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| public:t-vien-08-1:lab_4_materials [2008/01/31 04:02] – hannes | public:t-vien-08-1:lab_4_materials [2024/04/29 13:33] (current) – external edit 127.0.0.1 |
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| ====== Lab 4 - Events, Collision and Movement ====== | ====== Lab 4 - Events, Collision and Movement ====== |
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| ==== Before You Start ==== | ==== Before You Start ==== |
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| * Download and unzip the [[http://www.ru.is/kennarar/hannes/classes/ve2008/Lab4Assets.zip|Lab 4 Asset File]] into your working director | * Download and unzip the [[http://www.ru.is/kennarar/hannes/classes/ve2008/Lab4Assets.zip|Lab 4 Asset File]] into your working directory |
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| ==== Making a functional trap door ==== | ==== Making a functional trap door ==== |
| {{public:t-vien-07-1:ve-lab4-screenshot.jpg|}} | {{public:t-vien-07-1:ve-lab4-screenshot.jpg|}} |
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| - **Creating a new scene:**\\ Create a new program called "factory.py" and include the following imports at the beginning of the file:<code python> | - **Creating a New Scene:**\\ Create a new program called "factory.py" and include the following imports at the beginning of the file:<code python> |
| import direct.directbase.DirectStart | import direct.directbase.DirectStart |
| from direct.showbase.DirectObject import DirectObject | from direct.showbase.DirectObject import DirectObject |
| from direct.interval.IntervalGlobal import * | from direct.interval.IntervalGlobal import * |
| </code> In your code, you should disable the mouse and then place the **camera** at **(1,-8,5)** with a pitch of **-25 degrees**. Then define a class called **World** that derives from **DirectObject** (this allows **World** to receive events). In the constructor of the **World** class load and display two models: **./Models/factoryfloor.egg** and **./Models/box.egg**. Position the box at **(1,0,2)**, scale it down to **30%** and give it a heading of **45 degrees**. Make sure you can see both the floor and the box. | </code> In your code, you should disable the mouse and then place the **camera** at **(1,-8,5)** with a pitch of **-25 degrees**. Then define a class called **World** that derives from **DirectObject** (this allows **World** to receive events). In the constructor of the **World** class load and display two models: **./Models/factoryfloor.egg** and **./Models/box.egg**. Position the box at **(1,0,2)**, scale it down to **30%** and give it a heading of **45 degrees**. Make sure you can see both the floor and the box. |
| - **Opening and closing the door:**\\ The floor model contains a **door** sub-object. Acquire a pathnode to it, using ''<pathnode>.find'', and call it **door**. Create two **[[http://www.panda3d.org/wiki/index.php/Lerp_Intervals|LerpPosInterval]]**s for the **door**, one to open it by moving it to location **(-1,0,0)** and one to close it by moving it to location **(1,0,0)**. You can play with the duration but **2.0 seconds** is a good place to start. Make the **World** accept a 'space' (spacebar key) event and call the associated event handler **self.door_handler**. In that handler, either start the opening interval for the door or the closing interval, depending on whether it's open or closed already (you'll need a new boolean member variable to keep track of that). Make sure you can now open and close the door with the spacebar.\\ | - **Opening and Closing the Door:**\\ The floor model contains a **door** sub-object. Acquire a pathnode to it, using ''<pathnode>.find'', and call it **door**. Create two **[[http://www.panda3d.org/wiki/index.php/Lerp_Intervals|LerpPosInterval]]**s for the **door**, one to open it by moving it to location **(-1,0,0)** and one to close it by moving it to location **(1,0,0)**. You can play with the duration but **2.0 seconds** is a good place to start. Make the **World** accept a 'space' (spacebar key) event and call the associated event handler **self.door_handler**. In that handler, either start the opening interval for the door or the closing interval, depending on whether it's open or closed already (you'll need a new boolean member variable to keep track of that). Make sure you can now open and close the door with the spacebar.\\ |
| - **Using blendType and name to improve door movement:**\\ When you create the opening and closing intervals, give the constructor attribute **blendType** a value of **"easeInOut"** for a bit more realistic trap door motion (you can play with the other values **"easeIn"** and **"easeOut"** as well). Also, give the attribute **name** the same name for both intervals - this ensures that the first interval gets cancelled when the second one gets starts. | - **Using blendType and name to Improve Door Movement:**\\ When you create the opening and closing intervals, give the constructor attribute **blendType** a value of **"easeInOut"** for a bit more realistic trap door motion (you can play with the other values **"easeIn"** and **"easeOut"** as well). Also, give the attribute **name** the same name for both intervals - this ensures that the first interval gets cancelled when the second one gets starts. |
| - **Creating Collision Solids:**\\ Attach a new **CollisionNode** to the box pathnode and give it the name **"box"** (you pass the name into the constructor of the CollisionNode). To the node of this new pathnode, add a new collision solid of the type sphere and give it a radius of **1.5**.<code python> | - **Creating Collision Solids:**\\ Attach a new **CollisionNode** to the box pathnode and give it the name **"box"** (you pass the name into the constructor of the CollisionNode). To the node of this new pathnode, add a new collision solid of the type sphere and give it a radius of **1.5**.<code python> |
| # HINT - Creating and attaching a CollisionSphere | # HINT - Creating and attaching a CollisionSphere |
| nodepath.node().addSolid(CollisionPolygon(Point3(x1,y1,z1),Point3(x2,y2,z2),Point3(x3,y3,z3),Point3(x4,y4,z4))) | nodepath.node().addSolid(CollisionPolygon(Point3(x1,y1,z1),Point3(x2,y2,z2),Point3(x3,y3,z3),Point3(x4,y4,z4))) |
| </code> You can call **show()** on your new collision node nodepaths to see your collision solids as semi-transparent objects when you view your scene. Verify that your solids are in the right place and then remove the calls to show(). | </code> You can call **show()** on your new collision node nodepaths to see your collision solids as semi-transparent objects when you view your scene. Verify that your solids are in the right place and then remove the calls to show(). |
| - **Making the box move:**\\ Create a new **LerpPosInterval** for the box and have it move to the location **(1,0,-1)**. Make the **World** accept a 'mouse1' event and call a method that starts this interval playing. A duration of **3.0 seconds** for this movement seems good and you might want to try different blend types. Verify that you can make the box move by clicking the left mouse button. Notice that the box goes right through the door. | - **Making the Box Move:**\\ Create a new **LerpPosInterval** for the box and have it move to the location **(1,0,-1)**. Make the **World** accept a 'mouse1' event and call a method that starts this interval playing. A duration of **3.0 seconds** for this movement seems good and you might want to try different blend types. Verify that you can make the box move by clicking the left mouse button. Notice that the box goes right through the door. |
| - **Making a collision happen:**\\ In the **World** constructor, create a new instance of a **CollisionHandlerEvent** and add the event pattern shown below:<code python> | - **Making a Collision Happen:**\\ In the **World** constructor, create a new instance of a **CollisionHandlerEvent** and add the event pattern shown below:<code python> |
| collhandler = CollisionHandlerEvent() | collhandler = CollisionHandlerEvent() |
| collhandler.addInPattern('%fn-into-%in') # The event pattern | collhandler.addInPattern('%fn-into-%in') # The event pattern |
| print collEntry | print collEntry |
| </code> In addition to printing out some information like is done in this example, you should call the **pause()** method on the LerpPosInterval associated with the box object. This will stop the progress of the box movement. Verify that the box stops now when the door is closed but goes all the way down when the door is open. | </code> In addition to printing out some information like is done in this example, you should call the **pause()** method on the LerpPosInterval associated with the box object. This will stop the progress of the box movement. Verify that the box stops now when the door is closed but goes all the way down when the door is open. |
| - **Adding sounds:**\\ To add sounds to this scene, you can use **thud.wav** for when the box hits the door and **close.wav** for when the door slams shut. You don't have to localize these sounds, just load them in like this: <code python> | - **Adding Sounds:**\\ To add sounds to this scene, you can use **thud.wav** for when the box hits the door and **close.wav** for when the door slams shut. You don't have to localize these sounds, just load them in like this: <code python> |
| thudsound = loader.loadSfx("thud.wav") | thudsound = loader.loadSfx("thud.wav") |
| closesound = loader.loadSfx("close.wav") | closesound = loader.loadSfx("close.wav") |
| </code> The very last thing to do is to call **''self.contactgroup.empty()''** right after you have called **''self.world.step(0.04)''** in order to start looking for fresh collisions after each iteration. Test to see if everything is working. \\ | </code> The very last thing to do is to call **''self.contactgroup.empty()''** right after you have called **''self.world.step(0.04)''** in order to start looking for fresh collisions after each iteration. Test to see if everything is working. \\ |
| - Play with various simulation values to see what effect they have on the object behavior. You could also try adding more boxes and have them pile on top of each other! | - Play with various simulation values to see what effect they have on the object behavior. You could also try adding more boxes and have them pile on top of each other! |
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| | {{:public:t-vien-07-1:lab4solution.zip|.}} |
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