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WaleedH95

SDL FPS and Incrementing Issues

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Ok, so what I want to accomplish here is everytime I click on the screen a square (SDL_Rect) appears and moves downwards, once it reaches the end of the screen it's supposed to go back up to the top and back down again, and so on. But I have two problems. First, the rate at which the square is moving downwards varies, like first it'll go down slowly suddenly speed up and slow down again. Second, when the square reaches the end of the window I increment it's y value by -10 but all it does is go straight back up, doesn't even move backwards. Thanks in advance.

#include <SDL.h>
#include <SDL_mixer.h>
#include <SDL_image.h>
#include <vector>

using namespace std;

int main(int argc,char*args[]){

SDL_Event event;
bool running = true;
SDL_Init(SDL_INIT_EVERYTHING);

// the rectangle
vector<SDL_Rect> daSquares;

SDL_Rect daSquare;

// keys inputted
Uint8*keys = SDL_GetKeyState(NULL);

// regulating fps
int start;
int fps = 20;

// the screen
SDL_Surface* screen;
screen = SDL_SetVideoMode(640,480,32,SDL_SWSURFACE);

while(running == true){
start = SDL_GetTicks();
while(SDL_PollEvent(&event)){
if(event.type == SDL_MOUSEBUTTONDOWN){
if(event.button.button == SDL_BUTTON_LEFT){

int x = event.button.x;
int y = event.button.y;

daSquare.x = x;
daSquare.y = y;
daSquare.w = 20;
daSquare.h = 20;

daSquares.push_back(daSquare);
}
}
if(event.type == SDL_QUIT){
running = false;
}
}
// uodating the screen and regulating frameraate
SDL_Flip(screen);


if(1500/fps > start - SDL_GetTicks()){
SDL_Delay(1500/fps - (start - SDL_GetTicks()));
}

// filling the rectangles
SDL_FillRect(screen,&screen->clip_rect,SDL_MapRGB(screen->format,0,0,0));

// updating their locations
for(int i = 0; i <daSquares.size(); i++){

SDL_FillRect(screen,&daSquares,SDL_MapRGB(screen->format,0,200,0));
daSquares.y += 10;
if(daSquares.y >= 460)
{
while(daSquares.y >= 10)
{daSquares.y -= 10;}
}
}
}
SDL_Quit();
return 0;}

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