Hi, I'm Spanish and I don't know almost anything about English, so I'm going to use the google translator.

I am about to finish a modern c++ course and I would like to use allegro to create simple classic games like pong, arkanoid, asteroid, space invader, donkey kong, pacman etc...

I have never created a videogame and with c++ because I am a beginner who wants to start using it with the creation of games but I don't know how to make them, I would like to know if you can help me learn about allegro/c++ and the creation of games.

I'm starting from scratch, I was looking at the vivace tutorial, but apart from showing a graph I haven't known much else what to do and I don't understand anything that is explained either. Greetings and I look forward to your response and to be part of this community and learn everything that i can

Hello yellow, thanks for the suggestions, I'll try some steps and then post the code for tips.
But I don't know whether to post it in this thread or create another one for this game, I don't see any option to post code either, maybe I just put it here as if it were text. Regards

Actually, it's Amarillion, not Amarillo ;-)

I don't speak Spanish, but hello and good luck on your journey. There are a fair number of Spanish speakers around who can help you, like amarillion.

EDIT
I don't know if Neil Roy ever published the source code to his pacman games, but it would be worth looking at. Deluxe Pacman is what it is called.

https://nitehackr.github.io/games_index.html

Good, looks like you're off to a solid start.

Remember, if a problem is too difficult, you have to split it into smaller problems until you know how to solve them.

• If I tell you x=10 and y=5 - so the 10th column of the 5th row - can you tell me which character is at that position in the string?

• Can you create a nested loop that passes each x and each y of the map?

• Can you check each x,y in the map if it is the letter "s" or not?

• Can you check each x,y in the map, and draw a blue rectangle on the screen if it is a wall?

Your string layout is mapa1[y][x] not mapa1[x][y].

Think that each mapa1[y] is a string and [x] is the index in that string.

Personally, I would just single char array.

Access the array like this

char c = mapa1[x + y * width];

Also, think about the map itself. Think of it as one contiguous chunk of memory. It is more efficient to access memory next to each other. Otherwise there is a delay due to unloading and reloading memory into cache. It depends on the page size and what that delay is. For a simple game such as this, the time delay is negligible. However, it is better practice. Start learning better practice up front to make it a habit.

Your strings may or may not be contiguous in memory. Still, the same concept applies.

If you keep it as mapa1[y][x], the draw loop should draw row by row not column by column.

// access row by row
for <int y = 0; y < height; ++y)
{
    // for each row draw each index of that row.
    for <int x = 0; x < width; ++x)
    {
        // draw cell
    }
}

Cheating? Copy/Paste is the life-blood of programmers.

for the first example, I'm surprised this even compiled

sizeof(mapa1[0]).size()

sizeof(mapa1[0]) returns an unsigned int. Then you call size() on that.

Use the length of the string. If it is all 8-bit chars, you could use size as well.

for(int y{ 0 }; y < mapa1[0].size(); ++y)
  for(int x{ 0 }; x < mapa1[y].size(); ++x)

For the second example, what is wrong with this line?

for(int y{ 0 };y < sizeof(mapa2[0]);++y)

What is mapa2[0]? It is a char. What is a sizeof a char?

What I would do would hardcode length and width.

// in your class
const int map_width = 46;
const int map_height = 17;

// in drawing method
for(int y{ 0 }; y < map_height; ++y)
{
  for(int x{ 0 }; x < map_width; ++x)
  {
  }
}

Lastly, look at your draw line parameters. Then look at what they should be. You swapped x and y.

void al_draw_filled_rectangle(float x1, float y1, float x2, float y2,
   ALLEGRO_COLOR color)

Allegro is not a game engine.

Allegro Low Level Graphics (or Game) ROutines

---

You have to program collision on your own. Or use a map system with built-in collision detection.

1. If 's' is going to be in different places per level. Then run through the map and find 's'. Determine x and y of map position from that. Then scale it up to width and height.

2. Determine if a square is solid or not should be straightforward.

bool is_solid(int x, int y)
{
    return (mapa1[y][x] == 'x');
}

3. What state is pacman. Pacman has 4 main states.

Each 'frame', you need move him a 1/4 move (1/4 of the cell size) and increase the state and keep repeating.

When I say frame, I don't mean game frame. You need a timer on him to determine the rate he moves.

He is fully in a square when his mouth is closed. Only at that state and before you move again. Determine the square he is in by dividing my ancho_celda, alto_celda. Then check the next cell based on direction he is moving. If that cell is closed then stop him from moving.

int x = pacman.x / ancho_celda;
int y = pacman.y / alto_celda;

if (pacman.dir == PACMAN_LEFT && is_solid(x - 1, y))
{
  // stop moving
  pacman.dir = PACMAN_STOPPED;
}

// do the same for other directions.

You could also simplify it

int mx[4] = {-1, 1, 0, 0};
int my[4] = {0, 0, -1, 1};

if (pacman.dir != PACMAN_STOPPED && pacman.state == PACMAN_CLOSED)
{
  if (is_solid(pacman.x + mx[pacman.dir - PACMAN_LEFT], pacman.y + my[pacman.dir - PACMAN_LEFT]))
  {
    pacman.dir = PACMAN_STOPPED;
  }
}

Remember, just because I might do it this way doesn't mean it's the only way.

1. Declarations go in header files
2. Definitions go in source files

There are exceptions, such as templates. Templated classes and functions have to be in the header file. But that is a bit advanced coding.

Declare your class in its own header file with declarations only. Use header guards or '#pragma once' to safeguard your headers.

Define your class in a cpp file

I would also make a class with header and source for your map/grid as well.

Variables can be declared in headers, but do not define variables in header files. You can declare variables in header files with the keyword 'extern'

// test.h
extern int my_variable;




// test.cpp
#include "test.h"
int my_variable = 0;

Of course, variables defined in the global scope are frowned upon. Global scope means defining variables outside a class or function.

Once you find s and set the start position, then your done. No need to keep looking. So I return out of the function.

As for pacman stopping. What I told you earlier was a basic movement of 1/4 cell per frame. No velocity. If you want velocity, that is another problem altogether. And there are quite a few different options.

My example was based on constant speeds and integers.

With floats and velocities, it can be done. However, slightly more difficult.

One option would be to calculate your position to the wall that is facing the direction you're looking. If distance is less than velocity, then you hit wall. Reset position next to wall and reset velocity.

You can make assignments to a std::string.

For example,

if (mapa1[y][x] == '.') { mapa1[y][x] = ' '; }

The same goes for mapa2, but you'll have to calculate the index:

mapa2[x+y*ancho_celda] = ' ';