Color based detail map blending 1

This method use base color map and selected sample colors to blend the detail maps to the

target area.

This methods allow auto blending any numbers of  detail maps into one base map. The process

does not need interfere from artists but also can be interfere by artist if necessary.

Steps

Step 1 : color extracting

Decide how many detail map you want to use in the final blend and extract color from the base

abedo.

We run color quantization tool to extract selected numbers of colors mostly used in the image.

This example is using 2.

To visualize the color:

Step 2 : choose detail map and feed data to the shader.

Keep in mind that the color is the area where the corresponding maps will be filled in. In this

example brown is where earth texture will be blended in, green is where the grass will be

blended in.

Assign the color and corresponding detail maps to the shader.

Step 3: adjust blending methods according to need.

Blend Strength ：base abedo and detail map blending weight

from 0 to 1

Blending power ：how sharp the blending edge is

from 9 to 29

D1 / D2 value : blending area control

D1 :  from to

Further thinking

Compare to blend map

Color based blending:

  1. Production process is easier and faster , no need to create blend map.

2. Less memory footprint,  no need to store extra map.

3. In theory can blend in any numbers of detail maps.

4. Real time blend area control.
5. Different base map with similar color can use same setting without recalculate.

Blending map :

   1 . Have more control over how to blend.

2 . Requires less calculation on shader.

3.  Can overlay several detail map easily.

Vertex painting

This technique can used together with either Color based blending or blend map to give large

area of control.

Color extraction

Color quantization algorithm extract mostly used colors in a map. While most pixels are covered

in the palate, it has some problem.  

1 . feature colors could be ignored.

This is a test made with extracting 3 main color. The blue dot is too small (too few pixels) to be

count into the main colors.

2. Inaccurate gradiency.  To give a correct gradient on the detail map blending, it’s best to use extreme colors. However due to the character of the algorithm, more average colors are use.

These are the directions to improve the quantization algorithm.