Tonemapping

The tonemapping panel is raised from the top toolbar of the application:

On clicking the tonemapping button, a 3 tabs panel shows up:

The tonemapping panel wears the name of the scene it belongs to. Each scene has it's own tonemapping values.

Each tab of the panel covers a dedicated part in the image post-processing:

  1. The "Tone mapping" tab: this is the HDR to LDR image conversion. NDunes rendering pipeline is done using High Dynamic Range values (HDR) and gets converted back to Low Dynamic Range (LDR) values that can be displayed by common screens. The HDR to LDR conversion, also known as tonemapping, is ruled by parameters in this panel tab.
  2. The "Filters" tab: A number of post processing effects can be found there, such as glow, sharpen, depth-of-field, etc...
  3. The "Color" tab: This tab contains all color correction tools: color curve, gamma, white balance, LUT, etc...

Tonemapping modes

We'll detail all tonemapping modes available in this section, and how to change the resulting image. First let's have a look at the tonemapping modes available:

We have 4 distinct tonemapping modes, each of which uses some parameters of the panel. We also have 4 tonemapping parameters: "Exposure", "Luminance log average", "Luminance max" and "Luminance average".

Each tonemapping mode may use one or more of these parameters. Let's review each of them:

Your browser does not support the HTML5 canvas tag.

Exposure set to 10% on the left and 100% on the right

Your browser does not support the HTML5 canvas tag.

A comparison between exponential tonemapping (left) and photographic tonemapping (right)

Note that the image above uses a quite turbid sky with a thick atmosphere so its whiteness is rather normal.

Measuring image luminance

It may not be easy to guess luminance values in an image to define values to use for a given tonemapping mode. The next section of the tonemapping panel has a luminance measurement tool, so on clicking on the "Read" button, luminance values of the current image are measured. By pressing "Write" these are applied to the current tonemapping settings (also press Ctrl+L by default to perform a read + write in one click):

The image comparison above was performed with measured luminance values applied. This can be very convenient to setup a given tonemapping suitable for different lighting conditions or to adjust the tonemapping for a given need.

Tonemapping filters

Here are available a bunch of pretty standard effects:

Tonemapping color correction

Again, we'll find here a set of typical color correction tools: