SDL2, Gravidade?

[edub13]

Boas pessoal, gostava de saber como posso implementar "gravidade" no meu código, para por o boneco a saltar ?

Cumps

[HappyHippyHippo]

isso é uma pergunta ao qual a resposta tem de ser adaptada ao código que tens.

que bases de física é que possuis ?

[edub13]

Para ser sincero muito poucas:

Aqui vai o meu código (não está em C++ mas vou colocar mais tarde)

main.h

#include "SDL2/SDL.h"
#include "SDL2/SDL_image.h"
#include <iostream>
void Init(const char* title, int x, int y, int w, int h, Uint32 flags);
void Loop();
void Update();
void LoadResources();
void Draw();
bool isColliding(SDL_Rect* a, SDL_Rect* b);
bool WColliding(SDL_Rect* a);
void Exit();

SDL_Window* window;
SDL_Renderer* renderer;
SDL_Texture* background;
SDL_Texture* platform;
SDL_Texture* player;
int player_velX = 0;
int player_velY = 0;
SDL_Texture* ground;
SDL_Rect dstGroundRect = {0, (480 - dstGroundRect.h), 60, 60};
SDL_Rect platformRect = {0, 300, 150, 35};
SDL_Rect playerRect = {0, ((480 - 48) - 60), 20, 48};
SDL_Event event;
bool quit = false;
// Carregar imagens.
SDL_Texture* LoadIMG(const char* path, SDL_Renderer* r)
{
SDL_Texture* texture = nullptr;
SDL_Surface* surface = IMG_Load(path);

if(!surface)

	throw SDL_GetError();
else
	texture = SDL_CreateTextureFromSurface(r, surface);

	if(!texture)

		throw SDL_GetError();

SDL_FreeSurface(surface);

return texture;
}
// Inicializar SDL2.
void Init(const char* title, int x, int y, int w, int h, Uint32 flags){

 if(SDL_Init(SDL_INIT_VIDEO) != 0)
throw SDL_GetError();
 else{
window = SDL_CreateWindow(title, x, y, w, h, flags);
if(!window)
  throw SDL_GetError();
else{
  renderer = SDL_CreateRenderer(window, -1, 0);
  if(!renderer)
throw SDL_GetError();
}
 }
}
// Game loop
void Loop(){
 while(!quit){
while(SDL_PollEvent(&event)){
  switch(event.type){
case SDL_QUIT:
  quit = true;
  break;
case SDL_KEYDOWN:
  if(event.key.keysym.sym == SDLK_LEFT)
 player_velX = -3;
  if(event.key.keysym.sym == SDLK_RIGHT)
 player_velX =  3;


  break;
case SDL_KEYUP:
  if(event.key.keysym.sym == SDLK_LEFT)
 player_velX = 0;
  if(event.key.keysym.sym == SDLK_RIGHT)
 player_velX = 0;

  break;
  }
}

if(isColliding(&playerRect, &dstGroundRect) == true){
  playerRect.y = (480-60);
}

if(WColliding(&playerRect) == true){
  player_velX = 0;
}

playerRect.x += player_velX;
playerRect.y += player_velY;

Update();
 }
}
void Update(){
 SDL_RenderClear(renderer);
 Draw();
 SDL_RenderPresent(renderer);
}
void LoadResources(){

 background = LoadIMG("background.png", renderer);
 platform = LoadIMG("platform.png", renderer);
 player = LoadIMG("player.png", renderer);
 ground = LoadIMG("ground.png", renderer);
}
void Draw(){

 LoadResources();

 // Desenhar Fundo
 SDL_RenderCopy(renderer, background, NULL, NULL);

 // Desenhar "chão"
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 60;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 120;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 180;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 240;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 300;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 360;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 420;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 480;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 540;
 SDL_RenderCopy(renderer, ground, NULL, &dstGroundRect);
 dstGroundRect.x = 0 + 600;

 //Desenhar plataformas
 SDL_RenderCopy(renderer, platform, NULL, &platformRect);
 platformRect.x = 0;
 SDL_RenderCopy(renderer, platform, NULL, &platformRect);
 platformRect.x = 640 - 150;

 // Desenhar jogador
 SDL_RenderCopy(renderer, player, NULL, &playerRect);

}
bool isColliding(SDL_Rect* a, SDL_Rect* b)
{
if (a->x < b->x + b->w && a->x + a->w > b->x && a->y < b->y + b->h && a->h + a->y > b->y){
	return true;
}
return false;
}
bool WColliding(SDL_Rect* a)
{
if(a->x < 0){
	a->x = a->x + 1;
	return true;
}

if(a->y < 0){
	a->y = a->y + 1;
	return true;
}

if((a->x + a->w) > 640){
	a->x = 640 - a->w;
	return true;
}

if((a->y + a->h) > 480){
	a->y = 480 - a->h;
	return true;
}

return false;
}
void Exit(){

 SDL_DestroyTexture(platform);
 SDL_DestroyTexture(ground);
 SDL_DestroyTexture(background);

 SDL_DestroyRenderer(renderer);
 SDL_DestroyWindow(window);

 SDL_Quit();
}

main.cpp:

#include "main.h"
int main(){
 Init("Title", 0, 0, 640, 480, 0);
 Loop();
 Exit();
 return 0;
}

Edited September 21, 2014 by edub13

[HappyHippyHippo]

?????

void Update(){
 SDL_RenderClear(renderer);
 Draw();
 SDL_RenderPresent(renderer);
}

void LoadResources(){
 background = LoadIMG("background.png", renderer);
 platform = LoadIMG("platform.png", renderer);
 player = LoadIMG("player.png", renderer);
 ground = LoadIMG("ground.png", renderer);
}

void Draw(){
 LoadResources(); // <--- em todos os frames estás a ler os ficheiros de imagem ??
                  //      não só é um desperdício como como é um total "memory leak" de tamanho descomunal !!!

[edub13]

Realmente, agora percebo porque estava tão lento, já mudei isso:

void Init(const char* title, int x, int y, int w, int h, Uint32 flags){

 if(SDL_Init(SDL_INIT_VIDEO) != 0)
throw SDL_GetError();
 else{
window = SDL_CreateWindow(title, x, y, w, h, flags);
if(!window)
  throw SDL_GetError();
else{
  renderer = SDL_CreateRenderer(window, -1, 0);
  if(!renderer)
       throw SDL_GetError();
}
 }

 LoadResources(); // Aqui está

}

Edited September 21, 2014 by edub13