AtomicGameEngine-Examples/FeatureExamples/CSharp/Resources/Scripts/11_Physics.cs

//
// Copyright (c) 2008-2015 the Urho3D project.
// Copyright (c) 2015 Xamarin Inc
// Copyright (c) 2016 THUNDERBEAST GAMES LLC
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

using AtomicEngine;

namespace FeatureExamples
{
    public class PhysicsSample : Sample
    {
        Scene scene;
        bool drawDebug;

        public PhysicsSample() : base() { }

        public override void Start()
        {
            base.Start();
            CreateScene();
            SimpleCreateInstructionsWithWasd(
                "\nLMB to spawn physics objects\n" +
                "F5 to save scene, F7 to load\n" +
                "Space to toggle physics debug geometry");
            SetupViewport();
            SubscribeToEvents();
        }

        void SubscribeToEvents()
        {
            // Subscribe HandlePostRenderUpdate() function for
            // processing the post-render update event, sent after
            // Renderer subsystem is done with defining the draw
            // calls for the viewports (but before actually
            // executing them.) We will request debug geometry
            // rendering during that event

            SubscribeToEvent<PostRenderUpdateEvent>(e =>
            {
                // If draw debug mode is enabled, draw viewport debug geometry, which will show eg. drawable bounding boxes and skeleton
                // bones. Note that debug geometry has to be separately requested each frame. Disable depth test so that we can see the
                // bones properly
                if (drawDebug)
                {
                    GetSubsystem<Renderer>().DrawDebugGeometry(false);
                }
            });
        }

        protected override void Update(float timeStep)
        {
            base.Update(timeStep);

            var input = GetSubsystem<Input>();
            var fileSystem = GetSubsystem<FileSystem>();

            SimpleMoveCamera3D(timeStep);

            if (input.GetMouseButtonPress(Constants.MOUSEB_LEFT))
                SpawnObject();

            /* TODO: Scene.SaveXML/Scene.LoadXML

            if (input.GetKeyPress(Constants.KEY_F5))
                scene.SaveXml(fileSystem.UserDocumentsDir + "/Scenes/Physics.xml");

            if (input.GetKeyPress(Constants.KEY_F7))
                scene.LoadXml(fileSystem.UserDocumentsDir + "/Scenes/Physics.xml");

            */

            if (input.GetKeyPress(Constants.KEY_SPACE))
                drawDebug = !drawDebug;
        }

        void SetupViewport()
        {
            var renderer = GetSubsystem<Renderer>();
            renderer.SetViewport(0, new Viewport(scene, CameraNode.GetComponent<Camera>()));
        }

        void CreateScene()
        {
            var cache = GetSubsystem<ResourceCache>();
            scene = new Scene();

            // Create octree, use default volume (-1000, -1000, -1000) to (1000, 1000, 1000)
            // Create a physics simulation world with default parameters, which will update at 60fps. Like the Octree must
            // exist before creating drawable components, the PhysicsWorld must exist before creating physics components.
            // Finally, create a DebugRenderer component so that we can draw physics debug geometry
            scene.CreateComponent<Octree>();
            scene.CreateComponent<PhysicsWorld>();
            scene.CreateComponent<DebugRenderer>();

            // Create a Zone component for ambient lighting & fog control
            Node zoneNode = scene.CreateChild("Zone");
            Zone zone = zoneNode.CreateComponent<Zone>();
            zone.SetBoundingBox(new BoundingBox(-1000.0f, 1000.0f));
            zone.AmbientColor = new Color(0.15f, 0.15f, 0.15f);
            zone.FogColor = new Color(1.0f, 1.0f, 1.0f);
            zone.FogStart = 300.0f;
            zone.FogEnd = 500.0f;

            // Create a directional light to the world. Enable cascaded shadows on it
            Node lightNode = scene.CreateChild("DirectionalLight");
            lightNode.SetDirection(new Vector3(0.6f, -1.0f, 0.8f));
            Light light = lightNode.CreateComponent<Light>();
            light.LightType = LightType.LIGHT_DIRECTIONAL;
            light.CastShadows = true;
            light.ShadowBias = new BiasParameters(0.00025f, 0.5f);
            // Set cascade splits at 10, 50 and 200 world units, fade shadows out at 80% of maximum shadow distance
            light.ShadowCascade = new CascadeParameters(10.0f, 50.0f, 200.0f, 0.0f, 0.8f);

            // Create skybox. The Skybox component is used like StaticModel, but it will be always located at the camera, giving the
            // illusion of the box planes being far away. Use just the ordinary Box model and a suitable material, whose shader will
            // generate the necessary 3D texture coordinates for cube mapping
            Node skyNode = scene.CreateChild("Sky");
            skyNode.SetScale(500.0f); // The scale actually does not matter
            Skybox skybox = skyNode.CreateComponent<Skybox>();
            skybox.Model = cache.Get<Model>("Models/Box.mdl");
            skybox.SetMaterial(cache.Get<Material>("Materials/Skybox.xml"));

            {
                // Create a floor object, 1000 x 1000 world units. Adjust position so that the ground is at zero Y
                Node floorNode = scene.CreateChild("Floor");
                floorNode.Position = new Vector3(0.0f, -0.5f, 0.0f);
                floorNode.Scale = new Vector3(1000.0f, 1.0f, 1000.0f);
                StaticModel floorObject = floorNode.CreateComponent<StaticModel>();
                floorObject.Model = cache.Get<Model>("Models/Box.mdl");
                floorObject.SetMaterial(cache.Get<Material>("Materials/StoneTiled.xml"));

                // Make the floor physical by adding RigidBody and CollisionShape components. The RigidBody's default
                // parameters make the object static (zero mass.) Note that a CollisionShape by itself will not participate
                // in the physics simulation

                floorNode.CreateComponent<RigidBody>();
                CollisionShape shape = floorNode.CreateComponent<CollisionShape>();
                // Set a box shape of size 1 x 1 x 1 for collision. The shape will be scaled with the scene node scale, so the
                // rendering and physics representation sizes should match (the box model is also 1 x 1 x 1.)
                shape.SetBox(Vector3.One, Vector3.Zero, Quaternion.Identity);
            }

            {
                // Create a pyramid of movable physics objects
                for (int y = 0; y < 8; ++y)
                {
                    for (int x = -y; x <= y; ++x)
                    {
                        Node boxNode = scene.CreateChild("Box");
                        boxNode.Position = new Vector3((float)x, -(float)y + 8.0f, 0.0f);
                        StaticModel boxObject = boxNode.CreateComponent<StaticModel>();
                        boxObject.Model = cache.Get<Model>("Models/Box.mdl");
                        boxObject.SetMaterial(cache.Get<Material>("Materials/StoneEnvMapSmall.xml"));
                        boxObject.CastShadows = true;

                        // Create RigidBody and CollisionShape components like above. Give the RigidBody mass to make it movable
                        // and also adjust friction. The actual mass is not important; only the mass ratios between colliding 
                        // objects are significant
                        RigidBody body = boxNode.CreateComponent<RigidBody>();
                        body.Mass = 1.0f;
                        body.Friction = 0.75f;
                        CollisionShape shape = boxNode.CreateComponent<CollisionShape>();
                        shape.SetBox(Vector3.One, Vector3.Zero, Quaternion.Identity);
                    }
                }
            }

            // Create the camera. Limit far clip distance to match the fog. Note: now we actually create the camera node outside
            // the scene, because we want it to be unaffected by scene load / save
            CameraNode = new Node();
            Camera camera = CameraNode.CreateComponent<Camera>();
            camera.FarClip = 500.0f;

            // Set an initial position for the camera scene node above the floor
            CameraNode.Position = (new Vector3(0.0f, 5.0f, -20.0f));
        }

        void SpawnObject()
        {
            var cache = GetSubsystem<ResourceCache>();

            var boxNode = scene.CreateChild("SmallBox");
            boxNode.Position = CameraNode.Position;
            boxNode.Rotation = CameraNode.Rotation;
            boxNode.SetScale(0.25f);

            StaticModel boxModel = boxNode.CreateComponent<StaticModel>();
            boxModel.Model = cache.Get<Model>("Models/Box.mdl");
            boxModel.SetMaterial(cache.Get<Material>("Materials/StoneEnvMapSmall.xml"));
            boxModel.CastShadows = true;

            var body = boxNode.CreateComponent<RigidBody>();
            body.Mass = 0.25f;
            body.Friction = 0.75f;
            var shape = boxNode.CreateComponent<CollisionShape>();
            shape.SetBox(Vector3.One, Vector3.Zero, Quaternion.Identity);

            const float objectVelocity = 10.0f;

            body.SetLinearVelocity(CameraNode.Rotation * new Vector3(0f, 0.25f, 1f) * objectVelocity);
        }

    }
}