Messages

1

Graphics / Re: Sfml drawing faster algorithm slower

« on: December 18, 2019, 09:37:45 pm »

Well maybe I missunderstand something in vectors because I'm new in c++ but I got perfromance that I needed.

About 2 dimension VectorArray.

I need VectorArray of points (All of them make big square). I have to color every pixel.For example With RectangleShape[][] I could do something like that.

for(int i=0; i<1000; i++){
for(int j=0; j<1000; j++){
if(condition)
shape[i-1][j+1].setFillColor = Color::Red;
}
}

In vectors I have to add another field to iterate and for square of pixels it looks like that

int pom = 0;
        int j = 0;
        int i = 0;
        for (; i < 1000000; i = i + 1000) {
                for (j = 0; j < 1000; j++) {
if(condition)
vertex[pom-999].color = Color::Red;
pom++;

To make it easier for 1D VertexArray its much harder to make conditions of coloring than RectangleShape 2D array. Thats why I'm asking about it.

2

Graphics / Re: Sfml drawing faster algorithm slower

« on: December 18, 2019, 08:32:48 pm »

Well, im stupid. I used vectors for int and bool not a dynamic array. Now I got 800fps.

Still is there posibility to make 2 dimension vertex array without loosing efficiently on drawing? Its boring to make conditions for one dimension.

3

Graphics / Re: Sfml drawing faster algorithm slower

« on: December 18, 2019, 07:06:54 pm »

Ok my bad ^^

1. Every start of the program I make an VertexArray of primitve points. The code shows how I make it. I make 10k points, set color to green set position each of them that I got square of pixels (100x100). It's constructor.

2.In loop while(window.isOpen()) in other class I use the function that use this vertexArray (I declare this VertexArray once at the start of the game).

3.The function iterate through all elements of my VertexArray for(int i=0; i<VertexArray.size(); i++). So its 10k iterations.

4. In this function I check like 1-12 condition also I change like 1-8 colors. For example vert[i+1].color = Color::Red or vert[i-1].color = Color::Red.

5. Then I just turn off program. It looks like on youtube that I posted link.


The main problem is why this algorithm work faster on rectangle shapes? I dont have bigger loop or something.In two cases in my function I do the same things. Check some conditions and if they are true I increment some values(the same amount, expect one field) and change color of that poins/pixel/shape. And vertexArray its like 20x slower but drawing 20x faster. No idea why :/

I hope I make it clear

4

Graphics / Sfml drawing faster algorithm slower

« on: December 18, 2019, 03:42:06 pm »

Hi. (Sorry for grammar I don't use english everyday)

I have big problem. I wrote a lichen array function. The problem is with performance.

When I use 2 dimension array of rectangle shape (shape size 6x6). In my function I'm checking conditions and setting color of each rectangle. Then I draw it. So the time of draw is like 20ms and the time of iteriation 100x100 and setting colors/checking conditions  is under 1ms.

I have read that I should use VertexArray of points. So i did it. The draw time is under 0.1ms for 100x100 array and that is perfect but... iterating and swapping colors is over 25ms? No idea why I have the same amount of conditions etc. I just have one more field that I increment to 10000. So its O(1). Maybe the problem is with setting the array. For 100x100 I just set it like that in constructor. But I just do it once so I don't think so. (The Vertex is point and I add this point to VertexArray named vert, other two arrays are normal vectors)

int j = 0;
        int pom = 0;
        int pom2 = 0;
        for (int i = 0; i < 10000; i++) {
                odpornosc.push_back(0);
                flaga.push_back(true);
                if (i == 100) {
                        pom = i;
                        j++;
                        pom2 = 0;
                }
                if (pom + 100 == i) {
                        pom += 100;
                        j++;
                        pom2 = 0;
                }

                point.position = Vector2f(pom2, j);
                pom2++;
                point.color = Color::Green;
                vert.append(point);
        }
 

In my iteration function I use methods only like:

vert[pom].color = Color::Yellow;

Of course I use this function in loop while(window.isOpen())

It looks like that:

https://www.youtube.com/watch?v=XKkq8rPhtDk&feature=youtu.be


Maybe there is possibility to make 2 dimension vertex array and still draw efficiently?