6.6. Lighting Effects

6.6.1. Overview

Рисунок 17.118. The same image, before and after applying Lighting filter

The same image, before and after applying Lighting filter

Original image

The same image, before and after applying Lighting filter

Filter «Lighting Effects» applied


This filter simulates the effect you get when you light up a wall with a spot. It doesn't produce any drop shadows and, of course, doesn't reveal any new details in dark zones.

6.6.2. Activating the Filter

This filter is found in the main menu under FiltersLight and ShadowLighting Effects….

6.6.3. Options

Рисунок 17.119. «Lighting» filter options

«Lighting» filter options

Preview

When Interactive is checked, parameter setting results are interactively displayed in preview without modifying the image until you click on OK button.

If Interactive is not checked, changes are displayed in preview only when you click on the Update button. This option is useful with a slow computer.

Any other options are organized in tabs:

6.6.3.1. General Options

Рисунок 17.120. «Lighting» filter options (General Options)

«Lighting» filter options (General Options)

Transparent background

Makes destination image transparent when bumpmap height is zero (height is zero in black areas of the bumpmapped image).

Create new image

Creates a new image when applying filter.

Distance

You can specify the distance of the light source from the center of the image with this slider. The range of values is from 0.0 to 2.0.

6.6.3.2. Light Settings

Рисунок 17.121. «Lighting» filter options (Light Settings)

«Lighting» filter options (Light Settings)

In this tab, you can set light parameters. With Light 1 to Light 6 you can create six light sources and work on each of them separately.

Type

The filter provides several light types in a drop-down list:

None

This deletes the light source (light may persist).

Directional

The blue point is linked to preview center by a line which indicates the direction of light.

Point

Displays a blue point at center of preview. You can click and drag it to move light all over the preview.

Spot

Displays a blue point that cannot be moved. This light has a fixed direction.

Color

When you click on the color swatch, you bring a dialog up where you can select the light source color.

Intensity

With this option, you can set light intensity.

Position

Determines the light point position according to three coordinates: X coordinate for horizontal position, Y for vertical position, Z for source distance (the light darkens when distance increases). Values are from -1 to +1.

Direction

This option should allow you to fix the light direction in its three X, Y and Z coordinates.

Isolate

With this option, you can decide whether all light sources must appear in the Preview, or only the source you are working on.

Lighting presets

You can save your settings with the Save and get them back later with the Open.

6.6.3.3. Material Properties

Рисунок 17.122. «Lighting» filter options (Material Properties)

«Lighting» filter options (Material Properties)

These options don't concern light itself, but light reflected by objects.

Small spheres, on both ends of the input boxes, represent the action of every option, from its minimum (on the left) to its maximum (on the right). Help pop ups are more useful.

Ambient intensity

This option, also known as glowing, controls the amount of the original color to show where no direct light falls.

Diffuse intensity

This option, also known as brightness, controls the intensity of the original color to show when hit directly by a light source.

Diffuse reflectivity

This option controls how intense the light from the original color will be reflected.

Specular reflectivity

This option controls how intense the highlight will be.

Highlight

This option adjusts the polish or highlight. Higher values make the highlight more focused.

Metallic

When this option is checked, surfaces look metallic.

6.6.3.4. Bump Map

Рисунок 17.123. «Lighting» filter options (Bump Map)

«Lighting» filter options (Bump Map)

In this tab, you can set filter options that give relief to the image. See Рельєфність .

Enable bump mapping

With this option, bright parts of the image will appear raised and dark parts will appear depressed. The aspect depends on the light source position.

Bump map image

Select a grayscale image to use as a bump map. See the Bump Map plug-in for more information.

Curve

This option defines the method that will be used when applying the bump map; that is, the bump height is a function of the specified curve. Four curve types are available: Linear, Logarithmic, Sinusoidal and Spherical.

Maximum height

This is the maximum height of bumps.

6.6.3.5. Environment Map

Рисунок 17.124. «Lighting» filter options (Environment Map)

«Lighting» filter options (Environment Map)

Enable environment mapping

When you check this box, the following option is enabled:

Environment image

Select a RGB image to be used as environment map. Please note that for this option to work you should load another image with GIMP before using it.

An example can be found at [BUDIG01].