Add a palette class and use it for rendering

src/main/java/dan200/computercraft/shared/util/Palette.java

@@ -0,0 +1,79 @@
+package dan200.computercraft.shared.util;
+
+public class Palette
+{
+    private static class PaletteColour
+    {
+        private float m_r, m_g, m_b;
+
+        public PaletteColour(float r, float g, float b)
+        {
+            m_r = r;
+            m_g = g;
+            m_b = b;
+        }
+
+        @Override
+        public boolean equals(Object o)
+        {
+            if(this == o) return true;
+            if(o == null || getClass() != o.getClass()) return false;
+
+            PaletteColour that = (PaletteColour) o;
+
+            if(Float.compare( that.m_r, m_r ) != 0) return false;
+            if(Float.compare( that.m_g, m_g ) != 0) return false;
+            return Float.compare( that.m_b, m_b ) == 0;
+        }
+
+        @Override
+        public int hashCode()
+        {
+            int result = (m_r != +0.0f ? Float.floatToIntBits( m_r ) : 0);
+            result = 31 * result + (m_g != +0.0f ? Float.floatToIntBits( m_g ) : 0);
+            result = 31 * result + (m_b != +0.0f ? Float.floatToIntBits( m_b ) : 0);
+            return result;
+        }
+    }
+
+    private static final int PALETTE_SIZE = 16;
+    private final PaletteColour[] colours = new PaletteColour[ PALETTE_SIZE ];
+
+    public Palette()
+    {
+        // Get the default palette
+        resetColours();
+    }
+
+    public void setColour(int i, float r, float g, float b)
+    {
+        if( i >= 0 && i < colours.length )
+        {
+            colours[ i ] = new PaletteColour( r, g, b );
+        }
+    }
+
+    public void setColour(int i, Colour colour)
+    {
+        setColour( i, colour.getR(), colour.getG(), colour.getB() );
+    }
+
+    public float[] getColour( int i )
+    {
+        if( i >= 0 && i < colours.length )
+        {
+            PaletteColour c = colours[ i ];
+            return new float[] { c.m_r, c.m_g, c.m_b };
+        }
+        return null;
+    }
+
+    public void resetColours()
+    {
+        for(int i = 0; i < Colour.values().length; ++i)
+        {
+            Colour c = Colour.values()[ i ];
+            colours[i] = new PaletteColour( c.getR(), c.getG(), c.getB() );
+        }
+    }
+}