Merge pull request #2 from cpp-gamedev/reset-clock

Add tick state machine and clock reset animation

Author: karnkaul

src/main.cpp

@@ -1,19 +1,11 @@
 #include <cassert>
 #include <iostream>
-#include <context.hpp>
-#include <scene.hpp>
-
 #include <set>
+#include <context.hpp>
 #include <delta_time.hpp>
 #include <world_clock/gui.hpp>
 #include <world_clock/io.hpp>
 
-/*
-- poll
-- update / tick (based on dt and new events)
-- render / draw
-*/
-
 using namespace misc;
 
 namespace {
@@ -44,13 +36,50 @@ class input_t {
 	std::set<key_t> m_held;
 };
 
-void tick(world_clock_t& out_clock, input_t const& input, sec_t dt) noexcept {
-	static constexpr f32 scale = 10.0f;
-	f32 delta{};
-	if (input.any_held(key_t::Down, key_t::Left, key_t::S, key_t::A)) { delta += -1.0f; }
-	if (input.any_held(key_t::Up, key_t::Right, key_t::W, key_t::D)) { delta += 1.0f; }
-	out_clock += scale * delta * dt.count();
-}
+class clock_ticker_t {
+  public:
+	clock_ticker_t(input_t const* input, world_clock_t* clock) noexcept : m_input(input), m_clock(clock) {}
+
+	void operator()(sec_t dt) noexcept {
+		if (m_input->any_held(key_t::Enter, key_t::R)) { update(flag::zeroing); }
+		static constexpr f32 translation_scale = 10.0f;
+		if (test(flag::zeroing)) {
+			static constexpr f32 zeroing_scale = 5.0f;
+			hour_t const delta = zeroing_scale * translation_scale * dt.count();
+			if (m_offset.hour() > delta) {
+				add(-delta);
+			} else {
+				add(-m_offset.hour());
+				update(flag::none, flag::zeroing);
+			}
+		} else {
+			f32 delta{};
+			if (m_input->any_held(key_t::Down, key_t::Left, key_t::S, key_t::A)) { delta += -1.0f; }
+			if (m_input->any_held(key_t::Up, key_t::Right, key_t::W, key_t::D)) { delta += 1.0f; }
+			add(translation_scale * delta * dt.count());
+		}
+	}
+
+  private:
+	using flags_t = u8;
+	enum flag : flags_t { none = 0, zeroing = 1 << 0 };
+
+	input_t const* m_input;
+	world_clock_t* m_clock;
+	world_hour_t m_offset;
+	flags_t flags = flag::none;
+
+	bool test(flags_t f) const noexcept { return (flags & f) == f; }
+	void update(flags_t set, flags_t unset = 0) noexcept {
+		flags |= set;
+		flags &= ~unset;
+	}
+
+	void add(hour_t offset) noexcept {
+		(*m_clock) += offset;
+		m_offset += offset;
+	}
+};
 } // namespace
 
 int main() {
@@ -63,9 +92,10 @@ int main() {
 	std::cout << clock << '\n';
 	input_t input;
 	delta_time_t dt;
+	clock_ticker_t tick{&input, &clock};
 	while (ctx.running()) {
 		input.update(ctx.poll());
-		tick(clock, input, ++dt);
+		tick(++dt);
 		if (auto drawer = ctx.drawer()) { world_clock_drawer_t{}(drawer, clock, {}); }
 	}
 	std::cout << "\nCompleted successfully\n";

src/types.hpp

@@ -3,6 +3,7 @@
 
 namespace misc {
 using s32 = std::uint32_t;
+using u8 = std::uint8_t;
 using u32 = std::uint32_t;
 using f32 = float;
 } // namespace misc