From d4393ef179e287148cd4cfdc3a3abee9e9cf4413 Mon Sep 17 00:00:00 2001
From: zvon <tom.zvon@gmail.com>
Date: Fri, 6 Aug 2021 18:49:58 +0200
Subject: [PATCH] Mario: better handling of screen resize, when showing FPS
 consider input handling as well

---
 mario/main.cpp | 66 +++++++++++++++++++++++++++++---------------------
 1 file changed, 38 insertions(+), 28 deletions(-)

diff --git a/mario/main.cpp b/mario/main.cpp
index 0a1c6ff..1369aba 100644
--- a/mario/main.cpp
+++ b/mario/main.cpp
@@ -26,6 +26,7 @@ std::shared_ptr< SDLPP::Renderer > renderer = nullptr;
 std::shared_ptr< SDLPP::TextRenderer > fps = nullptr;
 std::shared_ptr< SDLPP::TextRenderer > coins = nullptr;
 int coin_count = 0;
+int global_frames = 0;
 
 std::vector< std::shared_ptr< MarioBlock > > moving_objects = {};
 
@@ -77,6 +78,32 @@ void handleKeyUp( SDL_Keycode key ) {
     }
 }
 
+void moveToMarioPosition( SDLPP::Scene &scene,
+                          SDLPP::Vec2D< double > &prev_mario ) {
+    auto rendDims = renderer->getDoubleDimensions();
+    if ( leftStop ) {
+        auto left =
+            rendDims.getX() < 2.0 ? -( rendDims.getX() - 1 ) / 2.0 - 0.1 : -0.5;
+        leftStop->setPos( left, 0 );
+    }
+    auto mario_pos_difference = prev_mario - mario->getAbsolutePos();
+    // sometimes there is a concurrency problem and prev_pos == cur_pos, in
+    // that case move everything so Mario is standing on the left edge of the
+    // screen
+    if(mario_pos_difference.getX() < 0.01 && mario_pos_difference.getX() > -0.01) {
+        // 0.01 is the width of visible leftStop
+        scene.moveEverything(-(mario->getAbsolutePos().getX() - 0.01), 0);
+    } else {
+        scene.moveEverything( mario_pos_difference.getX(), 0 );
+    }
+    scene.updateSizeAndPosition();
+    auto left_stop_rightmost = leftStop->getDoubleRect().first.getX() +
+                               leftStop->getDoubleRect().second.getX();
+    if ( mario->getPos().getX() < left_stop_rightmost ) {
+        mario->setPos( left_stop_rightmost, mario->getPos().getY() );
+    }
+}
+
 void pollEvents( SDLPP::Scene &scene ) {
     SDL_Event event;
     while ( SDLPP::getSDLEvent( event ) ) {
@@ -94,32 +121,9 @@ void pollEvents( SDLPP::Scene &scene ) {
             break;
         case SDL_WINDOWEVENT:
             if ( event.window.event == SDL_WINDOWEVENT_RESIZED ) {
+                auto prev_mario_pos = mario->getAbsolutePos();
                 scene.updateSizeAndPosition();
-                if ( leftStop ) {
-                    auto rendDims = renderer->getDoubleDimensions();
-                    auto left = rendDims.getX() < 2.0
-                                    ? -( rendDims.getX() - 1 ) / 2.0 - 0.1
-                                    : -0.5;
-                    leftStop->setPos( left, 0 );
-                }
-                auto dimensions = renderer->getDoubleDimensions();
-                auto leftmost = -( dimensions.getX() - 1 ) / 2.0;
-                auto rightmost = 1 - leftmost;
-                auto marioPos = mario->getPos();
-                if ( marioPos.getX() < leftmost ) {
-                    scene.moveEverything( leftmost - marioPos.getX(), 0 );
-                    update = true;
-                } else if ( marioPos.getX() > rightmost ) {
-                    scene.moveEverything( marioPos.getX() - rightmost, 0 );
-                    update = true;
-                }
-                if ( mario->getPos().getX() <
-                     leftStop->getDoubleRect().first.getX() +
-                         leftStop->getDoubleRect().second.getX() ) {
-                    mario->setPos( leftStop->getDoubleRect().first.getX() +
-                                       leftStop->getDoubleRect().second.getX(),
-                                   mario->getPos().getY() );
-                }
+                moveToMarioPosition( scene, prev_mario_pos );
             }
         default:
             break;
@@ -138,11 +142,12 @@ void doInput( std::shared_ptr< SDLPP::Scene > scene ) {
         scene->updateScene();
         auto prev_coin_count = coin_count;
         // TODO visit all moving objects
-        auto visitor = getVisitor(*mario, *scene, quit, coin_count, moving_objects);
+        auto visitor =
+            getVisitor( *mario, *scene, quit, coin_count, moving_objects );
         scene->visitCollisions( *mario, *visitor );
         mario->handleVisitor( *visitor );
 
-        if(coin_count != prev_coin_count) {
+        if ( coin_count != prev_coin_count ) {
             coins->changeText( std::to_string( coin_count ) + " COINS" );
         }
         // if player is > 0.7 of playground, move everything left
@@ -155,7 +160,8 @@ void doInput( std::shared_ptr< SDLPP::Scene > scene ) {
             ( playerX > rightBarrier && rightmostX > width ) *
                 ( rightBarrier - playerX ) / width,
             0 );
-        update = true;
+        update = playerX > rightBarrier && rightmostX > width;
+        global_frames++;
     }
 }
 
@@ -257,6 +263,10 @@ int main() {
         renderer->presentRenderer();
         frames++;
         if ( SDL_GetTicks() - base >= 1000 ) {
+            if ( global_frames < frames ) {
+                frames = global_frames;
+            }
+            global_frames = 0;
             fps->changeText( std::to_string( frames ) + " fps" );
             frames = 0;
             base = SDL_GetTicks();