I'm currently having a problem with my pong game. I'm trying to smooth out the player movement (so it wont stutter so much when is moves, and no delay after first keypress)
This is my code so far, problem is while I've got the movement smoother the _paddle move too fast! and I don't now how to make it move slower!
Is there a way i can make the _paddle move slower or did i write the code wrong?
maingame.h
#pragma once
#include <iostream>
#include <SDL/SDL.h>
#include <string>
#include "maingame.h"
class maingame
{
public:
maingame();
~maingame();
//loads pictures
bool loadMedia(std::string path);
//init the system
void init();
//runs the game
void run();
//THE EPIC GAMELOOP
void gameloop();
//draw the screen
void draw();
void UserInput();
private:
//window
SDL_Window* _window;
//redenderer
SDL_Renderer* _rend;
//the screens surface
SDL_Surface* _screensurface;
//player, ai and the ball
SDL_Rect _paddle;
SDL_Rect _ai;
SDL_Rect _ball;
//checks if you pressed down the W or S button
bool keydown_w = false;
bool keydown_s = false;
//Event for the pall stuff
SDL_Event e;
};
maingame.c
#include "maingame.h"
/*
PONG V0.2
Black background - CHECK
paddle appear on screen - CHECK
other paddle appear on screen - CHECK
ball appear on screen - CHECK
move player paddle - CHECK
impossible to move outside of map - CHECK
movement smoother -
make ball go around -
collison with paddles -
keep scores -
show scores -
make a 2nd player chooseable -
*/
//screen width and height
const int SCREEN_WIDTH = 1024;
const int SCREEN_HEIGHT = 768;
maingame::maingame()
{
_window = nullptr;
_rend = nullptr;
}
maingame::~maingame()
{
}
void maingame::init()
{
SDL_Init(SDL_INIT_EVERYTHING);
}
void maingame::run()
{
init();
//creating a windows
_window = SDL_CreateWindow("PONG", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
//create the render
_rend = SDL_CreateRenderer(_window, -1, SDL_RENDERER_ACCELERATED);
//set out the player
_paddle.x = 100;
_paddle.y = (SCREEN_HEIGHT / 2) - 100;
_paddle.w = 20;
_paddle.h = 200;
//set out the ai
_ai.x = SCREEN_WIDTH - 100;
_ai.y = (SCREEN_HEIGHT / 2) - 100;
_ai.w = 20;
_ai.h = 200;
//set out the ball
_ball.x = SCREEN_WIDTH / 2 - 20;
_ball.y = (SCREEN_HEIGHT / 2) - 20;
_ball.w = 20;
_ball.h = 20;
draw();
gameloop();
}
void maingame::draw()
{
//make the render be black
SDL_SetRenderDrawColor(_rend, 0, 0, 0, 0);
//Clear the render with the color we set with SDL_SetRenderDrawColor, in this case black
SDL_RenderClear(_rend);
//make the next things we will render white
SDL_SetRenderDrawColor(_rend, 255, 255, 255, 0);
//make the paddle, ai and ball the color of SDL_SetRenderDrawColor, which is whites in this case
SDL_RenderFillRect(_rend, &_paddle);
SDL_RenderFillRect(_rend, &_ai);
SDL_RenderFillRect(_rend, &_ball);
//SDL_RenderDrawRect(_rend, &_paddle);
//Present the render, draw it to the screen
SDL_RenderPresent(_rend);
}
bool maingame::loadMedia(std::string path)
{
//Loading success flag
bool success = true;
SDL_Surface* pic;
//Load splash image
pic = SDL_LoadBMP(path.c_str());
if (pic == NULL)
{
printf("Unable to load image %s! SDL Error: %s\n", "02_getting_an_image_on_the_screen/hello_world.bmp", SDL_GetError());
success = false;
}
return success;
}
void maingame::gameloop()
{
const Uint8 *keys = SDL_GetKeyboardState(NULL);
bool keydown_w = false;
bool keydown_s = false;
while (true)
{
while (SDL_PollEvent(&e) != 0)
{
//pressed the X, quit the program
if (e.type == SDL_QUIT)
{
exit(1);
}
UserInput();
}
UserInput();
draw();
}
}
void maingame::UserInput()
{
float lol = 0;
//Pressed a key!
if (e.type == SDL_KEYDOWN)
{
//pressed W, move the player
if (e.key.keysym.sym == SDLK_w)
{
keydown_w = true;
}
//pressed S, move the player
else if (e.key.keysym.sym == SDLK_s)
{
keydown_s = true;
}
}
if (e.type == SDL_KEYUP)
{
std::cout << keydown_w << std::endl;
if (e.key.keysym.sym == SDLK_w)
keydown_w = false;
if (e.key.keysym.sym == SDLK_s)
keydown_s = false;
}
if (keydown_w)
{
if (_paddle.y > 1)
{
_paddle.y -= 1;
}
std::cout << keydown_w << std::endl;
}
if (keydown_s)
{
if (_paddle.y < SCREEN_HEIGHT - _paddle.h)
{
_paddle.y += 1;
}
}
}
It maybe bad programming practice to do so but the only way I would see getting around your problem is to add an SDL_Delay() in your gameloop function. I would suggest you use it as a temporary fix until you find an alternative solution. Hope this helps.
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I'm trying to make a game in C++ with SDL2, and I can't even get a texture displaying. SDL_GetError() returns nothing.
I'm on a windows 10 pro using Visual Studio.
Here are my 3 files:
main.cpp
#include "Classes.h"
int MouseX = 0;
int MouseY = 0;
int PlayerX = 0;
int PlayerY = 0;
SDL_Renderer* renderer;
Tile tile = Tile({10, 10, TileTypes::Tile_Grass}, renderer);
EventReturns HandleEvent(SDL_Event* event) {
switch (event->type) {
case SDL_QUIT:
return EventReturns::Event_QUIT;
case SDL_KEYDOWN:
switch (event->key.keysym.sym) {
case SDLK_ESCAPE:
return EventReturns::Event_TryQuit;
default:
return EventReturns::Event_None;
}
default:
return EventReturns::Event_None;
}
}
int mainLoop(EventReturns eventReturn) {
SDL_GetMouseState(&MouseX, &MouseY);
if (eventReturn == EventReturns::Event_QUIT || eventReturn == EventReturns::Event_TryQuit) {
return 1;
}
return 0;
}
void render() {
SDL_SetRenderDrawColor(renderer, 100, 200, 200, 255);
SDL_RenderClear(renderer);
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
tile.SetPos(0, 0);
if (tile.Draw(renderer) != 0) {
SDL_ShowSimpleMessageBox(0, "ERROR", "ERROR: Rect in tile has 0x0 size, Please close this with the task manager", NULL);
}
SDL_RenderPresent(renderer);
}
int main(int argc, char* argv[]) {
SDL_Window* window = SDL_CreateWindow("Game", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 2880, 1600, SDL_WINDOW_SHOWN);
renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
bool running = true;
EventReturns eventReturn = EventReturns::Event_None;
SDL_Event event;
int quit = 0;
while (running) {
while (SDL_PollEvent(&event)) {
eventReturn = HandleEvent(&event);
}
quit = mainLoop(eventReturn);
render();
if (quit == 1) {
running = false;
}
}
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
Classes.h
#pragma once
#include <SDL.h>
#include <SDL_image.h>
#include <iostream>
#define SpriteSizeMult 1
enum class EventReturns {
Event_QUIT,
Event_None,
Event_TryQuit
};
enum class TileTypes {
Tile_Grass
};
struct TileStruct {
int x;
int y;
TileTypes type;
};
class Tile {
public:
Tile(int x, int y, char* TexturePath, SDL_Renderer* renderer);
Tile(TileStruct structure, SDL_Renderer* renderer);
Tile();
int Draw(SDL_Renderer* renderer);
void SetPos(int x, int y);
private:
int x = 0;
int y = 0;
int TextureWidth = 0;
int TextureHeight = 0;
SDL_Texture* texture;
SDL_Rect rect;
};
SDL_Point getsize(SDL_Texture* texture);
Classes.cpp
#include "Classes.h"
SDL_Point getsize(SDL_Texture* texture) {
SDL_Point size;
SDL_QueryTexture(texture, NULL, NULL, &size.x, &size.y);
return size;
}
Tile::Tile(int x, int y, char* TexturePath, SDL_Renderer* renderer)
{
this->x = x;
this->y = y;
this->texture = SDL_CreateTextureFromSurface(renderer, IMG_Load(TexturePath));
if (this->texture == nullptr) {
this->texture = SDL_CreateTextureFromSurface(renderer, IMG_Load("Assets/MissingTexture.png"));
std::cout << IMG_GetError();
}
SDL_Point point = getsize(this->texture);
this->TextureHeight = point.y;
this->TextureWidth = point.x;
this->rect = {this->x - ((this->TextureWidth * SpriteSizeMult) / 2), this->y - ((this->TextureHeight * SpriteSizeMult) / 2), this->TextureWidth * SpriteSizeMult, this->TextureHeight * SpriteSizeMult};
}
Tile::Tile(TileStruct structure, SDL_Renderer* renderer)
{
this->x = structure.x;
this->y = structure.y;
switch (structure.type) {
case TileTypes::Tile_Grass:
this->texture = SDL_CreateTextureFromSurface(renderer, IMG_Load("Assets/Tiles/Grass.png"));
default:
this->texture = SDL_CreateTextureFromSurface(renderer, IMG_Load("Assets/MissingTexture.png"));
}
if (this->texture == NULL) {
this->texture = SDL_CreateTextureFromSurface(renderer, IMG_Load("Assets/MissingTexture.png"));
if (this->texture == NULL) {
SDL_ShowSimpleMessageBox(0, "ERROR", "Failed to load texture", NULL);
SDL_ShowSimpleMessageBox(0, "ERROR", IMG_GetError(), NULL);
}
}
SDL_Point point = getsize(this->texture);
this->TextureHeight = point.y;
this->TextureWidth = point.x;
this->rect = { this->x - ((this->TextureWidth * SpriteSizeMult) / 2), this->y - ((this->TextureHeight * SpriteSizeMult) / 2), this->TextureWidth * SpriteSizeMult, this->TextureHeight * SpriteSizeMult };
}
Tile::Tile()
{
}
int Tile::Draw(SDL_Renderer* renderer)
{
if (rect.w == 0 || rect.h == 0) {
return -1;
}
this->rect.x = 0;
this->rect.y = 0;
SDL_RenderCopy(renderer, this->texture, NULL, &rect);
return 0;
}
void Tile::SetPos(int x, int y)
{
this->x = x;
this->y = y;
}
I'm sorry for the sheer amount of code that is, but I'd really appreciate the help. If there's any more info I need to put here, just let me know.
I'm fully aware that I should make a Minimal Reproducible Example, but as far as I'm aware, all the code listed here is necessary.
Finally, in case I've been unclear, when running the code the Missing Texture image that should appear isn't showing up.
I can't see SDL_INIT function in your code.
You should add this in the beginning of your main function.
if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
return 1;
You are initialising tile before creating a renderer so the constructor is trying to create a texture without a renderer.
SDL_Renderer* renderer;
Tile tile = Tile({10, 10, TileTypes::Tile_Grass}, renderer);
You should do something like this
#include "Classes.h"
int MouseX = 0;
int MouseY = 0;
int PlayerX = 0;
int PlayerY = 0;
SDL_Renderer* renderer;
EventReturns HandleEvent(SDL_Event* event) {
switch (event->type) {
case SDL_QUIT:
return EventReturns::Event_QUIT;
case SDL_KEYDOWN:
switch (event->key.keysym.sym) {
case SDLK_ESCAPE:
return EventReturns::Event_TryQuit;
default:
return EventReturns::Event_None;
}
default:
return EventReturns::Event_None;
}
}
int mainLoop(EventReturns eventReturn) {
SDL_GetMouseState(&MouseX, &MouseY);
if (eventReturn == EventReturns::Event_QUIT || eventReturn == EventReturns::Event_TryQuit) {
return 1;
}
return 0;
}
void render(Tile tile) {
SDL_SetRenderDrawColor(renderer, 100, 200, 200, 255);
SDL_RenderClear(renderer);
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
tile.SetPos(0, 0);
if (tile.Draw(renderer) != 0) {
SDL_ShowSimpleMessageBox(0, "ERROR", "ERROR: Rect in tile has 0x0 size, Please close this with the task manager", NULL);
}
SDL_RenderPresent(renderer);
}
int main(int argc, char* argv[]) {
if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
return 1;
SDL_Window* window = SDL_CreateWindow("Game", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 2880, 1600, SDL_WINDOW_SHOWN);
renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
Tile tile = Tile({ 10, 10, TileTypes::Tile_Grass }, renderer);
bool running = true;
EventReturns eventReturn = EventReturns::Event_None;
SDL_Event event;
int quit = 0;
while (running) {
while (SDL_PollEvent(&event)) {
eventReturn = HandleEvent(&event);
}
quit = mainLoop(eventReturn);
render(tile);
if (quit == 1) {
running = false;
}
}
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
I'm trying to make a simple Snake game. The self collision and a lot of things aren't ready. The problem is: Even with no errors, running just fine, changing "close()" to "endGame()" and reverting, rebuilding the entire program, i could not render anything with SDL_RenderCopy. You will see many unnecessary things in my code and some Brazilian-Portuguese comments, prepare yourself.
The image is a 16x16 png spritesheet, using the color #ff00ff as ColorKey. There are only 4 sprites in this spritesheet, respectively: Apple, Snake's Body, Snake's Head and Snake's Tail (still unused).
Whole code:
#include <iostream>
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <stdlib.h>
#include <time.h>
#include <stdio.h>
using namespace std;
const int CELL_SIZE = 16;
const int CELL_WIDTH = 16;
const int CELL_HEIGHT = 16;
const int SCREEN_WIDTH = CELL_SIZE * (CELL_WIDTH-1);
const int SCREEN_HEIGHT = CELL_SIZE * (CELL_HEIGHT-1);
SDL_Window* gWindow = NULL;
SDL_Renderer* gRenderer = NULL;
void loadTexture(string path);
SDL_Texture* spriteSheet = NULL;
void loadMedia();
void init();
class Snake {
int initialLength = 3; //from body (head incluse)
int length = initialLength;
int facing = DIR_UP;
//Head position in CELLS (multiplied for CELL_SIZE when drawed)
int x = 5;
int y = 5;
//UNUSED TEMPORARY COLORS - IGNORE
Uint8 color[3] = {0x22,0x88,0x44}; //Snake Color, em RGB
Uint8 headColor[3] = {0x11,0x44,0x44}; //Color for the Head of the Snek
int stepDelay = 60; //time in frames that the Snakes waits till move
int stepFramesRemaining = stepDelay;
int stepDelayReduction = 1; //reduces stepDelay every time the Snakes eats the apple
const int minStepDelay = 15; //the minimum delay
//For clipping the image (its an 16x16 png image)
const SDL_Rect clipHead = {0,8,8,8};
const SDL_Rect clipBody = {8,0,8,8};
const SDL_Rect clipTail = {8,8,8,8};
public:
enum direction { //direções nas quais a cobra pode se mover
DIR_UP,
DIR_RIGHT,
DIR_DOWN,
DIR_LEFT
};
/* The following var stores the entire Snake's body in an 2D Array. The number stored means how much "steps" it will survive.
When the value is zero, it means that there is no body in the place. The bodypart with value equivalent to "length" is the Head.
*/
int body[CELL_WIDTH][CELL_HEIGHT];
void init(); //initializes some vars
void tick(); //tick function
void stepFoward(); //moves Snake foward
void faceTo(int dir); //alters which direction Snake is faced
void eat(); //eats the apple
void draw(); //renders (or at least tries) to render the snake
int getLength(){
return length;
};
int getFacing(){
return facing;
};
} Snake;
class Food {
Uint8 color[3] = {0x85,0x22,0x10}; //RGB color of the Apple
bool visible = true;
public:
int x = 2;
int y = 2;
void respawn();
void destroy();
void draw();
} Food;
void Food::respawn(){
//teleports the apple to a random spot
x = rand() % (CELL_WIDTH-2);
y = rand() % (CELL_HEIGHT-2);
visible = true;
}
void Food::destroy(){
//Reset values
x = 0;
y = 0;
visible = false;
//resets
respawn();
}
void Food::draw(){
if(visible){
SDL_Rect rect = {x*CELL_SIZE,y*CELL_SIZE,CELL_SIZE,CELL_SIZE};
SDL_SetRenderDrawColor(gRenderer,color[0],color[1],color[2],0xff);
SDL_RenderFillRect(gRenderer, &rect);
}
}
void Snake::init(){
//Spawns in a vertical line
for(int i=0; i<length; i++){
body[x][y+i] = length-i;
}
}
void Snake::tick(){
if(stepFramesRemaining > 0){
stepFramesRemaining--;
} else {
//when 0, moves the snake
stepFramesRemaining = stepDelay;
stepFoward();
}
}
void Snake::eat(){
//increases the body size by 1
for(int i=0; i<CELL_HEIGHT; i++){
for(int j=0; j<CELL_WIDTH; j++){
if(body[j][i] > 0){
body[j][i]++;
}
}
}
length++;
if(stepDelay > minStepDelay){
stepDelay -= stepDelayReduction;
}
Food.destroy();
}
void Snake::draw(){
//SDL_SetRenderDrawColor(gRenderer,color[0],color[1],color[2],0xff);
SDL_Rect rect = {0,0,0,0}; //for later use
//Draws the body and head
for(int i=0; i<CELL_HEIGHT; i++){
for(int j=0; j<CELL_WIDTH; j++){
if(body[j][i] == length){
rect = {j*CELL_SIZE,i*CELL_SIZE,CELL_SIZE,CELL_SIZE};
SDL_SetRenderDrawColor(gRenderer,0x33,0xff,0x22,0xff);
SDL_RenderFillRect(gRenderer,&rect);
SDL_RenderCopy(gRenderer, spriteSheet, &clipHead, &rect);
} else if (body[j][i] > 0){
rect = {j*CELL_SIZE,i*CELL_SIZE,CELL_SIZE,CELL_SIZE};
//SDL_SetRenderDrawColor(gRenderer,color[0],color[1],color[2],0xff);
SDL_RenderCopyEx(gRenderer, spriteSheet, &clipBody, &rect, 0, NULL, SDL_FLIP_NONE);
SDL_SetRenderDrawColor(gRenderer,0x66,0xee,0x22,0xff);
SDL_RenderFillRect(gRenderer,&rect);
}
SDL_RenderFillRect(gRenderer,&rect);
}
}
//SDL_RenderFillRect(gRenderer,&rect);
}
void Snake::stepFoward(){
int headMoved = 0; //informs if the head already moved
//decreases the "body" lifespan and moves head
for(int i=0; i<CELL_HEIGHT; i++){
for(int j=0; j<CELL_WIDTH; j++){
if(body[j][i] > 0){
//Verifica se é a cabeça, para movê-la logo em seguida
if(body[j][i] == length && headMoved < 2){
//moves head position, looping if needed
switch(facing){
case DIR_UP:
if(y == 0){
body[x][CELL_HEIGHT-1] = length;
y = CELL_HEIGHT-1;
} else {
body[x][y-1] = length;
y--;
}
break;
case DIR_DOWN:
if(y == CELL_HEIGHT-2){
body[x][0] = length+1; //(+1 to avoid being subtracted twice)
y = 0;
} else {
body[x][y+1] = length+1;
y++;
}
break;
case DIR_LEFT:
if(x == 0){
body[CELL_WIDTH-1][y] = length;
x = CELL_WIDTH-1;
} else {
body[x-1][y] = length;
x--;
}
break;
case DIR_RIGHT:
if(x == CELL_WIDTH-2){
body[0][y] = length+1; //avoiding again the "-2" subtraction.
x = 0;
} else {
body[x+1][y] = length+1;
x++;
}
break;
}
headMoved++;
}
body[j][i]--; //decreases the "body" lifespan
}
}
}
//verifies if can eat (head in the same position as the apple)
if(x == Food.x && y == Food.y){
eat();
}
}
void Snake::faceTo(int dir){
facing = dir;
}
void init();
void close();
void init(){ //Initializes the game
gWindow = SDL_CreateWindow("· Snake ·", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
gRenderer = SDL_CreateRenderer( gWindow, -1, SDL_RENDERER_ACCELERATED );
if( gRenderer == NULL ){
printf( "Renderer could not be created! SDL Error: %s\n", SDL_GetError() );
}
int imgFlags = IMG_INIT_PNG;
if(!(IMG_Init(imgFlags) & imgFlags)){
cout << "IMG INIT error!" << endl;
}
loadMedia();
Snake.init();
}
void close(){ //Closes the program
SDL_DestroyTexture(spriteSheet);
spriteSheet = NULL;
SDL_DestroyRenderer(gRenderer);
gRenderer = NULL;
IMG_Quit();
SDL_Quit();
}
void loadTexture(string path){ //Almost the same function from LazyFoo tutorial
//The final texture
SDL_Texture* newTexture = NULL;
//Load image at specified path
SDL_Surface* loadedSurface = IMG_Load( path.c_str() );
if( loadedSurface == NULL )
{
printf( "Unable to load image %s! SDL_image Error: %s\n", path.c_str(), IMG_GetError() );
}
else
{
//Color key image
SDL_SetColorKey( loadedSurface, SDL_TRUE, SDL_MapRGB( loadedSurface->format, 0xff, 0x00, 0xff));
//Create texture from surface pixels
newTexture = SDL_CreateTextureFromSurface( gRenderer, loadedSurface);
if( newTexture == NULL ){
printf( "Unable to create texture from %s! SDL Error: %s\n", path.c_str(), SDL_GetError() );
}
//Get rid of old loaded surface
SDL_FreeSurface( loadedSurface );
}
spriteSheet = newTexture;
}
void loadMedia(){ //loads everything (it will load sound too, when i make the sounds of course)
loadTexture("spritesheet.png");
if(spriteSheet == NULL){
cout << "ERRO" << endl;
}
}
void tick(){
Snake.tick();
}
void draw(){ //Render Function
//Background
SDL_SetRenderDrawColor(gRenderer, 0xee, 0xf2, 0xf0, 0xff);
SDL_RenderClear(gRenderer);
Snake.draw();
Food.draw();
//Aplica as alterações
SDL_RenderPresent(gRenderer);
}
int main(){
srand (time (NULL));
init();
bool quit = false;
SDL_Event e; //Event Handling
while(!quit){
while(SDL_PollEvent(&e) != 0){
if(e.type == SDL_QUIT){
quit = true;
} else if(e.type == SDL_KEYDOWN){
switch(e.key.keysym.sym){
case SDLK_UP:
Snake.faceTo(Snake.DIR_UP);
break;
case SDLK_DOWN:
Snake.faceTo(Snake.DIR_DOWN);
break;
case SDLK_LEFT:
Snake.faceTo(Snake.DIR_LEFT);
break;
case SDLK_RIGHT:
Snake.faceTo(Snake.DIR_RIGHT);
break;
}
}
}
//Tick function
tick();
//Renders everything
draw();
SDL_RenderCopy(gRenderer, spriteSheet, NULL, NULL);
//Slows down the program just a bit (its not a time based frame system... yet)
SDL_Delay(3);
}
close(); //ends
return 0;
}
The portion of code who should be working, but isn't:
//Draws the body and head
for(int i=0; i<CELL_HEIGHT; i++){
for(int j=0; j<CELL_WIDTH; j++){
if(body[j][i] == length){
rect = {j*CELL_SIZE,i*CELL_SIZE,CELL_SIZE,CELL_SIZE};
SDL_SetRenderDrawColor(gRenderer,0x33,0xff,0x22,0xff);
SDL_RenderFillRect(gRenderer,&rect);
SDL_RenderCopy(gRenderer, spriteSheet, &clipHead, &rect);
} else if (body[j][i] > 0){
rect = {j*CELL_SIZE,i*CELL_SIZE,CELL_SIZE,CELL_SIZE};
//SDL_SetRenderDrawColor(gRenderer,color[0],color[1],color[2],0xff);
SDL_RenderCopyEx(gRenderer, spriteSheet, &clipBody, &rect, 0, NULL, SDL_FLIP_NONE);
SDL_SetRenderDrawColor(gRenderer,0x66,0xee,0x22,0xff);
SDL_RenderFillRect(gRenderer,&rect);
}
SDL_RenderFillRect(gRenderer,&rect);
}
}
//SDL_RenderFillRect(gRenderer,&rect);
}
I've been trying to send a log in the console to make sure the player was created, but here is the results:
Here is the code along the problematic part:
SDL_Log("%s has %i hp out of %i", player1.name, player1.health, player1.maxhealth);
systemValues.h:
// Core Libraries and Headers
// - Global includes
#include <SDL.h>
#include <SDL_image.h>
#include <stdio.h>
#include <string>
#include <typeinfo>
// Defines
#define GRAPHICS "../resources/"
struct Player
{
std::string sprite;
std::string name;
int level;
int size;
int health;
int maxhealth;
int magicpower; // Magic Points
int damages;
int armor;
int magic;
};
struct Enemy
{
std::string sprite;
std::string name;
int level;
int size;
int health;
int maxhealth;
int magicpower; // Magic Points
int damages;
int armor;
int magic;
};
Player createPlayer(std::string name);
Enemy createEnemy(std::string name, int level);
int damagePlayer(Player target, int damages);
int damageEnemy(Enemy target, int damages);
void close();
main.cpp:
// Local includes
// - Custom Headers
#include "systemValues.h"
// Screen constants and dimensions. (TODO: MOVE TO A PROPER HEADER FILE.)
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;
// The window that is rendered to
SDL_Window* window = NULL;
// Quit being false means the application is running and did not request to quit
bool quit = false;
// Event handler
SDL_Event e;
// The surface contained by the window
SDL_Surface* screenSurface = NULL;
// Main function
int main(int argc, char* args[])
{
// Initializing SDL
if (SDL_Init(SDL_INIT_VIDEO)<0)
{
SDL_Log("SDL could not initialize! SDL_Error: %s\n", SDL_GetError());
}
else
{
// Creating the window
window = SDL_CreateWindow("SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
if (window == NULL)
{
SDL_Log("The window could not be created! SDL_Error: %s\n", SDL_GetError());
}
else
{
Player player1 = createPlayer("Avarthar");
Enemy enemy1 = createEnemy("Blob", 1);
// Get the window surface
screenSurface = SDL_GetWindowSurface(window);
// While the application is running
while (!quit){
while (SDL_PollEvent(&e) != 0)
{
// User requests quit
if (e.type == SDL_QUIT)
{
quit = true;
}
// Checks for a key being pressed down
else if (e.type == SDL_KEYDOWN)
{
switch(e.key.keysym.sym)
{
// Checks if the key is F
case SDLK_f:
player1.health = damagePlayer(player1, 5);
SDL_Log("%s has %i hp out of %i", player1.name, player1.health, player1.maxhealth); // TODO - Remove the test line
break;
case SDLK_ESCAPE:
quit = true;
break;
}
}
}
// Test if player is created
if (player1.name == "Avarthar")
{
SDL_FillRect(screenSurface, NULL, SDL_MapRGB(screenSurface->format, (player1.health*-1+100*2), player1.health*2, 0));
}
else
{
SDL_FillRect(screenSurface, NULL, SDL_MapRGB(screenSurface->format, 255, 255, 255));
}
// Update the surface
SDL_UpdateWindowSurface(window);
}
}
}
close();
// Return 0 to terminate the program
return 0;
}
// Creates a player with the given varables
Player createPlayer(std::string name)
{
Player player;
player.sprite = "";
player.name = name;
player.level = 1;
player.size = 32;
player.health = 100;
player.maxhealth = 100;
player.magicpower = 100;
player.damages = 1;
player.armor = 0;
player.magic = 1;
return player;
}
Enemy createEnemy(std::string name, int level)
{
Enemy enemy;
enemy.sprite = "";
enemy.name = name;
enemy.level = level;
enemy.size = 32;
enemy.health = 100;
enemy.maxhealth = 100;
enemy.magicpower = 100; // Magic Points
enemy.damages = 1;
enemy.armor = 0;
enemy.magic = 1;
return enemy;
}
// Deals damage to the target of type Player
int damagePlayer(Player target, int damages)
{
target.health -= damages;
// Checks whether the target is in the health range or not
if (target.health < 0)
target.health = 0;
if (target.health > target.maxhealth)
target.health = target.maxhealth;
return target.health;
}
// Deals damage to the target of type Enemy
int damageEnemy(Enemy target, int damages)
{
target.health -= damages;
// Checks whether the target is in the health range or not
if (target.health < 0)
target.health = 0;
if (target.health > target.maxhealth)
target.health = target.maxhealth;
return target.health;
}
void close()
{
// Wait 0.1 seconds
SDL_Delay(100);
// Clear the window from the memory
SDL_DestroyWindow(window);
// Quit the SDL subsystems
SDL_Quit();
}
What I tried so far:
I tried with &player1.name and it didn't change anything.
I also tried with only SDL_Log("%s", player1.name); and it instead wrote a single ? in the outputs.
The color changing according to the player1.health is working without any problem, but as soon as I try getting and sending the name in the SDL_Log it sends the outputs shown in the screenshot above.
SDL_Log cannot do std::string. Use player1.name.c_str(). This should have triggered a warning, check your compiler flags. – Quentin
Thanks for the quick answer and also thanks for noticing another problem that I had with my compiler ^^
I'am new there. I've been learning classes and tried to make a very simple platform game. But I have problem now. I've wanted to set Class "Player" to collide with 2 objects of Class "Block" But Collision do not work for one of them.
Here is my code:
#include <iostream>
#include <SDL.h>
#include <SDL_image.h>
#undef main
class Block
{
private:
SDL_Texture *BlockTexture;
public:
Block(SDL_Renderer *renderTarget, std::string filePath, int xPos, int yPos, int Width, int Height);
~Block();
void Draw(SDL_Renderer *renderTarget);
SDL_Rect BlockPos;
};
Block::Block(SDL_Renderer *renderTarget, std::string filePath, int xPos, int yPos, int Width, int Height)
{
SDL_Surface *surface = IMG_Load(filePath.c_str());
{
BlockTexture = SDL_CreateTextureFromSurface(renderTarget, surface);
}
SDL_FreeSurface(surface);
BlockPos.x = xPos;
BlockPos.y = yPos;
BlockPos.w = Width;
BlockPos.h = Height;
}
Block::~Block()
{
SDL_DestroyTexture(BlockTexture);
}
void Block::Draw(SDL_Renderer *renderTarget)
{
SDL_RenderCopy(renderTarget, BlockTexture, NULL, &BlockPos);
}
class Player
{
private:
SDL_Texture *Texture;
float moveSpeed;
float jumpSpeed;
int falling = 0;
SDL_Scancode keys [3];
public:
SDL_Rect PlayerPos;
Player(SDL_Renderer *renderTarget, std::string filePath, int PosX, int PosY, int Width, int Height);
~Player();
void Update(float delta, const Uint8 *Keystate);
void Draw(SDL_Renderer *renderTarget);
bool Collision(Block &p);
};
Player::Player(SDL_Renderer *renderTarget, std::string filePath, int PosX, int PosY, int Width, int Height)
{
SDL_Surface *surface = IMG_Load(filePath.c_str());
{
Texture = SDL_CreateTextureFromSurface(renderTarget, surface);
}
SDL_FreeSurface(surface);
PlayerPos.x = PosX;
PlayerPos.y = PosY;
PlayerPos.w = Width;
PlayerPos.h = Height;
keys[0] = SDL_SCANCODE_UP;
keys[1] = SDL_SCANCODE_LEFT;
keys[2] = SDL_SCANCODE_RIGHT;
moveSpeed = 200.f;
jumpSpeed = 100.f;
}
Player::~Player()
{
SDL_DestroyTexture(Texture);
}
void Player::Update(float delta, const Uint8 *KeyState)
{
if(KeyState[keys[0]])
{
PlayerPos.y -= moveSpeed * delta;
}
if(KeyState[keys[1]])
{
PlayerPos.x -= (moveSpeed / 2) * delta;
}
if(KeyState[keys[2]])
{
PlayerPos.x += moveSpeed * delta;
}
if(falling == 0)
{
PlayerPos.y += jumpSpeed * delta;
}
}
void Player::Draw(SDL_Renderer *renderTarget)
{
SDL_RenderCopy(renderTarget, Texture, NULL, &PlayerPos);
}
bool Player::Collision(Block &p)
{
if(PlayerPos.x + PlayerPos.w <= p.BlockPos.x || PlayerPos.x >= p.BlockPos.x + p.BlockPos.w ||
PlayerPos.y + PlayerPos.h <= p.BlockPos.y || PlayerPos.y >= p.BlockPos.y + p.BlockPos.h)
{
falling = 0;
return true;
}
else
falling = 1;
return false;
}
SDL_Texture *LoadTexture(std::string filePath, SDL_Renderer *Renderer)
{
SDL_Texture *texture = NULL;
SDL_Surface *surface = IMG_Load(filePath.c_str());
{
texture = SDL_CreateTextureFromSurface(Renderer, surface);
}
SDL_FreeSurface(surface);
return texture;
}
int main(int argc, char *argv[])
{
SDL_Init(SDL_INIT_EVERYTHING);
SDL_Window *window = SDL_CreateWindow("Platform", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 800, 600, SDL_WINDOW_SHOWN);
SDL_Renderer *renderTarget = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
int imgFlags = IMG_INIT_PNG;
int currentTime = 0;
int previousTime = 0;
float delta = 0;
const Uint8 *Keystate;
Player Player(renderTarget, "BlockP.png", 100, 100, 50, 50);
Block Block1(renderTarget, "Block.png", 0, 500, 800, 100);
Block Block2(renderTarget, "Block.png", 100, 300, 300, 50);
bool isRunning = true;
SDL_Event ev;
while(isRunning)
{
Keystate = SDL_GetKeyboardState(NULL);
Player.Collision(Block1);
Player.Collision(Block2);
previousTime = currentTime;
currentTime = SDL_GetTicks();
delta = (currentTime - previousTime) / 1000.0f;
Player.Update(delta, Keystate);
while(SDL_PollEvent(&ev) != 0)
{
if(ev.type == SDL_QUIT)
isRunning = false;
}
SDL_RenderClear(renderTarget);
Player.Draw(renderTarget);
Block1.Draw(renderTarget);
Block2.Draw(renderTarget);
SDL_RenderPresent(renderTarget);
}
SDL_DestroyWindow(window);
SDL_DestroyRenderer(renderTarget);
window = NULL;
renderTarget = NULL;
SDL_Quit();
return 0;
}
The problem with your code is that each call to Player.Collision overwrites the "falling" variable.
Player.Collision(Block1); //this call calculates a falling value
Player.Collision(Block2); //...then this call overwrites falling with a new value
So effectively your code is only testing if the player is colliding with Block2, so collisions with Block1 are ignored.
Currently your Collision function is:
bool Player::Collision(Block &p)
{
if(PlayerPos.x + PlayerPos.w <= p.BlockPos.x || PlayerPos.x >= p.BlockPos.x + p.BlockPos.w ||
PlayerPos.y + PlayerPos.h <= p.BlockPos.y || PlayerPos.y >= p.BlockPos.y + p.BlockPos.h)
{
falling = 0;
return true;
}
else
falling = 1;
return false;
}
Firstly, your "return false;" is not actually part of the else, as you don't have {}. In this particular case it makes no difference as the else is exited and then the return happens but your indentation would suggest you expect the "return false;" line to be executed as part of the else block so you should put:
else
{
falling = 1;
return false;
}
Next you want to say if you have already detected a collision (eg, with Block1) then don't set falling to 1, to do this add an if statement.
else
{
if(falling != 0) //if we haven't already detected a collision this frame
{
falling = 1;
}
return false;
}
You will however need to set falling back to 1 at the start of each frame, otherwise if a collision is detected on one frame then the player will never fall on subsequent frames, even if they are not colliding with a block.
As a side note, your Player.Update code modifies the player's y position if falling == 0, this seems counter intuitive as usually 0 is false and 1 is true, hence you seem to be saying if not falling then update y, where as it should be if falling update y. Personally I would use a bool rather than an int to hold the value of falling, and then say if(falling) update y, this would make your code clearer.
I am attempting to make a simple scrolling shooter game with SDL2. I have a moving player on a screen, and I am trying to make the player shoot a bullet using an array (so they can shoot multiple bullets) however, when I press the space bar, nothing happens, and instead the bullet image sort of flashes in the top left corner.
Heres the same code in codepad: http://codepad.org/rOhE1AqY
#include <SDL.h>
#include <stdio.h> //use for things like printf, same as cout
#include <iostream>
#include <string>
#include <time.h>
using namespace std;
//screend dimensions& sprtie dimensions
const int SCREEN_HEIGHT = 600;
const int SCREEN_WIDTH = 400;
const int SPRITE_WIDTH = 60;
const int SPRITE_HEIGHT = 80;
const int MAX_BULLETS = 50;
SDL_Window* Window = NULL;//the window rendering to
SDL_Surface* ScreenSurface = NULL;//surface contained by window
SDL_Surface* Background = NULL;
SDL_Surface* Player = NULL;
SDL_Surface* Enemy = NULL;
SDL_Surface* Bullet = NULL;
SDL_Surface* newBullet = NULL;
SDL_Rect posPlayer, posEnemy, posBullet, posnewBullet;
const Uint8* keystate = SDL_GetKeyboardState(NULL);
SDL_Event event;
class thePlayer
{
public:
thePlayer();
void player_movement();
void show_player();
private:
};
class theBullet
{
public:
theBullet();
bool isActive;
int x_position;
int y_position;
void bullet_movement();
void add_new_bullet();
void show_bullet();
private:
};
theBullet arrayofBullets[MAX_BULLETS];
class theEnemy
{
public:
theEnemy();
void enemy_movement();
void show_enemy();
private:
};
thePlayer::thePlayer()
{
posPlayer.x = 170;
posPlayer.y = SCREEN_HEIGHT;
posPlayer.w = 20;
posPlayer.h = 30;
}
void thePlayer::player_movement()
{
if(keystate[SDL_SCANCODE_LEFT])
{
posPlayer.x -= 2;
}
if(keystate[SDL_SCANCODE_RIGHT])
{
posPlayer.x += 2;
}
if(keystate[SDL_SCANCODE_UP])
{
posPlayer.y -= 2;
}
if(keystate[SDL_SCANCODE_DOWN])
{
posPlayer.y += 2;
}
if ((posPlayer.x + SPRITE_WIDTH) > SCREEN_WIDTH)
{
posPlayer.x = (SCREEN_WIDTH - SPRITE_WIDTH);
}
if ((posPlayer.y + SPRITE_HEIGHT) > SCREEN_HEIGHT)
{
posPlayer.y = (SCREEN_HEIGHT - SPRITE_HEIGHT);
}
}
void thePlayer::show_player()
{
SDL_BlitSurface(Player, NULL, ScreenSurface, &posPlayer);
SDL_SetColorKey(Player, SDL_TRUE, SDL_MapRGB(Player->format, 255, 255, 255));
}
theBullet::theBullet()
{
/*posBullet.x;
posBullet.y;
posBullet.w = 10;
posBullet.h = 15;*/
}
void theBullet::bullet_movement()
{
/*if(keystate[SDL_SCANCODE_SPACE])
{
posBullet.x = posPlayer.x + 25;
posBullet.y = posPlayer.y + 10;
}
posBullet.y -= 2;
if(posBullet.y < 0)
{
posBullet.y = -50;
}*/
}
void theBullet::show_bullet()
{
//SDL_BlitSurface(Bullet, NULL, ScreenSurface, &posBullet);
//SDL_SetColorKey(Bullet, SDL_TRUE, SDL_MapRGB(Player->format, 255, 255, 255));//removes white background
}
theEnemy::theEnemy()
{
srand (time(NULL));
posEnemy.x = rand() % 300 + 50;
posEnemy.y =0;
posEnemy.w = 35;
posEnemy.h = 60;
}
void theEnemy::enemy_movement()
{
posEnemy.y += 1;
if(posEnemy.y > SCREEN_HEIGHT)
{
posEnemy.y = SCREEN_HEIGHT +50;
}
}
void theEnemy::show_enemy()
{
SDL_BlitSurface(Enemy, NULL, ScreenSurface, &posEnemy);
SDL_SetColorKey(Enemy, SDL_TRUE, SDL_MapRGB(Player->format, 255, 255, 255));
}
bool initialise()
{
bool success = true;
if (SDL_Init(SDL_INIT_EVERYTHING) !=0)
{
cout<<"SDL_Init Error."<<SDL_GetError()<<endl;
success = false;
}
else
{
//create the window for game
Window = SDL_CreateWindow("Scrolling Shooter Game", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
if (Window == NULL)
{
cout<<"Window Error"<<SDL_GetError()<<endl;
success = false;
}
else
{
//get window surface
ScreenSurface = SDL_GetWindowSurface(Window);
}
}
return success;
}
bool LoadingMedia()
{
bool success = true;
Background = SDL_LoadBMP("background.bmp");
if (Background == NULL)
{
cout<<"Error in loading background."<<SDL_GetError()<<endl;
success = false;
}
Player = SDL_LoadBMP("spaceship.bmp");
if (Player == NULL)
{
cout<<"Error in loading player."<<SDL_GetError()<<endl;
success = false;
}
Enemy = SDL_LoadBMP("enemy.bmp");
if (Enemy == NULL)
{
cout<<"Error in loading enemy."<<SDL_GetError()<<endl;
success = false;
}
Bullet = SDL_LoadBMP("bullet.bmp");
if (Bullet == NULL)
{
cout<<"Error in loading bullet."<<SDL_GetError()<<endl;
success = false;
}
return success;
}
void closedown()
{
SDL_FreeSurface(Background);
Background = NULL;
SDL_FreeSurface(Player);
Player = NULL;
SDL_FreeSurface(Enemy);
Enemy = NULL;
SDL_DestroyWindow(Window);
Window = NULL;
SDL_Quit();
}
int main(int argc, char** argv)
{
bool quit = false;
thePlayer myPlayer;
theEnemy myEnemy;
theBullet myBullet;
if (!initialise())
{
cout<<"Failed to initialise"<<SDL_GetError()<<endl;
}
else
{
if (!LoadingMedia())
{
cout<<"Error loading media"<<SDL_GetError()<<endl;
}
}
//makes all bullets false
for (int i=0; i<MAX_BULLETS; i++)
{
arrayofBullets[i].isActive = false;
}
//GAME LOOP
while (quit == false)
{
SDL_BlitSurface(Background, NULL, ScreenSurface, NULL);
myPlayer.show_player();
myPlayer.player_movement();
while (SDL_PollEvent(&event))
{
if( event.type == SDL_QUIT )
{
quit = true;
break;
}
if(keystate[SDL_SCANCODE_SPACE])
{
for (int i=0; i<MAX_BULLETS; i++)
{
if (arrayofBullets[i].isActive == false)
{
arrayofBullets[i].x_position = posPlayer.x + 25;
arrayofBullets[i].y_position = posPlayer.y + 10;
arrayofBullets[i].isActive = true;
break;
}
}
}
//update game objects
for (int i=0; i<MAX_BULLETS; i++)
{
if (arrayofBullets[i].isActive == true)
{
arrayofBullets[i].y_position -= 2;
if (arrayofBullets[i].y_position < 0)
{
arrayofBullets[i].isActive = false;
}
}
}
for (int i=0; i<MAX_BULLETS; i++)
{
if (arrayofBullets[i].isActive == true)
{
SDL_BlitSurface(Bullet, NULL, ScreenSurface, NULL);
}
}
}
//myPlayer.show_player();
//myBullet.show_bullet();
//myEnemy.show_enemy();
//myPlayer.player_movement();
//myBullet.bullet_movement();
//myEnemy.enemy_movement();
SDL_UpdateWindowSurface(Window); //updates screen
}
closedown();
return 0;
}
SDL_BlitSurface(Bullet, NULL, ScreenSurface, NULL);
You haven't specified destination rect, so it will blit on left-top corner.
It should be
SDL_Rect dstrect;
dstrect.x = arrayofBullets[i].x_position;
dstrect.y = arrayofBullets[i].y_position;
dstrect.w = Bullet->w;
dstrect.h = Bullet->h;
SDL_BlitSurface(Bullet, NULL, ScreenSurface, &dstrect);