• Create Account

\$10

Like
6Likes
Dislike

# Building a First-Person Shooter: Part 1.6 Sound

By ChrisVossen | Published Aug 23 2013 06:42 AM in Game Programming
Peer Reviewed by (ivan.spasov, Dave Hunt, Norman Barrows)

For a final touch we are going to add in sound effects. We begin by declaring a few variables to deal with the footstep sound effects times and frequencies:

footsteptimer=Time::GetCurrent();
footstepwalkfrequency=400;
footsteprunfrequency=320;


Next we load in our sound effects which are located in the MyGame/Sound folder. For variety’s sake we have four separate footstep sounds, four landing sounds, and one jumping grunt sound effect:

//Load Sound files
for (int i=0; i<4; ++i)
{
}
for (int i = 0; i < 4; ++i)
{
}
for (int i = 0; i < 1; ++i)
{
}


Inside our Update function we had our code to deal with the jumping mechanic, to add in our sound effects we will go back and work inside the section of the if statement where in the player is currently on the ground. We first check if jump is greater than 0, remember that since we are currently on the ground it means that the jump button was just recently hit thus we can now play the jumping grunt sound as the player starts his jump. Please note that we do not play the jump sound in the UpdateControl function when the Space bar is hit because then the sound effect would be played every time the button was pressed even if you were already jumping. The other key thing we do is set the landing variable to be true:

if (jump>0.0)
{
jumpsound[0]->Play();
landing = true;

if (velocity.z>movementspeed*0.85)
{
normalizedmovement.z *= jumpboost;
normalizedmovement.z = min(normalizedmovement.z,movementspeed*runboost);
maxaccel = 10;
}
}


Directly above the previous code we now add in a check for the landing variable. If the player is landing then we play the landsound and immediately set landing to be false.

//Play landing sounds
if(landing)
{
landsound[(int)Math::Random(0,3)]->Play();
landing = false;
}


All that is left to do is implement the footstep sounds. We first need to calculate ground speed , this will help us determine how often to play the footstep sounds:

Vec3 velocity = entity->GetVelocity(false);
float groundspeed = velocity.xz().Length();


After determining the ground speed it is time for the footsteps code. We start off by checking if that a footstep sound is not currently playing by seeing if the current time is greater than the footsteptimer, we also make sure that the player is not jumping, and that the player is actually moving. If all of these cases are true then we check to make sure the player is moving fast enough to warrant a sound effect, so if the groundspeed is greater than 1.0 we play a footstep. Directly after we decide how much to increment the footsteptimer, if the player is running fast we will increment the timer more than if the player is walking, this is determined by whether or not groundspeed has surpassed a little bit more than movement speed:

//Play footsteps
if (Time::GetCurrent()>footsteptimer && jump==0.0 && normalizedmovement.Length()>0.0)
{
if (groundspeed>1.0)
{
int soundindex = (int)Math::Random(0,3);
footstepsound[soundindex]->Play();
if (groundspeed>movementspeed*1.2)
{
footsteptimer = Time::GetCurrent() + footsteprunfrequency;
}
else
{
footsteptimer = Time::GetCurrent() + footstepwalkfrequency;
}
}
}


We finally have our complete player class. You can move around with the ‘W’ ‘A’ ‘S’ ‘D’ keys, run with Shift, jump with Space, and crouch with ‘C’. Hit F5 and see the game in action:

#include "MyGame.h"

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);

for (int i=0; i<4; ++i)
{
}
for (int i = 0; i < 4; ++i)
{
}
for (int i = 0; i < 1; ++i)
{
}
}

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
{
//Play landing sounds
if(landing)
{
landsound[(int)Math::Random(0,3)]->Play();
landing = false;
}

//Give an extra boost if jumping
if (jump>0.0)
{
jumpsound[0]->Play();
landing = true;
if (velocity.z>movementspeed*0.85)
{
normalizedmovement.z *= jumpboost;
normalizedmovement.z = min(normalizedmovement.z,movementspeed*runboost);
maxaccel = 10;
}
}

//Play footsteps
if (Time::GetCurrent()>footsteptimer && jump==0.0 && normalizedmovement.Length()>0.0)
{
if (groundspeed>1.0)
{
int soundindex = (int)Math::Rnd(0,4);
footstepsound[soundindex]->Play();
if (groundspeed>movementspeed*1.2)
{
footsteptimer = Time::GetCurrent() + footsteprunfrequency;
}
else
{
footsteptimer = Time::GetCurrent() + footstepwalkfrequency;
}
}
}
}

//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 );
}