renaming example

renaming example from physics_bouncing_balls to shapes_ball_physics

examples/shapes/shapes_ball_physics.c

@@ -0,0 +1,222 @@
+/*******************************************************************************************
+*
+*   raylib [shapes] example - physics bouncing balls
+*
+*   Example complexity rating: [★★☆☆] 2/4
+*
+*   Example originally created with raylib 5.5
+*
+*   Example contributed by David Buzatto (@davidbuzatto) and reviewed by Ramon Santamaria (@raysan5)
+*
+*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
+*   BSD-like license that allows static linking with closed source software
+*
+*   Copyright (c) 2025 David Buzatto (@davidbuzatto)
+*
+********************************************************************************************/
+
+#include <stdlib.h>
+#include <math.h>
+#include "raylib.h"
+
+#define MAX_BALLS 5000 // Maximum quantity of balls
+
+typedef struct Ball {
+    Vector2 pos;       // Position
+    Vector2 vel;       // Velocity
+    Vector2 ppos;      // Previous position
+    float radius;
+    float friction;   
+    float elasticity;
+    Color color;
+    bool grabbed;
+} Ball;
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib [shapes] example - physics bouncing balls");
+
+    Ball balls[MAX_BALLS] = {{
+        .pos = {GetScreenWidth()/2, GetScreenHeight()/2},
+        .vel = {200, 200},
+        .ppos = {0},
+        .radius = 40,
+        .friction = 0.99,
+        .elasticity = 0.9,
+        .color = BLUE,
+        .grabbed = false
+    }};
+    
+    int ballQuantity = 1;
+    Ball *grabbedBall = NULL;   // A pointer to the current ball that is grabbed
+    Vector2 pressOffset = {0};  // Mouse press offset relative to the ball that grabbedd
+
+    float gravity = 100;        // World gravity
+
+    SetTargetFPS(60);           // Set our game to run at 60 frames-per-second
+    //---------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        float delta = GetFrameTime();
+        Vector2 mousePos = GetMousePosition();
+
+        // Checks if a ball was grabbed
+        if (IsMouseButtonPressed(MOUSE_BUTTON_LEFT))
+        {
+            for (int i = ballQuantity - 1; i >= 0; i--) {
+
+                Ball *ball = &balls[i];
+                pressOffset.x = mousePos.x - ball->pos.x;
+                pressOffset.y = mousePos.y - ball->pos.y;
+
+                // If the distance between the ball position and the mouse press position
+                // is less or equal the ball radius, the event occured inside the ball
+                if (hypot(pressOffset.x, pressOffset.y) <= ball->radius)
+                {
+                    ball->grabbed = true;
+                    grabbedBall = ball;
+                    break;
+                }
+
+            }
+        }
+
+        // Releases any ball the was grabbed
+        if (IsMouseButtonReleased(MOUSE_BUTTON_LEFT))
+        {
+            if (grabbedBall != NULL)
+            {
+                grabbedBall->grabbed = false;
+                grabbedBall = NULL;
+            }
+        }
+
+        // Creates a new ball
+        if (IsMouseButtonPressed(MOUSE_BUTTON_RIGHT) || (IsKeyDown(KEY_LEFT_CONTROL) && IsMouseButtonDown(MOUSE_BUTTON_RIGHT))) {
+            if (ballQuantity < MAX_BALLS) {
+                balls[ballQuantity++] = (Ball) {
+                    .pos = mousePos,
+                    .vel = {GetRandomValue(-300, 300), GetRandomValue(-300, 300)},
+                    .ppos = {0},
+                    .radius = 20 + GetRandomValue(0, 30),
+                    .friction = 0.99,
+                    .elasticity = 0.9,
+                    .color = {GetRandomValue(0, 255), GetRandomValue(0, 255), GetRandomValue(0, 255), 255},
+                    .grabbed = false
+                };
+            }
+        }
+
+        // Shake balls
+        if (IsMouseButtonPressed(MOUSE_BUTTON_MIDDLE)) {
+            for (int i = 0; i < ballQuantity; i++) {
+                Ball *ball = &balls[i];
+                if (!ball->grabbed) {
+                    ball->vel = (Vector2) {GetRandomValue(-2000, 2000), GetRandomValue(-2000, 2000)};
+                }
+            }
+        }
+
+        // Changes gravity
+        gravity += GetMouseWheelMove() * 5;
+
+        // Updates each ball state
+        for (int i = 0; i < ballQuantity; i++) {
+
+            Ball *ball = &balls[i];
+
+            // The ball is not grabbed
+            if (!ball->grabbed) 
+            {
+                // Ball repositioning using the velocity
+                ball->pos.x += ball->vel.x * delta;
+                ball->pos.y += ball->vel.y * delta;
+
+                // Does the ball hit the screen right boundary?
+                if (ball->pos.x + ball->radius >= screenWidth) 
+                {
+                    ball->pos.x = screenWidth - ball->radius; // Ball repositioning
+                    ball->vel.x = -ball->vel.x * ball->elasticity;  // Elasticity makes the ball lose 10% of its velocity on hit
+                } 
+                // Does the ball hit the screen left boundary?
+                else if (ball->pos.x - ball->radius <= 0)
+                { 
+                    ball->pos.x = ball->radius;
+                    ball->vel.x = -ball->vel.x * ball->elasticity;
+                }
+
+                // The same for y axis
+                if (ball->pos.y + ball->radius >= screenHeight) 
+                {
+                    ball->pos.y = screenHeight - ball->radius;
+                    ball->vel.y = -ball->vel.y * ball->elasticity;
+                } 
+                else if (ball->pos.y - ball->radius <= 0) 
+                { 
+                    ball->pos.y = ball->radius;
+                    ball->vel.y = -ball->vel.y * ball->elasticity;
+                }
+
+                // Friction makes the ball lose 1% of its velocity each frame
+                ball->vel.x = ball->vel.x * ball->friction;
+                // Gravity affects only the y axis
+                ball->vel.y = ball->vel.y * ball->friction + gravity;
+
+            }
+            else
+            {
+                // Ball repositioning using the mouse position
+                ball->pos.x = mousePos.x - pressOffset.x;
+                ball->pos.y = mousePos.y - pressOffset.y;
+                // While the ball is grabbed, recalculates its velocity
+                ball->vel.x = (ball->pos.x - ball->ppos.x) / delta;
+                ball->vel.y = (ball->pos.y - ball->ppos.y) / delta;
+                ball->ppos = ball->pos;
+            }
+        }
+        
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(RAYWHITE);
+
+            for (int i = 0; i < ballQuantity; i++)
+            {
+                Ball *ball = &balls[i];
+                DrawCircleV(ball->pos, ball->radius, ball->color);
+                DrawCircleLinesV(ball->pos, ball->radius, BLACK);
+            }
+
+            DrawText("grab a ball by pressing with the mouse and throw it by releasing", 10, 10, 20, DARKGRAY);
+            DrawText("right click to create new balls (keep left control pressed to create a lot)", 10, 30, 20, DARKGRAY);
+            DrawText("use mouse wheel to change gravity", 10, 50, 20, DARKGRAY);
+            DrawText("middle click to shake", 10, 70, 20, DARKGRAY);
+            DrawText(TextFormat("ball quantity: %d", ballQuantity), 10, GetScreenHeight() - 55, 20, BLACK);
+            DrawText(TextFormat("gravity: %.2f", gravity), 10, GetScreenHeight() - 35, 20, BLACK);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    CloseWindow();        // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}