[Rendering] Add Cursor SetCursor/TryCreateCursorImage;

Author: LittleCodingFox

Engine/Core/Input/Cursor.cs

@@ -2,6 +2,9 @@
 
 namespace Staple;
 
+/// <summary>
+/// Mouse Cursor management class
+/// </summary>
 public static class Cursor
 {
     internal static IRenderWindow window;
@@ -91,4 +94,33 @@ internal static void ShowCursor()
     {
         window.ShowCursor();
     }
+
+    /// <summary>
+    /// Sets the mouse cursor to a specific image
+    /// </summary>
+    /// <param name="pixels">The image pixels</param>
+    /// <param name="width">The width of the image</param>
+    /// <param name="height">The height of the image</param>
+    /// <param name="hotX">The x position for the cursor hotspot</param>
+    /// <param name="hotY">The y position for the cursor hotspot</param>
+    public static bool TryCreateCursorImage(Color32[] pixels, int width, int height, int hotX, int hotY, out CursorImage image)
+    {
+        if(pixels.Length != width * height)
+        {
+            image = default;
+
+            return false;
+        }
+
+        return window.TryCreateCursorImage(pixels, width, height, hotX, hotY, out image);
+    }
+
+    /// <summary>
+    /// Changes the current cursor
+    /// </summary>
+    /// <param name="image">The cursor image. If it's null, resets to the arrow cursor</param>
+    public static void SetCursor(CursorImage image)
+    {
+        window.SetCursor(image);
+    }
 }

Engine/Core/Input/CursorImage.cs

@@ -0,0 +1,14 @@
+using System;
+
+namespace Staple;
+
+/// <summary>
+/// Represents an image for a cursor
+/// </summary>
+public abstract class CursorImage
+{
+    /// <summary>
+    /// Disposes the resources of this cursor
+    /// </summary>
+    public abstract void Dispose();
+}

Engine/Core/Rendering/Windowing/IRenderWindow.cs

@@ -43,6 +43,10 @@ bool Create(ref int width, ref int height, string title, bool resizable, WindowM
 
     void HideCursor();
 
+    bool TryCreateCursorImage(Color32[] pixels, int width, int height, int hotX, int hotY, out CursorImage image);
+
+    void SetCursor(CursorImage image);
+
     void SetIcon(RawTextureData icon);
 
     bool SetResolution(int width, int height, WindowMode windowMode);

Engine/Core/Rendering/Windowing/Impls/AndroidRenderWindow.cs

@@ -172,5 +172,16 @@ public bool SetResolution(int width, int height, WindowMode windowMode)
     {
         return false;
     }
+
+    public bool TryCreateCursorImage(Color32[] pixels, int width, int height, int hotX, int hotY, out CursorImage image)
+    {
+        image = default;
+
+        return false;
+    }
+
+    public void SetCursor(CursorImage image)
+    {
+    }
 }
 #endif

Engine/Core/Rendering/Windowing/Impls/SDL2RenderWindow.cs

@@ -11,21 +11,50 @@ internal class SDL2RenderWindow : IRenderWindow
 {
     private const short AxisDeadzone = 8000;
 
+    private class SDL2Cursor : CursorImage
+    {
+        public Color32[] pixels;
+        public nint surface = nint.Zero;
+        public nint cursor = nint.Zero;
+
+        public override void Dispose()
+        {
+            if (cursor != nint.Zero)
+            {
+                SDL.SDL_FreeCursor(cursor);
+
+                cursor = nint.Zero;
+            }
+
+            if(surface != nint.Zero)
+            {
+                SDL.SDL_FreeSurface(surface);
+
+                surface = nint.Zero;
+            }
+
+            pixels = [];
+        }
+    }
+
     private class GamepadState
     {
         public nint instance;
     }
 
     public nint window;
 
-    private Dictionary<int, GamepadState> gamepads = new();
+    private readonly Dictionary<int, GamepadState> gamepads = [];
+
+    private readonly List<SDL2Cursor> cursors = [];
 
     private bool movedWindow = false;
     private DateTime movedWindowTimer;
     private Vector2Int previousWindowPosition;
     private bool closedWindow = false;
     private bool windowFocused = true;
     private bool windowMaximized = false;
+    private nint defaultCursor = nint.Zero;
 
     private nint metalView = nint.Zero;
 
@@ -142,11 +171,18 @@ public bool Create(ref int width, ref int height, string title, bool resizable,
             windowMaximized = true;
         }
 
+        defaultCursor = SDL.SDL_CreateSystemCursor(SDL.SDL_SystemCursor.SDL_SYSTEM_CURSOR_ARROW);
+
         return true;
     }
 
     public void Destroy()
     {
+        foreach (var cursor in cursors)
+        {
+            cursor.Dispose();
+        }
+
         SDL.SDL_DestroyWindow(window);
     }
 
@@ -755,5 +791,59 @@ public bool SetResolution(int width, int height, WindowMode windowMode)
 
         return true;
     }
+
+    public bool TryCreateCursorImage(Color32[] pixels, int width, int height, int hotX, int hotY, out CursorImage image)
+    {
+        unsafe
+        {
+            var outValue = new SDL2Cursor
+            {
+                pixels = pixels
+            };
+
+            fixed (void *ptr = outValue.pixels)
+            {
+                var surface = SDL.SDL_CreateRGBSurfaceFrom((nint)ptr, width, height, 32, width * 4, 0, 0, 0, 0);
+
+                if(surface == nint.Zero)
+                {
+                    image = default;
+
+                    return false;
+                }
+
+                var cursor = SDL.SDL_CreateColorCursor(surface, hotX, hotY);
+
+                if(cursor == nint.Zero)
+                {
+                    SDL.SDL_FreeSurface(surface);
+
+                    image = default;
+
+                    return false;
+                }
+
+                outValue.surface = surface;
+                outValue.cursor = cursor;
+
+                image = outValue;
+
+                return true;
+            }
+        }
+    }
+
+    public void SetCursor(CursorImage image)
+    {
+        if(image is not SDL2Cursor cursor ||
+            cursor.cursor == nint.Zero)
+        {
+            SDL.SDL_SetCursor(defaultCursor);
+
+            return;
+        }
+
+        SDL.SDL_SetCursor(cursor.cursor);
+    }
 }
 #endif

Engine/Core/Rendering/Windowing/Impls/iOSRenderWindow.cs

@@ -174,5 +174,16 @@ public bool SetResolution(int width, int height, WindowMode windowMode)
     {
         return false;
     }
+
+    public bool TryCreateCursorImage(Color32[] pixels, int width, int height, int hotX, int hotY, out ICursorImage image)
+    {
+        image = default;
+
+        return false;
+    }
+
+    public void SetCursor(ICursorImage image)
+    {
+    }
 }
 #endif

Engine/Core/StapleCore.csproj

@@ -140,6 +140,7 @@
 		<Compile Include="Hooks\IStapleHook.cs" />
 		<Compile Include="Hooks\StapleHookEvent.cs" />
 		<Compile Include="Input\Cursor.cs" />
+		<Compile Include="Input\CursorImage.cs" />
 		<Compile Include="Input\CursorLockMode.cs" />
 		<Compile Include="Input\GamepadAxis.cs" />
 		<Compile Include="Input\GamepadButton.cs" />