//
// This code was created by Jeff Molofee '99
//
// If you've found this code useful, please let me know.
//
// Visit me at www.demonews.com/hosted/nehe
//
//=====================================================================
// Converted to C# and MonoMac by Kenneth J. Pouncey
// http://www.cocoa-mono.org
//
// Copyright (c) 2011 Kenneth J. Pouncey
//
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
// 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Drawing;
using MonoMac.Foundation;
using MonoMac.AppKit;

using MonoMac.OpenGL;

namespace NeHeLesson3
{
	public class Scene : NSObject
	{
		public Scene () : base()
		{
		}
		
		// Resize And Initialize The GL Window 
		//      - See also the method in the MyOpenGLView Constructor about the NSView.NSViewGlobalFrameDidChangeNotification
		public void ResizeGLScene (RectangleF bounds)
		{
			// Reset The Current Viewport
			GL.Viewport (0, 0, (int)bounds.Size.Width, (int)bounds.Size.Height);
			// Select The Projection Matrix
			GL.MatrixMode (MatrixMode.Projection);
			// Reset The Projection Matrix
			GL.LoadIdentity();
			
			// Set perspective here - Calculate The Aspect Ratio Of The Window
			Perspective (45, bounds.Size.Width / bounds.Size.Height, 0.1, 100);
			
			// Select The Modelview Matrix
			GL.MatrixMode (MatrixMode.Modelview);
			// Reset The Modelview Matrix
			GL.LoadIdentity ();
		}
		
		// This creates a symmetric frustum.
		// It converts to 6 params (l, r, b, t, n, f) for glFrustum()
		// from given 4 params (fovy, aspect, near, far)
		public static void Perspective (double fovY, double aspectRatio, double front, double back)
		{
		    const double DEG2RAD = Math.PI / 180;

		    // tangent of half fovY
		    double tangent = Math.Tan (fovY/2 * DEG2RAD);

		    // half height of near plane
		    double height = front * tangent;

		    // half width of near plane
		    double width = height * aspectRatio;
		
		    // params: left, right, bottom, top, near, far
		    GL.Frustum(-width, width, -height, height, front, back);
		}

		// This method renders our scene.
		// The main thing to note is that we've factored the drawing code out of the NSView subclass so that
		// the full-screen and non-fullscreen views share the same states for rendering 
		public bool DrawGLScene ()
		{
			// Clear The Screen And The Depth Buffer
			GL.Clear (ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
			// Reset The Current Modelview Matrix
			GL.LoadIdentity ();
			
			GL.Translate (-1.5f, 0.0f, -6.0f);                        // Move Left 1.5 Units And Into The Screen 6.0
			
			GL.Begin (BeginMode.Triangles);                          // Drawing Using Triangles
			GL.Color3 (1.0, 0.0, 0.0);                               // Set The Color To Red
			GL.Vertex3 ( 0.0f, 1.0f, 0.0f);                          // Top
			GL.Color3 (Color.Green);                                 // Set The Color To Green
			GL.Vertex3 (-1.0f,-1.0f, 0.0f);                          // Bottom Left
			GL.Color3 (NSColor.Blue.UsingColorSpace(NSColorSpace.CalibratedRGB));   // Set The Color To Blue
			GL.Vertex3 ( 1.0f,-1.0f, 0.0f);                          // Bottom Right
			GL.End ();                                               // Finished Drawing The Triangle
			
			GL.Translate (3.0f,0.0f,0.0f);                           // Move Right 3 Units
			
			GL.Color3 (0.5f,0.5f,1.0f);                              // Set The Color To Blue One Time Only
			GL.Begin (BeginMode.Quads);                               // Start Drawing Quads
			        GL.Vertex3 (-1.0f, 1.0f, 0.0f);                  // Left And Up 1 Unit (Top Left)
			        GL.Vertex3 ( 1.0f, 1.0f, 0.0f);                  // Right And Up 1 Unit (Top Right)
			        GL.Vertex3 ( 1.0f,-1.0f, 0.0f);                  // Right And Down One Unit (Bottom Right)
			        GL.Vertex3 (-1.0f,-1.0f, 0.0f);                  // Left And Down One Unit (Bottom Left)
			GL.End ();                                                // Done Drawing A Quad
			
			
			return true;
		}
	}
}

