c2dmatrix.cpp

游戏开发人工智能技术-AI.Techniques.for.Game.Programming

#include "C2DMatrix.h"

/////////////////////////////////////////////////////////////////////
//
//	Matrix functions
//
/////////////////////////////////////////////////////////////////////
//create an identity matrix
void C2DMatrix::Identity()
{
	m_Matrix._11 = 1.0f; m_Matrix._12 = 0.0f; m_Matrix._13 = 0.0f;

	m_Matrix._21 = 0.0f; m_Matrix._22 = 1.0f; m_Matrix._23 = 0.0f;

	m_Matrix._31 = 0.0f; m_Matrix._32 = 0.0f; m_Matrix._33 = 1.0f;

	}

//create a transformation matrix
void C2DMatrix::Translate(double x, double y)
{
	S2DMatrix mat;
	
	mat._11 = 1.0f; mat._12 = 0.0f; mat._13 = 0.0f;
	
	mat._21 = 0.0f; mat._22 = 1.0f; mat._23 = 0.0f;
	
	mat._31 = x;    mat._32 = y;    mat._33 = 1.0f;
	
	//and multiply
  S2DMatrixMultiply(mat);
}

//create a scale matrix
void C2DMatrix::Scale(double xScale, double yScale)
{
	S2DMatrix mat;
	
	mat._11 = xScale; mat._12 = 0.0f; mat._13 = 0.0f;
	
	mat._21 = 0.0f; mat._22 = yScale; mat._23 = 0.0f;
	
	mat._31 = 0.0f; mat._32 = 0.0f; mat._33 = 1.0f;
	
	//and multiply
  S2DMatrixMultiply(mat);
}


//create a rotation matrix
void C2DMatrix::Rotate(double rot)
{
	S2DMatrix mat;

	double Sin = sin(rot);
	double Cos = cos(rot);
	
	mat._11 = Cos;  mat._12 = Sin; mat._13 = 0.0f;
	
	mat._21 = -Sin; mat._22 = Cos; mat._23 = 0.0f;
	
	mat._31 = 0.0f; mat._32 = 0.0f;mat._33 = 1.0f;
	
	//and multiply
  S2DMatrixMultiply(mat);
}

//multiply two matrices together
void C2DMatrix::S2DMatrixMultiply(S2DMatrix &mIn)
{
	S2DMatrix mat_temp;
	
	//first row
	mat_temp._11 = (m_Matrix._11*mIn._11) + (m_Matrix._12*mIn._21) + (m_Matrix._13*mIn._31);
	mat_temp._12 = (m_Matrix._11*mIn._12) + (m_Matrix._12*mIn._22) + (m_Matrix._13*mIn._32);
	mat_temp._13 = (m_Matrix._11*mIn._13) + (m_Matrix._12*mIn._23) + (m_Matrix._13*mIn._33);

	//second
	mat_temp._21 = (m_Matrix._21*mIn._11) + (m_Matrix._22*mIn._21) + (m_Matrix._23*mIn._31);
	mat_temp._22 = (m_Matrix._21*mIn._12) + (m_Matrix._22*mIn._22) + (m_Matrix._23*mIn._32);
	mat_temp._23 = (m_Matrix._21*mIn._13) + (m_Matrix._22*mIn._23) + (m_Matrix._23*mIn._33);

	//third
	mat_temp._31 = (m_Matrix._31*mIn._11) + (m_Matrix._32*mIn._21) + (m_Matrix._33*mIn._31);
	mat_temp._32 = (m_Matrix._31*mIn._12) + (m_Matrix._32*mIn._22) + (m_Matrix._33*mIn._32);
	mat_temp._33 = (m_Matrix._31*mIn._13) + (m_Matrix._32*mIn._23) + (m_Matrix._33*mIn._33);

	m_Matrix = mat_temp;
}

//applies a 2D transformation matrix to a std::vector of SPoints
void C2DMatrix::TransformSPoints(vector<SPoint> &vPoint)
{
	for (int i=0; i<vPoint.size(); ++i)
	{
		double tempX =(m_Matrix._11*vPoint[i].x) + (m_Matrix._21*vPoint[i].y) + (m_Matrix._31);

		double tempY = (m_Matrix._12*vPoint[i].x) + (m_Matrix._22*vPoint[i].y) + (m_Matrix._32);
	
		vPoint[i].x = tempX;

		vPoint[i].y = tempY;

	}
}