2025-08-12 19:30:40 +02:00

443 lines
17 KiB
C#

using System.Runtime.InteropServices;
using ImGuiNET;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
namespace skyscraper8.UI.MonoGame.Bridge
{
/// <summary>
/// ImGui renderer for use with XNA-likes (FNA & MonoGame)
/// </summary>
public class ImGuiRenderer
{
private Game _game;
// Graphics
private GraphicsDevice _graphicsDevice;
private BasicEffect _effect;
private RasterizerState _rasterizerState;
private byte[] _vertexData;
private VertexBuffer _vertexBuffer;
private int _vertexBufferSize;
private byte[] _indexData;
private IndexBuffer _indexBuffer;
private int _indexBufferSize;
// Textures
private Dictionary<IntPtr, Texture2D> _loadedTextures;
private int _textureId;
private IntPtr? _fontTextureId;
// Input
private int _scrollWheelValue;
private int _horizontalScrollWheelValue;
private readonly float WHEEL_DELTA = 120;
private Keys[] _allKeys = Enum.GetValues<Keys>();
public ImGuiRenderer(Game game)
{
var context = ImGui.CreateContext();
ImGui.SetCurrentContext(context);
_game = game ?? throw new ArgumentNullException(nameof(game));
_graphicsDevice = game.GraphicsDevice;
_loadedTextures = new Dictionary<IntPtr, Texture2D>();
_rasterizerState = new RasterizerState()
{
CullMode = CullMode.None,
DepthBias = 0,
FillMode = FillMode.Solid,
MultiSampleAntiAlias = false,
ScissorTestEnable = true,
SlopeScaleDepthBias = 0
};
SetupInput();
}
#region ImGuiRenderer
private const bool DISABLE_FONT_ATLAS = false;
/// <summary>
/// Creates a texture and loads the font data from ImGui. Should be called when the <see cref="GraphicsDevice" /> is initialized but before any rendering is done
/// </summary>
public virtual unsafe void RebuildFontAtlas()
{
if (DISABLE_FONT_ATLAS)
return;
// Get font texture from ImGui
var io = ImGui.GetIO();
io.Fonts.GetTexDataAsRGBA32(out byte* pixelData, out int width, out int height, out int bytesPerPixel);
// Copy the data to a managed array
var pixels = new byte[width * height * bytesPerPixel];
unsafe { Marshal.Copy(new IntPtr(pixelData), pixels, 0, pixels.Length); }
// Create and register the texture as an XNA texture
var tex2d = new Texture2D(_graphicsDevice, width, height, false, SurfaceFormat.Color);
tex2d.SetData(pixels);
// Should a texture already have been build previously, unbind it first so it can be deallocated
if (_fontTextureId.HasValue) UnbindTexture(_fontTextureId.Value);
// Bind the new texture to an ImGui-friendly id
_fontTextureId = BindTexture(tex2d);
// Let ImGui know where to find the texture
io.Fonts.SetTexID(_fontTextureId.Value);
io.Fonts.ClearTexData(); // Clears CPU side texture data
}
/// <summary>
/// Creates a pointer to a texture, which can be passed through ImGui calls such as <see cref="ImGui.Image" />. That pointer is then used by ImGui to let us know what texture to draw
/// </summary>
public virtual IntPtr BindTexture(Texture2D texture)
{
var id = new IntPtr(_textureId++);
_loadedTextures.Add(id, texture);
return id;
}
/// <summary>
/// Removes a previously created texture pointer, releasing its reference and allowing it to be deallocated
/// </summary>
public virtual void UnbindTexture(IntPtr textureId)
{
_loadedTextures.Remove(textureId);
}
/// <summary>
/// Sets up ImGui for a new frame, should be called at frame start
/// </summary>
public virtual void BeforeLayout(GameTime gameTime)
{
ImGui.GetIO().DeltaTime = (float)gameTime.ElapsedGameTime.TotalSeconds;
UpdateInput();
ImGui.NewFrame();
}
/// <summary>
/// Asks ImGui for the generated geometry data and sends it to the graphics pipeline, should be called after the UI is drawn using ImGui.** calls
/// </summary>
public virtual void AfterLayout()
{
ImGui.Render();
unsafe { RenderDrawData(ImGui.GetDrawData()); }
}
#endregion ImGuiRenderer
#region Setup & Update
/// <summary>
/// Setup key input event handler.
/// </summary>
protected virtual void SetupInput()
{
var io = ImGui.GetIO();
// MonoGame-specific //////////////////////
_game.Window.TextInput += (s, a) =>
{
if (a.Character == '\t') return;
io.AddInputCharacter(a.Character);
};
///////////////////////////////////////////
// FNA-specific ///////////////////////////
//TextInputEXT.TextInput += c =>
//{
// if (c == '\t') return;
// ImGui.GetIO().AddInputCharacter(c);
//};
///////////////////////////////////////////
}
/// <summary>
/// Updates the <see cref="Effect" /> to the current matrices and texture
/// </summary>
protected virtual Effect UpdateEffect(Texture2D texture)
{
_effect = _effect ?? new BasicEffect(_graphicsDevice);
var io = ImGui.GetIO();
_effect.World = Matrix.Identity;
_effect.View = Matrix.Identity;
_effect.Projection = Matrix.CreateOrthographicOffCenter(0f, io.DisplaySize.X, io.DisplaySize.Y, 0f, -1f, 1f);
_effect.TextureEnabled = true;
_effect.Texture = texture;
_effect.VertexColorEnabled = true;
return _effect;
}
public int LastKnownMouseX { get; set; }
public int LastKnownMouseY { get; set; }
/// <summary>
/// Sends XNA input state to ImGui
/// </summary>
protected virtual void UpdateInput()
{
if (!_game.IsActive) return;
var io = ImGui.GetIO();
var mouse = Mouse.GetState();
LastKnownMouseX = mouse.X;
LastKnownMouseY = mouse.Y;
var keyboard = Keyboard.GetState();
io.AddMousePosEvent(mouse.X, mouse.Y);
io.AddMouseButtonEvent(0, mouse.LeftButton == ButtonState.Pressed);
io.AddMouseButtonEvent(1, mouse.RightButton == ButtonState.Pressed);
io.AddMouseButtonEvent(2, mouse.MiddleButton == ButtonState.Pressed);
io.AddMouseButtonEvent(3, mouse.XButton1 == ButtonState.Pressed);
io.AddMouseButtonEvent(4, mouse.XButton2 == ButtonState.Pressed);
io.AddMouseWheelEvent(
(mouse.HorizontalScrollWheelValue - _horizontalScrollWheelValue) / WHEEL_DELTA,
(mouse.ScrollWheelValue - _scrollWheelValue) / WHEEL_DELTA);
_scrollWheelValue = mouse.ScrollWheelValue;
_horizontalScrollWheelValue = mouse.HorizontalScrollWheelValue;
foreach (var key in _allKeys)
{
if (TryMapKeys(key, out ImGuiKey imguikey))
{
io.AddKeyEvent(imguikey, keyboard.IsKeyDown(key));
}
}
io.DisplaySize = new System.Numerics.Vector2(_graphicsDevice.PresentationParameters.BackBufferWidth, _graphicsDevice.PresentationParameters.BackBufferHeight);
io.DisplayFramebufferScale = new System.Numerics.Vector2(1f, 1f);
}
private bool TryMapKeys(Keys key, out ImGuiKey imguikey)
{
//Special case not handed in the switch...
//If the actual key we put in is "None", return none and true.
//otherwise, return none and false.
if (key == Keys.None)
{
imguikey = ImGuiKey.None;
return true;
}
imguikey = key switch
{
Keys.Back => ImGuiKey.Backspace,
Keys.Tab => ImGuiKey.Tab,
Keys.Enter => ImGuiKey.Enter,
Keys.CapsLock => ImGuiKey.CapsLock,
Keys.Escape => ImGuiKey.Escape,
Keys.Space => ImGuiKey.Space,
Keys.PageUp => ImGuiKey.PageUp,
Keys.PageDown => ImGuiKey.PageDown,
Keys.End => ImGuiKey.End,
Keys.Home => ImGuiKey.Home,
Keys.Left => ImGuiKey.LeftArrow,
Keys.Right => ImGuiKey.RightArrow,
Keys.Up => ImGuiKey.UpArrow,
Keys.Down => ImGuiKey.DownArrow,
Keys.PrintScreen => ImGuiKey.PrintScreen,
Keys.Insert => ImGuiKey.Insert,
Keys.Delete => ImGuiKey.Delete,
>= Keys.D0 and <= Keys.D9 => ImGuiKey._0 + (key - Keys.D0),
>= Keys.A and <= Keys.Z => ImGuiKey.A + (key - Keys.A),
>= Keys.NumPad0 and <= Keys.NumPad9 => ImGuiKey.Keypad0 + (key - Keys.NumPad0),
Keys.Multiply => ImGuiKey.KeypadMultiply,
Keys.Add => ImGuiKey.KeypadAdd,
Keys.Subtract => ImGuiKey.KeypadSubtract,
Keys.Decimal => ImGuiKey.KeypadDecimal,
Keys.Divide => ImGuiKey.KeypadDivide,
>= Keys.F1 and <= Keys.F24 => ImGuiKey.F1 + (key - Keys.F1),
Keys.NumLock => ImGuiKey.NumLock,
Keys.Scroll => ImGuiKey.ScrollLock,
Keys.LeftShift => ImGuiKey.LeftShift,
Keys.LeftControl => ImGuiKey.LeftCtrl,
Keys.LeftAlt => ImGuiKey.LeftAlt,
Keys.OemSemicolon => ImGuiKey.Semicolon,
Keys.OemPlus => ImGuiKey.Equal,
Keys.OemComma => ImGuiKey.Comma,
Keys.OemMinus => ImGuiKey.Minus,
Keys.OemPeriod => ImGuiKey.Period,
Keys.OemQuestion => ImGuiKey.Slash,
Keys.OemTilde => ImGuiKey.GraveAccent,
Keys.OemOpenBrackets => ImGuiKey.LeftBracket,
Keys.OemCloseBrackets => ImGuiKey.RightBracket,
Keys.OemPipe => ImGuiKey.Backslash,
Keys.OemQuotes => ImGuiKey.Apostrophe,
_ => ImGuiKey.None,
};
return imguikey != ImGuiKey.None;
}
#endregion Setup & Update
#region Internals
/// <summary>
/// Gets the geometry as set up by ImGui and sends it to the graphics device
/// </summary>
private void RenderDrawData(ImDrawDataPtr drawData)
{
// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers
var lastViewport = _graphicsDevice.Viewport;
var lastScissorBox = _graphicsDevice.ScissorRectangle;
var lastRasterizer = _graphicsDevice.RasterizerState;
var lastDepthStencil = _graphicsDevice.DepthStencilState;
var lastBlendFactor = _graphicsDevice.BlendFactor;
var lastBlendState = _graphicsDevice.BlendState;
_graphicsDevice.BlendFactor = Color.White;
_graphicsDevice.BlendState = BlendState.NonPremultiplied;
_graphicsDevice.RasterizerState = _rasterizerState;
_graphicsDevice.DepthStencilState = DepthStencilState.DepthRead;
// Handle cases of screen coordinates != from framebuffer coordinates (e.g. retina displays)
drawData.ScaleClipRects(ImGui.GetIO().DisplayFramebufferScale);
// Setup projection
_graphicsDevice.Viewport = new Viewport(0, 0, _graphicsDevice.PresentationParameters.BackBufferWidth, _graphicsDevice.PresentationParameters.BackBufferHeight);
UpdateBuffers(drawData);
RenderCommandLists(drawData);
// Restore modified state
_graphicsDevice.Viewport = lastViewport;
_graphicsDevice.ScissorRectangle = lastScissorBox;
_graphicsDevice.RasterizerState = lastRasterizer;
_graphicsDevice.DepthStencilState = lastDepthStencil;
_graphicsDevice.BlendState = lastBlendState;
_graphicsDevice.BlendFactor = lastBlendFactor;
}
private unsafe void UpdateBuffers(ImDrawDataPtr drawData)
{
if (drawData.TotalVtxCount == 0)
{
return;
}
// Expand buffers if we need more room
if (drawData.TotalVtxCount > _vertexBufferSize)
{
_vertexBuffer?.Dispose();
_vertexBufferSize = (int)(drawData.TotalVtxCount * 1.5f);
_vertexBuffer = new VertexBuffer(_graphicsDevice, DrawVertDeclaration.Declaration, _vertexBufferSize, BufferUsage.None);
_vertexData = new byte[_vertexBufferSize * DrawVertDeclaration.Size];
}
if (drawData.TotalIdxCount > _indexBufferSize)
{
_indexBuffer?.Dispose();
_indexBufferSize = (int)(drawData.TotalIdxCount * 1.5f);
_indexBuffer = new IndexBuffer(_graphicsDevice, IndexElementSize.SixteenBits, _indexBufferSize, BufferUsage.None);
_indexData = new byte[_indexBufferSize * sizeof(ushort)];
}
// Copy ImGui's vertices and indices to a set of managed byte arrays
int vtxOffset = 0;
int idxOffset = 0;
for (int n = 0; n < drawData.CmdListsCount; n++)
{
ImDrawListPtr cmdList = drawData.CmdLists[n];
fixed (void* vtxDstPtr = &_vertexData[vtxOffset * DrawVertDeclaration.Size])
fixed (void* idxDstPtr = &_indexData[idxOffset * sizeof(ushort)])
{
Buffer.MemoryCopy((void*)cmdList.VtxBuffer.Data, vtxDstPtr, _vertexData.Length, cmdList.VtxBuffer.Size * DrawVertDeclaration.Size);
Buffer.MemoryCopy((void*)cmdList.IdxBuffer.Data, idxDstPtr, _indexData.Length, cmdList.IdxBuffer.Size * sizeof(ushort));
}
vtxOffset += cmdList.VtxBuffer.Size;
idxOffset += cmdList.IdxBuffer.Size;
}
// Copy the managed byte arrays to the gpu vertex- and index buffers
_vertexBuffer.SetData(_vertexData, 0, drawData.TotalVtxCount * DrawVertDeclaration.Size);
_indexBuffer.SetData(_indexData, 0, drawData.TotalIdxCount * sizeof(ushort));
}
private unsafe void RenderCommandLists(ImDrawDataPtr drawData)
{
_graphicsDevice.SetVertexBuffer(_vertexBuffer);
_graphicsDevice.Indices = _indexBuffer;
int vtxOffset = 0;
int idxOffset = 0;
for (int n = 0; n < drawData.CmdListsCount; n++)
{
ImDrawListPtr cmdList = drawData.CmdLists[n];
for (int cmdi = 0; cmdi < cmdList.CmdBuffer.Size; cmdi++)
{
ImDrawCmdPtr drawCmd = cmdList.CmdBuffer[cmdi];
if (drawCmd.ElemCount == 0)
{
continue;
}
if (!_loadedTextures.ContainsKey(drawCmd.TextureId))
{
throw new InvalidOperationException($"Could not find a texture with id '{drawCmd.TextureId}', please check your bindings");
}
_graphicsDevice.ScissorRectangle = new Rectangle(
(int)drawCmd.ClipRect.X,
(int)drawCmd.ClipRect.Y,
(int)(drawCmd.ClipRect.Z - drawCmd.ClipRect.X),
(int)(drawCmd.ClipRect.W - drawCmd.ClipRect.Y)
);
var effect = UpdateEffect(_loadedTextures[drawCmd.TextureId]);
foreach (var pass in effect.CurrentTechnique.Passes)
{
pass.Apply();
#pragma warning disable CS0618 // // FNA does not expose an alternative method.
_graphicsDevice.DrawIndexedPrimitives(
primitiveType: PrimitiveType.TriangleList,
baseVertex: (int)drawCmd.VtxOffset + vtxOffset,
minVertexIndex: 0,
numVertices: cmdList.VtxBuffer.Size,
startIndex: (int)drawCmd.IdxOffset + idxOffset,
primitiveCount: (int)drawCmd.ElemCount / 3
);
#pragma warning restore CS0618
}
}
vtxOffset += cmdList.VtxBuffer.Size;
idxOffset += cmdList.IdxBuffer.Size;
}
}
#endregion Internals
}
}