Add bobbing

src/itemdrop.zig

@@ -543,27 +543,65 @@ pub const ClientItemDropManager = struct { // MARK: ClientItemDropManager
 	}
 };
 
-// Going to handle item animations and other things like - bobbing, interpolation, movement reactions
+// Going to handle item animations and other things like - interpolation, movement reactions
 pub const ItemDisplayManager = struct { // MARK: ItemDisplayManager
 	pub var showItem: bool = true;
 	var cameraFollow: Vec3f = @splat(0);
 	var cameraFollowVel: Vec3f = @splat(0);
 	const damping: Vec3f = @splat(130);
+	var bobPhase: f32 = 0;
 
 	pub fn update(deltaTime: f64) void {
 		if (deltaTime == 0) return;
 		const dt: f32 = @floatCast(deltaTime);
 
-		var playerVel: Vec3f = .{@floatCast((game.Player.super.vel[2]*0.009 + game.Player.eye.vel[2]*0.0075)), 0, 0};
-		playerVel = vec.clampMag(playerVel, 0.32);
+		const totalOffset = calculateAscentDescentOffset() + calculateBobOffset(dt);
 
 		// TODO: add *smooth* item sway
-		const n1: Vec3f = cameraFollowVel - (cameraFollow - playerVel)*damping*damping*@as(Vec3f, @splat(dt));
+		const n1: Vec3f = cameraFollowVel - (cameraFollow - totalOffset)*damping*damping*@as(Vec3f, @splat(dt));
 		const n2: Vec3f = @as(Vec3f, @splat(1)) + damping*@as(Vec3f, @splat(dt));
 		cameraFollowVel = n1/(n2*n2);
 
 		cameraFollow += cameraFollowVel*@as(Vec3f, @splat(dt));
 	}
+
+	fn calculateAscentDescentOffset() Vec3f {
+		const playerVel: Vec3f = .{@floatCast((game.Player.super.vel[2]*0.009 + game.Player.eye.vel[2]*0.0075)), 0, 0};
+		return vec.clampMag(playerVel, 0.32);
+	}
+
+	fn calculateBobOffset(dt: f32) Vec3f {
+		const bobSpeed: f32 = 1.2;
+		const bobAmountLateral: f32 = 0.007;
+		const bobAmountVertical: f32 = 0.006;
+		const bobSettle: f32 = 2.5;
+		const bobMovementScaleLimit: f32 = 10;
+
+		if (game.Player.isFlying.load(.monotonic) or game.Player.isGhost.load(.monotonic)) {
+			return @splat(0);
+		}
+
+		const horizontalVel: Vec3f = .{
+			@floatCast(game.Player.super.vel[0]),
+			@floatCast(game.Player.super.vel[1]),
+			0,
+		};
+
+		const movementScale = @min(vec.length(horizontalVel), bobMovementScaleLimit);
+
+		if (game.Player.onGround and movementScale > 0.01) {
+			bobPhase += dt*bobSpeed*movementScale;
+			bobPhase = std.math.mod(f32, bobPhase, 2*std.math.pi) catch unreachable;
+		} else {
+			bobPhase = std.math.lerp(bobPhase, 0, @min(dt*bobSettle, 1));
+		}
+
+		return .{
+			@abs(std.math.sin(bobPhase))*bobAmountVertical*movementScale,
+			0,
+			std.math.sin(bobPhase)*bobAmountLateral*movementScale,
+		};
+	}
 };
 
 pub const ItemDropRenderer = struct { // MARK: ItemDropRenderer