C++ Problem with Pointers in subclass objects - c++

I have a class touchButton in a separate header files below. This is as i need to create an object of Adafruit's RA8875 display in my main file, as i also need it there. Thats no problem, works out fine with the pointers like this. See example below.
touchButton.h
#ifndef TOUCHBUTTON_H
#define TOUCHBUTTON_H
#include "Adafruit_RA8875.h"
// Class for a touch button
class Button {
protected:
Adafruit_RA8875* tft;
uint16_t *tx;
uint16_t *ty;
uint16_t width, height, radius;
uint16_t x, y, color;
public:
// set Button values (x, y, width, height, radius, color)
void setButton(Adafruit_RA8875* tft, uint16_t* tx, uint16_t* ty, uint16_t _x, uint16_t _y, uint16_t _width, uint16_t _height, uint16_t _radius, uint16_t _color);
// prints button with corresponding values of setButton function
void printButton();
};
#endif
touchButton.cpp
#include "touchButton.h"
#include "GENERAL.h"
// set Button (x, y, width, height, radius, color)
void Button::setButton(Adafruit_RA8875* tft, uint16_t* tx, uint16_t* ty,uint16_t _x, uint16_t _y, uint16_t _width, uint16_t _height, uint16_t _radius, uint16_t _color) {
this->tft = tft;
this->tx = tx;
this->ty = ty;
x = _x;
y = _y;
width = _width;
height = _height;
radius = _radius;
color = _color;
}
// prints button with corresponding values of setButton function
void Button::printButton(){
tft->graphicsMode();
tft->drawRoundRect(x, y, width, height, radius, color);
}
example for main file:
#include "Adafruit_GFX.h"
#include "Adafruit_RA8875.h"
#include "GENERAL.h"
#include "touchButton.h"
// touch coordinates
uint16_t tx, ty;
// 800x480 TFT DISPLAY
Adafruit_RA8875 tft = Adafruit_RA8875(RA8875_CS, RA8875_RESET);
Button channel[18];
Button sceneLoad[6];
class Scenes {
public:
int number; // numer of scene and buttons
int textCoordinate_x; // x coordinate of load button (for displaying some text)
int textCoordinate_y; // y coordinate of load button (for displaying some text)
Scenes(int numberA, int x, int y){
number = numberA;
textCoordinate_x = x;
textCoordinate_y = y;
}
void printSceneBlock(){
tft.graphicsMode();
sceneLoad[number].printButton();
}
};
scene[2] = {Scenes(0,25,150), Scenes(1, 165,150)};
void setup(){
// set Button
channel[0].setButton(&tft,&tx,&ty,20,100,760,40,5, RA8875_WHITE);
}
void loop() {
channel[0].printButton();
scene[0].printSceneBlock();
}
But when using in the scenes class, my program crashes. This is only when i use the scene.printSceneBlock() function.
Before i changed this code in the separate header files, i used tft and tx and ty and passed it via reference in each function in the main file. this worked great, but used these passes in each function in the main file. now i changed the code so i just need to pass tft etc. in the .setButton function. As im not so experienced with pointers I'm not finding any answer that i understand. Would be much appreciated if somebody could help me explain what the problem here is. I am really stuck with this...

Related

Get certain pixels with their coordonates from an Image with Qt/QML

We are creating a game where there are maps. On those maps, players can walk, but to know if they can walk somewhere, we have another image, where the path is paint.
The player can move by clicking on the map, if the click match with the collider image, the character should go to the clicked point with a pathfinder. If not, the character don't move.
For example, here is a map and its collision path image :
How can I know if I've clicked on the collider (this is a png with one color and transparency) in Qt ?
I'm using QML and Felgo for rendering so if there is already a way to do it with QML, it's even better, but I can implement it in C++ too.
My second question is how can I do a pathfinder ? I know the algorithms for that but should I move by using pixels ?
I've seen the QPainterPath class which could be what i'm looking for, how can I read all pixels with a certain color of my image and know their coordonates ?
Thanks
QML interface doesn't provide efficient way to resolve your task. It should be done at C++ side.
To get image data you can use:
QImage to load image
Call N times QImage::constScanLine, each time read K pixels. N equals to image height in pixels, K equals to width.
How to deal with returned uchar* of QImage::constScanLine?
You should call QImage::format() to determine pixel format hidden by uchar*. Or you can call QImage::convertToFormat(QImage::Format_RGB32) and always cast pixel data from uchar* to your custom struct like PixelData:
#pragma pack(push, 1)
struct PixelData {
uint8_t padding;
uint8_t r;
uint8_t g;
uint8_t b;
};
#pragma pack(pop)
according to this documentation: https://doc.qt.io/qt-5/qimage.html#Format-enum
Here is compilable solution for loading image into RAM for further effective working with it's data:
#include <QImage>
#pragma pack(push, 1)
struct PixelData {
uint8_t padding;
uint8_t r;
uint8_t g;
uint8_t b;
};
#pragma pack(pop)
void loadImage(const char* path, int& w, int& h, PixelData** data) {
Q_ASSERT(data);
QImage initialImage;
initialImage.load(path);
auto image = initialImage.convertToFormat(QImage::Format_RGB32);
w = image.width();
h = image.height();
*data = new PixelData[w * h];
PixelData* outData = *data;
for (int y = 0; y < h; y++) {
auto scanLine = image.constScanLine(y);
memcpy(outData, scanLine, sizeof(PixelData) * w);
outData += w;
}
}
void pathfinder(const PixelData* data, int w, int h) {
// Your algorithm here
}
void cleanupData(PixelData* data) {
delete[] data;
}
int main(int argc, char *argv[])
{
int width, height;
PixelData* data;
loadImage("D:\\image.png", width, height, &data);
pathfinder(data, width, height);
cleanupData(data);
return 0;
}
You can access each pixel by calling this function
inline const PixelData& getPixel(int x, int y, const PixelData* data, int w) {
return *(data + (w * y) + x);
}
... or use this formula somewhere in your pathfinding algorithm, where it could be more efficient.

How to rotate the projectile based on where the user clicks the mouse in c++

Right now I have a player that i want to shoot a projectile every time the mouse is clicked. But depending on where the mouse is clicked, I want the projectile to rotate so that it appears that the projectile is always going straight out from the player. I am using sfml.
This checks if the mouse is clicked:
if (sf::Mouse::isButtonPressed(sf::Mouse::Left)){
projectile.fire();
}
which works fine, my problem is getting the rotation correct and getting the projectile to travel towards the mouse slowly and not teleporting there instantly, so basically the whole projectile.fire method.
Here is whats in my projectile.h:
#pragma once
#include "Entity.h"
class Projectile : public Entity {
public:
void fire() {
}
};
Not much because it inherits from Entity.h so here is Entity.h:
#pragma once
#include <iostream>
#include <SFML\Graphics.hpp>
#include <string>
class Entity {
public:
int x, y;
int speed = 1;
sf::Sprite sprite;
sf::Rect<float> size = sprite.getGlobalBounds();
void disappear() {
sprite.setPosition(-10, 0);
}
void setOriginToCenter() { // NEED TO FIX
sprite.setOrigin(sf::Vector2f(size.width / 2, size.height / 2));
}
void setOrigin(float x, float y) {
sprite.setOrigin(x, y);
}
sf::Vector2f getOrigin() {
return sprite.getOrigin();
}
void setPosition(float x, float y) {
sprite.setPosition(x, y);
}
sf::Vector2f getPosition() {
return sprite.getPosition();
}
void setScale(float xscale, float yscale) {
sprite.setScale(xscale, yscale);
}
void move(int ax, int ay) {
sf::Vector2f position = getPosition();
position.x += ax * speed;
position.y += ay * speed;
sprite.setPosition(position.x, position.y);
}
};
I'm not sure if I explained the problem well or provided enough code / information, so please do tell me if that is the case.
Thanks in advance for the help!
You can compute the required rotation like this:
#include <cmath>
float radians = std::atan2(buttonClickX, buttonClickY);
Most likely SFML now provides a function to rotate the sprite e.g.
sprite.rotate(radians);
You have to look up the documentation for thr exact function name.

Why is my class variable changing its value between methods?

I am trying to load a bitmap animation to the screen. I have a float variable holdTime that is specified to hold the "holdtime" value for the animation. In my constructor I set the holdtimevariable to 0.1f but when I try to access the method in the class that is using the holdTime variable, the value of holdTime has changed to -107374176f. So somewhere between my constructor call and the method call the value has changed from 0.1f to -107374176f.
To make things a little bit more clearer let me show you some code:
Here is the header file for the Game class, this is where I call the constructor of the Animation class that has the holdTime variable.
#pragma once
#include "Graphics.h"
#include "Surface.h"
#include "Animation.h"
#include "FrameTimer.h"
class Game
{
public:
Game( class MainWindow& wnd );
void Go();
private:
void UpdateModel();
private:
MainWindow& wnd;
FrameTimer ft;
Surface surf = Surface("Test32x48.bmp");
Animation testAnimation = Animation(0, 0, 32, 48, 4, surf, 0.1f);
};
You see that I have this testAnimation at the bottom of the class. The last argument in the constructor call is the value that is ought be in holdTime.
This is how my Animation header file looks like:
#include "Surface.h"
#include "Graphics.h"
#include <vector>
class Animation {
public:
Animation(int x, int y, int width, int height, int count, const Surface& sprite, float holdtime, Color chroma = Colors::Magenta);
void Update(float dt);
private:
void Advance();
private:
std::vector<RectI> frames;
int iCurFrame = 0;
float holdTime = 0;
float curFrameTime = 0.0f;
};
And this is the Animation Cpp file:
#include "Animation.h"
Animation::Animation(int x, int y, int width, int height, int count,
const Surface& sprite, float holdtime, Color chroma)
:
sprite(sprite),
holdTime(holdTime),
chroma(chroma)
{
for (int i = 0; i < count; i++)
{
frames.emplace_back(x + i * width, x + (i + 1) * width,y, y + height);
}
}
void Animation::Update(float dt)
{
curFrameTime += dt;
while(curFrameTime >= holdTime) {
Advance();
curFrameTime -= holdTime;
}
}
void Animation::Advance()
{
if (++iCurFrame >= frames.size()) {
iCurFrame = 0;
}
}
There is only one method that is making use of holdTime and that is the method Update(float dt).
If we go back to the Game class and look at the Game.cpp file:
#include "MainWindow.h"
#include "Game.h"
Game::Game( MainWindow& wnd )
:
wnd( wnd ),
gfx( wnd )
{
}
void Game::Go()
{
UpdateModel();
}
void Game::UpdateModel()
{
testAnimation.Update(ft.Mark());
}
In the Method Go() we call the method UpdateModel() which in turn is calling the Update() method in the animation class. This means that the first method to be executed in the Animation class after the constructor call is the update() method. When I debug the program I can see that the value of holdtime has changed between the constructor call and the Update() method call. But I don't know how since it I am not modifying the value somewhere else. It also seemes that the new value of holdTime is garbage value.
It became a lot of code in this question and it looks a bit messy and even though I lack the skills of writing a good Title I hope I made you somewhat clear what my problem is.
Thanks!
Update:
Here is the code for the FrameTimer class since the value returned from one of its methods is passed in into the Update() method:
FrameTimer.H:
#pragma once
#include <chrono>
class FrameTimer
{
public:
FrameTimer();
float Mark();
private:
std::chrono::steady_clock::time_point last;
};
FrameTimer.cpp:
#include "FrameTimer.h"
using namespace std::chrono;
FrameTimer::FrameTimer()
{
last = steady_clock::now();
}
float FrameTimer::Mark()
{
const auto old = last;
last = steady_clock::now();
const duration<float> frameTime = last - old;
return frameTime.count();
}
Edit:
main.cpp:
int WINAPI wWinMain( HINSTANCE hInst,HINSTANCE,LPWSTR pArgs,INT )
{
MainWindow wnd( hInst,pArgs );
Game game( wnd );
while( wnd.ProcessMessage() )
{
game.Go();
}
}
As you can see the game.Go() method is the first method that is called in main.
Your Animation constructor is at fault:
Animation::Animation(int x, int y, int width, int height, int count,
const Surface& sprite, float holdtime, Color chroma)
:
sprite(sprite),
holdTime(holdTime),
chroma(chroma)
{
for (int i = 0; i < count; i++)
{
frames.emplace_back(x + i * width, x + (i + 1) * width,y, y + height);
}
}
Here you attempt to initialise the member holdTime from the parameter holdTime.
Except, there is no parameter holdTime. There is only the parameter holdtime.
Hence instead you are actually initialising the member holdTime from itself (the next nearest "match" for that name), so it only retains its original, unspecified value (and in fact, reading an uninitialised variable results in your program having undefined behaviour).
So, you see, your member variable doesn't "change" at all — you never set it correctly. You'd have known that had you put some diagnostic output inside that constructor to examine the value and see whether it's what you thought it should be. None of the rest of the code was relevant or necessary.
A properly-configured compiler should have warned you about this.

Tiles being drawn in the wrong location

I've finally managed to get my tiles drawn on the screen somewhat in a correct way. Although the location is a bit off and I can't seem to figure out why...
I'm using SFML for drawing.
Tile.hpp:
#ifndef TILE_HPP
#define TILE_HPP
#include <SFML/Graphics.hpp>
#include <SFML/System.hpp>
#include "textureManager.hpp"
class Tile {
public:
Tile();
Tile(sf::Vector2i coord, int biome);
~Tile();
sf::Vector2i getCoord() const { return coord; };
int getBiome() const { return biome; };
void setCoord(sf::Vector2i coord) { this->coord = coord; };
void setBiome(int biome) { this->biome = biome; };
void draw(int x, int y, sf::RenderWindow* rw);
void update(sf::Texture& texture);
private:
sf::Vector2i coord;
int biome;
sf::Sprite sprite;
};
#endif
Tile.cpp
#include <SFML/Graphics.hpp>
#include <SFML/System.hpp>
#include "textureManager.hpp"
#include "tile.hpp"
Tile::Tile()
{}
Tile::Tile(sf::Vector2i coord, int biome) {
this->biome = biome;
this->coord = coord;
}
Tile::~Tile(){}
void Tile::draw(int x, int y, sf::RenderWindow* rw)
{
sprite.setPosition(x, y);
rw->draw(sprite);
}
void Tile::update(sf::Texture& texture)
{
switch (biome)
{
// Not important here
}
}
Now the more relevant part: the drawing
void StatePlay::draw(const float dt)
{
game->window.setView(view);
game->window.clear(sf::Color::Black);
sf::Vector2f offset = camera.getLocation();
int newX = (offset.x / map.getTileSize()) - (map.chunkSize / 2);
int newY = (offset.y / map.getTileSize()) - (map.chunkSize / 2);
for (int x = 0; x < map.chunkSize; x++)
{
for (int y = 0; y < map.chunkSize; y++)
{
Tile tile = map.getTile(newX + x, newY + y);
tile.draw((newX + x) * map.getTileSize(), (newY + y) * map.getTileSize(), &game->window);
}
}
return;
}
StatePlay::StatePlay(Game* game)
{
this->game = game;
sf::Vector2f pos = sf::Vector2f(game->window.getSize()); // 1366x768
view.setSize(pos);
pos *= 0.5f; // 688x384
view.setCenter(pos);
// Initialize map
map.init(game->gameTime, game->textureManager.getImage("tileset.png"));
float w = (float) map.getWidth(); // 500
float h = (float) map.getHeight(); // 500
w *= 0.5f; // 250
h *= 0.5f; // 250
w *= map.getTileSize(); // 250 * 32 = 8000
h *= map.getTileSize(); // 250 * 32 = 8000
// Move camera
// Uses view::move from sfml to move the view with w and h
// Also sets camera private to w and h values, return with camera::getLocation()
camera.setLocation(&view, sf::Vector2f(w, h));
}
The result is that I only see the ~10 tiles squared, in the bottom left corner of my screen, covering about 3/4.
The correct tiles are chosen, but the draw location is wrong... It should draw the center of 64x64 (x 32px each) tiles, as much as fit on the screen.
I have fixed the problem. It was a very stupid mistake...
At first without drawing anything, it is normal to center the view on 0.5f * sf::View::getSize() to get the view centered in your window. So the center was already at half of my window size. When using Camera::setLocation(), I used the sf::View::move() to move the view accordingly. So when trying to center it on the map, it added the x and y correctly, but also half of my window size. This resulted in having an offset which was incorrect. Substracting or leaving those values out has fixed this stupid problem.
Thank you for the help.

C calling a class function inside of another Class that is currently an Object

new here, so be gentle, I'm currently doing my Major Project for my course and, I'm not asking for homework to be done for me, i just can't wrap my head around a strange problem i am having and have not been able to find an answer for it, even on here. I'm using SDL for my Drawing.
I'm doing Object Orientated Programming with my Project or a "state Machine" (which sounds less painful in a newbies mind, believe me), and in the render part of my Class Game1.cpp i am trying to call a Draw Function of my Player Class, but for some unknown reason that i can not fathom, it just skips this function call completely.
I have no errors, i even used breakpoints to find out what was happening, but it just skipped it completely every time, it is drawing the screen black as well without fail. Any help as t why it is skipping this would be really appreciated.
I honestly feel like it's a simple rookie mistake, but any and all scrutiny is welcome of my code, anything i can do to better myself is appreciated.
Game1.cpp:
#include "Game1.h"
#include "PlayerCharacter.h"
Game1::Game1( World * worldObject )
{
//object setup
this->worldObject = worldObject;
setDone (false);
}
Game1::~Game1()
{
}
void Game1::handle_events()
{
//*******************************************
//**//////////////Call Input///////////////**
//*******************************************
//******Check for Keyboard Input*************
//******Check Keyboard Logic*****************
//******Check for Mouse Input****************
//The mouse offsets
x = 0, y = 0;
//If the mouse moved
if (SDL_PollEvent(&worldObject->event))
{
if( worldObject->event.type == SDL_MOUSEMOTION )
{
//Get the mouse offsets
x = worldObject->event.motion.x;
y = worldObject->event.motion.y;
}
}
//******Check Mouse Logic********************
}
void Game1::logic()
{
//*******************************************
//**//////////Collision Detection//////////**
//*******************************************
//******Check Player Bullet Collision Loop***
//Check for collision with enemies
//Check for collision with bitmap mask (walls)
//******Check Enemy Bullet Collision Loop****
//Check for Collision with Player
//Check for collision with bitmap mask (walls)
}
void Game1::render()
{
//*******************************************
//**////////////////Drawing////////////////**
//*******************************************
//******Blit Black Background****************
SDL_FillRect(worldObject->Screen , NULL , 0xff000000);
//******Blit Bitmap Mask*********************
//******Blit Flashlight**********************
//******Blit Map*****************************
//******Blit Pickups*************************
//******Blit Bullets*************************
//******Blit Player**************************
&PlayerCharacter.Draw; // <----- Skips this line completely, no idea why
//******Blit Enemies*************************
//******Blit Blackened Overlay***************
//******Blit HUD*****************************
//******Flip Screen**************************
SDL_Flip(worldObject->Screen);
}
Game1.h
#ifndef __Game1_H_INLUDED__
#define __Game1_H_INLUDED__
#include "GameState.h"
#include "SDL.h"
#include "ImageLoader.h"
using namespace IMGLoader;
class Game1 : public GameState
{
private:
//Menu Image
World * worldObject;
SDL_Rect PauseMenu,Item1Tile,Item2Tile,Item3Tile;
/*bool bPauseMenu, bItem1Tile, bItem2Tile, bItem3Tile;
int ButtonSpace,ButtonSize;
float x,y;
int Alpha1,Alpha2;*/
//Clipping Window
//SDL_Rect sclip,dclip;
public:
//Loads Menu resources
Game1 (World * worldObject);
//Frees Menu resources
~Game1();
//Main loop functions
void handle_events();
void logic();
void render();
};
#endif
PlayerCharacter.cpp
#include "PlayerCharacter.h"
SDL_Rect psclip,pdclip;
PlayerCharacter::PlayerCharacter ( float X, float Y, float dX, float dY, float Angle, float Speed, bool Existance, int Height, int Width, int Health, int Shield, SDL_Surface* Player ):Characters ( X, Y, dX, dY, Angle, Speed, Existance, Height, Width, Health )
{
this->Player = Player;
this->Shield = Shield;
this->Player = load_image("image\Player1.png");
}
void PlayerCharacter::setShield ( int Shield )
{
this->Shield = Shield;
}
int PlayerCharacter::getShield ( void )
{
return Shield;
}
void PlayerCharacter::Draw( )
{
psclip.x = 0; psclip.y = 0; psclip.w = 64; psclip.h = 64;
pdclip.x = 640; pdclip.y = 318; pdclip.w = 64; pdclip.h = 64;
SDL_BlitSurface(Player, &psclip, worldObject->Screen, &pdclip);
}
PlayerCharacter.h
#ifndef __PlayerCharacter_H_INCLUDED__
#define __PlayerCharacter_H_INCLUDED__
#include "Characters.h"
class PlayerCharacter : public Characters
{
private:
int Shield;
SDL_Surface* Player;
World *worldObject;
public:
PlayerCharacter ( float X, float Y, float dX, float dY, float Angle, float Speed, bool Existance, int Height, int Width, int Health, int Shield, SDL_Surface* Player );
void setShield ( int Shield );
int getShield ( void );
void Draw ( );
};
#endif
The line
&PlayerCharacter.Draw; // <----- Skips this line completely, no idea why
is not actually a function call. It's an expression that take the address of the Draw function in the PlayerCharacter class and does nothing with it.
I'm actually kind of surprised it compiles without errors, or at least tons of warnings.
You need to create a PlayerCharacter object, and then call the function in the object.
&PlayerCharacter.Draw is not a function call. PlayerCharacter::Draw() is not a static class method, so you need a PlayerCharacter object to invoke this method on.
You have a class PlayerCharacter, which defines what a PlayerCharacter is and what can be done with it. But as far as I see, you don't have a single PlayerCharacter object, i.e. no player character. If you had one, let's call him pc, then you could draw him with pc.Draw(). For that, you would have to instantiate the class, e.g. via PlayerCharacter pc( ... ), with the ... replaced by some appropriate values for the multitude of constructor parameters you have there. (You really want a default constructor, initializing all those to zero or other appropriate "start" value...)