Improve physics

src/ball.cpp

@@ -6,20 +6,34 @@
 #include <random>
 
 #define RADIUS 15
-#define TICK_SPEED 10
-#define MAX_SPEED 5.0
-#define GRAVITY 0.981
+#define TOP_MARGIN 35 // This is the menu bar height (no easy way to get programatically)
 
-double getRandomDouble(double maxValue);
+#define TICK_SPEED 10
+
+#define MAX_X_SPEED 5.0
+#define MIN_X_SPEED 2.0
+#define MAX_Y_SPEED 8.0
+#define MIN_Y_SPEED 4.0
+
+#define GRAVITY 0.022
+
+double getRandomDouble(double minValue, double maxValue);
 
 Ball::Ball(QWidget* parent, std::shared_ptr<Platform> platform) : m_parent{parent}, m_platform{platform}, m_isSpawning{true} {
     QRect rct = parent->rect();
 
-    m_x = rand() % rct.width(); // random x pos
+    m_x = rand() % (rct.width() - RADIUS * 2); // random x pos
     m_y = rct.height() + 5; // start below the screen
 
-    m_kx = getRandomDouble(MAX_SPEED); // random horizontal speed
-    m_ky = -MAX_SPEED;
+    // Random X speed, including rand direction
+    // (this isn't simply done with a negative minimum, as we
+    // don't want to allow speeds close to 0)
+    m_kx = getRandomDouble(MIN_X_SPEED, MAX_X_SPEED);
+    if (rand() % 2 == 0)
+        m_kx = -m_kx;
+
+    // Random Y speed (always starts going up / negative)
+    m_ky = -getRandomDouble(MIN_Y_SPEED, MAX_Y_SPEED);
 
     start(TICK_SPEED);
 }
@@ -29,20 +43,20 @@ void Ball::draw(QPainter& painter) {
 }
 
 void Ball::timerEvent(QTimerEvent*) {
-    if (m_ky < -MAX_SPEED)
-        m_ky = std::max(m_ky - GRAVITY, -MAX_SPEED);
+    m_ky = std::min(m_ky + GRAVITY, MAX_Y_SPEED);
+
+    QRect rct = m_parent->rect();
 
     // Horizontal wall collision
-    QRect rct = m_parent->rect();
-    if (m_x < RADIUS || m_x > rct.width() - RADIUS) {
+    if (m_x < 0 || m_x > rct.width() - RADIUS * 2.0)
         m_kx *= -1;
-    }
+
     // Ceiling collision
-    if (m_y < RADIUS) {
+    if (m_y < TOP_MARGIN)
         m_ky *= -1;
-    }
+
     // Bottom collision (only if no longer spawning)
-    if (!m_isSpawning && m_y > rct.height() - RADIUS) {
+    if (!m_isSpawning && m_y > rct.height() - RADIUS * 2.0) {
         emit fellThrough(this);
         stop();
         m_parent->update();
@@ -69,13 +83,13 @@ void Ball::timerEvent(QTimerEvent*) {
     m_parent->update();
 }
 
-double getRandomDouble(double maxValue) {
+double getRandomDouble(double minValue, double maxValue) {
     // Create a random device and a random engine
     std::random_device rd;
     std::mt19937 gen(rd());
 
     // Define the range from 0 to maxValue
-    std::uniform_real_distribution<> dis(0.0, maxValue);
+    std::uniform_real_distribution<> dis(minValue, maxValue);
 
     // Return the random value
     return dis(gen);

src/mainwindow.cpp

@@ -4,9 +4,9 @@
 #include <memory>
 #include <qnamespace.h>
 
-#define INIT_SPAWN_SPEED 1500.0
-#define SPAWN_SPEED_INCREASE 100.0
-#define MIN_SPAWN_SPEED 100.0
+#define INIT_SPAWN_SPEED 2000.0
+#define SPAWN_SPEED_INCREASE 50.0
+#define MIN_SPAWN_SPEED 800.0
 
 MainWindow::MainWindow(QWidget* parent) :
     QMainWindow(parent), ui(new Ui::MainWindow), leftArrowPressed{false}, rightArrowPressed{false}, m_spawnInterval{INIT_SPAWN_SPEED}, m_score{0} {
@@ -44,7 +44,6 @@ void MainWindow::deleteBall(Ball* ball) {
     // This will also free it (smart ptrs).
     for (auto it = balls.begin(); it != balls.end(); ++it) {
         if (it->get() == ball) {
-            qDebug() << "Deleting ball";
             balls.erase(it);
             break;
         }

src/platform.cpp

@@ -7,7 +7,7 @@
 #define PLATFORM_WIDTH 100
 #define PLATFORM_HEIGHT 20
 #define PLATFORM_MARGIN_BOTTOM 80
-#define SPEED 7.0
+#define SPEED 10.0
 
 Platform::Platform(MainWindow* parent) : m_parent{parent} {
     QRect rct = parent->rect();