JuicyGraphics/src/JuicyGraphics/ui/canvas.cs

using System;
using System.Windows.Forms;
using System.Windows;
using SharpGL.Enumerations;
using SharpGL.Version;
using SharpGL;
using System.ComponentModel;
using Graphics;
using Graphics.Objects;
using System.Numerics;
using System.Drawing;

namespace JuicyGraphics {
    class canvas : Control, ISupportInitialize {

        OpenGL GL = new OpenGL();
        renderCam rc;

        public canvas() {
            SetStyle(ControlStyles.AllPaintingInWmPaint, true);
            SetStyle(ControlStyles.UserPaint, true);
            InitializeOpenGL();
            rc = new renderCam(GL, this);
        }

        void InitializeOpenGL() {
            GL.Create(OpenGLVersion.OpenGL4_3, RenderContextType.NativeWindow, Width, Height, 32, this.Handle);
            GL.ShadeModel(OpenGL.GL_SMOOTH);
            GL.ClearDepth(1.0f);
            GL.Enable(OpenGL.GL_DEPTH_TEST);
            GL.DepthFunc(OpenGL.GL_LEQUAL);
            GL.Hint(OpenGL.GL_PERSPECTIVE_CORRECTION_HINT, OpenGL.GL_NICEST);
            GL.Viewport(0, 0, Width, Height);
        }

        bool renderingForDesigner() {
            if (this == null)
                return false;
            if (LicenseManager.UsageMode == LicenseUsageMode.Designtime)
                return true;
            Control p = this.Parent;
            while (p != null) {
                if (p.GetType().FullName.Contains(".DesignerFrame"))
                    return true;
                p = p.Parent;
            }
            return false;
        }

        protected override void OnPaintBackground(PaintEventArgs e) {
            if (renderingForDesigner()) { base.OnPaintBackground(e); }
            return;
        }

        protected override void OnPaint(PaintEventArgs e) {
            if (renderingForDesigner()) {
                SetStyle(ControlStyles.AllPaintingInWmPaint, true);
                SetStyle(ControlStyles.UserPaint, true);
                InitializeOpenGL();
            }
            GL.LoadIdentity();
            GL.Ortho(-(Width / 2160.0), Width / 2160.0,
                -(Height / 2160.0), Height / 2160.0,
                -1, 1);
            if (rc != null)
                rc.attacheMatrix();
            GL.MakeCurrent();
            GL.ClearColor(0.3f, 0.35f, 0.7f, 1f);
            GL.Clear(OpenGL.GL_COLOR_BUFFER_BIT | OpenGL.GL_DEPTH_BUFFER_BIT);

            GL.Begin(BeginMode.Triangles);
            GL.Color(0.9, 0.83, 0.1);
            GL.Vertex(1.0, 1.0);
            GL.Vertex(-1.0, -1.0);
            GL.Vertex(-1.0, 1.0);

            GL.Color(0, 0, 0);
            line testLine = new line(new Vector2(-0.4f, 0.4f), new Vector2(0.4f, -0.4f));
            testLine.render(rc);

            GL.End();
            GL.Flush();

            var handleDeviceContext = e.Graphics.GetHdc();
            GL.Blit(handleDeviceContext);
            e.Graphics.ReleaseHdc(handleDeviceContext);
        }

        protected override void OnSizeChanged(EventArgs e) {
            if (GL.RenderContextProvider == null)
                return;
            GL.SetDimensions(Width, Height);
            GL.Viewport(0, 0, Width, Height);
            Invalidate();
        }

        enum mouseInteractionMode { none, left, middle, right };
        mouseInteractionMode pressedMouseButton = mouseInteractionMode.none;
        Point prevMousePosition = Point.Empty;

        protected override void OnMouseDown(MouseEventArgs e) {
            switch (e.Button) {
                case MouseButtons.Left:
                    pressedMouseButton = mouseInteractionMode.left;
                    break;
                case MouseButtons.Middle:
                    pressedMouseButton = mouseInteractionMode.middle;
                    break;
                case MouseButtons.Right:
                    pressedMouseButton = mouseInteractionMode.right;
                    break;
            }
            prevMousePosition = MousePosition;
            this.Focus();
        }

        protected override void OnMouseMove(MouseEventArgs e) {
            switch (pressedMouseButton) {
                case mouseInteractionMode.left:
                    break;
                case mouseInteractionMode.middle:
                    rc.translation += new Vector2(MousePosition.X - prevMousePosition.X,
                        prevMousePosition.Y - MousePosition.Y) / 1080.0f;
                    Invalidate();
                    break;
                case mouseInteractionMode.right:
                    break;
            }
            prevMousePosition = MousePosition;
        }

        protected override void OnMouseUp(MouseEventArgs e) {
            switch (e.Button) {
                case MouseButtons.Left:
                    if (pressedMouseButton == mouseInteractionMode.left)
                        pressedMouseButton = mouseInteractionMode.none;
                    break;
                case MouseButtons.Middle:
                    if (pressedMouseButton == mouseInteractionMode.middle)
                        pressedMouseButton = mouseInteractionMode.none;
                    break;
                case MouseButtons.Right:
                    if (pressedMouseButton == mouseInteractionMode.right)
                        pressedMouseButton = mouseInteractionMode.none;
                    break;
            }
        }

        Control prevFocused = null;

        protected override void OnMouseEnter(EventArgs e) {
            prevFocused = Form.ActiveForm.ActiveControl;
            this.Focus();
        }

        protected override void OnMouseLeave(EventArgs e) {
            prevFocused.Focus();
        }

        protected override void OnMouseWheel(MouseEventArgs e) {
            Form.ActiveForm.Text = e.Delta.ToString();
            rc.scale *= Math.Pow(1.0008, e.Delta);
            Invalidate();
        }

        public void BeginInit() { }

        public void EndInit() {
            InitializeOpenGL();
            OnSizeChanged(null);
        }
    }
}