raylib-cs/Examples/Core/WorldScreen.cs

/*******************************************************************************************
*
*   raylib [core] example - world screen
*
*   Example complexity rating: [★★☆☆] 2/4
*
*   Example originally created with raylib 1.3, last time updated with raylib 1.4
*
*   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) 2015-2025 Ramon Santamaria (@raysan5)
*
********************************************************************************************/

namespace Examples.Core;

public partial class WorldScreen : IExample
{
    private const int screenWidth = 800;
    private const int screenHeight = 450;

    public string Name => "Core / World to Screen";

    public string Title => "raylib [core] example - world screen";

    public bool CursorDisabled => true;

    private Camera3D camera;
    private Vector3 cubePosition;
    private Vector2 cubeScreenPosition = new(0.0f, 0.0f);

    public void Init()
    {
        // Define the camera to look into our 3d world
        camera = new();
        camera.Position = new Vector3(10.0f, 10.0f, 10.0f); // Camera position
        camera.Target = new Vector3(0.0f, 0.0f, 0.0f);      // Camera looking at point
        camera.Up = new Vector3(0.0f, 1.0f, 0.0f);          // Camera up vector (rotation towards target)
        camera.FovY = 45.0f;                                // Camera field-of-view Y
        camera.Projection = CameraProjection.Perspective;   // Camera projection type

        cubePosition = new(0.0f, 0.0f, 0.0f);
    }

    public void Update()
    {
        // Update
        //----------------------------------------------------------------------------------
        UpdateCamera(ref camera, CameraMode.ThirdPerson);

        // Calculate cube screen space position (with a little offset to be in top)
        cubeScreenPosition = GetWorldToScreen(
            new Vector3(cubePosition.X, cubePosition.Y + 2.5f, cubePosition.Z),
            camera
        );
        //----------------------------------------------------------------------------------

        // Draw
        //----------------------------------------------------------------------------------
        BeginDrawing();
        ClearBackground(Color.RayWhite);

        BeginMode3D(camera);

        DrawCube(cubePosition, 2.0f, 2.0f, 2.0f, Color.Red);
        DrawCubeWires(cubePosition, 2.0f, 2.0f, 2.0f, Color.Maroon);

        DrawGrid(10, 1.0f);

        EndMode3D();

        DrawText(
            "Enemy: 100/100",
            (int)cubeScreenPosition.X - MeasureText("Enemy: 100/100", 20) / 2,
            (int)cubeScreenPosition.Y,
            20,
            Color.Black
        );

        DrawText(
            $"Cube position in screen space coordinates: [{(int)cubeScreenPosition.X}, {(int)cubeScreenPosition.Y}]",
            10,
            10,
            20,
            Color.Lime
        );
        DrawText("Text 2d should be always on top of the cube", 10, 40, 20, Color.Gray);

        EndDrawing();
        //----------------------------------------------------------------------------------
    }

    public void Unload()
    {
    }

    public static int Main()
    {
        // Initialization
        //--------------------------------------------------------------------------------------
        InitWindow(screenWidth, screenHeight, "raylib [core] example - world screen");

        DisableCursor();                    // Limit cursor to relative movement inside the window

        SetTargetFPS(60);                   // Set our game to run at 60 frames-per-second
        //--------------------------------------------------------------------------------------

        var game = new WorldScreen();
        game.Init();

        // Main game loop
        while (!WindowShouldClose())        // Detect window close button or ESC key
        {
            game.Update();
        }

        game.Unload();

        // De-Initialization
        //--------------------------------------------------------------------------------------
        CloseWindow();        // Close window and OpenGL context
        //--------------------------------------------------------------------------------------

        return 0;
    }
}