jumpartifact.com_demo_0/src/screen.cc

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#include "screen.h"
// standard library includes
#include <cassert>
#ifndef NDEBUG
#include <iostream>
#endif // NDEBUG
// local includes
#include "screen_test.h"
Screen::Screen(std::weak_ptr<ScreenStack> stack) : stack(stack) {}
ScreenStack::PendingAction::PendingAction() : screen(), action(Action::NOP) {}
ScreenStack::PendingAction::PendingAction(Action action)
: screen(), action(action) {}
ScreenStack::PendingAction::PendingAction(Screen::Ptr &&screen)
: screen(std::forward<Screen::Ptr>(screen)), action(Action::PUSH_SCREEN) {}
ScreenStack::Ptr ScreenStack::new_instance() {
std::shared_ptr<ScreenStack> ptr =
std::shared_ptr<ScreenStack>(new ScreenStack{});
ptr->self_weak = ptr;
return ptr;
}
void ScreenStack::update(float dt) {
handle_pending_actions();
auto idx = stack.size();
if (idx == 0) {
#ifndef NDEBUG
std::cerr << "WARNING: Stack is empty, pushing TestScreen...\n";
#endif // NDEBUG
push_screen(Screen::new_screen<TestScreen>(self_weak));
update(dt);
return;
}
while (idx > 0 && stack.at(--idx)->update(dt)) {
}
}
void ScreenStack::draw() {
auto idx = stack.size();
while (idx > 0 && stack.at(--idx)->draw()) {
}
}
void ScreenStack::push_screen(Screen::Ptr &&screen) {
actions.push_back(PendingAction(std::forward<Screen::Ptr>(screen)));
}
void ScreenStack::pop_screen() {
actions.push_back(PendingAction(Action::POP_SCREEN));
}
ScreenStack::ScreenStack() : self_weak(), stack(), actions() {}
void ScreenStack::handle_pending_actions() {
while (!actions.empty()) {
switch (actions.front().action) {
case Action::PUSH_SCREEN:
stack.push_back(std::move(actions.front().screen));
break;
case Action::POP_SCREEN:
if (!stack.empty()) {
stack.pop_back();
}
#ifndef NDEBUG
else {
std::cerr << "WARNING: Tried to pop screen when stack was empty!\n";
}
#endif // NDEBUG
break;
case Action::NOP:
// Intentionally left blank.
break;
default:
assert(!"unreachable");
break;
}
actions.pop_front();
}
}