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shapes_ball_physics.c
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221 lines (191 loc) · 8.28 KB
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/*******************************************************************************************
*
* raylib [shapes] example - ball physics
*
* Example complexity rating: [★★☆☆] 2/4
*
* Example originally created with raylib 5.6-dev, last time updated with raylib 5.6-dev
*
* 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 "raylib.h"
#include <stdlib.h>
#include <math.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 - ball physics");
Ball balls[MAX_BALLS] = {{
.pos = { GetScreenWidth()/2.0f, GetScreenHeight()/2.0f },
.vel = { 200, 200 },
.ppos = { 0 },
.radius = 40,
.friction = 0.99f,
.elasticity = 0.9f,
.color = BLUE,
.grabbed = false
}};
int ballCount = 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 = ballCount - 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 than or equal to the ball radius, the event occurred 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 (ballCount < MAX_BALLS)
{
balls[ballCount++] = (Ball){
.pos = mousePos,
.vel = { (float)GetRandomValue(-300, 300), (float)GetRandomValue(-300, 300) },
.ppos = { 0 },
.radius = 20.0f + (float)GetRandomValue(0, 30),
.friction = 0.99f,
.elasticity = 0.9f,
.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 < ballCount; i++)
{
if (!balls[i].grabbed) balls[i].vel = (Vector2){ (float)GetRandomValue(-2000, 2000), (float)GetRandomValue(-2000, 2000) };
}
}
// Changes gravity
gravity += GetMouseWheelMove()*5;
// Updates each ball state
for (int i = 0; i < ballCount; 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 < ballCount; i++)
{
DrawCircleV(balls[i].pos, balls[i].radius, balls[i].color);
DrawCircleLinesV(balls[i].pos, balls[i].radius, BLACK);
}
DrawText("grab a ball by pressing with the mouse and throw it by releasing", 10, 10, 10, DARKGRAY);
DrawText("right click to create new balls (keep left control pressed to create a lot)", 10, 30, 10, DARKGRAY);
DrawText("use mouse wheel to change gravity", 10, 50, 10, DARKGRAY);
DrawText("middle click to shake", 10, 70, 10, DARKGRAY);
DrawText(TextFormat("BALL COUNT: %d", ballCount), 10, GetScreenHeight() - 70, 20, BLACK);
DrawText(TextFormat("GRAVITY: %.2f", gravity), 10, GetScreenHeight() - 40, 20, BLACK);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}