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[kytuzian]

My girlfriend (who is more familiar with Lua than I am) was telling me that it should be capitalized. Then again it could have just been sleep deprived ramblings at 3 AM.

I just did a quick test, it is case=sensitive and the actual keyword is "and"

[Antsan]

I am attempting to do a game and for that game I thought I'd use collaborative diffusion. I've got the idea from this paper:
http://www.cs.colorado.edu/~ralex/papers/PDF/OOPSLA06antiobjects.pdf

This paper offers the following diffusion equation:
u(0,t+1)=u(0,t)+d*sum[across neighbours i](u(i,t) - u(0,t))
with u(0,t) being the diffusion value of the center,
u(i,t) being the diffusion values of it's neighbours and
d being the diffusion coefficient determining how fast diffusion happens. d is in the range [0,0.5]

This formula is very likely not correct, as for 2 neighbours, d=0.5 and u(i,t)=0 for all neighbours i it returns u(0,t+1)=0, which just doesn't seem right - I don't think that's how diffusion is supposed to behave.
Even worse: With more neighbours the value for u(0,t+1) can become negative and this is definitely not right, as the magnitude of the negatvie value becomes even bigger when the diffusion value at the center is more positive beforehand.
Does anyone know the correct diffusion equation for discrete grids?

I tried to do some corrections myself, such as not multiplying with d but instead with d/(number of neighbours) or using the sum
sum[across neighbours i](u(i,t) - u(0,t)/(number of neighbours))
instead, but the results of those seemed strange.

[RulerOfNothing]

If all neighbours have a value of 0, why should the value of the centre change at all?

[Antsan]

Because what is in the center dissipates into the neighbours. It diffuses.
The diffusion equation is calculated for any position on the map once per time step. In the end the diffusion equation is the rule of a continuously valued cellular automaton.

[AlleeCat]

Now we have another problem. I'm having a syntax error at the end of an if loop for some reason.

Code: [Select]

if gamestate == "credits" then
love.graphics.setColor(255,0,0)
love.graphics.setFont("buttonFont")
love.graphics.setColor(0,0,0)
love,graphics.print("Back",20,652)
endI cut out some extraneous bits in the middle. It's a long loop, but I'f got an even longer loop in the same file that works just fine. The error is telling me the syntax error is on line 52, and the only code on that line is "end".

[Skyrunner]

You typed a comma instead of a period on the 2nd to last line. After love.

[AlleeCat]

And this is why coding in the middle of the night is a bad idea.

EDIT:
I Also noticed another typo in that "Back" should be printed at 20,562 instead of 20,652. It was being drawn offscreen.

[My Name is Immaterial]

Hey, does anyone know how to make data selection start where the last one left off in Google Drive's Spreadsheets? I've got about 3500 datapoints starting in January of '09 going to April of '14, so I can't do it manually and stay sane.
Here's the code I have:

Code: [Select]

=average(Daily!D2:D32)
=average(Daily!D33:D60)
=average(Daily!D61:D91)
=average(Daily!D92:D121)
=average(Daily!D122:D152)
=average(Daily!D153:D182)
=average(Daily!D183:D213)
=average(Daily!D214:D244)
=average(Daily!D245:D274)
=average(Daily!D275:D305)
=average(Daily!D306:D335)
=average(Daily!D336:D366)
and I want that to continue to be and so on:

Code: [Select]

=average(Daily!D367:D397)
=average(Daily!D398:D425)
=average(Daily!D426:D456)
Should I just write a script that will set up this data field for me?

[My Name is Immaterial]

Or should I just do it in Excel?

[TolyK]

Excel's probably easier when it comes to formulas, afaik.

[SethCreiyd]

I'm having an issue in SDL2 with creating a window inside a class constructor, and I haven't any real idea about the cause.

Code: (C++) [Select]

class Window {
    public:
        Window(const char* title,
            int x=SDL_WINDOWPOS_UNDEFINED,
            int y=SDL_WINDOWPOS_UNDEFINED,
            int w=640, int h=480,
            Uint32 flags=SDL_WINDOW_RESIZABLE);
        virtual ~Window();
        SDL_Window* handle;
};

Window::Window(const char* title, int x, int y, int w, int h, Uint32 flags) {
    handle = SDL_CreateWindow(title, x, y, w, h, flags);
    // Check that the window was successfully made
    if (handle == NULL) {
        printf("Could not create window: %s\n", SDL_GetError());
    }
    SDL_Delay(5000);
    std::cout << "Window created." << std::endl;
}

Window::~Window() {
    SDL_DestroyWindow(handle);
    std::cout << "Window destroyed." << std::endl;
}

If I create the window in the main function, it works as expected:

Code: [Select]

int main(int argc, char **argv) {
    Application app;
    app.initialize();
    Window* window = new Window("This is a Test!");

    app.sleep(5000);

    return 0;
}

The problem occurs if I move the window creation to the Application initialization and store the pointer as an Application member:

Code: [Select]

int Application::initialize() {
    try {
        SDL sdl(SDL_INIT_VIDEO|SDL_INIT_TIMER);
        window = new Window("This is a Test!");
        return 0;
    } catch (const InitError& err) {
        std::cerr
        << "Error initializing SDL:  "
        << err.what()
        << std::endl;
    }
    return 1;
}

/*-----*/

int main(int argc, char **argv) {
    bool quit = false;
    SDL_Event event;

    Application app;
    app.initialize();

    app.sleep(5000);

    return 0;


This causes the window to pop up at first as it is apparently created successfully - then the window closes right away after the call to app.initialize() is finished, long before the Window destructor is called. The program still exits successfully, and at no point does SDL throw an error, the window just disappears.

For now, I'm just going to construct the Window in the main function so I can move on, but I'd really appreciate it if someone could explain the exact issue here. Constructing the new object in the Application constructor and storing the pointer as a member are clearly problematic, I just don't know why.

If it's just a quirk of SDL2 then that's one thing, but I suspect there is some aspect of the way C++ handles data that I'm missing.

[Normandy]

It might be from this line:

Code: [Select]

SDL sdl(SDL_INIT_VIDEO|SDL_INIT_TIMER);
I'm not sure what your SDL class does, but in this case sdl is being initialized then the destructor is called when the function returns. If you're quitting SDL on destruction then that might close the window immediately.

[SethCreiyd]

/facepalm

Yes, that was it. Thank you.

[thobal]

The (1st) problem was that I forgot to reset the least costly square so far...

Having some trouble with a* in c++:

Code: [Select]


struct Node
{
int parent;

int x;
int y;
int z;

int g; /// Cost to this point
int h; /// Est. cost to target
int f; /// Total Est. Cost

MOV_DIR direction;

Node(int,int,int,int,int,int, MOV_DIR);

};

Node::Node(int parentS, int xS, int yS, int zS, int gS, int hS, MOV_DIR dir)
{
parent = parentS;
x = xS;
y = yS;
z = zS;
g = gS;
h = hS;
f = g + h;
direction = dir;

}

bool AgentKing::aStarVer1(ObjLoc ori, ObjLoc tar, MovementPath& path)
{
    bool debug = true;

const int NSEW_COST = 10;
bool done = false;
bool fail = false;



int nodeCount = 0;
vector<Node> node;

int nodesThisRound = 0;

vector<int> open;
vector<int> closed;

node.push_back(Node(-1, ori.x, ori.y, ori.z, 0, 0, MD_DWN));
closed.push_back(nodeCount); nodeCount++;

int nodeToCheck = 0;
int n2cP = ori.p;
int n2cX;
int n2cY;
int n2cZ;


int leastEstCost = 999999999;
bool nodeClosed;



while(done == false && fail == false)
{
///Open all valid adjacent nodes
///First get the current location

if(debug)printf("\n\nNODE BEING CHECKED = %i", nodeToCheck);
            if(debug)printf("\nNODE X =%i", node[nodeToCheck].x);
            if(debug)printf("\nNODE Y =%i", node[nodeToCheck].y);
            if(debug)printf("\nNODE Z =%i", node[nodeToCheck].z);
n2cX = node[nodeToCheck].x;
n2cY = node[nodeToCheck].y;
n2cZ = node[nodeToCheck].z;
if (manhattanCostEst(n2cZ, n2cY, n2cX, tar) == 0)
{
done = true;
if(debug)printf("\nPATHING TARGET REACHED");
}
else
{
///Then check all 6-degrees
if (n2cY > 0 && locationPassable(n2cP, n2cZ, n2cY, n2cX, MD_N)) ///Northern Check
{
node.push_back(Node(nodeToCheck, n2cX, n2cY+1, n2cZ,
node[nodeToCheck].g + NSEW_COST, manhattanCostEst(n2cZ, n2cY+1, n2cX, tar), MD_N));
open.push_back(nodeCount); nodeCount++;
nodesThisRound++;
}
if (n2cY < planetYdimension - 1 && locationPassable(n2cP, n2cZ, n2cY, n2cX, MD_S)) ///Southern Check
{
node.push_back(Node(nodeToCheck, n2cX, n2cY-1, n2cZ,
node[nodeToCheck].g + NSEW_COST, manhattanCostEst(n2cZ, n2cY-1, n2cX, tar), MD_S));
open.push_back(nodeCount); nodeCount++;
nodesThisRound++;
}
                if (n2cX > 0 && locationPassable(n2cP, n2cZ, n2cY, n2cX, MD_E)) ///Eastern Check
{
node.push_back(Node(nodeToCheck, n2cX+1, n2cY, n2cZ,
node[nodeToCheck].g + NSEW_COST, manhattanCostEst(n2cZ, n2cY, n2cX+1, tar), MD_E));
open.push_back(nodeCount); nodeCount++;
nodesThisRound++;
}
                if (n2cX < planetXdimension - 1 && locationPassable(n2cP, n2cZ, n2cY, n2cX, MD_W)) ///Western Check
{
node.push_back(Node(nodeToCheck, n2cX-1, n2cY, n2cZ,
node[nodeToCheck].g + NSEW_COST, manhattanCostEst(n2cZ, n2cY, n2cX-1, tar), MD_W));
open.push_back(nodeCount); nodeCount++;
nodesThisRound++;
}
                if (n2cZ < planetZdimension - 1 && locationPassable(n2cP, n2cZ, n2cY, n2cX, MD_UP)) ///Upper Check
{
node.push_back(Node(nodeToCheck, n2cX, n2cY, n2cZ+1,
node[nodeToCheck].g + NSEW_COST, manhattanCostEst(n2cZ+1, n2cY, n2cX, tar), MD_UP));
open.push_back(nodeCount); nodeCount++;
nodesThisRound++;
}
                if (n2cZ > 0 && locationPassable(n2cP, n2cZ, n2cY, n2cX, MD_DWN)) ///Lower Check
{
node.push_back(Node(nodeToCheck, n2cX, n2cY, n2cZ-1,
node[nodeToCheck].g + NSEW_COST, manhattanCostEst(n2cZ-1, n2cY, n2cX, tar), MD_DWN));
open.push_back(nodeCount); nodeCount++;
nodesThisRound++;
}

while(nodesThisRound > 0) /// Find the lowest est cost of the <= 6 nodes opened and register node to check
{
    //if(debug)printf("\nNODES THIS ROUND = %i", nodesThisRound);
if (node[nodeCount - nodesThisRound].f < leastEstCost)
{
leastEstCost = node[nodeCount - nodesThisRound].f;
nodeToCheck = nodeCount - nodesThisRound;
}




nodesThisRound--;
}

///find if an opened node picked, if not, pick last new node created
nodeClosed = false;
for(int i = 0; i < closed.size(); i++)
{
if (closed[i] == nodeToCheck)
nodeClosed = true;
}
if (nodeClosed == true)
{
nodeToCheck = open[open.size()-1];
}
///Finally close the open node to be checked
for(int i = 0; i < open.size(); i++)
{
if(open[i] == nodeToCheck)
{
    ///if(debug)printf("\nNODES OPEN = %i", node.size());
open.erase(open.begin()+i);
closed.push_back(nodeToCheck);
fail = false;
break;
}
else
                    {
                        fail = true;
                    }
}

}

        if (done == true && fail == false)
        {
            if(debug)printf("DONE WITH PATHING, CAPTURING PATH");
            while (nodeToCheck != 0 && path.pathLength < 255)
            {
                nodeCount = 0;
                path.direction[nodeCount] = node[nodeToCheck].direction;
                path.pathLength++;
                nodeToCheck = node[nodeToCheck].parent;
                nodeCount++;
            }
        }
}



    return done;

}



I realize this is a massive block of code. For some reason it just keep recycling through a few points very close to origin without venturing outwards(the node checker I mean, it's an infinite loop). It's probably something obvious that I'm just not seeing...

[Valid_Dark]

So, I need to find a way to get the size (in pixels) of some text,  the only problem is it isn't monospaced,
I know I could find the size of each letter, and have a function that counts how many of what letters are in the text and add together the sizes, but I was wondering if there was an easier way?

I'm using SDL, is there any way to get the size of a surface? 

I haven't learned SDL2 yet, when I do I need to convert all of my program,  I was going to wait until I finish this first part of it first.

anyways, any ideas?

after a tiny bit of research I think I already found the answer I was looking for,

is there a way to delete a post?