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Editor/Util/DynamicArray2D.cpp

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+// DynamicArray2D.cpp: Implementation of the class CDynamicArray.
+//
+//////////////////////////////////////////////////////////////////////
+
+#include "stdafx.h"
+#include "DynamicArray2D.h"
+
+//////////////////////////////////////////////////////////////////////
+// Construction / destruction
+//////////////////////////////////////////////////////////////////////
+
+CDynamicArray2D::CDynamicArray2D(unsigned int iDimension1, unsigned int iDimension2)
+{
+	////////////////////////////////////////////////////////////////////////
+	// Declare a 2D array on the free store
+	////////////////////////////////////////////////////////////////////////
+
+	unsigned int i;
+
+	// Save the position of the array dimensions
+	m_Dimension1 = iDimension1;
+	m_Dimension2 = iDimension2;
+
+	// First dimension
+	m_Array = new float * [m_Dimension1];
+	VERIFY(m_Array);
+	
+	// Second dimension
+	for (i=0; i<m_Dimension1; ++i)
+	{
+		m_Array[i] = new float[m_Dimension2];
+				
+		// Init all fields with 0
+		memset(&m_Array[i][0], 0, m_Dimension2 * sizeof(float));
+	}
+}
+
+CDynamicArray2D::~CDynamicArray2D()
+{
+	////////////////////////////////////////////////////////////////////////
+	// Remove the 2D array and all its sub arrays from the free store
+	////////////////////////////////////////////////////////////////////////
+
+	unsigned int i;
+
+	for (i=0; i<m_Dimension1; ++i)   
+		delete [] m_Array[i];
+		
+	delete [] m_Array;
+	m_Array = 0;
+}
+
+void CDynamicArray2D::ScaleImage(CDynamicArray2D *pDestination)
+{
+	////////////////////////////////////////////////////////////////////////
+	// Scale an image stored (in an array class) to a new size
+	////////////////////////////////////////////////////////////////////////
+
+	unsigned int i, j, iOldWidth;
+	int iXSrcFl, iXSrcCe, iYSrcFl, iYSrcCe;
+	float fXSrc, fYSrc;
+	float fHeight[4];
+	float fHeightWeight[4];
+	float fHeightBottom;
+	float fHeightTop;
+
+	assert(pDestination);
+	assert(pDestination->m_Dimension1 > 1);
+
+	// Width has to be zero based, not a count
+	iOldWidth = m_Dimension1 - 1;
+
+	// Loop trough each field of the new image and interpolate the value
+	// from the source heightmap
+	for (i=0; i<pDestination->m_Dimension1; i++)
+	{
+		// Calculate the average source array position
+		fXSrc = i / (float) pDestination->m_Dimension1 * iOldWidth;
+		assert(fXSrc >= 0.0f && fXSrc <= iOldWidth);
+
+		// Precalculate floor and ceiling values. Use fast asm integer floor and
+		// fast asm float / integer conversion
+		iXSrcFl = ifloor(fXSrc);
+		iXSrcCe = FloatToIntRet((float) ceil(fXSrc));
+		
+		// Distribution between left and right height values
+		fHeightWeight[0] = (float) iXSrcCe - fXSrc;
+		fHeightWeight[1] = fXSrc - (float) iXSrcFl;
+
+		// Avoid error when floor() and ceil() return the same value
+		if (fHeightWeight[0] == 0.0f && fHeightWeight[1] == 0.0f)
+		{
+			fHeightWeight[0] = 0.5f;
+			fHeightWeight[1] = 0.5f;
+		}
+
+		for (j=0; j<pDestination->m_Dimension1; j++)
+		{
+			// Calculate the average source array position
+			fYSrc = j / (float) pDestination->m_Dimension1 * iOldWidth;
+			assert(fYSrc >= 0.0f && fYSrc <= iOldWidth);
+
+			// Precalculate floor and ceiling values. Use fast asm integer floor and
+			// fast asm float / integer conversion
+			iYSrcFl = ifloor(fYSrc);
+			iYSrcCe = FloatToIntRet((float) ceil(fYSrc));
+			
+			// Get the four nearest height values
+			fHeight[0] = m_Array[iXSrcFl][iYSrcFl];
+			fHeight[1] = m_Array[iXSrcCe][iYSrcFl];
+			fHeight[2] = m_Array[iXSrcFl][iYSrcCe];
+			fHeight[3] = m_Array[iXSrcCe][iYSrcCe];
+
+			// Calculate how much weight each height value has
+
+			// Distribution between top and bottom height values
+			fHeightWeight[2] = (float) iYSrcCe - fYSrc;
+			fHeightWeight[3] = fYSrc - (float) iYSrcFl;
+
+			// Avoid error when floor() and ceil() return the same value
+			if (fHeightWeight[2] == 0.0f && fHeightWeight[3] == 0.0f)
+			{
+				fHeightWeight[2] = 0.5f;
+				fHeightWeight[3] = 0.5f;
+			}
+
+			// Interpolate between the four nearest height values
+	
+			// Get the height for the given X position trough interpolation between
+			// the left and the right height
+			fHeightBottom = (fHeight[0] * fHeightWeight[0] + fHeight[1] * fHeightWeight[1]);
+			fHeightTop    = (fHeight[2] * fHeightWeight[0] + fHeight[3] * fHeightWeight[1]);
+
+			// Set the new value in the destination heightmap
+			pDestination->m_Array[i][j] = fHeightBottom * fHeightWeight[2] + fHeightTop * fHeightWeight[3];
+		}
+	}
+}