From da381fa32c82c7a72be43aa1ecaa53e610c8179c Mon Sep 17 00:00:00 2001
From: me <me@alloca.space>
Date: Fri, 11 Apr 2025 08:06:43 +0300
Subject: [PATCH] c moving ball

---
 .gitignore           |   4 ++
 c-moving-ball/main.c | 137 +++++++++++++++++++++++++++++++++++++++++++
 c-moving-ball/run.sh |   2 +
 license.txt          |  19 ++++++
 4 files changed, 162 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 c-moving-ball/main.c
 create mode 100755 c-moving-ball/run.sh
 create mode 100644 license.txt

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ba558bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,4 @@
+c-moving-ball/raylib.h
+c-moving-ball/wasm.sh
+c-moving-ball/wasm
+c-moving-ball/game
diff --git a/c-moving-ball/main.c b/c-moving-ball/main.c
new file mode 100644
index 0000000..a3602f7
--- /dev/null
+++ b/c-moving-ball/main.c
@@ -0,0 +1,137 @@
+/*
+
+Gist accompanying https://alloca.space/blog/c-lang.html 
+
+Build and Run
+-------------
+
+1. Install a C compiler and https://raylib.com on your system
+
+2. Build and run with:
+
+   cc main.c -lraylib -lGL -lm -lpthread -ldl -lrt -lX11 -o game && ./game
+
+*/
+
+#include <stdlib.h>
+#include "raylib.h"
+
+/* Constants */
+
+#define FPS 60
+#define SCREEN_WIDTH 640
+#define SCREEN_HEIGHT 480
+#define BALL_SPEED 200
+#define BALL_RADIUS 50
+
+/* Data types */
+
+typedef struct {
+  int x;
+  int y;
+} V2;
+
+typedef struct {
+  V2 position;
+  float radius;
+  V2 direction;
+  Color color;
+} Ball;
+
+/* Functions */
+
+Ball* createBall();
+void swing(int *position, int *direction, int min, int max);
+void swingBall(Ball* ball);
+void applyKeys(Ball* ball);
+void updateBall(Ball* ball);
+void initialize();
+
+/* Main */
+
+int main(void) {
+  initialize();
+
+  Ball* ball = createBall();
+  Color background_color = { 0x08, 0x18, 0x29, 0xff };
+
+  // Game loop
+  while (!WindowShouldClose()) {
+    // Update
+    updateBall(ball);
+
+    // Draw
+    BeginDrawing();
+
+      ClearBackground(background_color);
+      DrawCircle((*ball).position.x, (*ball).position.y, (*ball).radius, (*ball).color);
+
+    EndDrawing();
+  }
+
+  // De-Initialization
+  free(ball);
+  CloseWindow();
+
+  return 0;
+}
+
+/* Initialize window */
+
+void initialize() {
+  SetConfigFlags(FLAG_MSAA_4X_HINT);
+  InitWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "alloca.space - The C Programming Language");
+  SetTargetFPS(FPS);
+}
+
+/* Ball */
+
+Ball* createBall() {
+  Ball ball_value = {
+    .position = {
+      .x = SCREEN_WIDTH/3,
+      .y = SCREEN_HEIGHT/3,
+    },
+    .radius = BALL_RADIUS,
+    .direction = {
+      .x = 1,
+      .y = 1,
+    },
+    .color = { 0xf9, 0x92, 0x26, 0xff },
+  };
+
+  Ball* ball = (Ball*)malloc(sizeof(Ball));
+  *ball = ball_value;
+
+  return ball;
+}
+
+void updateBall(Ball* ball) {
+  applyKeys(ball);
+  swingBall(ball);
+}
+
+void applyKeys(Ball* ball) {
+    if (IsKeyDown(KEY_D)) { (*ball).direction.x = 1; }
+    if (IsKeyDown(KEY_A)) { (*ball).direction.x = -1; }
+    if (IsKeyDown(KEY_S)) { (*ball).direction.y = 1; }
+    if (IsKeyDown(KEY_W)) { (*ball).direction.y = -1; }
+}
+
+void swingBall(Ball* ball) {
+    swing(&(*ball).position.x, &(*ball).direction.x, 0 + (*ball).radius, SCREEN_WIDTH - (*ball).radius);
+    swing(&(*ball).position.y, &(*ball).direction.y, 0 + (*ball).radius, SCREEN_HEIGHT - (*ball).radius);
+}
+
+void swing(int *position, int *direction, int min, int max) {
+  if (*position <= min) {
+    *position = min;
+    *direction = 1;
+  }
+  else if (*position >= max) {
+    *position = max;
+    *direction = -1;
+  }
+  float dt = GetFrameTime();
+  *position += *direction * (BALL_SPEED * dt);
+}
diff --git a/c-moving-ball/run.sh b/c-moving-ball/run.sh
new file mode 100755
index 0000000..7686d65
--- /dev/null
+++ b/c-moving-ball/run.sh
@@ -0,0 +1,2 @@
+#!/bin/bash
+cc main.c -lraylib -lGL -lm -lpthread -ldl -lrt -lX11 -o game && ./game
diff --git a/license.txt b/license.txt
new file mode 100644
index 0000000..e359f5d
--- /dev/null
+++ b/license.txt
@@ -0,0 +1,19 @@
+zlib License
+
+(C) 2025 alloca.space
+
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgment in the product documentation would be
+   appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.