Class TCastleScene

Internal override test visibility.

Render shadow volume (sides and caps) of this scene, for shadow volume algorithm.

Uses ShadowVolumeRenderer for rendering, and to detect if rendering is necessary at all.

It always uses silhouette optimization. This is the usual, fast method of rendering shadow volumes.

All shadow quads are generated from scene triangles transformed by ParentTransform. We must be able to correctly detect front and back facing triangles with respect to light position, so ShadowVolumeRenderer.LightPosition and "this scene transformed by ParentTransform" must be in the same coordinate system. If ParentTransformIsIdentity then ParentTransform value is ignored and everything works like ParentTransform = identity matrix (and is a little faster in this special case).

Uses TrianglesListShadowCasters and ManifoldEdges and BorderEdges (so you may prefer to prepare it before, e.g. by calling PrepareResources with prShadowVolume included).

We look at some RenderOptions, like RenderOptions.Blending, because transparent triangles have to be handled a little differently, and when RenderOptions.Blending = false then all triangles are forced to be opaque. In other words, this takes RenderOptions into account, to cooperate with our Render method.

ShadowVolumeRenderer.LightPosition is the light position. ShadowVolumeRenderer.LightPosition[3] must be 1 (to indicate positional light) or 0 (a directional light). It's expected that ShadowVolumeRenderer is already initialized by ShadowVolumeRenderer.InitFrustumAndLight.

Faces (both shadow quads and caps) are rendered such that CCW <=> you're looking at it from outside (i.e. it's considered front face of this shadow volume).

Destroy any associations of this object with current OpenGL context. For example, release any allocated texture names.

Generally speaking, destroys everything that is allocated by PrepareResources call. It's harmless to call this method when there are already no associations with current OpenGL context. This is called automatically from the destructor.

Warning: this symbol is deprecated: this is internal; use TCastleViewport.PrepareResources to prepare transformations

Does this transform have a collision mesh that TCastleMeshCollider can use.

Enumerate triangles for a collision mesh that TCastleMeshCollider can use.

Warning: this symbol is deprecated: use RenderOptions

Create a scene with the same contents (X3D scene graph) as this one. The created scene has exactly the same class as this one (we use ClassType.Create to call a virtual constructor).

Note that this does not copy other scene properties, like ProcessEvents or Spatial or RenderOptions contents.

Whether the scene was (potentially, at least partially) visible in the last rendering event.

The "was visible" means that "some shape was visible", that is: some shape passed frustum culling, distance culling and occlusion culling (see https://castle-engine.io/occlusion_culling ) tests.

The result of this method is not affected by:

• Lights.

  That is, it doesn't matter whether this scene contains some lights (X3D light nodes in RootNode) that possibly make some other scenes brighter.

• Background.

  It doesn't matter whether the scene contains some background that affects TCastleViewport skybox.

• Children scenes.

  It doesn't matter if you have any children scenes (TCastleScene instances that are children of this) and whether they are visible. This follows the general rule that TCastleScene-specific features do not look/affect children scenes, including children TCastleScene. Only TCastleTransform features, like TCastleTransform.Exists, are applied recursively, i.e. they generally affect the children transformations.

To summarize and emphasize: for this method, only the visibility of shapes within this scene matters.

If this scene instance is used multiple times within some viewport, or when multiple viewports render the same scene, then it is enough that at least one shape in one of the scene instances was visible last frame.

TODO: For now, occlusion culling doesn't affect this, i.e. if the scene is not visible because occlusion culling.

Improve performance of rendering by checking for each shape whether it is inside frustum (camera pyramid of view) before rendering.

This is almost always a good idea. Exception may be when, in the most common scene position, all the shapes are inside the frustum, or all the shapes are outside the frustum. In this case this check is wasting time, and it matters if you have a lot of shapes. In such case, SceneFrustumCulling will be enough.

Improve performance of rendering by checking for the whole scene whether it is inside frustum (camera pyramid of view) before rendering.

This is almost always a good idea. Exception may be when the scene is almost always within the frustum, and you have a lot of scenes. In such case, this check may be a waste of time.

Does this scene receive shadows by shadow volumes.

Cull shapes farther than this distance. Ignored if <= 0.

Rendering options. You are free to change them at any time.

Lights defines by given scene shine on everything in the viewport, including all other TCastleScene.