Opentk/Source/OpenTK/Platform/X11/X11GraphicsMode.cs

#region --- License ---
/* Licensed under the MIT/X11 license.
 * Copyright (c) 2006-2008 the OpenTK Team.
 * This notice may not be removed from any source distribution.
 * See license.txt for licensing detailed licensing details.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;

using OpenTK.Graphics;

namespace OpenTK.Platform.X11
{
    class X11GraphicsMode : IGraphicsMode
    {
        internal X11GraphicsMode()
        {
        }

        public GraphicsMode SelectGraphicsMode(ColorFormat color, int depth, int stencil, int samples, ColorFormat accum,
                                               int buffers, bool stereo)
        {
            List<int> visualAttributes = new List<int>();

            if (color.BitsPerPixel > 0)
            {
                if (!color.IsIndexed)
                    visualAttributes.Add((int)GLXAttribute.RGBA);
                visualAttributes.Add((int)GLXAttribute.RED_SIZE);
                visualAttributes.Add(color.Red);
                visualAttributes.Add((int)GLXAttribute.GREEN_SIZE);
                visualAttributes.Add(color.Green);
                visualAttributes.Add((int)GLXAttribute.BLUE_SIZE);
                visualAttributes.Add(color.Blue);
                visualAttributes.Add((int)GLXAttribute.ALPHA_SIZE);
                visualAttributes.Add(color.Alpha);
            }

            if (depth > 0)
            {
                visualAttributes.Add((int)GLXAttribute.DEPTH_SIZE);
                visualAttributes.Add(depth);
            }

            if (buffers > 1)
                visualAttributes.Add((int)GLXAttribute.DOUBLEBUFFER);

            if (stencil > 1)
            {
                visualAttributes.Add((int)GLXAttribute.STENCIL_SIZE);
                visualAttributes.Add(stencil);
            }

            if (accum.BitsPerPixel > 0)
            {
                visualAttributes.Add((int)GLXAttribute.ACCUM_ALPHA_SIZE);
                visualAttributes.Add(accum.Alpha);
                visualAttributes.Add((int)GLXAttribute.ACCUM_BLUE_SIZE);
                visualAttributes.Add(accum.Blue);
                visualAttributes.Add((int)GLXAttribute.ACCUM_GREEN_SIZE);
                visualAttributes.Add(accum.Green);
                visualAttributes.Add((int)GLXAttribute.ACCUM_RED_SIZE);
                visualAttributes.Add(accum.Red);
            }

            if (stereo)
                visualAttributes.Add((int)GLXAttribute.STEREO);

            visualAttributes.Add((int)0);

            // Prepare Windows.Forms for creating OpenGL drawables.
            // We reuse the display connection.
            // TODO: Multiple screens.
            Type xplatui = Type.GetType("System.Windows.Forms.XplatUIX11, System.Windows.Forms");
            IntPtr display = (IntPtr)xplatui.GetField("DisplayHandle",
                System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic).GetValue(null);
            IntPtr root = (IntPtr)xplatui.GetField("RootWindow",
                System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic).GetValue(null);
            int screen = (int)xplatui.GetField("ScreenNo",
                System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic).GetValue(null);

            Debug.Print("Display: {0}, Screen: {1}, RootWindow: {2}", display, screen, root);

            IntPtr visual = Glx.ChooseVisual(display, screen, visualAttributes.ToArray());

            if (visual == IntPtr.Zero)
                throw new GraphicsContextException("Requested GraphicsMode not available.");

            XVisualInfo info = (XVisualInfo)Marshal.PtrToStructure(visual, typeof(XVisualInfo));

            // See what we *really* got:
            int r, g, b, a;
            Glx.GetConfig(display, ref info, GLXAttribute.ALPHA_SIZE, out a);
            Glx.GetConfig(display, ref info, GLXAttribute.RED_SIZE, out r);
            Glx.GetConfig(display, ref info, GLXAttribute.GREEN_SIZE, out g);
            Glx.GetConfig(display, ref info, GLXAttribute.BLUE_SIZE, out b);
            int ar, ag, ab, aa;
            Glx.GetConfig(display, ref info, GLXAttribute.ACCUM_ALPHA_SIZE, out aa);
            Glx.GetConfig(display, ref info, GLXAttribute.ACCUM_RED_SIZE, out ar);
            Glx.GetConfig(display, ref info, GLXAttribute.ACCUM_GREEN_SIZE, out ag);
            Glx.GetConfig(display, ref info, GLXAttribute.ACCUM_BLUE_SIZE, out ab);
            Glx.GetConfig(display, ref info, GLXAttribute.DEPTH_SIZE, out depth);
            Glx.GetConfig(display, ref info, GLXAttribute.STENCIL_SIZE, out stencil);
            Glx.GetConfig(display, ref info, GLXAttribute.SAMPLES, out samples);
            Glx.GetConfig(display, ref info, GLXAttribute.DOUBLEBUFFER, out buffers);
            ++buffers;  // the above lines returns 0 - false and 1 - true.
            int st;
            Glx.GetConfig(display, ref info, GLXAttribute.STEREO, out st);
            stereo = st != 0;

            GraphicsMode gfx = new GraphicsMode(info.visualid, new ColorFormat(r, g, b, a), depth, stencil, samples,
                                                new ColorFormat(ar, ag, ab, aa), buffers, stereo);

            xplatui.GetField("CustomVisual", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)
                .SetValue(null, visual);
            xplatui.GetField("CustomColormap", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic)
                .SetValue(null, API.CreateColormap(display, root, visual, 0));

            return gfx;
        }
    }
}