feat: backporting existing raylib-cs examples and new official raylib examples to WASM, adopting raylib's original code style

Examples/Shapes/EllipseCollision.cs

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+/*******************************************************************************************
+*
+*   raylib [shapes] example - ellipse collision
+*
+*   Example complexity rating: [★★☆☆] 2/4
+*
+*   Example originally created with raylib 5.5, last time updated with raylib 5.5
+*
+*   Example contributed by Ziya (@Monjaris)
+*
+*   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 Ziya (@Monjaris)
+*
+********************************************************************************************/
+
+using System;
+using System.Numerics;
+using static Raylib_cs.Raylib;
+
+namespace Examples.Shapes;
+
+public partial class EllipseCollision : IExample
+{
+    private const int screenWidth = 800;
+    private const int screenHeight = 450;
+
+    public string Name => "Shapes / Ellipse Collision";
+
+    public string Title => "raylib [shapes] example - collision ellipses";
+
+    private Vector2 ellipseACenter;
+    private float ellipseARx;
+    private float ellipseARy;
+
+    private Vector2 ellipseBCenter;
+    private float ellipseBRx;
+    private float ellipseBRy;
+
+    // 0 = controlling A, 1 = controlling B
+    private int controlled;
+
+    // Check if point is inside ellipse
+    private static bool CheckCollisionPointEllipse(Vector2 point, Vector2 center, float rx, float ry)
+    {
+        float dx = (point.X - center.X) / rx;
+        float dy = (point.Y - center.Y) / ry;
+        return (dx * dx + dy * dy) <= 1.0f;
+    }
+
+    // Check if two ellipses collide
+    // Uses radial boundary distance in the direction between centers — scales correctly with radii
+    private static bool CheckCollisionEllipses(Vector2 c1, float rx1, float ry1, Vector2 c2, float rx2, float ry2)
+    {
+        float dx = c2.X - c1.X;
+        float dy = c2.Y - c1.Y;
+        float dist = MathF.Sqrt(dx * dx + dy * dy);
+
+        // Ellipses are on top of each other
+        if (dist == 0.0f)
+        {
+            return true;
+        }
+
+        float theta = MathF.Atan2(dy, dx);
+        float cosT = MathF.Cos(theta);
+        float sinT = MathF.Sin(theta);
+
+        // Radial distance from center to ellipse boundary in direction theta
+        // r(theta) = (rx * ry) / sqrt((ry*cos)^2 + (rx*sin)^2)
+        float r1 = (rx1 * ry1) / MathF.Sqrt((ry1 * cosT) * (ry1 * cosT) + (rx1 * sinT) * (rx1 * sinT));
+        float r2 = (rx2 * ry2) / MathF.Sqrt((ry2 * cosT) * (ry2 * cosT) + (rx2 * sinT) * (rx2 * sinT));
+
+        return dist <= (r1 + r2);
+    }
+
+    public void Init()
+    {
+        ellipseACenter = new((float)screenWidth / 4, (float)screenHeight / 2);
+        ellipseARx = 120.0f;
+        ellipseARy = 70.0f;
+
+        ellipseBCenter = new((float)screenWidth * 3 / 4, (float)screenHeight / 2);
+        ellipseBRx = 90.0f;
+        ellipseBRy = 140.0f;
+
+        // 0 = controlling A, 1 = controlling B
+        controlled = 0;
+    }
+
+    public void Update()
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        if (IsKeyPressed(KeyboardKey.A))
+        {
+            controlled = 0;
+        }
+        if (IsKeyPressed(KeyboardKey.B))
+        {
+            controlled = 1;
+        }
+
+        if (controlled == 0)
+        {
+            ellipseACenter = GetMousePosition();
+        }
+        else
+        {
+            ellipseBCenter = GetMousePosition();
+        }
+
+        bool ellipsesCollide = CheckCollisionEllipses(
+            ellipseACenter, ellipseARx, ellipseARy,
+            ellipseBCenter, ellipseBRx, ellipseBRy
+        );
+
+        bool mouseInA = CheckCollisionPointEllipse(GetMousePosition(), ellipseACenter, ellipseARx, ellipseARy);
+        bool mouseInB = CheckCollisionPointEllipse(GetMousePosition(), ellipseBCenter, ellipseBRx, ellipseBRy);
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+        ClearBackground(Color.RayWhite);
+
+        DrawEllipse((int)ellipseACenter.X, (int)ellipseACenter.Y, ellipseARx, ellipseARy, ellipsesCollide ? Color.Red : Color.Blue);
+
+        DrawEllipse((int)ellipseBCenter.X, (int)ellipseBCenter.Y, ellipseBRx, ellipseBRy, ellipsesCollide ? Color.Red : Color.Green);
+
+        DrawEllipseLines((int)ellipseACenter.X, (int)ellipseACenter.Y, ellipseARx, ellipseARy, Color.White);
+
+        DrawEllipseLines((int)ellipseBCenter.X, (int)ellipseBCenter.Y, ellipseBRx, ellipseBRy, Color.White);
+
+        DrawCircleV(ellipseACenter, 4, Color.White);
+        DrawCircleV(ellipseBCenter, 4, Color.White);
+
+        if (ellipsesCollide)
+        {
+            DrawText("ELLIPSES COLLIDE", screenWidth / 2 - 120, 40, 28, Color.Red);
+        }
+        else
+        {
+            DrawText("NO COLLISION", screenWidth / 2 - 80, 40, 28, Color.DarkGray);
+        }
+
+        DrawText(controlled == 0 ? "Controlling: A" : "Controlling: B", 20, screenHeight - 40, 20, Color.Yellow);
+
+        if (mouseInA && controlled != 0)
+        {
+            DrawText("Mouse inside ellipse A", 20, screenHeight - 70, 20, Color.Blue);
+        }
+        if (mouseInB && controlled != 1)
+        {
+            DrawText("Mouse inside ellipse B", 20, screenHeight - 70, 20, Color.Green);
+        }
+
+        DrawText("Press [A] or [B] to switch control", 20, 20, 20, Color.Gray);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    public void Unload()
+    {
+    }
+
+    public static int Main()
+    {
+        // Initialization
+        //--------------------------------------------------------------------------------------
+        InitWindow(screenWidth, screenHeight, "raylib [shapes] example - collision ellipses");
+        SetTargetFPS(60);
+
+        var game = new EllipseCollision();
+        game.Init();
+
+        // Main game loop
+        while (!WindowShouldClose())    // Detect window close button or ESC key
+        {
+            game.Update();
+        }
+
+        game.Unload();
+
+        // De-Initialization
+        //--------------------------------------------------------------------------------------
+        CloseWindow();
+        //--------------------------------------------------------------------------------------
+
+        return 0;
+    }
+}