C++ VMatrix::Init方法代码示例

void MatrixBuildOrtho( VMatrix& dst, double left, double top, double right, double bottom, double zNear, double zFar )
{
	// FIXME: This is being used incorrectly! Should read:
	// D3DXMatrixOrthoOffCenterRH( &matrix, left, right, bottom, top, zNear, zFar );
	// Which is certainly why we need these extra -1 scales in y. Bleah

	// NOTE: The camera can be imagined as the following diagram:
	//		/z
	//	   /
	//	  /____ x	Z is going into the screen
	//	  |
	//	  |
	//	  |y
	//
	// (0,0,z) represents the upper-left corner of the screen.
	// Our projection transform needs to transform from this space to a LH coordinate
	// system that looks thusly:
	// 
	//	y|  /z
	//	 | /
	//	 |/____ x	Z is going into the screen
	//
	// Where x,y lies between -1 and 1, and z lies from 0 to 1
	// This is because the viewport transformation from projection space to pixels
	// introduces a -1 scale in the y coordinates
	//		D3DXMatrixOrthoOffCenterRH( &matrix, left, right, top, bottom, zNear, zFar );

	dst.Init(	 2.0f / ( right - left ),						0.0f,						0.0f, ( left + right ) / ( left - right ),
				0.0f,	 2.0f / ( bottom - top ),						0.0f, ( bottom + top ) / ( top - bottom ),
				0.0f,						0.0f,	 1.0f / ( zNear - zFar ),			 zNear / ( zNear - zFar ),
				0.0f,						0.0f,						0.0f,								1.0f );
}

void MatrixBuildPerspectiveX( VMatrix& dst, double flFovX, double flAspect, double flZNear, double flZFar )
{
	float flWidth = 2.0f * flZNear * tanf( flFovX * M_PI / 360.0f );
	float flHeight = flWidth / flAspect;
	dst.Init(   2.0f * flZNear / flWidth,						0.0f,							0.0f,										0.0f,
				0.0f,  2.0f  * flZNear/ flHeight,							0.0f,										0.0f,
				0.0f,						0.0f,  flZFar / ( flZNear - flZFar ),	 flZNear * flZFar / ( flZNear - flZFar ),
				0.0f,						0.0f,						   -1.0f,										0.0f );
}

void CSplinePatch::SetupPatchQuery( float s, float t )
{
	m_is = (int)s;
	m_it = (int)t;

	if( m_is >= m_Width )
	{
		m_is = m_Width - 1;
		m_fs = 1.0f;
	}
	else
	{
		m_fs = s - m_is;
	}

	if( m_it >= m_Height )
	{
		m_it = m_Height - 1;
		m_ft = 1.0f;
	}
	else
	{
		m_ft = t - m_it;
	}

	ComputeIndices( );

	// The patch equation is:
	// px = S * M * Gx * M^T * T^T 
	// py = S * M * Gy * M^T * T^T 
	// pz = S * M * Gz * M^T * T^T 
	// where S = [s^3 s^2 s 1], T = [t^3 t^2 t 1]
	// M is the patch type matrix, in my case I'm using a catmull-rom
	// G is the array of control points. rows have constant t

	// We're gonna cache off S * M and M^T * T^T...
	Vector4D svec, tvec;
 	float fs2 = m_fs * m_fs;
	svec[0] = fs2 * m_fs; svec[1] = fs2; svec[2] = m_fs; svec[3] = 1.0f;
	float ft2 = m_ft * m_ft;
	tvec[0] = ft2 * m_ft; tvec[1] = ft2; tvec[2] = m_ft; tvec[3] = 1.0f;

	// This sets up the catmull rom matrix based on the blend factor!!
	// we can go from linear to curvy!
	s_CatmullRom.Init(  -0.5 * m_LinearFactor,  1.5 * m_LinearFactor, -1.5 * m_LinearFactor,  0.5 * m_LinearFactor,
						       m_LinearFactor, -2.5 * m_LinearFactor,    2 * m_LinearFactor, -0.5 * m_LinearFactor,
						-0.5 * m_LinearFactor,   -1 + m_LinearFactor,    1 - 0.5 * m_LinearFactor,    0,
											0,					   1,					  0,    0 );
	Vector4DMultiplyTranspose( s_CatmullRom, svec, m_SVec );
	Vector4DMultiplyTranspose( s_CatmullRom, tvec, m_TVec );
}

void MatrixBuildPerspectiveOffCenterX( VMatrix& dst, double flFovX, double flAspect, double flZNear, double flZFar, double bottom, double top, double left, double right )
{
	float flWidth = 2.0f * flZNear * tanf( flFovX * M_PI / 360.0f );
	float flHeight = flWidth / flAspect;

	// bottom, top, left, right are 0..1 so convert to -<val>/2..<val>/2
	float flLeft   = -(flWidth/2.0f)  * (1.0f - left)   + left   * (flWidth/2.0f);
	float flRight  = -(flWidth/2.0f)  * (1.0f - right)  + right  * (flWidth/2.0f);
	float flBottom = -(flHeight/2.0f) * (1.0f - bottom) + bottom * (flHeight/2.0f);
	float flTop    = -(flHeight/2.0f) * (1.0f - top)    + top    * (flHeight/2.0f);

	dst.Init(   (2.0f * flZNear) / (flRight-flLeft),                           0.0f, (flLeft+flRight)/(flRight-flLeft),                            0.0f,
				0.0f,  2.0f*flZNear/(flTop-flBottom), (flTop+flBottom)/(flTop-flBottom),                            0.0f,
				0.0f,                           0.0f,           flZFar/(flZNear-flZFar),  flZNear*flZFar/(flZNear-flZFar),
				0.0f,                           0.0f,                             -1.0f,                            0.0f );
}

void VMatrix::MatrixMul( const VMatrix &vm, VMatrix &out ) const
{
	out.Init(
		m[0][0]*vm.m[0][0] + m[0][1]*vm.m[1][0] + m[0][2]*vm.m[2][0] + m[0][3]*vm.m[3][0],
		m[0][0]*vm.m[0][1] + m[0][1]*vm.m[1][1] + m[0][2]*vm.m[2][1] + m[0][3]*vm.m[3][1],
		m[0][0]*vm.m[0][2] + m[0][1]*vm.m[1][2] + m[0][2]*vm.m[2][2] + m[0][3]*vm.m[3][2],
		m[0][0]*vm.m[0][3] + m[0][1]*vm.m[1][3] + m[0][2]*vm.m[2][3] + m[0][3]*vm.m[3][3],

		m[1][0]*vm.m[0][0] + m[1][1]*vm.m[1][0] + m[1][2]*vm.m[2][0] + m[1][3]*vm.m[3][0],
		m[1][0]*vm.m[0][1] + m[1][1]*vm.m[1][1] + m[1][2]*vm.m[2][1] + m[1][3]*vm.m[3][1],
		m[1][0]*vm.m[0][2] + m[1][1]*vm.m[1][2] + m[1][2]*vm.m[2][2] + m[1][3]*vm.m[3][2],
		m[1][0]*vm.m[0][3] + m[1][1]*vm.m[1][3] + m[1][2]*vm.m[2][3] + m[1][3]*vm.m[3][3],

		m[2][0]*vm.m[0][0] + m[2][1]*vm.m[1][0] + m[2][2]*vm.m[2][0] + m[2][3]*vm.m[3][0],
		m[2][0]*vm.m[0][1] + m[2][1]*vm.m[1][1] + m[2][2]*vm.m[2][1] + m[2][3]*vm.m[3][1],
		m[2][0]*vm.m[0][2] + m[2][1]*vm.m[1][2] + m[2][2]*vm.m[2][2] + m[2][3]*vm.m[3][2],
		m[2][0]*vm.m[0][3] + m[2][1]*vm.m[1][3] + m[2][2]*vm.m[2][3] + m[2][3]*vm.m[3][3],

		m[3][0]*vm.m[0][0] + m[3][1]*vm.m[1][0] + m[3][2]*vm.m[2][0] + m[3][3]*vm.m[3][0],
		m[3][0]*vm.m[0][1] + m[3][1]*vm.m[1][1] + m[3][2]*vm.m[2][1] + m[3][3]*vm.m[3][1],
		m[3][0]*vm.m[0][2] + m[3][1]*vm.m[1][2] + m[3][2]*vm.m[2][2] + m[3][3]*vm.m[3][2],
		m[3][0]*vm.m[0][3] + m[3][1]*vm.m[1][3] + m[3][2]*vm.m[2][3] + m[3][3]*vm.m[3][3]
		);
}