[RESOLVED] Debug Assertion Failed:vector subscript out of range

[A_Singh]

I am experiencing a problem : 'Debug Assertion Failed : vector subscript out of range : line:1234'. I have used call stack to locate the line in my code with the error. The following is my code:-(i have commented the line with the error)

#include<SFML\Graphics.hpp>
using namespace sf;

int width = 1024;
int height = 768;
int roadW = 2000;
int segL = 200;// segment length
float camD = 0.84;// camera depth

struct Line
{
	float x, y, z; // 3D center of line
	float X, Y, W; // screen coord
	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 - camY)) * height / 2;
		W = scale * roadW * width / 2;
	}
};

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);
}

int main()
{
	RenderWindow app(VideoMode(width, height), "Outrun Racing!");
	app.setFramerateLimit(60);

	std::vector<Line> lines;

	for (int i = 0; i < 1600; i++)
	{
		Line line;
		line.z = i*segL;
		lines.push_back(line);
	}

	int N = lines.size();

	while (app.isOpen())
	{
		Event e;
		while (app.pollEvent(e))
		{
			if (e.type == Event::Closed)
				app.close();
		}

		app.clear();

		///////draw road///////
		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, 255) : Color(0, 0, 0);
			Color road = (n / 3) % 2 ? Color(107, 107, 107) : Color(105, 105, 105);

			Line p = lines[(n - 1 % N)];// error somewhere here

			drawQuad(app, grass, 0, p.Y, width, 0, l.Y, width);
			drawQuad(app, rumble, p.X, p.Y, p.W*1.2, l.X, l.Y, l.W*1.2);
			drawQuad(app, road, p.X, p.Y, p.W, l.X, l.Y, l.W);
		}
		app.display();
	}

	return 0;

}

Line 1234 in the file vector says that:-

	reference operator[](size_type _Pos)
		{	// subscript mutable sequence
 #if _ITERATOR_DEBUG_LEVEL == 2
		if (size() <= _Pos)
			{	// report error
			_DEBUG_ERROR("vector subscript out of range");
			_SCL_SECURE_OUT_OF_RANGE;
			}

Please suggest a suitable fix.

[VictorN]

[moved from Visual C++ Bugs & Fixes forum]

[VictorN]

Line 1234 in the file vector says that:-

	reference operator[](size_type _Pos)
		{	// subscript mutable sequence
 #if _ITERATOR_DEBUG_LEVEL == 2
		if (size() <= _Pos)
			{	// report error
			_DEBUG_ERROR("vector subscript out of range");
			_SCL_SECURE_OUT_OF_RANGE;
			}

Please suggest a suitable fix.

Well, the debugger shows you the error reason very clear: "vector subscript out of range"!
So you are trying to use the vector index that is => the vector size!
And it is what you have now to fix!

[2kaud]

Line p = lines[(n - 1 % N)];// error somewhere here

% has higher precedence than - so this is

Line p = lines[n - (1 % N)];// error somewhere here

when n is 0, 1 % N is greater than n so you are trying to access lines with a negative index!

[A_Singh]

Thank you all so much for your kind replays. But that didn't work for me.Im a bit new to visual c++. So if you could send me the line with the fix. It would be better.

[2kaud]

Line p = lines[(n - 1 % N)];// error somewhere here

What are you trying to achieve? N is the number of elements in the vector lines (which from the code is 1600) and n varies between 0 and 299. I suspect you are trying to mean

Line p = lines[(n - 1) % N];// error somewhere here

but when n is 0, n - 1 is negative so this is again a negative index into the vector which is the problem.

Do you mean something like this

for (int n = 1; n < 300; n++)
{
    Line &l = lines[(n - 1) % 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, 255) : Color(0, 0, 0);
    Color road = (n / 3) % 2 ? Color(107, 107, 107) : Color(105, 105, 105);

    Line p = lines[n % N];// error somewhere here

    drawQuad(app, grass, 0, p.Y, width, 0, l.Y, width);
    drawQuad(app, rumble, p.X, p.Y, p.W*1.2, l.X, l.Y, l.W*1.2);
    drawQuad(app, road, p.X, p.Y, p.W, l.X, l.Y, l.W);
}

[A_Singh]

Thanks so much.I have completed my code.So could you please correct it in this code:-

#include<SFML\Graphics.hpp>
using namespace sf;

int width = 1024;
int height = 768;
int roadW = 2000;
int segL = 200;// segment length
float camD = 0.84;// camera depth

struct Line
{
	float x, y, z; // 3D center of line
	float X, Y, W; // screen coord
	float scale, curve, spriteX, clip;
	Sprite sprite;

	Line() {curve = 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 - camY)) * height / 2;
		W = scale * roadW * width / 2;
	}
	void drawSprite(RenderWindow &app)
	{
		Sprite s = sprite;
		int w = s.getTextureRect().width;
		int h = s.getTextureRect().height;

		float destX = X + scale * spriteX * width / 2;
		float destY = Y + 4;
		float destW = w * W / 266;
		float destH = h * W / 266;

		destX += destW * spriteX; // offsetX
		destY += destH * (-1); // offsetY

		float clipH = destY + destH - clip;
		if (clipH >= destH) return;
		s.setTextureRect(IntRect(0, 0, w, h - h*clipH / destH));
		s.setScale(destW / w, destH / h);
		s.setPosition(destX, destY);
		app.draw(s);

	}
};

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);
}

int main()
{
	RenderWindow app(VideoMode(width, height), "Outrun Racing!");
	app.setFramerateLimit(60);

	Texture bg;
	bg.loadFromFile("bg.png");
	bg.setRepeated(true);
	Sprite sBackground(bg);

	Texture t;
	t.loadFromFile("tree.png");
	Sprite sTree(t);

	std::vector<Line> lines;

	for (int i = 0; i < 1600; i++)
	{
		Line line;
		line.z = i*segL;

		if (i > 300 && i < 700) line.curve = 0.5;

		if (i > 750) line.y = sin(i / 30.0) * 1500;

		if (i % 20 == 0) { line.spriteX = -2.5; line.sprite = sTree;}

		lines.push_back(line);
	}

	int N = lines.size();
	int pos = 0;
	int playerX = 0;

	while (app.isOpen())
	{
		Event e;
		while (app.pollEvent(e))
		{
			if (e.type == Event::Closed)
				app.close();
		}
		if (Keyboard::isKeyPressed(Keyboard::Right)) playerX += 200;
		if (Keyboard::isKeyPressed(Keyboard::Left)) playerX -= 200;
		if (Keyboard::isKeyPressed(Keyboard::Up)) pos += 200;
		if (Keyboard::isKeyPressed(Keyboard::Down)) pos -= 200;

		while (pos >= N*segL) pos -= N*segL;
		while (pos < 0) pos += N*segL;

		app.clear();
		int startPos = pos / segL;
		int camH = 1500 + lines[startPos].y;
		float x = 0, dx = 0;
		int maxy = height;

		///////draw road///////
		for (int n = startPos; n <startPos+300; n++)
		{
			Line &l = lines[n%N];
			l.project(playerX - x, camH, pos - (n>=N?N*segL:0));
			x += dx;
			dx + l.curve;

			if (l.y >= maxy) continue;
			maxy = l.y;

			Color grass = (n / 3) % 2 ? Color(16, 200, 16) : Color(0, 154, 0);
			Color rumble = (n / 3) % 2 ? Color(255, 255, 255) : Color(0, 0, 0);
			Color road = (n / 3) % 2 ? Color(107, 107, 107) : Color(105, 105, 105);

			Line p = lines[(n - 1 % N)]; // previous line

			drawQuad(app, grass, 0, p.Y, width, 0, l.Y, width);
			drawQuad(app, rumble, p.X, p.Y, p.W*1.2, l.X, l.Y, l.W*1.2);
			drawQuad(app, road, p.X, p.Y, p.W, l.X, l.Y, l.W);
		}

		///////draw objects///////
		for (int n = startPos + 300; n > startPos; n--)
			lines[n%N].drawSprite(app);

		app.display();
	}

	return 0;

}

[2kaud]

When posting code, please use code tags so that the code is readable. Go Advanced, select the formatted code and click '#'.

This may or not be what you mean.

for (int n = startPos + 1; n <startPos+300; n++)
...
Line p = lines[(n - 1) % N]; // previous line

[A_Singh]

Thank, I will check that and tell you.As i am new to this website, can anyone tell me how to use code tags?

[A_Singh]

Thanks so much, It did work for me.

[A_Singh]

But I can't get the desired results

[VictorN]

But I can't get the desired results

What are the "desired results"?
What are the results you get?
What is the difference between them?

[A_Singh]

The graphics which should appear with my coding, aren't coming,instead using the solution given by 2kaud, I am getting strange results.How can I send the picture of the desired results?, though I can send of what I am getting.

[A_Singh]

I want that a road should appear with grass on the side, and I have saved special images for background(bg.png) and trees(tree.png) as I have mentioned in my code.

[VictorN]

How can I send the picture of the desired results?, though I can send of what I am getting.

You can attach your pictures/images and other files to your post.
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