1-- Urho2D physics sample.
2-- This sample demonstrates:
3--     - Creating both static and moving 2D physics objects to a scene
4--     - Displaying physics debug geometry
5
6require "LuaScripts/Utilities/Sample"
7
8function Start()
9    -- Execute the common startup for samples
10    SampleStart()
11
12    -- Create the scene content
13    CreateScene()
14
15    -- Create the UI content
16    CreateInstructions()
17
18    -- Setup the viewport for displaying the scene
19    SetupViewport()
20
21    -- Set the mouse mode to use in the sample
22    SampleInitMouseMode(MM_FREE)
23
24    -- Hook up to the frame update events
25    SubscribeToEvents()
26end
27
28function CreateScene()
29    scene_ = Scene()
30
31    -- Create the Octree component to the scene. This is required before adding any drawable components, or else nothing will
32    -- show up. The default octree volume will be from (-1000, -1000, -1000) to (1000, 1000, 1000) in world coordinates it
33    -- is also legal to place objects outside the volume but their visibility can then not be checked in a hierarchically
34    -- optimizing manner
35    scene_:CreateComponent("Octree")
36    scene_:CreateComponent("DebugRenderer")
37
38    -- Create a scene node for the camera, which we will move around
39    -- The camera will use default settings (1000 far clip distance, 45 degrees FOV, set aspect ratio automatically)
40    cameraNode = scene_:CreateChild("Camera")
41    -- Set an initial position for the camera scene node above the plane
42    cameraNode.position = Vector3(0.0, 0.0, -10.0)
43    local camera = cameraNode:CreateComponent("Camera")
44    camera.orthographic = true
45    camera.orthoSize = graphics.height * PIXEL_SIZE
46    camera.zoom = 1.2 * Min(graphics.width / 1280, graphics.height / 800) -- Set zoom according to user's resolution to ensure full visibility (initial zoom (1.2) is set for full visibility at 1280x800 resolution)
47
48    -- Create 2D physics world component
49    scene_:CreateComponent("PhysicsWorld2D")
50
51    local boxSprite = cache:GetResource("Sprite2D", "Urho2D/Box.png")
52    local ballSprite = cache:GetResource("Sprite2D", "Urho2D/Ball.png")
53
54    -- Create ground.
55    local groundNode = scene_:CreateChild("Ground")
56    groundNode.position = Vector3(0.0, -3.0, 0.0)
57    groundNode.scale = Vector3(200.0, 1.0, 0.0)
58
59    -- Create 2D rigid body for gound
60    local groundBody = groundNode:CreateComponent("RigidBody2D")
61
62    local groundSprite = groundNode:CreateComponent("StaticSprite2D")
63    groundSprite.sprite = boxSprite
64
65    -- Create box collider for ground
66    local groundShape = groundNode:CreateComponent("CollisionBox2D")
67    -- Set box size
68    groundShape.size = Vector2(0.32, 0.32)
69    -- Set friction
70    groundShape.friction = 0.5
71
72    local NUM_OBJECTS = 100
73    for i = 1, NUM_OBJECTS do
74        local node  = scene_:CreateChild("RigidBody")
75        node.position = Vector3(Random(-0.1, 0.1), 5.0 + i * 0.4, 0.0)
76
77        -- Create rigid body
78        local body = node:CreateComponent("RigidBody2D")
79        body.bodyType = BT_DYNAMIC
80
81        local staticSprite = node:CreateComponent("StaticSprite2D")
82        local shape = nil
83        if i % 2 == 0 then
84            staticSprite.sprite = boxSprite
85            -- Create box
86            shape = node:CreateComponent("CollisionBox2D")
87            -- Set size
88            shape.size = Vector2(0.32, 0.32)
89        else
90            staticSprite.sprite = ballSprite
91            -- Create circle
92            shape = node:CreateComponent("CollisionCircle2D")
93            -- Set radius
94            shape.radius = 0.16
95        end
96        -- Set density
97        shape.density = 1.0
98        -- Set friction
99        shape.friction = 0.5
100        -- Set restitution
101        shape.restitution = 0.1
102    end
103end
104
105function CreateInstructions()
106    -- Construct new Text object, set string to display and font to use
107    local instructionText = ui.root:CreateChild("Text")
108    instructionText:SetText("Use WASD keys and mouse to move, Use PageUp PageDown to zoom.")
109    instructionText:SetFont(cache:GetResource("Font", "Fonts/Anonymous Pro.ttf"), 15)
110
111    -- Position the text relative to the screen center
112    instructionText.horizontalAlignment = HA_CENTER
113    instructionText.verticalAlignment = VA_CENTER
114    instructionText:SetPosition(0, ui.root.height / 4)
115end
116
117function SetupViewport()
118    -- Set up a viewport to the Renderer subsystem so that the 3D scene can be seen. We need to define the scene and the camera
119    -- at minimum. Additionally we could configure the viewport screen size and the rendering path (eg. forward / deferred) to
120    -- use, but now we just use full screen and default render path configured in the engine command line options
121    local viewport = Viewport:new(scene_, cameraNode:GetComponent("Camera"))
122    renderer:SetViewport(0, viewport)
123end
124
125function MoveCamera(timeStep)
126    -- Do not move if the UI has a focused element (the console)
127    if ui.focusElement ~= nil then
128        return
129    end
130
131    -- Movement speed as world units per second
132    local MOVE_SPEED = 4.0
133
134    -- Read WASD keys and move the camera scene node to the corresponding direction if they are pressed
135    if input:GetKeyDown(KEY_W) then
136        cameraNode:Translate(Vector3(0.0, 1.0, 0.0) * MOVE_SPEED * timeStep)
137    end
138    if input:GetKeyDown(KEY_S) then
139        cameraNode:Translate(Vector3(0.0, -1.0, 0.0) * MOVE_SPEED * timeStep)
140    end
141    if input:GetKeyDown(KEY_A) then
142        cameraNode:Translate(Vector3(-1.0, 0.0, 0.0) * MOVE_SPEED * timeStep)
143    end
144    if input:GetKeyDown(KEY_D) then
145        cameraNode:Translate(Vector3(1.0, 0.0, 0.0) * MOVE_SPEED * timeStep)
146    end
147
148    if input:GetKeyDown(KEY_PAGEUP) then
149        local camera = cameraNode:GetComponent("Camera")
150        camera.zoom = camera.zoom * 1.01
151    end
152
153    if input:GetKeyDown(KEY_PAGEDOWN) then
154        local camera = cameraNode:GetComponent("Camera")
155        camera.zoom = camera.zoom * 0.99
156    end
157end
158
159function SubscribeToEvents()
160    -- Subscribe HandleUpdate() function for processing update events
161    SubscribeToEvent("Update", "HandleUpdate")
162
163    -- Unsubscribe the SceneUpdate event from base class to prevent camera pitch and yaw in 2D sample
164    UnsubscribeFromEvent("SceneUpdate")
165end
166
167function HandleUpdate(eventType, eventData)
168    -- Take the frame time step, which is stored as a float
169    local timeStep = eventData["TimeStep"]:GetFloat()
170
171    -- Move the camera, scale movement with time step
172    MoveCamera(timeStep)
173end
174
175-- Create XML patch instructions for screen joystick layout specific to this sample app
176function GetScreenJoystickPatchString()
177    return
178        "<patch>" ..
179        "    <remove sel=\"/element/element[./attribute[@name='Name' and @value='Button0']]/attribute[@name='Is Visible']\" />" ..
180        "    <replace sel=\"/element/element[./attribute[@name='Name' and @value='Button0']]/element[./attribute[@name='Name' and @value='Label']]/attribute[@name='Text']/@value\">Zoom In</replace>" ..
181        "    <add sel=\"/element/element[./attribute[@name='Name' and @value='Button0']]\">" ..
182        "        <element type=\"Text\">" ..
183        "            <attribute name=\"Name\" value=\"KeyBinding\" />" ..
184        "            <attribute name=\"Text\" value=\"PAGEUP\" />" ..
185        "        </element>" ..
186        "    </add>" ..
187        "    <remove sel=\"/element/element[./attribute[@name='Name' and @value='Button1']]/attribute[@name='Is Visible']\" />" ..
188        "    <replace sel=\"/element/element[./attribute[@name='Name' and @value='Button1']]/element[./attribute[@name='Name' and @value='Label']]/attribute[@name='Text']/@value\">Zoom Out</replace>" ..
189        "    <add sel=\"/element/element[./attribute[@name='Name' and @value='Button1']]\">" ..
190        "        <element type=\"Text\">" ..
191        "            <attribute name=\"Name\" value=\"KeyBinding\" />" ..
192        "            <attribute name=\"Text\" value=\"PAGEDOWN\" />" ..
193        "        </element>" ..
194        "    </add>" ..
195        "</patch>"
196end
197