Anaglym exposes a Lua library named ag which contains functions for interfacing with the Engine. In addition to the ag library, there is a std library which contains a "standard library" of Lua functions that do not directly interface with the Anaglym engine. The library functions are documented below.
ag.clearEventHandler(event_name)
This function removes a Lua callback function from being associated with the engine event specified. event_name should be one of the following strings:
ag.doPhysics()
This function invokes the physics processing part of the engine. It is invoked automatically every update step if the "AutoPhysics" mode is enabled; this mode is enabled by default. See setAutoPhysics for more information.
ag.drawObjects()
This function instructs the engine to draw all visible objects. It is invoked automatically every update step if the "AutoDrawObjects" mode is enabled; this mode is enabled by default. See setAutoDrawObjects for more information.
elapsed_msec = ag.elapsedTime()
This function returns the number of milliseconds that have elapsed since the beginning of the program.
ag.endFrame()
This function signals the engine that all drawing is complete for the current update frame. It is invoked automatically if the "AutoEndFrame" mode is enabled; this mode is enabled by default. See setAutoEndFrame for more information.
ag.exit()
This function instructs the engine to exit. Internally, this function enqueues an "exit" event on the event queue to be processed by the engine. This means that Lua code following the call to exit() will be executed and callbacks to other events may still be called. The engine should exit within one update step.
eye_x, eye_y, eye_z, center_x, center_y, center_z, up_x, up_y, up_z = ag.getCamera()
This function returns the camera position (eye coordinates), focus position (center coordinates), and up vector for the current camera settings.
width, height = ag.getScreenSize()
This function returns the dimensions of the engine window, in pixels.
ag.import(lua_source_name)
This function instructs the engine to import a Lua source file named lua_source_name, which should be a string specifying the name of the Lua library without the ".lua" extension. Source files are searched for relative to the folder containing the hosted script first, then relative to the engine library folder. The import() function can be used to load Lua code that is broken into separate source files, and to load libraries such as std.
result = ag.isKeyDown(key)
This function returns a boolean value for whether or not the key given by key is currently pressed or not. key should be a string corresponding to a key name. See keys for key names.
object = ag.loadModel(model_name [, scale])
This function loads an object file and returns the object loaded. If the returned value is nil, loading of the object failed. model_name should be a string specifying the base name of the model file, without the ".obj" extension. Models are searched for relative to the folder containing the hosted script first, then relative to the engine library folder. scale is an optional parameter that defaults to 1.0.
object = ag.loadModelStatic(model_name [, scale])
loadModelStatic() is the same as loadModel(), with the exception that the object loaded is created as a static object. A static object can still be placed with setPosition() and setRotation(). A static object will participate in collision detection when physics computations are performed, however a static object will not be moved by any colliding objects.
texture = ag.loadTexture(texture_name)
This function loads a texture file from the file system and returns a Lua reference to the loaded texture. nil is returned if loading the texture fails. The texture_name should contain the file extension, since multiple formats are supported (.jpg, .png, .bmp, etc...). Textures are searched for relative to the folder containing the hosted script first, then relative to the engine library folder.
ag.print(args...)
This function prints its arguments to the standard output. It is mainly used for debugging when developing Lua scripts. On Windows, this output stream may be redirected to a file (stdout.txt). Example usage:
local x, y, z = my_obj:getPosition()
ag.print("my_obj position: (", x, ", ", y, ", ", z, ")")
ag.println(args...)
Identical to print() but automatically prints a newline ("\n") after printing the arguments.
ag.registerEventHandler(event_name, handler)
This function registers a Lua callback function (handler) to be called when the engine event specified by event_name occurs. There can be only one registered handler per event, so if a previous Lua function was registered for event_name, it will be overwritten to call the new handler. event_name should be one of:
When the Lua script is initially loaded, any functions found that have names matching an event name with "_event" appended (ex. "mouse_motion_event" for the "mouse_motion" event) are registered automatically as handlers for their corresponding events.
ag.setAutoDrawObjects(enable_flag)
This function sets the "AutoDrawObjects" mode. enable_flag should be true or false. If AutoDrawObjects mode is enabled, then all visible objects in the engine will be drawn automatically every update step. If it is not enabled, one can call ag.drawObjects() to draw all visible objects in the scene. The AutoDrawObjects mode is initially enabled.
ag.setAutoEndFrame(enable_flag)
This function sets the "AutoEndFrame" mode. enable_flag should be true or false. If AutoEndFrame mode is enabled, then ag.endFrame() will be invoked automatically after executing the update and update_overlay Lua callback functions. The AutoEndFrame mode is initially enabled.
ag.setAutoPhysics(enable_flag)
This function sets the "AutoPhysics" mode. enable_flag should be true or false. If AutoPhysics mode is enabled, then collision detection and physics processing are performed automatically on every update step. If it is not enabled, one can call ag.doPhysics() to perform physics updates. The AutoPhysics mode is initially enabled.
ag.setAutoStartFrame(enable_flag)
This function sets the "AutoStartFrame" mode. enable_flag should be true or false. If AutoStartFrame mode is enabled, then ag.startFrame() will be invoked automatically prior to executing the update and update_overlay Lua callback functions. The AutoStartFrame mode is initially enabled.
ag.setCamera(eye_x, eye_y, eye_z [, center_x, center_y, center_z [, up_x, up_y, up_z] ])
This function sets the camera position (eye coordinates), focus point (center coordinates), and up vector. If the center coordinates or up vector are not specified, their values are unchanged from the previous invocation of setCamera(). The default center point is (0, 0, 0). The default up vector is (0, 0, 1).
ag.startFrame()
This function instructs the engine to begin drawing a frame. It is not necessary to call this function if the "AutoStartFrame" mode is enabled. See ag.setAutoStartFrame().
The following functions can be used to create "managed" objects. These objects are "managed" by the Lua script (as opposed to having all of their attributes defined in a model file). The properties of managed objects, such as the color, texture, position, and rotation, can be controlled by using the object member functions.
obj = ag.createBox(width, depth, height)
This function creates a managed object which is a box with dimensions given by (width, depth, height).
obj = ag.createBoxStatic(width, depth, height)
Identical to ag.createBox() except that the created object is static.
obj = ag.createCapsule(radius, length)
This function creates a capsule managed object. A capsule is like a cylinder, but has a half-sphere "capping" each end of the cylinder. radius specifies the radius of the cylinder (and caps). length specifies the length of the straight part of the capsule (not including the caps). The capsule is oriented with its axis along the Z axis and its center point at the origin.
obj = ag.createCapsuleStatic(radius, length)
Identical to ag.createCapsule() except that the created object is static.
obj = ag.createCylinder(radius, length)
This function creates a cylinder managed object. radius specifies the radius of the cylinder. length specifies the length of the cylinder. The cylinder is oriented with its axis along the Z axis and its center point at the origin.
obj = ag.createCylinderStatic(radius, length)
Identical to ag.createCylinder() except that the created object is static.
1) obj = ag.createPlane(a, b, c, d)
2) obj = ag.createPlane(x, y, z, rot_x, rot_y, rot_z)
The createPlane() function creates a managed plane object. All planes are static and are not moved as a result of physics collisions (other objects can still bounce off them). In the four-argument form, the plane is created with equation ax + by + cz = d. (a, b, c) specifies the normal vector for the plane. In the six-argument form, the plane is created by specifying a point on the plane, with coordinates (x, y, z), and the Euler rotation angles around the x, y, and z axis. Specifying no rotation would use the default plane normal of (0, 0, 1). If you would like to create a plane by specifying a point on the surface and the surface normal, see the std.createPlanePtNormal() function.
obj = ag.createSphere(radius)
This function creates a managed sphere object with the radius given.
obj = ag.createSphereStatic(radius)
Identical to ag.createSphere() except that the created object is static.
obj:addForce(xf, yf, zf)
This function adds a one-time force to obj with a force vector (xf, yf, zf).
obj:addForceRel
This function adds a one-time force to obj with a force vector (xf, yf, zf) which is relative to the local reference frame of obj.
obj:addTorque(xr, yr, zr)
This function adds torque (a rotational force) to obj. The torque vector around global axes x, y, z is given by (xr, yr, zr).
obj:addTorqueRel(xr, yr, zr)
This function adds torque (a rotational force) to obj. The torque vector around the local axes x, y, z of obj is given by (xr, yr, zr).
new_obj = obj:clone()
This function makes a copy of the object in the engine. This is more efficient then recreating the object in whatever manner was used to create obj. new_obj will have all of its own parameters - position, rotation, color, texture, etc... However, these parameters will be instantiated with the corresponding values from obj at the time of cloning. One should call new_obj:setPosition() in order to place new_obj somewhere where it is not intersecting with other objects in order to pacify the physics engine.
obj:destroy()
This function destroys the object in the engine. obj should not be used after this method is called.
obj:draw()
This function will draw obj to the screen. It is called automatically by ag.drawObjects(), so calling it is only required if the "AutoDrawObjects" mode is disabled, and ag.drawObjects() is not called.
mass = obj:getMass()
This function returns the mass of obj.
x, y, z = obj:getPosition()
This function returns the coordinates (x, y, z) of the object. Normally, the center-of-mass of the object is located at its local origin. The coordinates of the object's local origin are returned by this call, so these coordinates will be the coordinates of the object's center-of-mass.
obj:setColor(r, g, b)
This function sets the color of the object. The parameters correspond to the red, green, and blue components of the object color. Each component should be between 0.0 and 1.0.
obj:setMass(new_mass)
This function sets the mass of obj to new_mass.
obj:setPosition(x, y, z)
This function sets the coordinates for the object's center-of-mass (local origin) to (x, y, z).
obj:setRotation(xr, yr, zr)
This function sets the object's rotation to that specified by Euler angles (xr, yr, zr).
obj:setTexture(tex)
This function sets the texture of obj to tex. tex is a Lua reference to a texture loaded with ag.loadTexture().
obj:setVisible(visible_flag)
This function sets the visibility of obj to visible_flag. If visible_flag is true, then the object will be drawn.