using OpenTK.Graphics.OpenGL;
using OpenTK.Mathematics;

namespace Yw.WinFrmUI.Test.Core
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
            this.glControl1.Load += GlControl1_Load;
            this.glControl1.Paint += GlControl1_Paint;
            this.glControl1.Resize += GlControl1_Resize;
        }

        private Matrix4 _projectionMatrix;
        private Matrix4 _viewMatrix;
        private Matrix4 _modelMatrix;
        private float _translationX, _translationY;
        private float _rotationX, _rotationY;

        private void GlControl1_Load(object sender, EventArgs e)
        {
            InitializeGLState();
        }

        private void GlControl1_Resize(object sender, EventArgs e)
        {
            UpdateViewPort();
            UpdateModelMatrix();
            UpdateViewMatrix();
            UpdateProjectionMatrix();
        }

        private void GlControl1_Paint(object sender, PaintEventArgs e)
        {
            this.glControl1.MakeCurrent();
            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit | ClearBufferMask.StencilBufferBit);

            // 旋转立方体
            _rotationX += 0.001f;
            //_rotationY += 0.01f;

            //投影矩阵
            GL.MatrixMode(MatrixMode.Projection);
            GL.LoadMatrix(ref _projectionMatrix);

            //视图矩阵
            GL.MatrixMode(MatrixMode.Modelview);
            var viewMatrix = _viewMatrix;
            GL.LoadMatrix(ref viewMatrix);
            GL.MultMatrix(ref _modelMatrix);


            //GL.Rotate(_rotationY, Vector3.UnitY); // 绕Y轴旋转45度
            //GL.Rotate(_rotationX, Vector3.UnitX); // 绕X轴旋转30度

            // 绘制立方体
            DrawCube(100);
            Draw3DAxes(100);

            this.glControl1.SwapBuffers();
            UpdateViewPort();
            UpdateModelMatrix();
            UpdateViewMatrix();
            UpdateProjectionMatrix();

            this.glControl1.Invalidate();
        }




        //初始化GL状态
        private void InitializeGLState()
        {
            GL.ClearColor(Color.Transparent);
            GL.Enable(EnableCap.DepthTest);
        }

        //设置ViewPort
        private void UpdateViewPort()
        {
            GL.Viewport(0, 0, Width, Height);
        }

        //更新投影矩阵
        private void UpdateProjectionMatrix()
        {
            var width = this.glControl1.Width;
            var height = this.glControl1.Height;
            _projectionMatrix = Matrix4.CreateOrthographic(width, height, 0.1f, 1000f);
        }

        //更新视图矩阵
        private void UpdateViewMatrix()
        {
            _viewMatrix = Matrix4.LookAt(
                new Vector3(0, 0, 150), // 摄像机位置
                Vector3.Zero,           // 观察目标
                Vector3.UnitY           // 上方向
            );
        }

        //更新模型矩阵
        private void UpdateModelMatrix()
        {
            _modelMatrix = Matrix4.CreateScale(2f) * Matrix4.CreateRotationX(_rotationX)
                * Matrix4.CreateRotationY(_rotationY);

        }




        void Draw3DAxes(float length)
        {
            GL.LineWidth(3);
            GL.Begin(PrimitiveType.Lines);

            // X轴 (红)
            GL.Color3(1, 0, 0);
            GL.Vertex3(0, 0, 0); GL.Vertex3(length, 0, 0);

            // Y轴 (绿)
            GL.Color3(0, 1, 0);
            GL.Vertex3(0, 0, 0); GL.Vertex3(0, length, 0);

            // Z轴 (蓝)
            GL.Color3(0, 0, 1);
            GL.Vertex3(0, 0, 0); GL.Vertex3(0, 0, length);

            GL.End();
        }

        void DrawCube(float size)
        {
            float half = size / 2;

            GL.Begin(PrimitiveType.Quads);

            // 前面 (Z+ 方向，红色)
            GL.Color3(1.0, 0.0, 0.0);
            GL.Vertex3(-half, -half, half);
            GL.Vertex3(half, -half, half);
            GL.Vertex3(half, half, half);
            GL.Vertex3(-half, half, half);

            // 后面 (Z- 方向，绿色)
            GL.Color3(0.0, 1.0, 0.0);
            GL.Vertex3(-half, -half, -half);
            GL.Vertex3(-half, half, -half);
            GL.Vertex3(half, half, -half);
            GL.Vertex3(half, -half, -half);

            // 左面 (X- 方向，蓝色)
            GL.Color3(0.0, 0.0, 1.0);
            GL.Vertex3(-half, -half, -half);
            GL.Vertex3(-half, -half, half);
            GL.Vertex3(-half, half, half);
            GL.Vertex3(-half, half, -half);

            // 右面 (X+ 方向，黄色)
            GL.Color3(1.0, 1.0, 0.0);
            GL.Vertex3(half, -half, half);
            GL.Vertex3(half, -half, -half);
            GL.Vertex3(half, half, -half);
            GL.Vertex3(half, half, half);

            // 顶面 (Y+ 方向，品红)
            GL.Color3(1.0, 0.0, 1.0);
            GL.Vertex3(-half, half, half);
            GL.Vertex3(half, half, half);
            GL.Vertex3(half, half, -half);
            GL.Vertex3(-half, half, -half);

            // 底面 (Y- 方向，青色)
            GL.Color3(0.0, 1.0, 1.0);
            GL.Vertex3(-half, -half, -half);
            GL.Vertex3(half, -half, -half);
            GL.Vertex3(half, -half, half);
            GL.Vertex3(-half, -half, half);

            GL.End();
        }


    }
}