Initial source commit

minorGems/graphics/3d/LandscapePrimitive3D.h

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+/*
+ * Modification History
+ *
+ * 2001-January-9		Jason Rohrer
+ * Created.  Copied from LandscapePrimitiveGL, which this class will replace
+ *
+ * 2001-January-15		Jason Rohrer
+ * Fixed a bug in the constructor.
+ *
+ * 2001-January-17		Jason Rohrer
+ * Fliped how x and y in height map correspond to x and z in the terrain.
+ *
+ * 2001-January-19		Jason Rohrer
+ * Changed to support multi-texturing.
+ *
+ * 2001-January-30		Jason Rohrer
+ * Fixed a bug that occurs when the class defaults to no detail texture.
+ *
+ * 2001-March-11   Jason Rohrer
+ * Fixed a bug in the texture map anchor points.  
+ */
+
+#ifndef LANDSCAPE_PRIMITIVE_3D_INCLUDED
+#define LANDSCAPE_PRIMITIVE_3D_INCLUDED 
+ 
+#include "Primitive3D.h"
+ 
+/**
+ * Primitive 3D lanscape object.
+ *
+ * Made from a height map.  Mesh generated spans both x and z between -1 and
+ * 1, and can vary in height (y) from 0 to 1.
+ *
+ * @author Jason Rohrer 
+ */
+class LandscapePrimitive3D : public Primitive3D { 
+	
+	public:
+		
+		
+		/**
+		 * Constructs a LandscapePrimitive with a multi-layer texture.
+		 *
+		 * @param inWide width of mesh in number of vertices.
+		 *   Must be even and at least 2.
+		 * @param inHigh height of mesh in number of vertices.
+		 * @param inHeights array of heights for each vertex, each in 
+		 *   [0,1]. Must be destroyed by caller.  
+		 * @param inTexture the texture to map onto the lanscape.
+		 *   Texture is anchored by its corners to the corners of the 
+		 *   lanscape.  inTexture is destroyed when primitive is destroyed.
+		 * @param inDetailTexture the second layer in the multi-texture.
+		 *   The alpha channel of inDetailTexture will be used as
+		 *   the blending factor to mix the detail with the global texture.
+		 *   Set to NULL to use only a single layer.
+		 * @param inDetailScale the scale factor of the detailed texture.
+		 *   Setting to 1.0 will anchor the detail at the corners of the 
+		 *   mesh (just like inTexture).  Setting to 0.25 will cause
+		 *   the detail texture to cycle 4 times across the surface of the
+		 *   mesh.
+		 */
+		LandscapePrimitive3D( int inWide, int inHigh, double *inHeights,
+			RGBAImage *inTexture, RGBAImage *inDetailTexture = NULL,
+			double inDetailScale = 1.0 );
+		
+	};
+	
+
+
+inline LandscapePrimitive3D::LandscapePrimitive3D( int inWide, 
+	int inHigh, double *inHeights,
+	RGBAImage *inTexture, RGBAImage *inDetailTexture,
+	double inDetailScale ) {
+	
+	// first, set Primitve3D members
+	mHigh = inHigh;
+	mWide = inWide;
+	mNumVertices = mHigh * mWide;
+	
+	if( inDetailTexture == NULL ) {
+		mNumTextures = 1;
+		mTexture = new RGBAImage*[1];
+		mTexture[0] = inTexture;
+		
+		mAnchorX = new double*[1];
+		mAnchorY = new double*[1];
+		mAnchorX[0] = new double[mNumVertices];
+		mAnchorY[0] = new double[mNumVertices];
+		}
+	else {
+		mNumTextures = 2;
+		mTexture = new RGBAImage*[2];
+		mTexture[0] = inTexture;
+		mTexture[1] = inDetailTexture;	
+		
+		mAnchorX = new double*[2];
+		mAnchorY = new double*[2];
+		mAnchorX[0] = new double[mNumVertices];
+		mAnchorY[0] = new double[mNumVertices];
+		mAnchorX[1] = new double[mNumVertices];
+		mAnchorY[1] = new double[mNumVertices];
+		}
+		
+	
+	mVertices = new Vector3D*[mNumVertices];
+	
+	// anchor at texture corners, and step linearly through texture
+	double anchorYStep = 1.0 / ( mHigh - 1 );
+	double anchorXStep = 1.0 / ( mWide - 1 );
+
+	double detailAnchorYStep = 1.0 / ( ( mHigh - 1 ) * inDetailScale );
+	double detailAnchorXStep = 1.0 / ( ( mWide - 1 ) * inDetailScale );
+	
+	for( int y=0; y<mHigh; y++ ) {
+		for( int x=0; x<mWide; x++ ) {
+			int index = y * mWide + x;
+			
+			mAnchorX[0][index] = anchorXStep * x;
+			mAnchorY[0][index] = anchorYStep * y;
+			
+			if( mNumTextures == 2 ) {
+				mAnchorX[1][index] = detailAnchorXStep * x;
+				mAnchorY[1][index] = detailAnchorYStep * y;
+				}
+			
+			// add height for this x and y position
+			mVertices[index] = new Vector3D( 2 * mAnchorX[0][index] - 1, 
+				inHeights[index], -2 * mAnchorY[0][index] + 1  );
+			// note that y coordinates in the 2d height map must be
+			// inverted before they can be used as z coordinates in the mesh
+			}
+		}	
+	
+	generateNormals();
+	}
+
+	
+#endif