How can I make this list work - c++

Question

I'm trying to make a simple game by just using hexagons. However the std::vector isn't working for some reason. It should be creating a list but its just NULL? What its origionaly suppost to do is add trapazoids to create a track. From that point on its mostly camera moving. I am current using a add on called SFML and its mainly used to create images like openGL.
///////////////////////////////////////////////////////////////////////////////////////////////////////////
#include <SFML\Graphics.hpp>
#include <iostream>
///////////////////////////////////////////////////////////////////////////////////////////////////////////
using namespace sf;
int width = 1024;
int height = 768;
char title[] = "Racing";
int roadW = 2000;
int segL = 200; //segment length
float camD = 0.84; //camera debth
int update(RenderWindow &w);
void drawQuad(RenderWindow &w, Color c, int x1, int y1, int w1, int x2, int y2, int w2);
///////////////////////////////////////////////////////////////////////////////////////////////////////////
struct Line
{
float x, y, z; //segment length
float X, Y, W; //screen cordinates
float scale;
Line() { x = y = z = 0; }
//from world to screen coordinates
void project(int camx, int camy, int camz)
{
scale = camD / (z - camz);
X = (1 + scale*(x - camx))*width / 2;
Y = (1 - scale*(y - camx))*height / 2;
W = scale * roadW * width / 2;
}
};
std::vector<Line> lines; //main track
int N = lines.size();
///////////////////////////////////////////////////////////////////////////////////////////////////////////
int main()
{
std::cout << "Starting up... \n";
std::cout << "Creating RenderWindow...(VideoMode(" << width << "," << height << "), " << title << "\n";
RenderWindow window(VideoMode(width, height), title);
window.setFramerateLimit(60);
std::cout << "Creating std::vector<Lines> lines... \n";
for (int i = 0; i < 1600; i++)
{
Line line;
line.z = i*segL;
lines.push_back(line);
}
std::cout << "Total Length[" << N << "]\n";
std::cout << "\nRunning...\n";
while (window.isOpen())
{
if (update(window) != 0) return 0;
}
return 0;
}
int update(RenderWindow &w)
{
///│LOGIC////
///└EVENTS///
Event e;
while (w.pollEvent(e))
{
if (e.type == Event::Closed) return 1;
}
///│RENDER///
///├CLEAR////
///├ROAD/////
///└CLEAR////
w.clear();
for (int n = 0; n < 300; n++)
{
Line &l = lines[n%N];
l.project(0, 1500, 0);
Color grass = (n / 3) % 2 ? Color(16, 200, 16) : Color(0, 154, 0);
Color rumble = (n / 3) % 2 ? Color(255, 255, 2555) : Color(0, 0, 0);
Color road = (n / 3) % 2 ? Color(107, 107, 107) : Color(105, 105, 105);
Line p = lines[(n - 1) % N];
drawQuad(w, grass, 0, p.Y, width, 0, l.Y, width);
drawQuad(w, rumble, p.X, p.Y, p.W*1.2, l.X, l.Y, l.W*1.2);
drawQuad(w, road, p.X, p.Y, p.W, l.X, l.Y, l.W);
}
w.display();
return 0;
}
void drawQuad(RenderWindow &w, Color c, int x1, int y1, int w1, int x2, int y2, int w2)
{
ConvexShape shape(4);
shape.setFillColor(c);
shape.setPoint(0, Vector2f(x1 - w1, y1));
shape.setPoint(1, Vector2f(x2 - w2, y2));
shape.setPoint(2, Vector2f(x2 + w2, y2));
shape.setPoint(3, Vector2f(x1 + w1, y1));
w.draw(shape);
}
Thanks
-Logan

Answer 1

Apparently, N stands for zero because in the beginning of the code it gets the number of lines not whenever you call it refreshes!