quad

using ImGuiNET;
using System;
using System.IO;
using System.Numerics;
using System.Text;
using Veldrid;
using Veldrid.ImageSharp;
using Veldrid.Sdl2;
using Veldrid.StartupUtilities;
namespace GarPixel
{
    class Program
    {

        static void Main(string[] args)
        {
            App app = new App();
            app.Run();
        }
    }
    public class App
    {
        Sdl2Window AppWindow;
        GraphicsDevice Device;
        ResourceFactory Factory;

        CommandList CmdList;
        DeviceBuffer CanvasVertextBuffer;
        DeviceBuffer CanvasIndexBuffer;
        DeviceBuffer ModelBuffer;
        DeviceBuffer ProjectionBuffer;
        ResourceSet ModelProjectionSet;
        ResourceLayout ModelProjectionLayout;
        Texture CanvasTexture;
        TextureView CanvasTextureView;
        ResourceSet CanvasTextureSet;
        ResourceLayout CanvasTextureLayout;
        Pipeline CanvasPipeline;
        ImGuiRenderer GuiRenderer;

        string ImageUrl = @"C:\LocalProjects\GarPixel\GarPixel\asset\elf.png";

        //Quad points 
        readonly float[] QuadVerts = new float[] {
         // Pos      // Tex
        0.0f, 1.0f, 0.0f, 1.0f,
        1.0f, 0.0f, 1.0f, 0.0f,
        0.0f, 0.0f, 0.0f, 1.0f,

        0.0f, 1.0f, 0.0f, 1.0f,
        1.0f, 1.0f, 1.0f, 1.0f,
        1.0f, 0.0f, 1.0f, 0.0f
     };

        ushort[] QuadIndices = { 0, 1, 2, 3, 4, 5 };

        public App()
        {
            WindowCreateInfo windowCI = new WindowCreateInfo()
            {
                X = 100,
                Y = 100,
                WindowWidth = 1280,
                WindowHeight = 720,
                WindowTitle = "Gar Pixel"
            };
            AppWindow = VeldridStartup.CreateWindow(ref windowCI);
            Device = VeldridStartup.CreateGraphicsDevice(AppWindow, GraphicsBackend.OpenGL);
            CreateResources();
        }

        const string VertexShaderSource = @"
        #version 330
        layout(location = 0) in vec4 posuv;

        out vec2 TexCoords;

        uniform mat4 model;
        uniform mat4 projection; 

        void main(void)
        {
            TexCoords = posuv.zw; 
            gl_Position = projection * model * vec4(posuv.xy, 0.0, 1.0);
        }
    ";

        const string FragmentShaderSource = @"
        #version 330
        in vec2 TexCoords;
        out vec4 color; 

        uniform sampler2D image; 

        void main(void)
        {
            color = texture(image, TexCoords);
        }
    ";

        private void CreateResources()
        {
            Factory = Device.ResourceFactory;

            CmdList = Factory.CreateCommandList();
            GuiRenderer = new ImGuiRenderer(
                Device,
                Device.MainSwapchain.Framebuffer.OutputDescription,
                AppWindow.Width,
                AppWindow.Height
                );

            AppWindow.Resized += () =>
            {
                GuiRenderer.WindowResized(AppWindow.Width, AppWindow.Height);
                Device.MainSwapchain.Resize((uint)AppWindow.Width, (uint)AppWindow.Height);

            };

            CanvasVertextBuffer = Factory.CreateBuffer(new BufferDescription((uint)(QuadVerts.Length * sizeof(float)),
                BufferUsage.VertexBuffer));
            CanvasIndexBuffer = Factory.CreateBuffer(new BufferDescription(6 * sizeof(ushort), BufferUsage.IndexBuffer));
            Device.UpdateBuffer(CanvasVertextBuffer, 0, QuadVerts);
            Device.UpdateBuffer(CanvasIndexBuffer, 0, QuadIndices);

            ModelBuffer = Factory.CreateBuffer(new BufferDescription(
                64,
                BufferUsage.UniformBuffer
                ));
            ProjectionBuffer = Factory.CreateBuffer(new BufferDescription(
                64,
                BufferUsage.UniformBuffer
                ));

            ModelProjectionLayout = Factory.CreateResourceLayout
                (
                    new ResourceLayoutDescription
                    (
                        new ResourceLayoutElementDescription
                        (
                            "model",
                            ResourceKind.UniformBuffer,
                            ShaderStages.Vertex
                        ),
                        new ResourceLayoutElementDescription
                        (
                            "projection",
                            ResourceKind.UniformBuffer,
                            ShaderStages.Vertex
                        )
                    )
                );

            ModelProjectionSet = Factory.CreateResourceSet(
                new ResourceSetDescription(ModelProjectionLayout, ModelBuffer, ProjectionBuffer));

            Shader vertexShader = Factory.CreateShader(new ShaderDescription(
                ShaderStages.Vertex,
                Encoding.ASCII.GetBytes(VertexShaderSource),
                "VS"
                ));
            Shader fragmentShader = Factory.CreateShader(new ShaderDescription(
                ShaderStages.Fragment,
                Encoding.ASCII.GetBytes(FragmentShaderSource),
                "FS"
                ));

            CanvasTextureLayout = Factory.CreateResourceLayout(
                new ResourceLayoutDescription(
                    new ResourceLayoutElementDescription("image", ResourceKind.TextureReadOnly, ShaderStages.Fragment)
                    )
            );

            CanvasTexture = new ImageSharpTexture(ImageUrl, false).CreateDeviceTexture(Device, Factory);
            CanvasTextureView = Factory.CreateTextureView(CanvasTexture);
            CanvasTextureSet = Factory.CreateResourceSet
                (
                    new ResourceSetDescription(
                        CanvasTextureLayout,
                        CanvasTextureView)
                );

            GraphicsPipelineDescription pipelineDescription = new GraphicsPipelineDescription
                (
                    BlendStateDescription.SingleAlphaBlend,
                    DepthStencilStateDescription.Disabled,
                    RasterizerStateDescription.CullNone,
                    PrimitiveTopology.TriangleList,
                    new ShaderSetDescription(
                        new VertexLayoutDescription[]
                        {
                        new VertexLayoutDescription(
                            16,
                            new VertexElementDescription
                            (
                                "posuv",
                                VertexElementSemantic.Position, VertexElementFormat.Float4
                            )
                        )
                        },
                        new Shader[] { vertexShader, fragmentShader }
                        ),
                    new[] { ModelProjectionLayout, CanvasTextureLayout },
                    Device.MainSwapchain.Framebuffer.OutputDescription
                );
            pipelineDescription.BlendState = BlendStateDescription.SingleOverrideBlend;

            CanvasPipeline = Factory.CreateGraphicsPipeline(pipelineDescription);
        }

        public void Run()
        {
            while (AppWindow.Exists)
            {
                InputSnapshot snapshot = AppWindow.PumpEvents();

                GuiRenderer.Update(1f / 60f, snapshot);

                bool showWindow = true;
                ImGuiNative.igShowDemoWindow(ref showWindow);
                if (ImGui.BeginWindow("Test"))
                {
                    ImGui.Text("Hello");
                    if (ImGui.Button("Quit"))
                    {
                    }
                    ImGui.EndWindow();
                }

                Device.UpdateBuffer(ProjectionBuffer, 0,
                    Matrix4x4.CreateOrthographic(AppWindow.Width, AppWindow.Height,
                    -1, 1));

                Matrix4x4 model = Matrix4x4.Identity;
                model *= Matrix4x4.CreateScale(200);
                model *= Matrix4x4.CreateTranslation(100, 100, 0);

                Device.UpdateBuffer(ModelBuffer, 0, model);

                CmdList.Begin();
                CmdList.SetFramebuffer(Device.MainSwapchain.Framebuffer);
                CmdList.ClearColorTarget(0, new RgbaFloat(.3f, .3f, .3f, 1f));
                //GuiRenderer.Render(Device, CmdList);

                CmdList.SetPipeline(CanvasPipeline);
                CmdList.SetVertexBuffer(0, CanvasVertextBuffer);
                CmdList.SetIndexBuffer(CanvasIndexBuffer, IndexFormat.UInt16);
                CmdList.SetGraphicsResourceSet(0, ModelProjectionSet);
                CmdList.SetGraphicsResourceSet(1, CanvasTextureSet);
                CmdList.DrawIndexed(6);

                CmdList.End();
                Device.SubmitCommands(CmdList);
                Device.SwapBuffers(Device.MainSwapchain);
            }
        }
    }
}