public void Init()
{
context.imguiContext = ImGui.CreateContext();
ImGui.SetCurrentContext(context.imguiContext);
var io = ImGui.GetIO();
io.BackendFlags |= ImGuiBackendFlags.RendererHasVtxOffset;
fontTexture = new Texture2D();
context.renderTargets["imgui_font"] = fontTexture;
ImFontPtr font = io.Fonts.AddFontFromFileTTF("c:\\Windows\\Fonts\\SIMHEI.ttf", 14, null, io.Fonts.GetGlyphRangesChineseFull());
io.Fonts.GetTexDataAsRGBA32(out byte *pixels, out int width, out int height, out int bytesPerPixel);
io.Fonts.TexID = context.GetStringId("imgui_font");
fontTexture.width = width;
fontTexture.height = height;
fontTexture.mipLevels = 1;
fontTexture.format = Format.R8G8B8A8_UNorm;
imguiMesh = context.GetMesh("imgui_mesh");
GPUUpload gpuUpload = new GPUUpload();
gpuUpload.texture2D = fontTexture;
gpuUpload.format = Format.R8G8B8A8_UNorm;
gpuUpload.textureData = new byte[width * height * bytesPerPixel];
new Span <byte>(pixels, gpuUpload.textureData.Length).CopyTo(gpuUpload.textureData);
context.uploadQueue.Enqueue(gpuUpload);
}