descr

Author: adammaj1

README.md

@@ -1,5 +1,5 @@
 [Procedural texture](https://en.wikipedia.org/wiki/Procedural_texture) 
-* 2D [color gradient](https://en.wikipedia.org/wiki/Color_gradient)
+* 2D [color gradient](https://en.wikipedia.org/wiki/Color_gradient). For 1D color gradient see [here](https://gitlab.com/adammajewski/color_gradient)
 * [defined by a function whose value is computed rather than looked up](http://math.hws.edu/graphicsbook/c7/s3.html)
 
 
@@ -64,7 +64,6 @@
 ![](./images/cabsi.png "cabs inverted") 
 
 ### carg(z)
-![](./images/carg.png "carg") 
 ![](./images/cargm.png "carg modified") 
 ![](./images/cturn.png "cturn") 
 ![](./images/conic.png "conic") 
@@ -115,12 +114,16 @@ Parts
 
 
 ## color modes
+* color depth
+* color from palette
+
 
 [Color depth](https://en.wikipedia.org/wiki/Color_depth)
 * 24 bit color (rgb) 
 * 8 bit color mode: gray shades ( where r=g=b)
 * 1 bit color mode: Black and White ( b&w )
-* direct color, palette mode
+
+
 
 ```pas
  case ColorType of
@@ -222,9 +225,10 @@ double conic(double complex z)
 
 // https://en.wikipedia.org/wiki/Himmelblau%27s_function
 double GiveHimmelblau(double x, double y){
-	// mapped input to [-6,6]x[-6,6]
-	x *= 6.0;
-	y *= 6.0;
+	// map input to [-m,m]x[-m,m]
+	double m = 6.0;
+	x *= m;
+	y *= m;
 	double a = x*x+y-11.0;
 	double b = x+y*y-7.0;
 	// mapped output to 
@@ -241,11 +245,15 @@ double GiveHimmelblau(double x, double y){
 */
 double checker( double x, double y){
 
-	int ix = floor(5.0*x);
-	int iy = floor(5.0*y);
+	double m = 5.0; 
+	// map input from [-1,1]x[-1,1] to [-m,m]x[-m,m]
+	int ix = floor(m*x);
+	int iy = floor(m*y);
 
 
 	return abs(ix + iy) % 2;
+
+
 }
 ```