SDL collision Detection

I am making a game to where if the ball goes below the paddle you lose its not done yet but i made the collision detection but when the ball hits the paddle it bounces off but i doent look fluid and if the ball hits the edges of the paddle it doesnt bounce off it goes through the paddle any help would be nice.
Something else if i reset the ball with reset() in the ball class the velocity goes super fast but it is supposed to go slowely i dont know why.
Thank you

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#include "SDL.h"
#include "SDL_ttf.h"
#include "SDL_image.h"
#include <iostream>
#include <sstream>
using namespace std;
string convertInt(int h);

class bar{
    int x,y,xvel,life;
    SDL_Rect rt;
    SDL_Texture *pic = nullptr;
    bool dead;
public:
    void init(SDL_Surface* my,SDL_Renderer* scre)
    {
        dead = false;
        x = 250;
        life = 3;
        y = 470;
        xvel = 0;
        pic = SDL_CreateTextureFromSurface(scre,my);
    }
    SDL_Rect GetP()
    {
        rt.x = x;
        rt.y = y;
        rt.w = 50;
        rt.h = 15;

        return rt;
    }
    void Hevent(int h)
    {
        if(h == 0)
            xvel = 0;

        else if(h == 1) // left
            xvel = -9;

        else if(h == 2)
            xvel = 9;
    }
    SDL_Texture* Get(){return pic;}
    void move()
    {
        x += xvel;
        if(x < 0)
        {
            x = 0;
        }
        else if(x > 450)
        {
            x = 450;
        }
    }
    bool isDead(){kill(); return dead;}
    void kill()
    {
        if(life == 0)
            dead = true;
    }

};

class ball{
    int x,y,xvel,yvel;
    SDL_Rect rt;
    SDL_Texture *pic = nullptr;
    bool Under;
public:
    void init(SDL_Surface* va,SDL_Renderer* my)
    {
        x = 250;
        y = 150;
        xvel = 3;
        yvel = 3;
        pic = SDL_CreateTextureFromSurface(my,va);
        Under = false;
    }
    SDL_Rect* GetP()
    {
        rt.x = x;
        rt.y = y;
        rt.w = 25;
        rt.h = 25;
        return &rt;
    }
    void reset()
    {
        x = 250;
        y = 150;
        xvel = 10;
        yvel = 13;
        Under = false;
    }
    bool Hit(SDL_Rect bp)
    {
        if((x > bp.x) && (x < bp.x + 50) && (y>bp.y) && (y < bp.y + 15))
        {
            return true;
        }
        else
            return false;
    }
    bool isUnder(){return Under;}
    SDL_Texture* Get(){return pic;}
    void move(SDL_Rect hy)
    {
        x += xvel;
        y += yvel;
        x < 250 ? x -= 1 : x += 1;
        if(Hit(hy) == true)
        {
            y = hy.y - 50;
            yvel *= -1;
        }
        if(y > 475)
        {
            reset();
            Under = true;
        }
        else if( y < 0)
        {
            y = 0;
            yvel *= -1;
        }
        if(x < 0)
        {
            x = 0;
            xvel *= -1;
        }
        else if(x > 475)
        {
            x = 475;
            xvel *= -1;
        }
    }
};
int main(int argc, char *argv[])
{
    SDL_Init(SDL_INIT_EVERYTHING);
    IMG_Init(IMG_INIT_PNG);
    TTF_Init();
    SDL_Color col = {255,255,255,255};
    SDL_Event event;
    SDL_Rect tpos,t;
    SDL_Window *win;
    SDL_Texture *time;
    string timet = "";
    int timecount = 0,pcount = 0,ht = 0;
    bool quit = false;
    TTF_Font *myfont;
    SDL_Surface* m,*tm;
    SDL_Renderer *screen;
    bar mbar;
    ball tball;

    win = SDL_CreateWindow("Jumping Ball",SDL_WINDOWPOS_CENTERED,SDL_WINDOWPOS_CENTERED,500,500,SDL_WINDOW_SHOWN);
    screen = SDL_CreateRenderer(win,-1,SDL_RENDERER_ACCELERATED);
    SDL_SetRenderDrawColor(screen,0,0,0,255);

    tpos.x = 400;
    tpos.y = 35;
    tpos.w = 30;
    tpos.h = 35;

    m = IMG_Load("bar.png");
    tm = IMG_Load("ball.png");
    mbar.init(m,screen);
    tball.init(tm,screen);
    timecount = SDL_GetTicks();
    myfont = TTF_OpenFont("arial.ttf",28);
    timet = convertInt(timecount/1000);
    time = SDL_CreateTextureFromSurface(screen,TTF_RenderText_Solid(myfont,timet.c_str(),col));
    
    SDL_RenderClear(screen);
    SDL_RenderCopy(screen,tball.Get(),NULL,tball.GetP());
    t = mbar.GetP();
    SDL_RenderCopy(screen,mbar.Get(),NULL,&t);
    SDL_RenderCopy(screen,time,NULL,&tpos);
    SDL_RenderPresent(screen);

    while(quit == false)
    {
        while(SDL_PollEvent(&event))
        {
            if(event.type == SDL_QUIT)
                quit = true;

            else if(event.type == SDL_KEYDOWN)
            {
                if(event.key.keysym.sym == SDLK_LEFT)
                {
                    ht = 1;
                }
                else if(event.key.keysym.sym == SDLK_RIGHT)
                {
                    ht = 2;
                }
                else if(event.key.keysym.sym == SDLK_r)
                {

                }
            }
            else if(event.type == SDL_KEYUP)
            {
                ht = 0;
            }
        }
        mbar.Hevent(ht);
        mbar.move();
        t = mbar.GetP();
        tball.move(t);
        SDL_DestroyTexture(time);
        
        time = nullptr;
        timecount = SDL_GetTicks();
        timet = convertInt(timecount/1000);
        time = SDL_CreateTextureFromSurface(screen,TTF_RenderText_Solid(myfont,timet.c_str(),col));
        
        SDL_RenderClear(screen);
        SDL_RenderCopy(screen,tball.Get(),NULL,tball.GetP());
        t = mbar.GetP();
        SDL_RenderCopy(screen,mbar.Get(),NULL,&t);
        SDL_RenderCopy(screen,time,NULL,&tpos);
        SDL_RenderPresent(screen);
        SDL_Delay(15); // Delay frames
    }
    
    SDL_DestroyWindow(win);
    SDL_DestroyRenderer(screen);
    SDL_DestroyTexture(time);
    IMG_Quit();
    TTF_Quit();
    SDL_Quit();
    return 0;
}
string convertInt(int h)
{
    stringstream ht;
    ht << h;
    return ht.str();
}
Would you mind posting your coordinate system? Also, instead of all those numbers (line 112, 115, 118,...) better put formulas. A description of what your motion should be would be extremely helpful.
well i m working on a collision detector just like you mine is not perfect either but i can give you some links to check which is what i m doing now

http://www.sdltutorials.com/sdl-collision
http://www.sdltutorials.com/sdl-collision-events
http://lazyfoo.net/SDL_tutorials/lesson17/index.php
http://lazyfoo.net/SDL_tutorials/lesson18/index.php
http://lazyfoo.net/SDL_tutorials/lesson19/index.php

believe me these are awesome tutorials. i m working on them
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