Class TCastleViewport

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Warning: this symbol is deprecated: this default is not used; ProjectionFar in orthographic projection is now automatically adjusted to what you display

referencing deprecated in deprecated

Warning: this symbol is deprecated: this default is not used; ProjectionNear in orthographic projection is now automatically adjusted to what you display

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Rendering pass, for user purposes. Useful to keep shaders cached when you render the same scene multiple times in the same frame (under different lighting conditions or other things that change shaders). By default this is always 0, the engine doesn't modify this. You can set this field manually.

At design-time (in CGE editor), this is the camera used by the editor. Usually use InternalCamera, to automatically pick either design-time camera or runtime Camera.

Calculate projection parameters. Determines if the view is perspective or orthogonal and exact field of view parameters. Called each time at the beginning of rendering.

The default implementation of this method in TCastleViewport calculates projection based on the Camera parameters.

In turn, the Camera parameters may be automatically calculated (if AutoCamera) based on the nodes in the TCastleRootTransform.MainScene. Nodes like TViewpointNode or TOrthoViewpointNode or TNavigationInfoNode determine the default camera and projection details.

You can override this method, or assign the OnProjection event to adjust the projection settings. But please note: instead of overriding this method, it's usually easier (and more advised) to simply change the Camera properties, like Camera.ProjectionType or Camera.Orthographic.Width or Camera.Perspective.FieldOfView.

Prepare lights shining on everything. GlobalLights contents should be initialized here. The implementation in this class adds headlight determined by the Items.UseHeadlight value.

Warning: this symbol is deprecated: use InitializeGlobalLights

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Render everything from given camera view (as TRenderingCamera). Given RenderingCamera.Target says to where we generate the image. This method must take care of making many rendering passes for shadow volumes, but doesn't take care of updating generated textures.

Render the scene, assuming that buffers were already cleared and background was rendered. Called by RenderFromViewEverything at the end. Lights are calculated in Params at this point.

Render one pass, with current camera and parameters. All current camera settings are saved in RenderParams.RenderingCamera.

Parameters

Params

Rendering parameters, see TRenderParams. TODO: move all relevant to TRenderOnePassParams.

PassParams

Rendering parameters of this pass, see TRenderOnePassParams.

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Called when PointingDevicePress was not handled by any TCastleTransform object. You can override this to make a message / sound signal to notify user that his Input_Interact click was not successful.

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This item has no description. Showing description inherited from TCastleScreenEffects.RenderWithoutScreenEffects.

Descendants with special rendering code should override this, and never override Render or RenderOverChildren (as those two methods have special implementation in this class).

This rendering method will be called regardless if we have or not some screen effects. When no screen effects are actually used (e.g. AddScreenEffect wasn't used, InternalExtraScreenEffectsCount is zero), then our Render trivially calls this method without doing anything else.

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This item has no description. Showing description inherited from TCastleUserInterface.AllowSuspendForInput.

Allow window containing this control to suspend waiting for user input. Typically you want to override this to return False when you do something in the overridden Update method.

In this class, this simply returns always True.

This item has no description. Showing description inherited from TCastleUserInterface.Press.

Override this method to react to user pressing a key, mouse button or mouse wheel. Return True if the event was handled, which prevents from passing this event to other UI controls.

When implementing in descendants it is best to override it like this:

function TMyControl.Press(const Event: TInputPressRelease): boolean;
begin
  Result := inherited;
  if Result then Exit; // exit if ancestor already handled this event

  if Event.IsKey(keyEnter) then
  begin
    // do something in reaction to Enter key
    ...
    // let engine know that this input event was handled
    Exit(true);
  end;

  if Event.IsMouseButton(buttonLeft) then
  begin
    // do something in reaction to left mouse button press
    ...
    // let engine know that this input event was handled
    Exit(true);
  end;
end;

These events are generated for all UI controls, whether they are considered "interactive" or not. These events are generated for non-interactive controls like TCastleRectangleControl or TCastleLabel as well. For example, these events ignore the TCastleButton.Enabled state, they are generated always (see https://github.com/castle-engine/castle-engine/issues/413 ). Use instead TCastleButton.OnClick to detect clicks on a button in a way that honors the TCastleButton.Enabled state.

When a control returns True from Press, it means it starts to "capture" subsequent mouse events: subsequent mouse moves and release will be send to this control even if mouse will move outside of this control.

The events Press and Release are passed to the parent only after the children had a chance to process this event. Overriding them makes sense if you draw something that "looks clickable" in TCastleUserInterface.Render, which is the standard place you should draw stuff. For example our TCastleButton draws there.

In contrast, the events PreviewPress and PreviewRelease are passed first to the parent control, before children have a chance to process this event. In partcular, overriding them makes sense if you draw something that "looks clickable" in TCastleUserInterface.RenderOverChildren.

This item has no description. Showing description inherited from TCastleUserInterface.Release.

Override this method to react to user releasing a key, mouse button. Return True if the event was handled, which prevents from passing this event to other UI controls.

This is counterpart to Press method. See Press for more details.

Note: We'd like this method to also be called when user releases a mouse wheel. But currently releasing of the mouse wheel is not reported now by any backend. Only releasing of keys and mouse buttons is reported.

This item has no description. Showing description inherited from TCastleUserInterface.Motion.

Motion of mouse or touch.

This item has no description. Showing description inherited from TCastleUserInterface.Update.

Control may do here anything that must be continuously repeated. E.g. camera handles here falling down due to gravity, rotating model in Examine mode, and many more.

This method may be used, among many other things, to continuously react to the fact that user pressed some key (or mouse button). For example, if holding some key should move some 3D object, you should do something like:

if HandleInput then
begin
  if Container.Pressed[keyArrowRight] then
  begin
    Transform.Position := Transform.Position + Vector3(SecondsPassed * 10, 0, 0);
    HandleInput := false;
  end;
end;

Instead of directly using a key code, consider also using TInputShortcut that makes the input key nicely configurable. See engine tutorial about handling inputs.

Multiplying movement by SecondsPassed makes your operation frame-rate independent. Object will move by 10 units in a second, regardless of how many FPS your game has.

The code related to HandleInput is important if you write a generally-useful control that should nicely cooperate with all other controls, even when placed on top of them or under them. The correct approach is to only look at pressed keys/mouse buttons if HandleInput is True. Moreover, if you did check that HandleInput is True, and you did actually handle some keys, then you have to set HandleInput := false. This will prevent the other controls (behind the current control) from handling the keys (they will get HandleInput = False). And this is important to avoid doubly-processing the same key press, e.g. if two controls react to the same key, only the one on top should process it.

Note that to handle a single press / release (like "switch light on when pressing a key") you should rather use Press and Release methods. Use this method only for continuous handling (like "holding this key makes the light brighter and brighter").

To understand why such HandleInput approach is needed, realize that the "Update" events are called differently than simple mouse and key events like "Press" and "Release". "Press" and "Release" events return whether the event was somehow "handled", and the container passes them only to the controls under the mouse (decided by TCastleUserInterface.CapturesEventsAtPosition). And as soon as some control says it "handled" the event, other controls (even if under the mouse) will not receive the event.

This approach is not suitable for Update events. Some controls need to do the Update job all the time, regardless of whether the control is under the mouse and regardless of what other controls already did. So all controls (well, all controls that exist, in case of TCastleUserInterface, see TCastleUserInterface.Exists) receive Update calls.

So the "handled" status is passed through HandleInput. If a control is not under the mouse, it will receive HandleInput = False. If a control is under the mouse, it will receive HandleInput = True as long as no other control on top of it didn't already change it to False.

This item has no description. Showing description inherited from TCastleUserInterface.BeforeRender.

Prepare your resources, right before drawing. Called only when Exists and GLInitialized.

Do not explicitly call this method. Instead, render controls by adding them to the TCastleContainer.Controls list, or render them explicitly (for off-screen rendering) by TCastleContainer.RenderControl.

This item has no description. Showing description inherited from TCastleComponent.PropertySections.

Section where to show property in the editor.

This item has no description. Showing description inherited from TCastleComponent.CustomSerialization.

Override this method to call various methods of SerializationProcess, which in turn allows to serialize/deserialize things that are not published. This allows to serialize/deserialize with more freedom, e.g. to serialize/deserialize some private field.

Warning: this symbol is deprecated: use Items.MainScene

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Set current camera vectors and projection, to best reflect current Items.MainScene or current Items bounding box.

If Items.MainScene is set and it has a preferred camera (TViewpointNode, which can be specified in X3D, glTF, Collada files) then it will be used. Otherwise we calculate camera using CameraViewpointForWholeScne to see the whole world.

This method only fills existing Camera with contents, it doesn't change the Camera to a new component. It will do nothing if Camera is Nil.

This is automatically used at first rendering if AutoCamera (deprecated, only sensible now if you make X3D browser that must react to X3D events changing viewpoint). You can also use it explicitly (this is recommended).

Does the graphic card support our ScreenSpaceAmbientOcclusion shader. This does not depend on the current state of ScreenSpaceAmbientOcclusion property. You can use it e.g. to disable the menu item to switch SSAO in 3D viewer.

Does the graphic card support our ScreenSpaceReflections shader. This does not depend on the current state of ScreenSpaceReflections property. You can use it e.g. to disable the menu item to switch SSR in 3D viewer.

This item has no description. Showing description inherited from TCastleUserInterface.GLContextOpen.

Initialize your OpenGL resources.

This is called when OpenGL context of the container is created, or when the control is added to the already existing context. In other words, this is the moment when you can initialize OpenGL resources, like display lists, VBOs, OpenGL texture names, etc.

As an exception, this is called regardless of the Exists value. This way a control can prepare it's resources, regardless if it exists now.

This item has no description. Showing description inherited from TCastleUserInterface.GLContextClose.

Destroy your OpenGL resources.

Called when OpenGL context of the container is destroyed. Also called when controls is removed from the container Controls list. Also called from the destructor.

You should release here any resources that are tied to the OpenGL context. In particular, the ones created in GLContextOpen.

As an exception, this is called regardless of the Exists value. This way a control can release it's resources, regardless if it exists now.

Warning: this symbol is deprecated: use TCastleViewport.PrepareResources to prepare transforms

Parameters to prepare items that are to be rendered within this world. This should be passed to TCastleTransform.PrepareResources.

Note: Instead of using TCastleTransform.PrepareResources, and this method, it's usually easier to call TCastleViewport.PrepareResources. Then the appropriate TPrepareParams will be passed automatically.

Warning: this symbol is deprecated: this is internal info, you should not need this; use PrepareParams to get opaque information to pass to TCastleTransform.PrepareResources

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Statistics about last rendering frame. See TRenderStatistics docs.

Current 3D triangle under the mouse cursor. Updated in every mouse move. May be Nil.

Utility method to set camera to a suitable state for 2D games.

• Sets both initial and current camera vectors like this:

  • Position camera at (0, 0, 500),

  • Looks along the -Z direction,

  • "Up" vector is in +Y.

  This way the 2D world spans horizontally in X and vertically in Y. The Z (depth) can be used to put things in front/behind each other.

  Since this initialized the camera sensibly, we also set AutoCamera to false.

• Sets orthographic projection for the camera (TCastleCamera.ProjectionType set to ptOrthographic).

  By default our visible X range is [0..viewport width in pixels], visible Y range is [0..viewport height in pixels]. Use the properties of Camera.Orthographic to control the projection. For example set Camera.Orthographic.Width and/or Camera.Orthographic.Height to define visible projection size (horizontal or vertical) explicitly, regardless of the viewport size.

  Setting Camera.Orthographic.Origin is also often useful, e.g. set it to (0.5,0.5) to make the things positioned at (0,0) in the world visible at the middle of the viewport.

  By default our visible Z range is [-1500, 500], because this sets ProjectionNear to -1000, ProjectionFar to 1000, and camera default depth (Camera.Translation.Z) is 500. This was chosen to be comfortable for all cases – you can keep camera Z unchanged and comfortably position things around [-500, 500], or set camera Z to zero and then comfortably position things around [-1000, 1000].

Convert 2D position on the viewport into 3D "world coordinates", by colliding camera ray with a plane parallel to the viewport at given Depth. "World coordinates" are coordinates space seen by TCastleTransform / TCastleScene inside viewport Items. Use Depth > 0 for positions in front of the camera.

This is similar to "Unproject" GLU routine. It allows to map points from the 2D viewport back to the 3D space inside viewport.

The interpretation of Position depends on ContainerCoordinates:

• When ContainerCoordinates = True, then Position is relative to the whole container (like TCastleWindow or TCastleControl).

  And it is expressed in real device coordinates, just like TInputPressRelease.Position when mouse is being clicked, or like TInputMotion.Position when mouse is moved.

• When ContainerCoordinates = False, then Position is relative to this UI control.

  And it is expressed in coordinates after UI scaling. IOW, if the size of this control is Width = 100, then Position.X between 0 and 100 reflects the visible range of this control.

Returns true and sets 3D PlanePosition if such intersection is found. Returns false if it's not possible to determine such point (which should not be possible, unless camera field of view is larger than 180 degrees).

Convert 2D position on the viewport into 3D ray.

The interpretation of Position depends on ContainerCoordinates:

• When ContainerCoordinates = True, then Position is relative to the whole container (like TCastleWindow or TCastleControl).

  And it is expressed in real device coordinates, just like TInputPressRelease.Position when mouse is being clicked, or like TInputMotion.Position when mouse is moved.

• When ContainerCoordinates = False, then Position is relative to this UI control.

  And it is expressed in coordinates after UI scaling. IOW, if the size of this control is Width = 100, then Position.X between 0 and 100 reflects the visible range of this control.

Convert 2D position on the viewport into 3D "world coordinates", by colliding camera ray with a plane at constant X, Y or Z. "World coordinates" are coordinates space seen by TCastleTransform / TCastleScene inside viewport Items.

This works with any projection (perspective or orthographic).

You can use it to pick a point on any plane with constant X (PlaneConstCoord = 0), constant Y (PlaneConstCoord = 1), constant Z (PlaneConstCoord = 2).

This intersects the ray cast by Camera with a plane where given coordinate (PlaneConstCoord) has value equal to PlaneConstValue. The parameter names and interpretation is consistent e.g. with TrySimplePlaneRayIntersection.

The interpretation of Position depends on ContainerCoordinates:

• When ContainerCoordinates = True, then Position is relative to the whole container (like TCastleWindow or TCastleControl).

  And it is expressed in real device coordinates, just like TInputPressRelease.Position when mouse is being clicked, or like TInputMotion.Position when mouse is moved.

• When ContainerCoordinates = False, then Position is relative to this UI control.

  And it is expressed in coordinates after UI scaling. IOW, if the size of this control is Width = 100, then Position.X between 0 and 100 reflects the visible range of this control.

Returns true and sets 3D PlanePosition (the PlaneConstCoord component of this vector must always be equal to PlaneConstValue) if such intersection is found. Returns false if it's not possible to determine such point (when the camera looks in the other direction).

Warning: this symbol is deprecated: use PositionToWorldPlane overload with PlaneConstCoord parameter; this version assumes PlaneConstCoord = 2

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Convert 2D position into "world coordinates", which is the coordinate space seen by TCastleTransform / TCastleScene inside viewport Items, assuming that we use orthographic projection in XY axes.

The interpretation of Position depends on ContainerCoordinates:

• When ContainerCoordinates = True, then Position is relative to the whole container (like TCastleWindow or TCastleControl).

  And it is expressed in real device coordinates, just like TInputPressRelease.Position when mouse is being clicked, or like TInputMotion.Position when mouse is moved.

• When ContainerCoordinates = False, then Position is relative to this UI control.

  And it is expressed in coordinates after UI scaling. IOW, if the size of this control is Width = 100, then Position.X between 0 and 100 reflects the visible range of this control.

This assumes that camera "up vector" is +Y, and it is looking along the negative Z axis. It also assumes orthographic projection (Camera.ProjectionType equal ptOrthographic). These are default camera direction, up and projection types set by Setup2D.

Invert PositionTo2DWorld, converting the "world coordinates" (the coordinate space seen by TCastleTransform / TCastleScene inside viewport Items) into final screen position.

Just like PositionTo2DWorld, this assumes that camera "up vector" is +Y, and it is looking along the negative Z axis. It also assumes orthographic projection (Camera.ProjectionType equal ptOrthographic). These are default camera direction, up and projection types set by Setup2D.

Project 3D coordinates (the coordinate space seen by TCastleTransform / TCastleScene inside viewport Items) into 2D position on the viewport UI.

The resulting position is relative to this viewport control and it is expressed in coordinates after UI scaling. IOW, if the size of this control is EffectiveWidth = 100, then Position.X between 0 and 100 reflects the visible range of this control. This is like using ContainerCoordinates = False with PositionToRay.

Warning: this symbol is deprecated: use overload without DisplayProgressTitle: String

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Warning: this symbol is deprecated: use overload without DisplayProgressTitle: String

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Prepare resources, to make various methods (like Render) execute fast. Call it only when rendering context is initialized (ApplicationProperties.IsGLContextOpen).

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Current TCastleTransform pointed by the mouse cursor position. This is the first object being hit by the ray from camera through the mouse cursor position.

Automatically updated to always reflect the current mouse position. May be Nil if nothing is hit.

The "mouse cursor position" on touch devices is just the last touch point. When the navigation uses mouse look (like TCastleWalkNavigation.MouseLook), we automatically use viewport center as the "mouse cursor position".

See also

MouseRayHit

Current components (TCastleTransform hierarchy) pointed by the mouse cursor position.

TRayCollision.Transform

TCastleTransform that was hit by given ray.

Current TCastleTransform hit by the ray from given Position over the viewport.

Position and ContainerCoordinates meaning is the same as for PositionToRay:

• When ContainerCoordinates = True, then Position is in real device coordinates and relative to whole container.

  E.g. passing a Position equal to MyViewport.RenderRect.Center means shooting a ray from the center of the viewport.

  E.g. passing a Position equal to Container.MousePosition means shooting a ray from the current mouse position.

• When ContainerCoordinates = False, then Position is in scaled UI coordinates and relative to the viewport.

  E.g. passing a Position equal to Vector2(MyViewport.EffectiveWidth / 2, MyViewport.EffectiveHeight / 2) means shooting a ray from the center of the viewport.

  E.g. passing a Position equal to Vector2(0, 0) means shooting a ray from the left-bottom corner of the viewport.

Similar to TransformUnderMouse, this method returns the first TCastleTransform hit by the ray.

Create new camera and make it used by this viewport. This creates new unnamed TCastleCamera, owned by this viewport, assigns it to Camera and adds it to Items.

Call this only when Camera is Nil.

This is done automatically when creating TCastleViewport (not in design-mode, not at deserialization) using the standard TCastleViewport.Create constructor. So you likely don't need to call this in typical applications.

Note: Even when used from CGE editor (CastleDesignMode), this creates non-design camera. This way viewports created with InternalCreateNonDesign have also non-design cameras. This is important, so that e.g. camera has no bounding box, and thus AssignDefaultCamera in sprite sheet editor doesn't put camera further and further away.

Export whole viewport contents to a node. This is useful to save viewport contents to X3D, STL or other files that we can save. This tries to export as much as we can express using nodes, which includes everything in Items (transformations, scenes, lights and more) and optional things like TCastleNavigation types (fly, walk, examine...), current Background, current Fog.

Why is this an internal method?

• Because for Castle Game Engine usage, we advice to save things using CastleComponentSerialize unit, like UserInterfaceSave(MyViewport, 'viewport-with-contents.castle-user-interface'). The CastleComponentSerialize routines with reliably save 100% of Pascal published properties.

• In contrast, this method only saves a subset of engine features – the ones that can be expressed in a straightforward fashion as X3D nodes.

• See TCastleTransform.InternalBuildNode for more explanation. including why it's an internal method.

Warning: this symbol is deprecated: in most cases, you can instead read Camera parameters, like Camera.Orthographic.EffectiveWidth, Camera.Orthographic.EffectiveHeight

Current projection parameters, calculated by last CalculateProjection call, adjusted by OnProjection. This is read only. To change the projection parameters, override CalculateProjection or handle event OnProjection.

Background color. Displayed only if Background is Nil and MainScene doesn't define any background either.

Ignored if Transparent.

Dark gray (DefaultBackgroundColor) by default.

Enable built-in SSAO screen effect in the world.

Enable built-in SSR screen effect in the world.

Adjust SSR default surface glossiness.

Called on any camera change.

Current components (TCastleTransform hierarchy) pointed by the mouse cursor position. This is the first object being hit by the ray from camera through the mouse cursor position.

Automatically updated to always reflect the current mouse position. May be Nil if nothing is hit.

The "mouse cursor position" on touch devices is just the last touch point. When the navigation uses mouse look (like TCastleWalkNavigation.MouseLook), we automatically use viewport center as the "mouse cursor position".

See also

TransformUnderMouse

Current TCastleTransform pointed by the mouse cursor position.

Do not collide with this object when moving by Navigation. It makes sense to put here player avatar (in 3rd person view) or player collision volume (in 1st person view) to allow player to move, not colliding with its own body.

Warning: this symbol is deprecated: use Items.Paused

See TCastleAbstractRootTransform.Paused.

Warning: this symbol is deprecated: assign Items from one TCastleViewport to another to view the same world from multiple viewports

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Warning: this symbol is deprecated: instead of this property: to get, just remember current navigation instance on your side; to set, add it like "MyViewport.InsertBack(MyNavigation)"

Navigation method is an optional component that handles the user input to control the camera.

This is a deprecated property. There's no point in assigning current navigation like this. Instead add the TCastleNavigation instance as a child of TCastleViewport and it will affect the viewport automatically. This property is now only a shortcut to

- get the current TCastleNavigation child (if multiple present, it is undefined which is returned)

- make the given set TCastleNavigation as the only child.

You can assign here an instance of TCastleNavigation, like TCastleWalkNavigation or TCastleExamineNavigation. Or you can leave it as Nil.

Transformations and scenes visible in this viewport. You should add here your TCastleTransform and TCastleScene instances.

It is by default created (not Nil), but you can also assign here your own TCastleRootTransform instance. You can also copy a TCastleRootTransform from one TCastleViewport to another, that is multiple TCastleViewport can refer to the same TCastleRootTransform instance.

Note that assigning here Nil is allowed, but under the hood it just creates an empty TCastleRootTransform instance. So this property is never Nil when reading. But try to not depend on it for the future, at some point this property may be allowed to be Nil, for consistency.

Camera determines the viewer position and orientation.

You should create TCastleCamera, assign to this property, and add it somewhere to Items.

Note that camera can be placed anywhere within Items, not necessary as direct child of Items. For example it can be a children of some deeper TCastleTransform, this way you can attach camera e.g. to some bone or to a moving object.

Generally, TCastleCamera is a regular component that can be added and removed freely from Items, renamed, freed etc. And setting this property is an independent action that doesn't add/remove any camera from Items. This property can also be set to Nil.

For convenience, there are however some moments when we set up this property and add camera to Items automatically:

1. When you create TCastleViewport from code (not by deserializing some xxx.castle-user-interface file, not in design-mode in editor) then we automatically add new (unnamed) camera and set Viewport.Camera and add it to Viewport.Items.

2. Only at design-time (in editor): creating new viewport by editor menu also adds a default camera to it. In this case camera component is named and owned by the same owner as viewport. This is done right after TCastleViewport creation and only at design-time.

3. For backward compatibility, after deserializing file from previous engine versions, we add the camera from it to Viewport.Items. This is made strictly for backward compatibility, only when deserializing, and it shouldn't occur when reading new design files.

It's important to note that when deserializing camera from new engine versions, there's no "magic". We just expect that Viewport.Camera and Viewport.Items are good. Trying to do something automatic/smart in this case turned out to be quite troublesome and breaking more than helping.

Should we render with shadow volumes. You can change this at any time, to switch rendering shadows on/off.

This works only if OpenGL context actually can render shadow volumes, checked by GLFeatures.ShadowVolumesPossible, which means that you have to initialize OpenGL context with stencil buffer.

The shadow volumes algorithm is used only if shadow caster is 2-manifold, that is has a correctly closed volume. Also you need a light source marked as the main shadow volumes light (shadowVolumes = shadowVolumesMain = TRUE). See [https://castle-engine.io/x3d_extensions.php#section_ext_shadows] for details.

Actually draw the shadow volumes to the color buffer, for debugging. If shadows are rendered (see GLFeatures.ShadowVolumesPossible and ShadowVolumes), you can use this to actually see shadow volumes, for debug / demo purposes. Shadow volumes will be rendered on top of the scene, as yellow blended polygons.

Background (like a skybox) to display behind the Items. Displayed only when not Transparent. See https://castle-engine.io/background

Fog to use to display viewport contents in Items. See https://castle-engine.io/fog

If True then the background (from Background or MainScene) will be rendered wireframe, over the solid background filled with BackgroundColor. Useful for debugging when you want to see how your background geometry looks like.

Ignored if Transparent.

If True then the viewport will not draw a background and the UI underneath will be visible. The UI underneath is visible at pixels which are not covered by items on Items, and where items Items have partially-transparent materials.

If True, the Background, BackgroundColor, BackgroundWireframe, and any background defined inside MainScene will be ignored.

At the beginning of rendering, viewport by default clears the depth buffer. This makes every viewport draw everything on top of the previous 2D and 3D stuff (including on top of previous viewport), like a layer.

You can disable this, which allows to combine together the 3D objects rendered by various viewports (and by custom OpenGL rendering), such that the 3D positions determime what overlaps what. This only makes sense if you have a number of TCastleViewport instances, that share the same size and position on the screen, same projection and the same camera.

It's your responsibility in such case to clear the depth buffer. E.g. place one viewport in the back that has ClearDepth = True. Or place a TCastleUserInterface descendant in the back, that calls TRenderContext.Clear RenderContext.Clear in overridden TCastleUserInterface.Render.

Note: to disable clearning the color buffer, set Transparent to False.

Note: if you use shadow volumes, we will still clear the stencil buffer at the beginning of rendering.

Warning: this symbol is deprecated: if you need to tweak this, then do not use MainScene; use regular TCastleScene and set CastGlobalLights as needed

Let lights in MainScene shine on every other TCastleScene, not only MainScene. This is an easy way to lit your whole world with lights defined inside MainScene file. Be sure to set X3D lights global=TRUE.

Warning: this symbol is deprecated: configure fog by assigning to TCastleViewport.Fog component; leave deprecated TCastleViewport.MainScene nil

Let the fog defined in MainScene affect all objects, not only MainScene. This is consistent with UseGlobalLights, that allows lights from MainScene to shine on all objects.

Help user to activate pointing device sensors and pick items. Every time you press Input_Interact (by default just left mouse button), we look if current mouse/touch position hits an object (TCastleTransform) that actually does something on activation. The object may do various stuff inside TCastleTransform.PointingDevicePress, generally this causes various picking/interaction with the object (like pulling a level, opening a door), possibly dragging, possibly with the help of VRML/X3D pointing device and drag sensors.

When this is True, we try harder to hit some 3D object that handles PointingDevicePress. If there's nothing interesting under mouse/touch, we will retry a couple of other positions around the current mouse/touch.

This should be usually used when you use TCastleMouseLookNavigation.MouseLook, or other navigation when mouse cursor is hidden. It allows user to only approximately look at interesting item and hit interaction button or key. Otherwise, activating a small object is difficult, as you don't see the cursor.

Warning: this symbol is deprecated: adjust projection by changing Camera.ProjectionType and other projection parameters inside Camera

Adjust the projection parameters. This event is called before every render. See the CalculateProjection for a description how to default projection parameters are calculated.

Enable to drag a parent control, for example to drag a TCastleScrollView that contains this TCastleViewport, even when the scene inside contains clickable elements (using TouchSensor node).

To do this, you need to turn on TCastleScrollView.EnableDragging, and set EnableParentDragging=True here. In effect, viewport will cancel the click operation once you start dragging, which allows the parent to handle all the motion events for dragging.

Warning: this symbol is deprecated: it is simpler to set camera at design-time explicitly, or use CameraViewpointForWholeScene to auto-adjust camera; if you want to animate the camera, attach TCastleCamera to a bone transformation exposed by Scene.ExposeTransforms

Assign initial camera properties (initial position, direction, up, TCastleCamera.ProjectionNear) by looking at the initial world (Items) when rendering the first frame.

The AssignDefaultCamera is automatically called only if this property is True.

Also, only if this property is True, we synchronize camera when X3D Viewpoint node changes, or a new X3D Viewpoint node is bound.

By default it is False, which means you control Camera properties on your own.

Called when bound Viewpoint node changes. Called exactly when TCastleSceneCore.ViewpointStack.OnBoundChanged is called.

Called when bound NavigationInfo changes (to a different node, or just a field changes).

Protect from falling down because of gravity when position is outside of world bounding box. This is a nice thing for general model viewers (like castle-model-viewer), to prevent from accidentally falling down when using "Walk" mode.

This is only used by navigations performing gravity internally, that is right now: TCastleWalkNavigation (when TCastleWalkNavigation.Gravity = True).

Combine (right before rendering) multiple shapes with a similar appearance into one. This can drastically reduce the number of "draw calls", making rendering much faster.

To debug effectiveness of this, display TCastleViewport.Statistics. In CGE editor (at design-time), use menu item "Edit -> Show Statistics" (F8). When dynamic batching works, the number of rendered shapes and the number of "Draw Calls" should be much smaller.

Use the occlusion culling to optimize the rendering. The shapes obscured by other shapes will not be rendered. This makes sense when in your view, many shapes are typically obscured by others.

See the https://castle-engine.io/occlusion_culling for details how does this work.

To debug effectiveness of this, display TCastleViewport.Statistics. In CGE editor (at design-time), use menu item "Edit -> Show Statistics" (F8). If you look closely at a wall that obscures many shapes behind it, you should see the number of rendered shapes drop significantly using occlusion culling.

This is ignored if GPU doesn't support the necessary functionality (TGLFeatures.OcclusionQuery).

Sort the opaque shapes when rendering, from front to back. This may make a speedup when big shapes in front of camera obscure many shapes behind. This is only an optimization: regardless of the value of this, rendering opaque objects will be always correct. Different values of this properly may merely increase / decrease rendering performance (frames per second).

In general this is an independent optimization from OcclusionCulling, albeit it makes sense in similar situations.

When combined with OcclusionCulling, it makes occlusion culling even more effective. Occlusion culling can reject more shapes, because the things that obscure them are rendered earlier to the depth buffer.

See https://castle-engine.io/occlusion_culling#occlusion_sort for more details.

The default value, sortAuto, for now is equivalent to sortNone. It may change in the future to perform sorting esp. when OcclusionCulling is True, as OcclusionCulling and sorting are a natural pair, sorting make occlusion culling even more effective.

Sort the blending (partially-transparent) shapes when rendering, from back to front.

This makes blending correct when there are multiple partially-transparent objects visible. See blending manual. Invalid value of this may cause rendering artifacts when rendering multiple partially-transparent objects.

The default value, sortAuto, automatically detects if camera is 2D (orthographic, looking in -Z) and if yes, it behaves like sort2D. Otherwise it behaves like sort3D.

Used to sort shapes, if TCastleViewport.BlendingSort or TCastleViewport.OcclusionSort indicate sortCustom. See TShapeSortEvent for usage details and example.

Should the sound listener (that determines how the sounds are heard) be updated to reflect this viewport's active camera. This is True by default, so that 3D sound "just works" out-of-the-box when you have 3D sounds in the TCastleViewport. However, if you use multiple viewports to display the same world from multiple cameras, you should set this to False for all but one viewport.

Active camera comes from Items.MainCamera and should match Camera in all normal circumstances, if you haven't customized Items.MainCamera manually.

BackgroundColor that can be visually edited in Castle Game Engine Editor, Lazarus and Delphi. Normal user code does not need to deal with this, instead read or write BackgroundColor directly.

See also

BackgroundColor

Background color.