//-----------------------------------------------------------------------------
// File: D3DUtil.cs
//
// Desc: Shortcut functions for using DX objects
//
// Copyright (c) Microsoft Corporation. All rights reserved
//-----------------------------------------------------------------------------
using System;
using System.Windows.Forms;
using System.Drawing;
using Microsoft.DirectX;
using Microsoft.DirectX.Direct3D;
using Direct3D = Microsoft.DirectX.Direct3D;




/// <summary>
/// Various helper functions for graphics samples
/// </summary>
public class GraphicsUtility
{
    /// <summary>
    /// Private Constructor 
    /// </summary>
    private GraphicsUtility() 
    { 
    }



    /// <summary>
    /// Initializes a Material structure, setting the diffuse and ambient
    /// colors. It does not set emissive or specular colors.
    /// </summary>
    /// <param name="c">The ambient and diffuse color</param>
    /// <returns>A defined material</returns>
	public static Direct3D.Material InitMaterial(System.Drawing.Color c)
	{
		Material mtrl = new Material();
		mtrl.Ambient = mtrl.Diffuse = c;
		return mtrl;
	}




    /// <summary>
    /// Initializes a light, setting the light position. The
    /// diffuse color is set to white; specular and ambient are left as black.
    /// </summary>
    /// <param name="light">Which light to initialize</param>
    /// <param name="ltType">The type</param>
	public static void InitLight(Light light, LightType ltType, float x, float y, float z)
	{
		light.Type        = ltType;
		light.Diffuse = System.Drawing.Color.White;
		light.Position = new Vector3(x,y,z);
		light.Direction = Vector3.Normalize(light.Position);
		light.Range        = 1000.0f;
	}




    /// <summary>
    /// Helper function to create a texture. It checks the root path first,
    /// then tries the DXSDK media path (as specified in the system registry).
    /// </summary>
	public static Texture CreateTexture(Device device, string textureFilename, Format format)
	{
		// Get the path to the texture
		string path = DXUtil.FindMediaFile(null, textureFilename);

		// Create the texture using D3DX
		return TextureLoader.FromFile(device, path, D3DX.Default, D3DX.Default, D3DX.Default, 0, format, 
			Pool.Managed, Filter.Triangle|Filter.Mirror, 
			Filter.Triangle|Filter.Mirror, 0);
	}




    /// <summary>
    /// Helper function to create a texture. It checks the root path first,
    /// then tries the DXSDK media path (as specified in the system registry).
    /// </summary>
    public static Texture CreateTexture(Device device, string textureFilename)
	{
		return GraphicsUtility.CreateTexture(device, textureFilename, Format.Unknown);
	}





    /// <summary>
    /// Returns a view matrix for rendering to a face of a cubemap.
    /// </summary>
	public static Matrix GetCubeMapViewMatrix(CubeMapFace face)
	{
		Vector3 vEyePt = new Vector3(0.0f, 0.0f, 0.0f);
		Vector3 vLookDir = new Vector3();
		Vector3 vUpDir = new Vector3();

		switch (face)
		{
			case CubeMapFace.PositiveX:
				vLookDir = new Vector3(1.0f, 0.0f, 0.0f);
				vUpDir   = new Vector3(0.0f, 1.0f, 0.0f);
				break;
			case CubeMapFace.NegativeX:
				vLookDir = new Vector3(-1.0f, 0.0f, 0.0f);
				vUpDir   = new Vector3(0.0f, 1.0f, 0.0f);
				break;
			case CubeMapFace.PositiveY:
				vLookDir = new Vector3(0.0f, 1.0f, 0.0f);
				vUpDir   = new Vector3(0.0f, 0.0f,-1.0f);
				break;
			case CubeMapFace.NegativeY:
				vLookDir = new Vector3(0.0f,-1.0f, 0.0f);
				vUpDir   = new Vector3(0.0f, 0.0f, 1.0f);
				break;
			case CubeMapFace.PositiveZ:
				vLookDir = new Vector3(0.0f, 0.0f, 1.0f);
				vUpDir   = new Vector3(0.0f, 1.0f, 0.0f);
				break;
			case CubeMapFace.NegativeZ:
				vLookDir = new Vector3(0.0f, 0.0f,-1.0f);
				vUpDir   = new Vector3(0.0f, 1.0f, 0.0f);
				break;
		}

		// Set the view transform for this cubemap surface
		Matrix matView = Matrix.LookAtLH(vEyePt, vLookDir, vUpDir);
		return matView;
	}




    /// <summary>
    /// Returns a quaternion for the rotation implied by the window's cursor position
    /// </summary>
	public static Quaternion GetRotationFromCursor(System.Windows.Forms.Form control, float fTrackBallRadius)
	{
		System.Drawing.Point pt = System.Windows.Forms.Cursor.Position;
		System.Drawing.Rectangle rc = control.ClientRectangle;
		pt = control.PointToClient(pt);
		float xpos = (((2.0f * pt.X) / (rc.Right-rc.Left)) - 1);
		float ypos = (((2.0f * pt.Y) / (rc.Bottom-rc.Top)) - 1);
		float sz;

		if (xpos == 0.0f && ypos == 0.0f)
			return new Quaternion(0.0f, 0.0f, 0.0f, 1.0f);

		float d2 = (float)Math.Sqrt(xpos*xpos + ypos*ypos);

		if (d2 < fTrackBallRadius * 0.70710678118654752440) // Inside sphere
			sz = (float)Math.Sqrt(fTrackBallRadius*fTrackBallRadius - d2*d2);
		else                                                 // On hyperbola
			sz = (fTrackBallRadius*fTrackBallRadius) / (2.0f*d2);

		// Get two points on trackball's sphere
		Vector3 p1 = new Vector3(xpos, ypos, sz);
		Vector3 p2 = new Vector3(0.0f, 0.0f, fTrackBallRadius);

		// Get axis of rotation, which is cross product of p1 and p2
		Vector3 axis = Vector3.Cross(p1,p2);

		// Calculate angle for the rotation about that axis
		float t = Vector3.Length(Vector3.Subtract(p2,p1)) / (2.0f*fTrackBallRadius);
		if (t > +1.0f) t = +1.0f;
		if (t < -1.0f) t = -1.0f;
		float fAngle = (float)(2.0f * Math.Asin(t));

		// Convert axis to quaternion
		return Quaternion.RotationAxis(axis, fAngle);
	}




    /// <summary>
    /// Returns a quaternion for the rotation implied by the window's cursor position
    /// </summary>
	public static Quaternion GetRotationFromCursor(System.Windows.Forms.Form control)
	{
		return GetRotationFromCursor(control, 1.0f);
	}




    /// <summary>
    /// Axis to axis quaternion double angle (no normalization)
    /// Takes two points on unit sphere an angle THETA apart, returns
    /// quaternion that represents a rotation around cross product by 2*THETA.
    /// </summary>
	public static Quaternion D3DXQuaternionUnitAxisToUnitAxis2(Vector3 fromVector, Vector3 toVector)
	{
		Vector3 axis = Vector3.Cross(fromVector, toVector);    // proportional to sin(theta)
		return new Quaternion(axis.X, axis.Y, axis.Z, Vector3.Dot(fromVector, toVector));
	}




    /// <summary>
    /// Axis to axis quaternion 
    /// Takes two points on unit sphere an angle THETA apart, returns
    /// quaternion that represents a rotation around cross product by theta.
    /// </summary>
	public static Quaternion D3DXQuaternionAxisToAxis(Vector3 fromVector, Vector3 toVector)
	{
		Vector3 vA = Vector3.Normalize(fromVector), vB = Vector3.Normalize(toVector);
		Vector3 vHalf = Vector3.Add(vA,vB);
		vHalf = Vector3.Normalize(vHalf);
		return GraphicsUtility.D3DXQuaternionUnitAxisToUnitAxis2(vA, vHalf);
	}



    
    /// <summary>
    /// Gets the number of ColorChanelBits from a format
    /// </summary>
	static public int GetColorChannelBits(Format format)
	{
		switch (format)
		{
			case Format.R8G8B8:
				return 8;
			case Format.A8R8G8B8:
				return 8;
			case Format.X8R8G8B8:
				return 8;
			case Format.R5G6B5:
				return 5;
			case Format.X1R5G5B5:
				return 5;
			case Format.A1R5G5B5:
				return 5;
			case Format.A4R4G4B4:
				return 4;
			case Format.R3G3B2:
				return 2;
			case Format.A8R3G3B2:
				return 2;
			case Format.X4R4G4B4:
				return 4;
			case Format.A2B10G10R10:
				return 10;
			case Format.A2R10G10B10:
				return 10;
			default:
				return 0;
		}
	}




    /// <summary>
    /// Gets the number of alpha channel bits 
    /// </summary>
	static public int GetAlphaChannelBits(Format format)
	{
		switch (format)
		{
			case Format.R8G8B8:
				return 0;
			case Format.A8R8G8B8:
				return 8;
			case Format.X8R8G8B8:
				return 0;
			case Format.R5G6B5:
				return 0;
			case Format.X1R5G5B5:
				return 0;
			case Format.A1R5G5B5:
				return 1;
			case Format.A4R4G4B4:
				return 4;
			case Format.R3G3B2:
				return 0;
			case Format.A8R3G3B2:
				return 8;
			case Format.X4R4G4B4:
				return 0;
			case Format.A2B10G10R10:
				return 2;
			case Format.A2R10G10B10:
				return 2;
			default:
				return 0;
		}
	}



    
    /// <summary>
    /// Gets the number of depth bits
    /// </summary>
	static public int GetDepthBits(DepthFormat format)
	{
		switch (format)
		{
			case DepthFormat.D16:
				return 16;
			case DepthFormat.D15S1:
				return 15;
			case DepthFormat.D24X8:
				return 24;
			case DepthFormat.D24S8:
				return 24;
			case DepthFormat.D24X4S4:
				return 24;
			case DepthFormat.D32:
				return 32;
			default:
				return 0;
		}
	}




    /// <summary>
    /// Gets the number of stencil bits
    /// </summary>
	static public int GetStencilBits(DepthFormat format)
	{
		switch (format)
		{
			case DepthFormat.D16:
				return 0;
			case DepthFormat.D15S1:
				return 1;
			case DepthFormat.D24X8:
				return 0;
			case DepthFormat.D24S8:
				return 8;
			case DepthFormat.D24X4S4:
				return 4;
			case DepthFormat.D32:
				return 0;
			default:
				return 0;
		}
	}




    /// <summary>
    /// Assembles and creates a file-based vertex shader
    /// </summary>
	public static VertexShader CreateVertexShader(Device device, string filename)
	{
		GraphicsStream code = null;
		string path = null;
	
		// Get the path to the vertex shader file
		path = DXUtil.FindMediaFile(null, filename);

		// Assemble the vertex shader file
		code = ShaderLoader.FromFile(path, null, 0);

		// Create the vertex shader
		return new VertexShader(device, code);
	}

}




/// <summary>
/// An arc ball class
/// </summary>
public class GraphicsArcBall
{
	private int internalWidth;   // ArcBall's window width
	private int internalHeight;  // ArcBall's window height
	private float internalradius;  // ArcBall's radius in screen coords
	private float internalradiusTranslation; // ArcBall's radius for translating the target

	private Quaternion internaldownQuat;               // Quaternion before button down
	private Quaternion internalnowQuat;                // Composite quaternion for current drag
	private Matrix internalrotationMatrix;         // Matrix for arcball's orientation
	private Matrix internalrotationDelta;    // Matrix for arcball's orientation
	private Matrix internaltranslationMatrix;      // Matrix for arcball's position
	private Matrix internaltranslationDelta; // Matrix for arcball's position
	private bool internaldragging;               // Whether user is dragging arcball
	private bool internaluseRightHanded;        // Whether to use RH coordinate system
	private int saveMouseX = 0;      // Saved mouse position
	private int saveMouseY = 0;
	private Vector3 internalvectorDown;         // Button down vector
	System.Windows.Forms.Control parent; // parent




    /// <summary>
    /// Constructor
    /// </summary>
	public GraphicsArcBall(System.Windows.Forms.Control p)
	{
		internaldownQuat = Quaternion.Identity;
		internalnowQuat = Quaternion.Identity;
		internalrotationMatrix = Matrix.Identity;
		internalrotationDelta = Matrix.Identity;
		internaltranslationMatrix = Matrix.Identity;
		internaltranslationDelta  = Matrix.Identity;
		internaldragging = false;
		internalradiusTranslation = 1.0f;
		internaluseRightHanded = false;

		parent = p;
		// Hook the events 
		p.MouseDown += new MouseEventHandler(this.OnContainerMouseDown);
		p.MouseUp += new MouseEventHandler(this.OnContainerMouseUp);
		p.MouseMove += new MouseEventHandler(this.OnContainerMouseMove);
	}




    /// <summary>
    /// Set the window dimensions
    /// </summary>
	public void SetWindow(int width, int height, float radius)
	{
		// Set ArcBall info
		internalWidth  = width;
		internalHeight = height;
		internalradius = radius;
	}




    /// <summary>
    /// Screen coords to a vector
    /// </summary>
	private Vector3 ScreenToVector(int xpos, int ypos)
	{
		// Scale to screen
		float x   = -(xpos - internalWidth/2)  / (internalradius*internalWidth/2);
		float y   =  (ypos - internalHeight/2) / (internalradius*internalHeight/2);

		if (internaluseRightHanded)
		{
			x = -x;
			y = -y;
		}

		float z   = 0.0f;
		float mag = x*x + y*y;

		if (mag > 1.0f)
		{
			float scale = 1.0f/(float)Math.Sqrt(mag);
			x *= scale;
			y *= scale;
		}
		else
			z = (float)Math.Sqrt(1.0f - mag);

		// Return vector
		return new Vector3(x, y, z);
	}




    /// <summary>
    /// Fired when the containers mouse button is down
    /// </summary>
	private void OnContainerMouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
	{
		// Store off the position of the cursor when the button is pressed
		saveMouseX = e.X;
		saveMouseY = e.Y;

		if (e.Button == System.Windows.Forms.MouseButtons.Left)
		{
			// Start drag mode
			internaldragging = true;
			internalvectorDown = ScreenToVector(e.X, e.Y);
			internaldownQuat = internalnowQuat;
		}
	}




    /// <summary>
    /// Fired when the containers mouse button has been released
    /// </summary>
	private void OnContainerMouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
	{
		if (e.Button == System.Windows.Forms.MouseButtons.Left)
		{