Initial source commit

gamma256/gameSource/landscape.h

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+
+
+
+#ifndef LANDSCAPE_INCLUDED
+#define LANDSCAPE_INCLUDED
+
+
+
+/**
+ * Gets height samples from an "infinite" fractal landscape.
+ * The landscape can change over time by varying t.
+ *
+ * @param x the x coordinate of the sample.
+ * @param y the y coordinate of the sample.
+ * @param t the time of the sample.
+ * @param baseFrequency the frequency to use for the lowest detail component.
+ * @param inRoughness the roughness of the landscape (how much high frequencies
+ *   are factored in).  Should be in the range [0..1] with 0 making a very
+ *   smooth landscape and 1 making a very rough landscape.
+ * @param detail the detail level.  Larger numbers result in more
+ *   detail.  Defaults to 10.
+ *
+ * @return the height of the landscape at the sample point/time.
+ */
+double landscape( double inX, double inY, double inT,
+                  double inBaseFrequency, double inRoughness,
+                  int inDetail = 10 );
+
+
+
+/**
+ * Samples height of a landscape that varies in roughness over the xy plane.
+ *
+ * @params same as for landscape, except:
+ * @param inRoughnessChangeFrequency the rate at which roughness changes
+ *  over space.  Should, in general, be less than inBaseFrequency.
+ * @param inMinRoughness the minimum roughness value, in the range [0..1].
+ * @param inMaxRoughness the maximum roughness value, in the range [0..1].
+ *
+ * @return same as for landscape.
+ */
+double variableRoughnessLandscape( double inX, double inY, double inT,
+                                   double inBaseFrequency,
+                                   double inRoughnessChangeFrequency,
+                                   double inMinRoughness,
+                                   double inMaxRoughness,
+                                   int inDetail );
+
+
+
+/**
+ * Computes linearly-blended random values in the range [-1..1] from a
+ * 4d parameterized noise space.
+ *
+ * @param x, y, z, t  the 4d floating-point coordinates.
+ *
+ * @return a blended random value in the range [-1..1].
+ */
+double noise4d( double x,
+                double y,
+                double z,
+                double t );
+
+
+
+/**
+ * Computes linearly-blended random values in the range [-1..1] from a
+ * 4d parameterized noise space (keeping one dimension constant).
+ *
+ * Should be faster than noise4D.
+ *
+ * @param x, y, z  the 3d floating-point coordinates.
+ *
+ * @return a blended random value in the range [-1..1].
+ */
+double noise3d( double x,
+                double y,
+                double z );
+
+
+
+/**
+ * Gets a set of randomly-chosen (though stable) points in a given
+ * region of the landscape.
+ *
+ * @param inStartX, inEndX the x region.
+ * @param inStartY, inEndY the y region.
+ * @param inT the time.
+ * @param inSampleStepSize the step size in the sample grid.
+ *   Higher values are faster but result in sparser distributions of points.
+ * @param inDensity the density of points, in the range [0,1].
+ * @param outXCoordinates pointer to where array of x coordinates should
+ *   be returned.  Array must be destroyed by caller.
+ * @param outYCoordinates pointer to where array of x coordinates should
+ *   be returned.  Array must be destroyed by caller.
+ *
+ * @return the number of points (the length of outXCoordinates).
+ */
+int getRandomPoints( double inStartX, double inEndX,
+                     double inStartY, double inEndY,
+                     double inT,
+                     double inSampleStepSize,
+                     double inDensity,
+                     double **outXCoordinates,
+                     double **outYCoordinates );
+                     
+
+
+#endif
+
+
+
+