Color and Alpha Maps

Introduction

One of the central features of the Enhance:DT components is the color and alpha maps. A color map consists of eight colors and eight blend points. When the Blend Function input is linked it returns a value which is then mapped to a color based on the color map. The easy way to understand how this works is to think of a simple color map going from Yellow at 0% to Red at 100%. If the texture function returned 0% then this would map directly to Yellow. Similarly, if the texture function returned 100% this would map to Red. However, if the texture function returned 50% then this would map to a mix of 50% Yellow and 50% Red, i.e. Orange. Two simple color maps are shown below along with how the look mapped to fBm on a simple plane.

Simple Gradient 1

Here a simple gradient has been set up to go from Yellow at 0% of the texture function to Red at 100%.

Simple Gradient 2

Here a simple gradient has been set up to go from Yellow at 0% of the texture function to green at 50% and on to Red at 100%.

Enable Colors

The alpha map is derived in the same way as the colors except that they are percentage value. This percentage value then controls the color map's opacity. If the alpha map returns 0% for a given point then the color will be the color derived directly from the control map. However, if the alpha returns 100% then the color map is deemed to be transparent and the background color shows through. Alpha values between 0% and 100% are blends between the color derived from the color map and the back ground color. This allows holes to be made in the actual color map allowing parts of the background color to shown through. An example of how this works is shown below.

Simple Gradient 3

Here a simple gradient has been set up to go from Yellow at 0% of the texture function to green at 50% and on to Red at 100%. However, Alpha 2 has bee set to 100% effectively disabling that section of the color map so that the underlying color, the checker board pattern in this case, shows through.

Do Blend

The Do Blend check box controls whether the color and alpha maps are blended or use discrete steps. With the check box enabled the blends are smooth transitions for one value to the next, just like the ones shown above. When the Do Blends is switched off the transitions are discrete. It is important to note the when blending is switched off the first blend point, Blend 1, sets the point at which Color 1 transitions to Color 2. So if Blend 1 is 0% then none of Color 1 is shown as the color map transitions straight to Color 2. An example of the discrete blends can be seen below:

Non-Blended Color Map 1

Here a simple gradient has been set up to go from Yellow to Red. As the Do Blend check box has been disabled the color map is done using discrete steps.