Bullet Tracers

In game/Projectile.h in the public section of the ProjectileData class definition(around line 63) add:

F32 tracerLength; // Length of the tracer, also distance from source object that tracer will start being visible
ColorF tracerColor; // Color of tracers

In the Projectile class definition(around line 178) add:

Point3F mInitialPosition; // Initial position of projectile when created

Now we will be modifying game/Projectile.cc:

In the ProjectileData constructor we will put the default values for the tracer attributes, add (around line 91):

tracerLength = 0;
tracerColor.set(1.0, 1.0, 0.55);

Down a little bit in ProjectileData::initPersistFields() add (around line 147):

addNamedField(tracerLength, TypeF32, ProjectileData);
addNamedField(tracerColor, TypeColorF, ProjectileData);

A little further down at the very end of ProjectileData::packData() add (around line 304):

stream->write(tracerLength);
   stream->writeFloat(tracerColor.red, 7);
   stream->writeFloat(tracerColor.green, 7);
   stream->writeFloat(tracerColor.blue, 7);

Then in ProjectileData::unpackData() add (around line 372):

stream->read(&tracerLength);
   tracerColor.red = stream->readFloat(7);
   tracerColor.green = stream->readFloat(7);
   tracerColor.blue = stream->readFloat(7);

Scroll down a ways to Projectile::unpackData() at about line 1062 and find:

mCurrDeltaBase = pos;
      mCurrBackDelta = mCurrPosition - pos;
      mCurrPosition  = pos;
      setPosition(mCurrPosition);

and right before

mCurrDeltaBase = pos;

add:

mInitialPosition = pos;

And finally the part that makes it all work, scroll down to Projectile::renderObject() and right before:

dglSetCanonicalState();

add (about line 1266):

if (mDataBlock->tracerLength > 0) {
		Point3F end = mCurrVelocity;
		end.normalize(mClampF((mCurrPosition - mInitialPosition).len(), 1.0, mDataBlock->tracerLength));
		glLineWidth(0.5); 
		glBegin(GL_LINES);
		glColor3fv(mDataBlock->tracerColor);      
		glVertex3f(mCurrPosition.x, mCurrPosition.y, mCurrPosition.z);      
		end = mCurrPosition - end;
		glVertex3f(end.x, end.y, end.z);      
		glEnd();  
		glLineWidth(.1f);
       }

To turn the tracers on you will need to goto your script file containing your ProjectileData datablocks for the Projectiles you would like to add tracers to and place:

tracerLength = 50;
	tracerColor = "1.0 1.0 0.55";

somewhere within them. You may need to tweak the tracerLength and tracerColor values to get the effect you want.


Hopefully that should work! :)