[SOLVED] Allocation errors occuring from animation of mesh colors

@AceSlowman wrote:

I was trying to come to an efficient method for animating movement along a line segment. In update, there is always a "lead" vertex, and using another for loop, a length of vertices behind that lead are colored with a decreasing alpha value, making it appear to have a trail behind it.

int leadVertex = fmodf(ofGetElapsedTimef()*speed,150);

for(int i=0; i<150; i++){
    connections.setColor(i,ofColor(ofColor(255),0));
}

//as we count to the 50 trailing vertices, the number for the alpha value decreases    
for(int i=0, cc=50; i<50; i++,cc--){ 
    connections.setColor(leadVertex-i,ofColor(ofColor(255),ofMap(cc,0,50,0,255)));
}

And here is the update method in this larger project:

void oscThread::update()
{
    float time = ofGetElapsedTimef()/speed;
    int leadVertex = fmodf(ofGetElapsedTimef()*cSpeed,res);
    
    for (int x=0;x<res;x++){
        ofVec3f oscTemp = this->getMesh().getVertex(x);
        float p = x;
        float oscillation = amp * sin(2 * pi * f * time + p)/20;
        oscTemp.rotate(x/f,ofVec3f(1,0,0));
        this->getMesh().setVertex(x,oscTemp);
        this->getMesh().setColor(x,ofColor(ofColor(255),0));
    }
   
    for(int i=0, tAlpha=100; i<100; i++,tAlpha--){
        this->getMesh().setColor(leadVertex-i,ofColor(ofColor(255),ofMap(tAlpha,0,50,0,255)));
    }
 }

What I believe is going on is while trying to select the previous 100 vertices behind the leadVertex, it points to vertices that are not there (until of course leadVertex-i actually exists). Does anyone have some tips on how to assure those actually exist? Or make leadVertex-i never go below 0? Thank you.

ofApp.h
http://pastebin.com/D3D1LLbb

ofApp.cpp
http://pastebin.com/BD0zMyvL

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