Black Dragon Viewer Guide: #3 Shadows

What is it?

Shadows, the bread and butter of Deferred Rendering and Black Dragon. Shadows completely change the environment, the mood, the scene in and around. Having shadows is the difference between day and night. Both sun and moon are a global light and in addition projectors can also be used as light sources casting shadows.

How does it look?

As you can see shadows make a huge difference, they change the entire scene from a brightly lit 'outdoor' place into a proper closed building with a roof on top. Combined with SSAO they are the single biggest visual improvement you can enable in any Viewer.

How can i use it ?

You can enable Shadows by opening 'Preferences' and selecting the 'Display' tab, here you'll navigate into the 'Deferred Rendering' section where you'll find 'Shadows' which feature off, sun and moon only or sun, moon and projectors.

What can i change?

You can change whether you want to see shadows from sun and moon only or want to include those of projectors as well. Further you can control how much ground shadows should cover and which resolution each of the 4 sections has. Note that changing the distance of one section can negatively impact the accuracy, more ground covered means less accuracy. You'll want to keep the first two sections very small. Further each projector shadows resolution can be changed as well. Shadows are also affected by 'Light Softening', as without shadows will have no blur and will appear pixelated.

Caveats

Shadow resolution has a huge impact on performance and so does the complexity of the scene itself. The more complex a scene is the higher the impact of shadows will have on your framerate this is just amplified by shadow resolution. Shadows will also always appear pixelated if cast by a semi transparent object or surface or are falling onto one. Nothing can be done about that, it's a rendering limitation of how alphas and light blur is implemented.

Projectors are a massive performance impact if used wrong and changing increasing their resolution just worsens it.

Shadow distance can make or break your shadows, if you configure them badly you'll end up trashing your shadows completely, if you can't figure out good distances, try the 'Automatic Shadow Distance' option, it gives you far less options but does a decent job if you can't do it better yourself.