License, readme and stuff

1 files changed, 106 insertions, 2 deletions

diff --git a/ihl/utils/IHLMathUtils.java b/ihl/utils/IHLMathUtils.java
index cfd6931..1200fd5 100644
--- a/ihl/utils/IHLMathUtils.java
+++ b/ihl/utils/IHLMathUtils.java
@@ -3,8 +3,9 @@ package ihl.utils;
 public class IHLMathUtils 
 {
 	private final static int accuracy_level=65536;
-	private static float[] sin_table=new float[accuracy_level];
-	private static float[] atan_table=new float[accuracy_level];
+	private final static float[] sin_table=new float[accuracy_level];
+	private final static float[] atan_table=new float[accuracy_level];
+	private final static float[] sqrt_table=new float[accuracy_level];
 	private final static float PI=(float)Math.PI;
 	
 	public static float sin(float angle)
@@ -17,6 +18,18 @@ public class IHLMathUtils
 		return sin_table[(int)(angle1*accuracy_level/2/PI)];
 	}
 	
+	public static float sqrt(float value)
+	{
+		float value1 = value;
+		int multiplier = 2;
+		while(value1 >= 1.0f)
+		{
+			multiplier*=multiplier;
+			value1 /=multiplier*multiplier;
+		}
+		return ((multiplier>2)?multiplier:1)*sqrt_table[(int)(value1*accuracy_level)];
+	}
+	
 	public static float atan(float tan_value)
 	{
 		if(tan_value<-32f)
@@ -32,7 +45,54 @@ public class IHLMathUtils
 			return atan_table[(int)((tan_value+32f)*accuracy_level/64f)];
 		}
 	}
+	
+	public static float[] vector_vector_multiply(float[] v1, float[] v2)
+	{
+		float c_x = v1[1]*v2[2] - v2[1]*v1[2];
+		float c_y = v2[0]*v1[2] - v1[0]*v2[2];
+		float c_z = v1[0]*v2[1] - v2[0]*v1[1];
+		return new float[] {c_x,c_y,c_z};
+	}
+
+	public static void normalize_vector(float[] v1)
+	{
+		float d = (float)Math.sqrt(v1[0]*v1[0]+v1[1]*v1[1]+v1[2]*v1[2]);
+		if(d == 0)
+		{ // Nothing can we do. Create new vector towards up direction.
+			v1[0]=0;
+			v1[1]=1;
+			v1[2]=0;
+		}
+		else
+		{
+			v1[0]/=d;
+			v1[1]/=d;
+			v1[2]/=d;
+		}
+	}
 
+	public static void scale_vector_to_value(float[] v1, float v2)
+	{
+		float d = (float)Math.sqrt(v1[0]*v1[0]+v1[1]*v1[1]+v1[2]*v1[2]);
+		if(d == 0)
+		{ // Nothing can we do. Create new vector towards up direction.
+			v1[0]=0;
+			v1[1]=v2;
+			v1[2]=0;
+		}
+		else
+		{
+			v1[0]=v1[0]*v2/d;
+			v1[1]=v1[1]*v2/d;
+			v1[2]=v1[2]*v2/d;
+		}
+	}
+	
+	public static void vector_add(float[] fs, float x, float y, float z) {
+		fs[0]+=x;
+		fs[1]+=y;
+		fs[2]+=z;
+	}
 	
 	static
 	{
@@ -44,5 +104,49 @@ public class IHLMathUtils
 		{
 			atan_table[i]=(float) Math.atan(-32d+64d*i/accuracy_level);
 		}
+		for(int i=0;i<accuracy_level;i++)
+		{
+			sqrt_table[i]=(float) Math.sqrt((double)i/accuracy_level);
+		}
+	}
+
+	public static float[] vector_return_difference(double[] v1, double[] v2) {
+		return new float[] {
+    			(float)(v1[0]-v2[0]),
+    			(float)(v1[1]-v2[1]),
+    			(float)(v1[2]-v2[2])};
+	}
+
+	public static float[] vector_return_difference(float[] v1, double[] v2) {
+		return new float[] {
+    			(float)(v1[0]-v2[0]),
+    			(float)(v1[1]-v2[1]),
+    			(float)(v1[2]-v2[2])};
 	}
+
+	public static float[] vector_return_difference(int[] v1, double[] v2) {
+		return new float[] {
+    			(float)(v1[0]-v2[0]),
+    			(float)(v1[1]-v2[1]),
+    			(float)(v1[2]-v2[2])};
+	}
+
+	public static void multiply_vector_to_value(float[] v1, float v2) {
+		v1[0]*=v2;
+		v1[1]*=v2;
+		v1[2]*=v2;
+	}
+
+	public static void vector_add(double[] v1, float[] v2) {
+		v1[0]+=v2[0];
+		v1[1]+=v2[1];
+		v1[2]+=v2[2];
+	}
+	
+	public static float[] get_triangle_normal(double[][] triangle1) {
+		float[] v1 = vector_return_difference(triangle1[1],triangle1[0]);
+		float[] v2 = vector_return_difference(triangle1[2],triangle1[0]);
+		return vector_vector_multiply(v1,v2);
+	}
+	
 }