Cameras

Trial offers a generic camera system as well as a couple of different default cameras. However, it is very likely that you'll want to heavily customise them to your particular use-case, as optimal camera movement in games is a very difficult and situation-specific topic.

At the basis is the camera, which sets up a projection-matrix via setup-perspective and the view-matrix via project-view. the Each of the cameras also implements a focal-point, which is used for certain rendering optimisations and can be used for special effects as well. It should be the world coordinate of the point the camera is focusing on. You can also test whether an object is visible via in-view-p and query (or override) the approximate size an object takes up on screen via screen-area. The former is used for culling via map-visible, and the latter is used for selecting different LODs. Every camera also holds a near-plane and far-plane used for depth-clipping, a location that describes the camera's eye position, and a bsize that defines the view size.

When a camera is activated, it is simply set as the camera of the current scene object. A scene can have an arbitrary number of cameras registered, but only one active camera at a time. When the camera is switched, the projection matrix is updated anew and rendering will use the new camera. Inactive cameras will still receive events however. It is up to you to only handle events for cameras when they should as needed for your game.

Trial attempts to do a best-effort at determining frustum culling automatically. However, it may be useful to override in-view-p for your own cameras and objects to customise their visibility behaviour.

2D Cameras

The 2d-camera is the base class used for orthographic projection 2D cameras.

The sidescroll-camera adds a zoom factor and will smoothly track towards a target location or object.

the 2d-editor-camera implements basic WASD movement, with C and Space for lateral movement. You can hold left shift for faster movement, and left alt for slower movement, and customise the base move-speed. This camera will inherit the previous camera's location when activated, making it an easy way to switch into an "editor mode".

3D Cameras

The 3d-camera is the base class used for perspective projection 3D cameras, based on the fov parameter. The fov is designated in degrees, and should be between 0 and 180.

The target-camera simply ensures that the camera is always looking at the target position. The target should be some kind of object with a location that resolves to a world-space position.

The following-camera instead uses the camera's location as a fixed offset from the target.

The fps-camera implements basic first-person look using mouse input. Using the x-acceleration and y-acceleration properties you can control the speed of the turning and invert it for each axis separately as well.

The freeroam-camera additionally implements moving and strafing on top of the fps-camera using basic WASD movement, with C and Space for lateral movement. You can hold left shift for faster movement, and left alt for slower movement, and customise the base move-speed. However, since neither the freeroam nor the basic fps camera use the action system, it is recommended that you instead replicate their logic in your own system.

The editor-camera builds further upon the freeroam-camera, locking the looking behind holding left control or middle mouse, to ensure you can interact without changing the view. This camera will also inherit the previous camera's parameters when activated, making it an easy way to switch into an "editor mode".