example: add easing_ball_anim

examples/shapes/easings_ball_anim.zig

@@ -0,0 +1,86 @@
+const rl = @import("raylib");
+const reasings = @import("reasings.zig");
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+pub fn main() anyerror!void {
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const screenWidth = 800;
+    const screenHeight = 450;
+
+    rl.initWindow(screenWidth, screenHeight, "raylib [shapes] example - easings ball anim");
+    defer rl.closeWindow(); // Defer closing window and OpenGL context
+
+    // Ball variable value to be animated with easings
+    var ballPositionX: i32 = -100;
+    var ballRadius: f32 = 20;
+    var ballAlpha: f32 = 0;
+
+    var state: i32 = 0;
+    var framesCounter: i32 = 0;
+
+    rl.setTargetFPS(60); // Set our game to run at 60 frames-per-second
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!rl.windowShouldClose()) // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        switch (state) {
+            0 => { // Move ball position X with easing
+                framesCounter += 1;
+                ballPositionX = @intFromFloat(reasings.elasticOut(@floatFromInt(framesCounter), -100, @as(f32, @floatFromInt(screenWidth)) / 2 + 100, 120));
+
+                if (framesCounter >= 120) {
+                    framesCounter = 0;
+                    state = 1;
+                }
+            },
+            1 => { // Increase ball radius with easing
+                framesCounter += 1;
+                ballRadius = reasings.elasticIn(@floatFromInt(framesCounter), 20, 500, 200);
+
+                if (framesCounter >= 200) {
+                    framesCounter = 0;
+                    state = 2;
+                }
+            },
+            2 => { // Change ball alpha with easing (background color blending)
+                framesCounter += 1;
+                ballAlpha = reasings.cubicOut(@floatFromInt(framesCounter), 0.0, 1.0, 200);
+                if (framesCounter >= 200) {
+                    framesCounter = 0;
+                    state = 3;
+                }
+            },
+            3 => { // Reset state to play again
+                if (rl.isKeyPressed(.enter)) {
+                    ballPositionX = -100;
+                    ballRadius = 20;
+                    ballAlpha = 0.0;
+                    state = 0;
+                }
+            },
+            else => unreachable,
+        }
+
+        if (rl.isKeyPressed(.r)) framesCounter = 0;
+        //----------------------------------------------------------------------------------
+        // Draw
+        //----------------------------------------------------------------------------------
+        rl.beginDrawing();
+        defer rl.endDrawing();
+
+        rl.clearBackground(.ray_white);
+
+        if (state >= 2) rl.drawRectangle(0, 0, screenWidth, screenHeight, .green);
+        rl.drawCircle(ballPositionX, 200, ballRadius, .fade(.red, 1.0 - ballAlpha));
+
+        if (state == 3) rl.drawText("PRESS [ENTER] TO PLAY AGAIN!", 240, 200, 20, .black);
+
+        //----------------------------------------------------------------------------------
+    }
+}