ = self.pickups.swapRemove(index);
+            } else {
+                index += 1;
+            }
+        }
+    }
+
     {
         var i: usize = 0;
         while (i < self.bullets.items.len) {
@@ -371,6 +440,8 @@ pub fn tick(self: *Game, frame: *Engine.Frame) !void {
         @divFloor(wave_timer_s, 60),
         @mod(wave_timer_s, 60)
     });
+
+    frame.drawTextFormat(.init(10, 30), text_opts, "{d}", .{ self.player.money });
 }
 
 pub fn debug(self: *Game) !void {
@@ -387,6 +458,9 @@ pub fn debug(self: *Game) !void {
         try self.spawnEnemy();
     }
 
+    const time_left_til_pickup = self.next_pickup_spawn_at - self.wave_timer;
+
     imgui.textFmt("Waves: {}\n", .{self.waves.items.len});
     imgui.textFmt("Enemies: {}\n", .{self.enemies.items.len});
+    imgui.textFmt("Time until next pickup: {d:.2}s\n", .{@as(f32, @floatFromInt(time_left_til_pickup)) / std.time.ns_per_s});
 }