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Graphics / Issue with rendering sprites

« on: October 13, 2023, 07:10:01 am »

Hi to all!)
I started learning c++ and to make it more interesting I make a small game pseudo3d racing.
And i have a strange problem, maybe with sprites or maybe with my c++ skills)
so, i have struct that contains information about traffic cars

struct trafficCar
{
    sf::Sprite sprite;
    int index;    
    float xOffset;
    float speed;
    float zPosition;
    float percent;
};

also i have struct that describes info about 1 road segment, here is part of code

struct segment
{
        //variables

    std::vector<billboardSprite> sideRoadSprites;

    std::vector<trafficCar*> segmentTrafficCars;


    void renderSprite()
    {          
        for (int i = 0; i < sideRoadSprites.size(); i++)
        {
            auto& roadSprite = sideRoadSprites[i];
            float spriteScale = point1.screenScale*1300.f;
            float spriteX = point1.screenPosition.x + (point1.screenScale * roadSprite.xOffset * roadWidth * wWidth /2.f);
            float spriteY = point1.screenPosition.y;

            const float destX = 215.f / 215.f * spriteScale;
            const float destY = 540.f / 540.f * spriteScale;
           
            roadSprite.sprite.setPosition(sf::Vector2f(spriteX, spriteY));
            roadSprite.sprite.setScale(destX, destY);
        }

        for (int i = 0; i < segmentTrafficCars.size(); i++)
        {
            auto& car = segmentTrafficCars[i];
            float spriteScale = interpolate(point1.screenScale,point2.screenScale,car->percent) *1300.f;
            float spriteX = interpolate(point1.screenPosition.x,point2.screenPosition.x,car->percent) + (spriteScale * car->xOffset * roadWidth * wWidth/2.f);
            float spriteY = interpolate(point1.screenPosition.y,point2.screenPosition.y,car->percent);

            const float destX = 80.f / 80.f * spriteScale;
            const float destY = 57.f / 57.f * spriteScale;
           
            car->sprite.setPosition(sf::Vector2f(spriteX, spriteY));
            car->sprite.setScale(destX, destY);
        }
    }
       
        //calculation functions
};

in segment i have vector array of pointers to trafficCar struct
and also i have vector array that contains all cars for track
here is how i create all this

void resetTrafficCars()
{
    std::random_device rd; // a seed source for the random number engine
    std::mt19937 gen(rd()); // mersenne_twister_engine seeded with rd()
    std::uniform_int_distribution<> distrib(0, 1);
    std::uniform_int_distribution<> distrib1(0, roadSegments.size());
   
    for(int i=0;i<100;i++)
    {
        trafficCar car;
        car.index = i;
        car.speed = maxSpeed/4 + distrib(gen) * maxSpeed/4.f;
        car.xOffset = 0;
        car.percent = 0;
        car.zPosition = distrib1(gen)*segmentLength;
        car.sprite.setTexture(testBotCarTexture);
        car.sprite.setTextureRect(sf::IntRect(sf::Vector2<int>(1383,894),sf::Vector2<int>(80,57)));
        car.sprite.setOrigin(80.f/2,57);
        auto& segment = roadSegments[(static_cast<int>(car.zPosition) / static_cast<int>(segmentLength)) %
        roadSegments.size()];
        segment.segmentTrafficCars.push_back(&car);
        allTrafficCars.push_back(car);        
    }
}

and here is function that update car state, in general it calculates car position and swap car between segment pointers array, i store them in segment to properly render later

void updateTrafficCars(float dt, segment* playerSegment,float playerW)
{
    for(int i=0;i<allTrafficCars.size();i++)
    {
        auto& car = allTrafficCars[i];
        auto& oldSegment = roadSegments[(static_cast<int>(car.zPosition) / static_cast<int>(segmentLength)) %
        roadSegments.size()];
        car.zPosition = increase(car.zPosition,dt * car.speed,trackLength);
        car.percent = percentRemaining(car.zPosition,segmentLength);
        auto& newSegment = roadSegments[(static_cast<int>(car.zPosition) / static_cast<int>(segmentLength)) %
        roadSegments.size()];

        if(oldSegment.index != newSegment.index)
        {
            int index = 0;
            for(int i=0;i<oldSegment.segmentTrafficCars.size();i++)
            {
                const auto& carPointer = oldSegment.segmentTrafficCars[i];
                if(carPointer->index == car.index)
                {
                    index = i;
                    break;
                }                
            }
            //switch car arrays
            oldSegment.segmentTrafficCars.erase(oldSegment.segmentTrafficCars.begin() + index);
            newSegment.segmentTrafficCars.push_back(&car);
        }
    }
}

and here is part of render code

for (auto& sideRoadSprite : roadSegments[currentIndex].sideRoadSprites)
                window.draw(sideRoadSprite.sprite);
           
            for (auto& trafficCar : roadSegments[currentIndex].segmentTrafficCars)
            {
                window.draw(trafficCar->sprite);
            }

so my problem is - a lot of pointers in segmentTrafficCars contains weird corrupted data, and it crush on trying to render it, even if i try to filter this pointers so it contain proper data, still i have black square instead of sprite,
i tested this sprite separatly and it loads and render's properly
also i tried for test create vector array for all sideRoadSprites and store pointers there, it also fails to render via pointer, help me pls with this)