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  • My app has some basic problems, and it stops working

    - by user2882662
    I am writing a basic application which contains two activities. Both contain a TextView showing the title and the first one contains an EditText in which the user types a message and clicks on a button on its side, the second activity is launched which shows the message the user types. It has the following problems: The title (the first TextView in both the activities) doesn't show in the middle of the line, despite of the android:gravity="center_horizontal" attribute. The EditText in the first activity does not show at all. When I click on the button, the app stops saying "Unfortunately Write n Display and stopped.", rather than launching the second activity at all. I don't have adequate knowledge about logcat, but I have followed the steps somebody had told me, that is WindowOpen Perspective Other DDMS Then run the app and select the package name from the Devices and click on log cat, select the exception(s) and export to text file. All contained in the text file is : : E/(): Device disconnected: 1 Since I am not sure of using log cat, so I am posting a screenshot to make clear what I have done. CODE OF FIRST ACTIVITY: - package com.practice.myfirstapp1; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.EditText; //import android.view.Menu; public class MainActivity extends Activity { public static final String key_name="com.practice.firstApp.key"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } private void sendMessage(View view){ Intent intent= new Intent(this, SecondActivity.class); EditText editText=(EditText) findViewById(R.id.EditText1_MainActivity); String key_value= editText.getText().toString(); intent.putExtra(key_name, key_value); startActivity(intent); } } LAYOUT OF FIRST ACTIVITY: - <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" > <TextView android:id="@+id/TextView1_MainActivity" android:layout_alignParentTop="true" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@+string/title_MainActivity" android:gravity="center_horizontal" android:textStyle="bold"/> <EditText android:id="@+id/EditText1_MainActivity" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_below="@+id/TextView1_MainActivity" android:hint="@string/EditText_MainActivity" android:textStyle="italic" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/TextView1_MainActivity" android:layout_toRightOf="@id/EditText1_MainActivity" android:text="@string/Button_MainActivity" android:onClick="sendMessage"/> </RelativeLayout> CODE OF SECOND ACTIVITY: - package com.practice.myfirstapp1; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.widget.TextView; class SecondActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); Intent intent= getIntent(); String intent_value= intent.getStringExtra(MainActivity.key_name); TextView textView= new TextView(this); textView= (TextView) findViewById(R.id.TextView2_SecondActivity); textView.setText(intent_value); } } LAYOUT OF SECOND ACTIVITY: - <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="horizontal" tools:context=".SecondActivity"> <TextView android:layout_alignParentTop="true" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@+string/title_SecondActivity" android:gravity="center_horizontal" android:textStyle="bold"/> <TextView android:id="@+id/TextView2_SecondActivity" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </RelativeLayout> STRINGS RESOURCE FILE:- <?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">Write n Display</string> <string name="action_settings">Settings</string> <string name="title_MainActivity">WRITE</string> <string name="EditText_MainActivity">Your Message here</string> <string name="Button_MainActivity">Send</string> <string name="title_SecondActivity">DISPLAY</string> </resources> ANDROID MANIFEST FILE: - <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.practice.myfirstapp1" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="18" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" android:debuggable="true" > <activity android:name="com.practice.myfirstapp1.MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name="com.practive.myfirstapp1.SecondActivity" android:label="@string/app_name"> </activity> </application> </manifest>

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  • coloring box2d body in LibGDX

    - by ved
    I want to color polygon of box2d in LibGDX. Found below useful class for that. http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/graphics/glutils/ShapeRenderer.html But, it is not coloring the body instead making colored shapes. I want colored bodies having all the property like gravity, restitution etc. In brief, I want to make colored ball and surface.And i don't want to attach sprite on bodies. Want just fill color in bodies. Need some guidance????

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  • Game Physics: Implementing Normal Reaction from ground correctly

    - by viraj
    I am implementing a simple side scrolling platform game. I am using the following strategy while coding the physics: Gravity constantly acts on the character. When the character is touching the floor, a normal reaction is exerted by the floor. I face the following problem: If the character is initially at a height, he acquires velocity in the -Y direction. Thus, when he hits the floor, he falls through even though normal force is being exerted. I could fix this by setting the Y velocity to 0, and placing him above the floor if he has collided with it. But this often leads to the character getting stuck in the floor or bouncing around it. Is there a better approach ?

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  • How to do reflective collisions with particles hitting background tiles?

    - by Shawn LeBlanc
    In my 2d pixel old-school platformer, I'm looking for methods for bouncing particles off of background tiles. Particles aren't affected by gravity and collisions are "reflective". By that I mean a particle hitting the side of a square tile at 45 degrees should bounce off at 45 degrees as well. We can assume that tiles will always be perfectly square. No slopes or anything. What are efficient methods and algorithms to do this? I'd be implementing this on a Sega Genesis.

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  • How to change speed without changing path travelled?

    - by Ben Williams
    I have a ball which is being thrown from one side of a 2D space to the other. The formula I am using for calculating the ball's position at any one point in time is: x = x0 + vx0*t y = y0 + vy0*t - 0.5*g*t*t where g is gravity, t is time, x0 is the initial x position, vx0 is the initial x velocity. What I would like to do is change the speed of this ball, without changing how far it travels. Let's say the ball starts in the lower left corner, moves upwards and rightwards in an arc, and finishes in the lower right corner, and this takes 5s. What I would like to be able to do is change this so it takes 10s or 20s, but the ball still follows the same curve and finishes in the same position. How can I achieve this? All I can think of is manipulating t but I don't think that's a good idea. I'm sure it's something simple, but my maths is pretty shaky.

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  • 2D Platformer Collision Handling

    - by defender-zone
    Hello, everyone! I am trying to create a 2D platformer (Mario-type) game and I am some having some issues with handling collisions properly. I am writing this game in C++, using SDL for input, image loading, font loading, etcetera. I am also using OpenGL via the FreeGLUT library in conjunction with SDL to display graphics. My method of collision detection is AABB (Axis-Aligned Bounding Box), which is really all I need to start with. What I need is an easy way to both detect which side the collision occurred on and handle the collisions properly. So, basically, if the player collides with the top of the platform, reposition him to the top; if there is a collision to the sides, reposition the player back to the side of the object; if there is a collision to the bottom, reposition the player under the platform. I have tried many different ways of doing this, such as trying to find the penetration depth and repositioning the player backwards by the penetration depth. Sadly, nothing I've tried seems to work correctly. Player movement ends up being very glitchy and repositions the player when I don't want it to. Part of the reason is probably because I feel like this is something so simple but I'm over-thinking it. If anyone thinks they can help, please take a look at the code below and help me try to improve on this if you can. I would like to refrain from using a library to handle this (as I want to learn on my own) or the something like the SAT (Separating Axis Theorem) if at all possible. Thank you in advance for your help! void world1Level1CollisionDetection() { for(int i; i < blocks; i++) { if (de2dCheckCollision(ball,block[i],0.0f,0.0f)==true) { int up = 0; int left = 0; int right = 0; int down = 0; if(ball.coords[0] < block[i].coords[0] && block[i].coords[0] < ball.coords[2] && ball.coords[2] < block[i].coords[2]) { left = 1; } if(block[i].coords[0] < ball.coords[0] && ball.coords[0] < block[i].coords[2] && block[i].coords[2] < ball.coords[2]) { right = 1; } if(ball.coords[1] < block[i].coords[1] && block[i].coords[1] < ball.coords[3] && ball.coords[3] < block[i].coords[3]) { up = 1; } if(block[i].coords[1] < ball.coords[1] && ball.coords[1] < block[i].coords[3] && block[i].coords[3] < ball.coords[3]) { down = 1; } cout << left << ", " << right << ", " << up << ", " << down << ", " << endl; if (left == 1) { ball.coords[0] = block[i].coords[0] - 16.0f; ball.coords[2] = block[i].coords[0] - 0.0f; } if (right == 1) { ball.coords[0] = block[i].coords[2] + 0.0f; ball.coords[2] = block[i].coords[2] + 16.0f; } if (down == 1) { ball.coords[1] = block[i].coords[3] + 0.0f; ball.coords[3] = block[i].coords[3] + 16.0f; } if (up == 1) { ball.yspeed = 0.0f; ball.gravity = 0.0f; ball.coords[1] = block[i].coords[1] - 16.0f; ball.coords[3] = block[i].coords[1] - 0.0f; } } if (de2dCheckCollision(ball,block[i],0.0f,0.0f)==false) { ball.gravity = -0.5f; } } } To explain what some of this code means: The blocks variable is basically an integer that is storing the amount of blocks, or platforms. I am checking all of the blocks using a for loop, and the number that the loop is currently on is represented by integer i. The coordinate system might seem a little weird, so that's worth explaining. coords[0] represents the x position (left) of the object (where it starts on the x axis). coords[1] represents the y position (top) of the object (where it starts on the y axis). coords[2] represents the width of the object plus coords[0] (right). coords[3] represents the height of the object plus coords[1] (bottom). de2dCheckCollision performs an AABB collision detection. Up is negative y and down is positive y, as it is in most games. Hopefully I have provided enough information for someone to help me successfully. If there is something I left out that might be crucial, let me know and I'll provide the necessary information. Finally, for anyone who can help, providing code would be very helpful and much appreciated. Thank you again for your help!

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  • Trying to develop a game with android for cracking glasses in different dimensions

    - by user46514
    I am trying to develop a game in android where I will have to punch a hole to get through the glass but not shatter the glass completely. The glass will show up in different forms of polygons and when a hole is created by a projectile, the rest of the polygon will still remain intact.Only a polygonal opening will get created at the point of impact with the projectile. I am new at game design in android but I was thinking that I would create a random polygon shape to show in the path and then at the point where the projectile hits it, I could create a glass polygon to create a splinter effect. The rest of the part of the glass that is randomly created at the point of impact, I could further splinter it into polygons flying at different angle. since I also need to capture the bits of glasses flying off and falling down with gravity. Is my solution the best efficient one at performance of threads or is there a better solution for this glass breaking effect. Thanks Dhiren

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  • Simulating an object floating on water

    - by Aaron M
    I'm working on a top down fishing game. I want to implement some physics and collision detection regarding the boat moving around the lake. I would like for be able to implement thrust from either the main motor or trolling motor, the effect of wind on the object, and the drag of the water on the object. I've been looking at the farseer physics engine, but not having any experience using a physics engine, I am not quite sure that farseer is suitable for this type of thing(Most of the demos seem to be the application of gravity to a vertical top/down type model). Would the farseer engine be suitable? or would a different engine be more suitable?

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  • Physics timestep questions

    - by SSL
    I've got a projectile working perfectly using the code below: //initialised in loading screen 60 is the FPS - projectilEposition and velocity are Vector3 types gravity = new Vector3(0, -(float)9.81 / 60, 0); //called every frame projectilePosition += projectileVelocity; This seems to work fine but I've noticed in various projectile examples I've seen that the elapsedtime per update is taken into account. What's the difference between the two and how can I convert the above to take into account the elapsedtime? (I'm using XNA - do I use ElapsedTime.TotalSeconds or TotalMilliseconds)? Edit: Forgot to add my attempt at using elapsedtime, which seemed to break the physics: projectileVelocity.Y += -(float)((9.81 * gameTime.ElapsedGameTime.TotalSeconds * gameTime.ElapsedGameTime.TotalSeconds) * 0.5f); Thanks for the help

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  • Actionscript 3.0 - Enemies do not move right in my platformer game

    - by Christian Basar
    I am making a side-scrolling platformer game in Flash (Actionscript 3.0). I have made lots of progress lately, but I have come across a new problem. I will give some background first. My game level's terrain (or 'floor') is referenced by a MovieClip variable called 'floor.' My desire is to have the Player and enemy characters walk along the terrain. I have gotten the Player character to move on the terrain just fine; he walks up/down hills and falls whenever there is no ground beneath him. Here is the code I created to allow the Player to follow the terrain correctly. Much more code is used to control the Player, but only this code deals with the Player character's following of the terrain and gravity. // If the Player's not on the ground (not touching the 'floor' MovieClip)... if (!onGround) { // Disable ducking downKeyPressed = false; // Increase the Player's 'y' position by his 'y' velocity player.y += playerYVel; } // Increase the 'playerYVel' variable so that the Player will fall // progressively faster down the screen. This code technically // runs "all the time" but in reality it only affects the player // when he's off the ground. playerYVel += gravity; // Give the Player a terminal velocity of 15 px/frame if (playerYVel > 15) { playerYVel = 15; } // If the Player has not hit the 'floor,' increase his falling //speed if (! floor.hitTestPoint(player.x, player.y, true)) { player.y += playerYVel; // The Player is not on the ground when he's not touching it onGround = false; } Since getting this code to work for the Player, I have created a 'SkullDemon' class, which is one of the planned enemies for my game. I want the 'SkullDemon' objects to move along the terrain like the Player does. With lots of great help, I have already coded the EventListeners, etc. necessary for the 'SkullDemons' to move. Unfortunately, I am having trouble getting them to move along the terrain. In fact, they do not touch the terrain at all; they move along the top of the boundary of the 'floor' MovieClip! I had a simple text diagram showing what I mean, but unfortunately Stackoverflow does not format it correctly. I hope my problem is clear from my description. Strangely enough, my code for the Player's movement and the 'SkullDemon's' movement is almost exactly the same, yet the 'SkullDemons' do not move like the Player does. Here is my code for the SkullDemon movement: // Move all of the Skull Demons using this method protected function moveSkullDemons():void { // Go through the whole 'skullDemonContainer' for (var skullDi:int = 0; skullDi < skullDemonContainer.numChildren; skullDi++) { // Set the SkullDemon 'instance' variable to equal the current SkullDemon skullDIns = SkullDemon(skullDemonContainer.getChildAt(skullDi)); // For now, just move the Skull Demons left at 5 units per second skullDIns.x -= 5; // If the Skull Demon has not hit the 'floor,' increase his falling //speed if (! floor.hitTestPoint(skullDIns.x, skullDIns.y, true)) { // Increase the Skull Demon's 'y' position by his 'y' velocity skullDIns.y += skullDIns.sdYVel; // The Skull Demon is not on the ground when he's not touching it skullDIns.sdOnGround = false; } // Increase the 'sdYVel' variable so that the Skull Demon will fall // progressively faster down the screen. This code technically // runs "all the time" but in reality it only affects the Skull Demon // when he's off the ground. if (! skullDIns.sdOnGround) { skullDIns.sdYVel += skullDIns.sdGravity; // Give the Skull Demon a terminal velocity of 15 px/frame if (skullDIns.sdYVel > 15) { skullDIns.sdYVel = 15; } } // What happens when the Skull Demon lands on the ground after a fall? // The Skull Demon is only on the ground ('onGround == true') when // the ground is touching the Skull Demon MovieClip's origin point, // which is at the Skull Demon's bottom centre for (var i:int = 0; i < 10; i++) { // The Skull Demon is only on the ground ('onGround == true') when // the ground is touching the Skull Demon MovieClip's origin point, // which is at the Skull Demon's bottom centre if (floor.hitTestPoint(skullDIns.x, skullDIns.y, true)) { skullDIns.y = skullDIns.y; // Set the Skull Demon's y-axis speed to 0 skullDIns.sdYVel = 0; // The Skull Demon is on the ground again skullDIns.sdOnGround = true; } } } } // End of 'moveSkullDemons()' function It is almost like the 'SkullDemons' are interacting with the 'floor' MovieClip using the hitTestObject() function, and not the hitTestPoint() function which is what I want, and which works for the Player character. I am confused about this problem and would appreciate any help you could give me. Thanks!

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  • Platformer Starter Kit - Collision Issues

    - by Cyral
    I'm having trouble with my game that is based off the XNA Platformer starter kit. My game uses smaller tiles (16x16) then the original (32x40) which I'm thinking may be having an effect on collision (Being it needs to be more precise). Standing on the edge of a tile and jumping causes the player to move off the the tile when he lands. And 80% of the time, when the player lands, he goes flying though SOLID tiles in a diagonal fashion. This is very annoying as it is almost impossible to test other features, when spawning and jumping will result in the player landing in another part of the level or falling off the edge completely. The code is as follows: /// <summary> /// Updates the player's velocity and position based on input, gravity, etc. /// </summary> public void ApplyPhysics(GameTime gameTime) { float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; Vector2 previousPosition = Position; // Base velocity is a combination of horizontal movement control and // acceleration downward due to gravity. velocity.X += movement * MoveAcceleration * elapsed; velocity.Y = MathHelper.Clamp(velocity.Y + GravityAcceleration * elapsed, -MaxFallSpeed, MaxFallSpeed); velocity.Y = DoJump(velocity.Y, gameTime); // Apply pseudo-drag horizontally. if (IsOnGround) velocity.X *= GroundDragFactor; else velocity.X *= AirDragFactor; // Prevent the player from running faster than his top speed. velocity.X = MathHelper.Clamp(velocity.X, -MaxMoveSpeed, MaxMoveSpeed); // Apply velocity. Position += velocity * elapsed; Position = new Vector2((float)Math.Round(Position.X), (float)Math.Round(Position.Y)); // If the player is now colliding with the level, separate them. HandleCollisions(); // If the collision stopped us from moving, reset the velocity to zero. if (Position.X == previousPosition.X) velocity.X = 0; if (Position.Y == previousPosition.Y) velocity.Y = 0; } /// <summary> /// Detects and resolves all collisions between the player and his neighboring /// tiles. When a collision is detected, the player is pushed away along one /// axis to prevent overlapping. There is some special logic for the Y axis to /// handle platforms which behave differently depending on direction of movement. /// </summary> private void HandleCollisions() { // Get the player's bounding rectangle and find neighboring tiles. Rectangle bounds = BoundingRectangle; int leftTile = (int)Math.Floor((float)bounds.Left / Tile.Width); int rightTile = (int)Math.Ceiling(((float)bounds.Right / Tile.Width)) - 1; int topTile = (int)Math.Floor((float)bounds.Top / Tile.Height); int bottomTile = (int)Math.Ceiling(((float)bounds.Bottom / Tile.Height)) - 1; // Reset flag to search for ground collision. isOnGround = false; // For each potentially colliding tile, for (int y = topTile; y <= bottomTile; ++y) { for (int x = leftTile; x <= rightTile; ++x) { // If this tile is collidable, ItemCollision collision = Level.GetCollision(x, y); if (collision != ItemCollision.Passable) { // Determine collision depth (with direction) and magnitude. Rectangle tileBounds = Level.GetBounds(x, y); Vector2 depth = RectangleExtensions.GetIntersectionDepth(bounds, tileBounds); if (depth != Vector2.Zero) { float absDepthX = Math.Abs(depth.X); float absDepthY = Math.Abs(depth.Y); // Resolve the collision along the shallow axis. if (absDepthY < absDepthX || collision == ItemCollision.Platform) { // If we crossed the top of a tile, we are on the ground. if (previousBottom <= tileBounds.Top) isOnGround = true; // Ignore platforms, unless we are on the ground. if (collision == ItemCollision.Impassable || IsOnGround) { // Resolve the collision along the Y axis. Position = new Vector2(Position.X, Position.Y + depth.Y); // Perform further collisions with the new bounds. bounds = BoundingRectangle; } } else if (collision == ItemCollision.Impassable) // Ignore platforms. { // Resolve the collision along the X axis. Position = new Vector2(Position.X + depth.X, Position.Y); // Perform further collisions with the new bounds. bounds = BoundingRectangle; } } } } } // Save the new bounds bottom. previousBottom = bounds.Bottom; } It also tends to jitter a little bit sometimes, I'm solved some of this with some fixes I found here on stackexchange, But Ive only seen one other case of the flying though blocks problem. This question seems to have a similar problem in the video, but mine is more crazy. Again this is a very annoying bug! Any help would be greatly appreciated! EDIT: Speed stuff // Constants for controling horizontal movement private const float MoveAcceleration = 13000.0f; private const float MaxMoveSpeed = 1750.0f; private const float GroundDragFactor = 0.48f; private const float AirDragFactor = 0.58f; // Constants for controlling vertical movement private const float MaxJumpTime = 0.35f; private const float JumpLaunchVelocity = -3500.0f; private const float GravityAcceleration = 3400.0f; private const float MaxFallSpeed = 550.0f; private const float JumpControlPower = 0.14f;

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  • Appropriate level of granularity for component-based architecture

    - by Jon Purdy
    I'm working on a game with a component-based architecture. An Entity owns a set of Component instances, each of which has a set of Slot instances with which to store, send, and receive values. Factory functions such as Player produce entities with the required components and slot connections. I'm trying to determine the best level of granularity for components. For example, right now Position, Velocity, and Acceleration are all separate components, connected in series. Velocity and Acceleration could easily be rewritten into a uniform Delta component, or Position, Velocity, and Acceleration could be combined alongside such components as Friction and Gravity into a monolithic Physics component. Should a component have the smallest responsibility possible (at the cost of lots of interconnectivity) or should related components be combined into monolithic ones (at the cost of flexibility)? I'm leaning toward the former, but I could use a second opinion.

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  • Ever wonder why Earth spins?

    - by Gopinath
    Have you ever wonder why Earth spins on its axis and completes a revolution every day? Is there any force that keeps Earth spinning? Is that because of  Gravity or any Magnetic force? Check out this video to learn why Earth spins and the basics of physics behind the magic If you find that above video is in simple English and it’s not convincing physicist inside you, lets hear from a NASA scientist in the embedded video. A NASA scientist explains how Earth rotation has started, how fast it was billions of years ago and what caused it to slow down to 24 hours to complete a revolution   Thanks @pinaldev

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  • The how of a collision engine

    - by JXPheonix
    This is a very, very broad question - what is the general algorithm of how a collision engine works? No code in specific, but rather, just a general idea of how a collision engine does what it does, constantly refreshing the points of an object and comparing it to other objects? (see, I have the general gist of it here.) A collision engine is basically an engine used in games (generally) so that your player (call him Bob), whenever bob moves into a wall, Bob stops, Bob does not walk through the wall. They also generally handle the gravity in a game and environmental things like that.

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  • How does a collision engine work?

    - by JXPheonix
    Original question: Click me How exactly does a collision engine work? This is an extremely broad question. What code keeps things bouncing against each other, what code makes the player walk into a wall instead of walk through the wall? How does the code constantly refresh the players position and objects position to keep gravity and collision working as it should? If you don't know what a collision engine is, basically it's generally used in platform games to make the player acutally hit walls and the like. There's the 2D type and the 3D type, but they all accomplish the same thing: collision. So, what keeps a collision engine ticking?

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  • From where does the game engines add location of an object?

    - by Player
    I have started making my first game( a pong game )with ruby (Gosu). I'm trying to detect the collision of two images using their location by comparing the location of the object (a ball) to another one(a player). For example: if (@player.x - @ball.x).abs <=184 && (@player.y - @ball.y).abs <= 40 @ball.vx = [email protected] @ball.vy = [email protected] But my problem is that with these numbers, the ball collides near the player sometimes, even though the dimensions of the player are correct. So my question is from where does the x values start to count? Is it from the center of gravity of the image or from the beginning of the image? (i.e When you add the image on a specific x,y,z what are these values compared to the image?

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  • The how of a collision engine

    - by JXPheonix
    This is a very, very broad question - what is the general algorithm of how a collision engine works? No code in specific, but rather, just a general idea of how a collision engine does what it does, constantly refreshing the points of an object and comparing it to other objects? (see, I have the general gist of it here.) A collision engine is basically an engine used in games (generally) so that your player (call him Bob), whenever bob moves into a wall, Bob stops, Bob does not walk through the wall. They also generally handle the gravity in a game and environmental things like that.

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  • Find angle for projectile to meet target in parabolic arc

    - by TheBroodian
    I'm making a thing that launches projectiles in 2D. Its projectiles are fired with a set initial velocity, and are only affected by gravity. Assuming that its target is within range, and that there aren't any obstacles, how would my thing find the appropriate angle at which to launch its projectile (in radians)? The equation for this is found here: Wikipedia: Angle Required to Hit Coordinate Sadly, I'm not a physicist (a.k.a. can't read smart people math) and am having a hard time reading its breakdown. If not only for the sake of anybody else that might read this other than myself, would anybody be kind enough to break the equation down into baby words please?

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  • Calculating the rotational force of a 2D sprite

    - by Jon
    I am wondering if someone has an elegant way of calculating the following scenario. I have an object of (n) number of squares, random shapes, but we will pretend they are all rectangles. We are dealing with no gravity, so consider the object in space, from a top down perspective. I am applying a force to the object at a specific square (as illustrated below). How do I calculate the rotational angle, based on the force being applied, at the location being applied. If applied in the center square, it would go straight. How should it behave the further I move from the center? How do I calculate the rotational velocity?

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  • Friday Fun: Sugar, Sugar 2

    - by Asian Angel
    In this week’s game you indulge in sugary-sweet fun as you control the direction sugar flows while working to fill all the empty cups waiting for you. Whether it is a downward flow, redirected off-screen and back, reverse gravity, or teleportation you will certainly find your ingenuity tested as you try to win before the flow of sugar runs out! HTG Explains: What Is Windows RT and What Does It Mean To Me? HTG Explains: How Windows 8′s Secure Boot Feature Works & What It Means for Linux Hack Your Kindle for Easy Font Customization

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  • How does a collison engine work?

    - by JXPheonix
    Original question: Click me How exactly does a collision engine work? This is an extremely broad question. What code keeps things bouncing against each other, what code makes the player walk into a wall instead of walk through the wall? How does the code constantly refresh the players position and objects position to keep gravity and collision working as it should? If you don't know what a collision engine is, basically it's generally used in platformer games to make the player acutally hit walls and the like. There's the 2d type and the 3d type, but they all accomplish the same thing: collision. So, what keeps a collision engine ticking?

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  • How to make my sprite jump properly?

    - by Matthew Morgan
    I'm currently working on a 2D platformer in XNA. I have, however been having some trouble with creating a fully functional jumping algorithm. This is what I have so far: if (keystate.IsKeyDown(Keys.W)) if (onGround = true) //"onground" is true when the collision between the main sprite and the ground is detected { spritePosition.Y = velocity.Y = -5; } So, the problem I am now having is that as soon as the jump starts the variable "onGround" = false and the sprite is brought back the ground by the simple gravity I have implemented. The other problem I have is creating a limit to the height after which the sprite should automatically return to the ground. Any advice or suggestions would be greatly appreciated.

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  • I am new to game development, what do I need to know? [closed]

    - by farmdve
    I am unsure if this question is a duplicate, I hope it isn't. Are there any resources on the terminology when doing game development? Because, even if you tell me to learn some graphics API, how would I understand the things it does, if I am not well into the terminology(voxel,mesh,polygon,shading). What about the math that is involved in the game(geometry) or the concept of the gravity,collision detection in the game and their respective maths? I am very bad at math, never was good, because I have ADHD, but I won't give up just yet. I look at a game, and I see "textures", but how am I walking on them, how do they take substance so I don't fall off of them? And depth? This is what I need information about, not just a link to a library like SDL(which I have compiled under MinGW and MinGW-W64) and tell me to learn it and the cliché answer "start simple/small". I hope the question(s) are not too vague.

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  • Jumping over non-stationary objects without problems ... 2-D platformer ... how could this be solved? [on hold]

    - by help bonafide pigeons
    You know this problem ... take Super Mario Bros. for example. When Mario/Luigi/etc. comes in proximity with a nearing pipe image an invisible boundary setter must prevent him from continuing forward movement. However, when you jump and move both x and y you are coordinately moving in two dimensions at an exact time. When nearing the pipe in mid-air as you are falling, i.e. implementation of gravity in the computer program "pulling" the image back down, and you do not want them to get "stuck" in both falling and moving. That problem is solved, but how about this one: The player controlling the ball object is attempting to jump and move rightwards over the non-stationary block that moves up and down. How could we measure its top and lower x+y components to determine the safest way for the ball to accurately either fall back down, or catch the ledge, or get pushed down under it, etc.?

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  • Making video from 3D gaphics in OpenGL

    - by MVTC
    What are some of the preferred methods or libraries for creating video from an OpenGL graphics simulation? For example, I want to create a visualization(video) of an N-Body gravity simulation by rendering non-real-time OpenGL frames. The simulation is already coded, I just don't know how to convert it to video. EDIT: I am also interested in providing the described functionality: The user can adjust parameters including the time step between captured frames and then initiate the simulation. The user waits for the simulation to complete, and then can watch the results. The user is able to increase or decrease the playback speed of the simulation whereas in slow motion, more frames are used i.e., you see higher resolution time steps, and when the speed is increased, you see lower resolution time steps at a higher rate, but the frames per second flashing on the screen is constant.

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