CODEWITHSUNDEEP
c++visual-studiodebuggingfor-loop
celphy
celphy

Reputation: 127

C++ VS Debugger diverting behaviour?

I'm currently struggling to debug the following code part. I'm using VS2015 community edition on windows 10.

[(BR)] is a breakpoint

The following is a (slimmed down) version of my code. I basically have nested for loops that extract all points (X&Y coordinates) from all gameObjects.

As you can see I set two breakpoints.

I hit the debug button and it stops at the first breakpoint - success. Important local variable counterVertices is zero. Great as well.

Then I hit continue. It goes TO THE SAME BREAKPOINT THREE TIMES.

Then I get to the second breakpoint. counterVertices shows zero. Why?

int counterVertices = 0;
    int counterIndices = 0;
    int beginningOfPolygon = 0;
    //GetData
    for (auto& it : this->gameObjects) { //Iterate over all gameObjects
        beginningOfPolygon = counterIndices;
        for (int i = 0; i < it->getOutline().getNumber(); i++) { //Iterate over all points of the gameObject
            [(BR)]this->vertices[counterVertices] = it->getRenderPoint(i).x;
            counterVertices++;
            this->vertices[counterVertices] = it->getRenderPoint(i).y;
            counterVertices++;
            [(BR)]if (this->vertices[counterVertices-2] == this->vertices[counterVertices-1] && this->vertices[counterVertices-1] == 0.0f) {
                cout << "A point on 0/0." << endl;
            }
            this->vertices[counterVertices] = 0.0f;
            counterVertices++;
            //Add Line to draw
            this->indices[counterIndices * 2] = counterIndices;
            this->indices[(counterIndices * 2) + 1] = counterIndices + 1;
            counterIndices++;
        }
        this->indices[(counterIndices * 2) - 1] = beginningOfPolygon; 

    }

I'm completely lost as this isn't even the problem I wanted to solve in the first place but rather got stuck on trying to figure on my original issue.

Thanks already for your time

PS: I have screenshots of the whole thing and the process is recreatable. I can clean and rebuild the solution, restart and do a backflip. Debugging behaviour doesn't change.

PPS: The program behaves/works in a way that suggest that counterVertices is increased correctly but the debugger information contradicts that.

Upvotes: 3

Views: 44

Answers (1)

David Bradley
David Bradley

Reputation: 196

Make sure you have optimizations turned off. Optimizations can really make it hard to debug, as values will be held in registers and not stored until it needs to. And code flow can be very unintuitive.

Upvotes: 4

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