Jump to content
  • Advertisement
  • 08/19/13 02:20 PM
    Sign in to follow this  

    Building a First-Person Shooter: Part 1.5 Running, Jumping, & Crouching

    General and Gameplay Programming

    ChrisVossen
    At this point making the player run at a faster speed is a simple two step process, we need to detect if the shift key is hit and then multiply movespeed. We start off by adding in two variables to detect if the player is running and a multiplier value for increasing movespeed: running=false; runboost = 2.0; In the UpdateControls function we add in a line to check if the shift key has been hit: running = Window::GetCurrent()->KeyDown(Key::Shift); Then in the player Update, multiply movespeed by the runboost factor and increase maxaccel: //Run if shift key is pressed if (running) movespeed *= runboost; if (running) maxaccel *= 2.0; Your player class should now look like the following: #include "MyGame.h" using namespace Leadwerks; Player::Player() { //Create the entity entity = Pivot::Create(); entity->SetUserData(this); //Initialize values standheight=1.7; crouchheight=1.2; cameraheight = standheight; move = 0.0; strafe = 0.0; movementspeed = 3.0; maxacceleleration = 0.5; sensitivity=1.0; smoothedcamerapositiony = 0; cameraypositionsmoothing = 3.0; cameralooksmoothing = 2.0; runboost = 2.0; running=false; //Set up player physics entity->SetPhysicsMode(Entity::CharacterPhysics); entity->SetCollisionType(Collision::Character); entity->SetMass(10.0); //Player position entity->SetPosition(0,0,0,true); //Create the player camera camera = Camera::Create(); camera->SetPosition(0,entity->GetPosition().y + cameraheight,0,true); } Player::~Player() { if (camera) { camera->Release(); camera = NULL; } } void Player::UpdateControls() { Window* window = Window::GetCurrent(); Context* context = Context::GetCurrent(); //Get inputs from the controller class move = window->KeyDown(Key::W) - window->KeyDown(Key::S); strafe = window->KeyDown(Key::D) - window->KeyDown(Key::A); running = Window::GetCurrent()->KeyDown(Key::Shift); //Get the mouse movement float sx = context->GetWidth()/2; float sy = context->GetHeight()/2; //Get the mouse position Vec3 mouseposition = window->GetMousePosition(); //Move the mouse to the center of the screen window->SetMousePosition(sx,sy); //Get change in mouse position float dx = mouseposition.x - sx; float dy = mouseposition.y - sy; //Mouse smoothing mousespeed.x = Math::Curve(dx,mousespeed.x,cameralooksmoothing/Time::GetSpeed()); mousespeed.y = Math::Curve(dy,mousespeed.y,cameralooksmoothing/Time::GetSpeed()); //Adjust and set the camera rotation playerrotation.x += mousespeed.y*sensitivity / 10.0; playerrotation.y += mousespeed.x*sensitivity / 10.0; //Prevent inhuman looking angles playerrotation.x = Math::Clamp(playerrotation.x,-90,90); } //Update function void Player::Update() { UpdateControls(); float maxaccel = this->maxacceleleration; float movespeed = this->movementspeed; //Run if shift key is pressed if (running) movespeed *= runboost; //Make sure movements are normalized so that moving forward at the same time as strafing doesn't move your character faster normalizedmovement.z = move; normalizedmovement.x = strafe; normalizedmovement = normalizedmovement.Normalize() * movespeed; //Set camera rotation camera->SetRotation(playerrotation,true); //Set player input if (running) maxaccel *= 2.0; entity->SetInput(playerrotation.y,normalizedmovement.z,normalizedmovement.x,0,false,maxaccel); //Set the camera position & smooth cameraposition = entity->GetPosition(); camera->SetPosition(cameraposition.x, cameraposition.y + cameraheight, cameraposition.z ); }

    Jumping and Crouching

    Since jumping and crouching both affect camera height we are going to implement both of them at the same time. Like normal we add in the needed variables into the constructor: jump = 0.0; jumpforce = 6.0; jumpboost=2.0; crouched = false; Now we turn our attention to the UpdateControl function. We check if the space key has been hit and then multiply it by a jump force. We also look to see if the 'C' button is hit, but only if the player is not in the air: jump = window->KeyDown(Key::Space) * jumpforce; if (!entity->GetAirborne()) { crouched = window->KeyDown(Key::C); } Player Update is our next focus and we begin to set the camera to its proper height. If the player is crouching we increment the camera height by the crouchheight but if the player is standing normally we increment it by standheight: if (entity->GetCrouched()) { cameraheight = Math::Inc(crouchheight,cameraheight,0.1); } else { cameraheight = Math::Inc(standheight,cameraheight,0.1); } To implement the jumping mechanic we continue our work in the Update function. If the entity is in the air we set jump to 0 to prevent the player from in-air jumps. To achieve the long jump feeling we want from our FPS we decided to boost the player's velocity while in-air: if (entity->GetAirborne()) //Player is in the air { //if the player is in the air don't let them jump jump = 0.0; } else //Player is on the ground { //Give an extra boost if jumping if (jump>0.0) { if (velocity.z>movementspeed*0.85) { normalizedmovement.z *= jumpboost; normalizedmovement.z = min(normalizedmovement.z,movementspeed*runboost); maxaccel = 10; } } } Now that we have a jump and crouch value we have to remember to change our SetInput function to the correct values: entity>SetInput(playerrotation.y,normalizedmovement.z,normalizedmovement.x,jump,crouched,maxaccel); With all the jumping and crouching going on, our camera's y position will be changing often, this means that we should now smooth the camera's y movements: //Set the camera position & smooth cameraposition = entity->GetPosition(); if (cameraposition.y>smoothedcamerapositiony) { smoothedcamerapositiony = Math::Curve(cameraposition.y, smoothedcamerapositiony, cameraypositionsmoothing / Time::GetSpeed()); cameraposition.y=smoothedcamerapositiony; } else { smoothedcamerapositiony = cameraposition.y; } camera->SetPosition(cameraposition.x, cameraposition.y + cameraheight, cameraposition.z ); Our quickly growing player class will now look like so: #include "MyGame.h" using namespace Leadwerks; Player::Player() { //Create the entity entity = Pivot::Create(); entity->SetUserData(this); //Initialize values standheight=1.7; crouchheight=1.2; cameraheight = standheight; move = 0.0; strafe = 0.0; movementspeed = 3.0; maxacceleleration = 0.5; sensitivity=1.0; smoothedcamerapositiony = 0; cameraypositionsmoothing = 3.0; cameralooksmoothing = 2.0; runboost = 2.0; jump = 0.0; jumpforce = 6.0; jumpboost = 2.0; footstepwalkfrequency=400; footsteprunfrequency=320; footsteptimer=Time::GetCurrent(); running=false; crouched = false; landing = false; //Set up player physics entity->SetPhysicsMode(Entity::CharacterPhysics); entity->SetCollisionType(Collision::Character); entity->SetMass(10.0); //Player position entity->SetPosition(0,0,0,true); //Create the player camera camera = Camera::Create(); camera->SetPosition(0,entity->GetPosition().y + cameraheight,0,true); } Player::~Player() { if (camera) { camera->Release(); camera = NULL; } } void Player::UpdateControls() { Window* window = Window::GetCurrent(); Context* context = Context::GetCurrent(); //Get inputs from the controller class move = window->KeyDown(Key::W) - window->KeyDown(Key::S); strafe = window->KeyDown(Key::D) - window->KeyDown(Key::A); jump = window->KeyDown(Key::Space) * jumpforce; if (!entity->GetAirborne()) { crouched = window->KeyDown(Key::C); } running = Window::GetCurrent()->KeyDown(Key::Shift); //Get the mouse movement float sx = context->GetWidth()/2; float sy = context->GetHeight()/2; //Get the mouse position Vec3 mouseposition = window->GetMousePosition(); //Move the mouse to the center of the screen window->SetMousePosition(sx,sy); //Get change in mouse position float dx = mouseposition.x - sx; float dy = mouseposition.y - sy; //Mouse smoothing mousespeed.x = Math::Curve(dx,mousespeed.x,cameralooksmoothing/Time::GetSpeed()); mousespeed.y = Math::Curve(dy,mousespeed.y,cameralooksmoothing/Time::GetSpeed()); //Adjust and set the camera rotation playerrotation.x += mousespeed.y*sensitivity / 10.0; playerrotation.y += mousespeed.x*sensitivity / 10.0; //Prevent inhuman looking angles playerrotation.x = Math::Clamp(playerrotation.x,-90,90); } //Update function void Player::Update() { UpdateControls(); if (entity->GetCrouched()) { cameraheight = Math::Inc(crouchheight,cameraheight,0.1); } else { cameraheight = Math::Inc(standheight,cameraheight,0.1); } float maxaccel = maxacceleleration; Vec3 velocity = entity->GetVelocity(false); float groundspeed = velocity.xz().Length(); float movespeed = this->movementspeed; //Run if shift key is pressed if (running) movespeed *= runboost; //Make sure movements are normalized so that moving forward at the same time as strafing doesn't move your character faster normalizedmovement.z = move; normalizedmovement.x = strafe; normalizedmovement = normalizedmovement.Normalize() * movespeed; if (entity->GetAirborne()) //Player is in the air { //if the player is in the air don't let them jump jump = 0.0; } else //Player is on the ground { //Give an extra boost if jumping if (jump>0.0) { if (velocity.z>movementspeed*0.85) { normalizedmovement.z *= jumpboost; normalizedmovement.z = min(normalizedmovement.z,movementspeed*runboost); maxaccel = 10; } } } } //Set camera rotation camera->SetRotation(playerrotation,true); //Set player input if (running) maxaccel *= 2.0; entity->SetInput(playerrotation.y,normalizedmovement.z,normalizedmovement.x,jump,crouched,maxaccel); //Set the camera position & smooth cameraposition = entity->GetPosition(); if (cameraposition.y>smoothedcamerapositiony) { smoothedcamerapositiony = Math::Curve(cameraposition.y, smoothedcamerapositiony, cameraypositionsmoothing / Time::GetSpeed()); cameraposition.y=smoothedcamerapositiony; } else { smoothedcamerapositiony = cameraposition.y; } camera->SetPosition(cameraposition.x, cameraposition.y + cameraheight, cameraposition.z ); }


      Report Article
    Sign in to follow this  


    User Feedback


    you may want to do a follow up article that implements a more realistic flight model for jumping instead of the usual "just fake it" stuff seen in shooters. 

     

    however i understand this is just a tutorial, and such exercises are usually considered beyond the scope of such articles and therefore left to the reader.

    Share this comment


    Link to comment
    Share on other sites

    I see two serious issues here:

     

    1. Source formatting seems rather sloppy, makes things harder to read. Visual Studio should be able to do that for you as well. Seeing as many articles in these series consist of more than 50% of source code, it's quite important to make it easily readable.

     

    2. A lot of the implementation details are hidden in the engine and never really explained. Differences between node/entity, Math::Curve, entity->GetAirborne() and all that. If you don't want to get into detail there, the article name "building a FPS" is highly misleading. You're building a FPS in Leadwerks. Hiding all these important parts makes the tutorial rather useless for those who want to know all about FPS making, not just how someone uses this engine.

    Share this comment


    Link to comment
    Share on other sites


    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!