shadow_stencil

Determines the type of dynamic shadows cast by models.

Range:

off - Z buffer shadows (default).
on - Stencil buffer shadows.

Type:

var, redefinable.

Remarks:

Stencil buffer shadows look better than z buffer shadows: they 'bend' around corners, and objects cast shadows on themselves. Due to the hard shadow edges, especially with self shadows, they work best with high polygon models and rather dark levels with hard light contrasts. Stencil buffer shadows have the following restrictions:

Stencil buffer shadows are slower than z buffer shadows, and only run on 3D cards with 8 bit stencil buffer support. Most 3D cards manufactured after 2000 fulfil this requirement.
Stencil buffer shadows can only be cast by nontransparent models consisting of closed meshes with no holes or polygons intersecting or touching each other with their flat side. Otherwise rendering errors (dark lines projecting from the model to the shadow) can be visible. In a closed mesh, every edge is shared by exactly two triangles. If the model's mesh is not closed, create a closed mesh LOD model for shadow casting. The MED meshtester can be used for determining whether a mesh is closed or not.
Dynamic shadows are not clipped by walls. A shadow can be cast on a wall, at the back side of the wall, and on the floor behind the wall at the same time. Take care that level and models are very dark in unlit parts (or use the cast flag) to cover or suppress unwanted shadows.
Stencil shadows are also visible on model polygons that point away from the light source, which can lead to undesired flickering shadow polygons. To avoid this, use a material with low ambient and a high diffuse part.
For speed reasons, a z-pass stencil shadow algorithm is used that does not allow to move the camera into a shadow volume. Therefore the player should only cast a stencil shadow when using a 3rd person camera. In first person mode the player's shadow is automatically switched off when stencil shadows are activated.

Z buffer shadows behave the following way:

They are projected onto the floor below the model only.
The projection direction is given by the sun azimuth and elevation (sun_angle).

Example:

var shadow_stencil = on;