278 lines
10 KiB
C#
278 lines
10 KiB
C#
/*******************************************************************************************
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*
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* raylib [shapes] example - ball physics
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*
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* Example complexity rating: [★★☆☆] 2/4
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*
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* Example originally created with raylib 6.0, last time updated with raylib 6.0
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*
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* Example contributed by David Buzatto (@davidbuzatto) and reviewed by Ramon Santamaria (@raysan5)
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*
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* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
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* BSD-like license that allows static linking with closed source software
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*
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* Copyright (c) 2025 David Buzatto (@davidbuzatto)
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*
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********************************************************************************************/
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using static Raylib_cs.Raymath;
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namespace Examples.Shapes;
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public partial class BallPhysics : IExample
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{
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private const int screenWidth = 800;
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private const int screenHeight = 450;
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private const int MAX_BALLS = 5000; // Maximum quantity of balls
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public string Name => "Shapes / Ball Physics";
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public string Title => "raylib [shapes] example - ball physics";
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//----------------------------------------------------------------------------------
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// Types and Structures Definition
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//----------------------------------------------------------------------------------
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// Ball data type
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private struct Ball
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{
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public Vector2 position;
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public Vector2 speed;
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public Vector2 prevPosition;
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public float radius;
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public float friction;
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public float elasticity;
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public Color color;
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public bool grabbed;
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}
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private Ball[] balls;
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private int ballCount;
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private int grabbedBallIndex; // Index of the current ball that is grabbed (-1 if none)
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private Vector2 pressOffset; // Mouse press offset relative to the ball that grabbedd
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private float gravity; // World gravity
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private Vector2 windowPosition;
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public void Init()
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{
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balls = new Ball[MAX_BALLS];
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// Init first ball in the array
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balls[0] = new Ball
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{
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position = new Vector2(GetScreenWidth()/2.0f, GetScreenHeight()/2.0f),
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speed = new Vector2(200, 200),
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prevPosition = new Vector2(0, 0),
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radius = 40,
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friction = 0.99f,
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elasticity = 0.9f,
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color = Color.Blue,
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grabbed = false
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};
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ballCount = 1;
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grabbedBallIndex = -1; // A reference to the current ball that is grabbed
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pressOffset = new Vector2(0, 0); // Mouse press offset relative to the ball that grabbedd
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gravity = 100; // World gravity
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windowPosition = GetWindowPosition();
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}
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public void Update()
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{
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// Update
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//----------------------------------------------------------------------------------
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float delta = GetFrameTime();
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Vector2 mousePos = GetMousePosition();
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// Checks if a ball was grabbed
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if (IsMouseButtonPressed(MouseButton.Left))
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{
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for (int i = ballCount - 1; i >= 0; i--)
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{
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pressOffset.X = mousePos.X - balls[i].position.X;
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pressOffset.Y = mousePos.Y - balls[i].position.Y;
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// If the distance between the ball position and the mouse press position
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// is less than or equal to the ball radius, the event occurred inside the ball
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if (MathF.Sqrt(pressOffset.X*pressOffset.X + pressOffset.Y*pressOffset.Y) <= balls[i].radius)
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{
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balls[i].grabbed = true;
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grabbedBallIndex = i;
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break;
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}
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}
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}
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// Releases any ball the was grabbed
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if (IsMouseButtonReleased(MouseButton.Left))
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{
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if (grabbedBallIndex != -1)
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{
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balls[grabbedBallIndex].grabbed = false;
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grabbedBallIndex = -1;
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}
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}
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// Creates a new ball
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if (IsMouseButtonPressed(MouseButton.Right) || (IsKeyDown(KeyboardKey.LeftControl) && IsMouseButtonDown(MouseButton.Right)))
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{
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if (ballCount < MAX_BALLS)
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{
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balls[ballCount++] = new Ball
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{
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position = mousePos,
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speed = new Vector2(GetRandomValue(-300, 300), GetRandomValue(-300, 300)),
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prevPosition = new Vector2(0, 0),
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radius = 20.0f + GetRandomValue(0, 30),
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friction = 0.99f,
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elasticity = 0.9f,
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color = new Color(GetRandomValue(0, 255), GetRandomValue(0, 255), GetRandomValue(0, 255), 255),
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grabbed = false
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};
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}
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}
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// Get window position change for shaking
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Vector2 windowPositionDelta = Vector2Subtract(windowPosition, GetWindowPosition());
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if (Vector2Length(windowPositionDelta) > 5.0f)
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{
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for (int i = 0; i < ballCount; i++)
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{
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if (!balls[i].grabbed)
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{
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balls[i].speed = Vector2Add(balls[i].speed, Vector2Scale(windowPositionDelta, 10.0f));
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}
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}
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}
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// Shake balls
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if (IsMouseButtonPressed(MouseButton.Middle))
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{
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for (int i = 0; i < ballCount; i++)
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{
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if (!balls[i].grabbed)
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{
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balls[i].speed = new Vector2(GetRandomValue(-2000, 2000), GetRandomValue(-2000, 2000));
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}
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}
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}
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// Changes gravity
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gravity += GetMouseWheelMove()*5;
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// Updates each ball state
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for (int i = 0; i < ballCount; i++)
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{
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// The ball is not grabbed
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if (!balls[i].grabbed)
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{
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// Ball repositioning using the velocity
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balls[i].position.X += balls[i].speed.X * delta;
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balls[i].position.Y += balls[i].speed.Y * delta;
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// Does the ball hit the screen right boundary?
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if ((balls[i].position.X + balls[i].radius) >= screenWidth)
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{
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balls[i].position.X = screenWidth - balls[i].radius; // Ball repositioning
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balls[i].speed.X = -balls[i].speed.X*balls[i].elasticity; // Elasticity makes the ball lose 10% of its velocity on hit
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}
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// Does the ball hit the screen left boundary?
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else if ((balls[i].position.X - balls[i].radius) <= 0)
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{
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balls[i].position.X = balls[i].radius;
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balls[i].speed.X = -balls[i].speed.X*balls[i].elasticity;
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}
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// The same for y axis
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if ((balls[i].position.Y + balls[i].radius) >= screenHeight)
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{
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balls[i].position.Y = screenHeight - balls[i].radius;
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balls[i].speed.Y = -balls[i].speed.Y*balls[i].elasticity;
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}
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else if ((balls[i].position.Y - balls[i].radius) <= 0)
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{
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balls[i].position.Y = balls[i].radius;
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balls[i].speed.Y = -balls[i].speed.Y*balls[i].elasticity;
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}
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// Friction makes the ball lose 1% of its velocity each frame
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balls[i].speed.X = balls[i].speed.X*balls[i].friction;
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// Gravity affects only the y axis
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balls[i].speed.Y = balls[i].speed.Y*balls[i].friction + gravity;
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}
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else
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{
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// Ball repositioning using the mouse position
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balls[i].position.X = mousePos.X - pressOffset.X;
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balls[i].position.Y = mousePos.Y - pressOffset.Y;
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// While the ball is grabbed, recalculates its velocity
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balls[i].speed.X = (balls[i].position.X - balls[i].prevPosition.X)/delta;
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balls[i].speed.Y = (balls[i].position.Y - balls[i].prevPosition.Y)/delta;
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balls[i].prevPosition = balls[i].position;
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}
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}
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windowPosition = GetWindowPosition();
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//----------------------------------------------------------------------------------
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// Draw
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//----------------------------------------------------------------------------------
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BeginDrawing();
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ClearBackground(Color.RayWhite);
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for (int i = 0; i < ballCount; i++)
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{
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DrawCircleV(balls[i].position, balls[i].radius, balls[i].color);
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DrawCircleLinesV(balls[i].position, balls[i].radius, Color.Black);
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}
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DrawText("grab a ball by pressing with the mouse and throw it by releasing", 10, 10, 10, Color.DarkGray);
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DrawText("right click to create new balls (keep left control pressed to create a lot)", 10, 30, 10, Color.DarkGray);
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DrawText("use mouse wheel to change gravity", 10, 50, 10, Color.DarkGray);
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DrawText("middle click to shake", 10, 70, 10, Color.DarkGray);
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DrawText($"BALL COUNT: {ballCount}", 10, GetScreenHeight() - 70, 20, Color.Black);
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DrawText($"GRAVITY: {gravity:F2}", 10, GetScreenHeight() - 40, 20, Color.Black);
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EndDrawing();
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//----------------------------------------------------------------------------------
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}
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public void Unload()
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{
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}
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public static int Main()
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{
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// Initialization
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//--------------------------------------------------------------------------------------
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InitWindow(screenWidth, screenHeight, "raylib [shapes] example - ball physics");
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SetTargetFPS(60); // Set our game to run at 60 frames-per-second
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//--------------------------------------------------------------------------------------
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var game = new BallPhysics();
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game.Init();
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// Main game loop
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while (!WindowShouldClose()) // Detect window close button or ESC key
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{
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game.Update();
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}
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game.Unload();
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// De-Initialization
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//--------------------------------------------------------------------------------------
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CloseWindow(); // Close window and OpenGL context
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//--------------------------------------------------------------------------------------
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return 0;
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}
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}
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