New with SDL and need little help for my assignment

SDL Development
1

Hello!
This is the first time i use SDL in my software life :smiley: . I have seen alot of videos to help me structure my mind to think correctly when using this library.

I am currently doing a little game in C using this library for my assignment and the game is essentially the replica of superhexagon. (https://www.superhexagon.com/)

In my project, i use sdl2.h :

#include <SDL.h>
#include <SDL_image.h>
#include <SDL2_gfxPrimitives.h>

I’ve structured the project for it to contain :

  • assets → all sorts of images for my menu
  • src → main.c, application.c, menu.c, game.c, spritesheet.c, sdl2.h, Makefile + all the header files

I alredy have understood how to handle events with switch that i have implemented in my menu and a basic form of it in game.c. My program can enter in a “playing” phase when i click on play end come back to the “menu” phase.
example:

    //-------------------------------------------------------
    //We are payng
    game->state = PLAYING;
    SDL_Event event;
    SDL_bool GameRunning = SDL_TRUE;
    while (GameRunning) //while the player didnt loose, the game is running
    {

        while (SDL_PollEvent(&event))
        {
            /* code */
                switch (event.type)
                {
                //when a key is pressed
                case SDL_KEYDOWN:
                                    //Detecting the pressed key
                                    switch (event.key.keysym.sym)
                                    {
                                    case SDLK_LEFT:
                                        printf("Left key pressed\n");
                                        break;
                                    case SDLK_RIGHT:
                                        printf("Right key pressed\n");
                                        break;

                                    default:
                                        break;
                                    }
                    break;
                //when a key is unpressed
                case SDL_KEYUP:
                                    switch (event.key.keysym.sym)
                                    {
                                    case SDLK_LEFT:
                                        printf("Left key up\n");
                                        break;
                                    case SDLK_RIGHT:
                                        printf("Right key up\n");
                                        break;

                                    default:
                                        break;
                                    }
                    break;
                //if the user quit the game
                case SDL_QUIT:
                    //The game is over
                    GameRunning = SDL_FALSE;
                    game->state = GAME_OVER;
                    break;

                default:
                    break;
                }
        }
        
    }

But except that, i am a little lost when i try to render some arcs (my teacher said to start rendering my objects before i start animating them). I have to use sdl_gfx.

I’ve read the documentation to see how to animate stuff but its hard to have a general view of the steps to follow. For example :

        filledCircleRGBA(game->renderer,SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2, 10,255, 255, 255, 255) 
        arcRGBA(  game->renderer, SCREEN_WIDTH/2, SCREEN_HEIGHT/2, 100, 0, 80, 255, 255, 255, 255 );
        //i want to animate this little triangle around my circle, how??
        filledTrigonRGBA (game->renderer, CURSOR_POSITION_X-10, CURSOR_POSITION_Y, CURSOR_POSITION_X+10, CURSOR_POSITION_Y, CURSOR_POSITION_X, CURSOR_POSITION_Y+10, 255, 255, 255, 255);
        SDL_RenderPresent(game->renderer);

Thank you and sorry for my english (i speak french)

2

Hello and welcome to the forum!

Do you want to animate the triangle like, for example, changing its color over time or do you want to animate the triangle like, for example, moving it around in a circular motion?

1 Like
3

Helloo
Thank you very much. The step i’m trying to figure out right now is how to move the triangle around my little circle when he triggers an event with the keyboard :slight_smile:

4

I have seen some examples about animating srpitsheets, but not how to animate something i have drawn in the renderer :confused: I want to understand how animation works when i render elements using gfx functions…Is it even possible? or do i have to do a type of converson to a movable structure like load the drawn elements into a SDL_Surface first??

5

This is how it look like

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412022×1546 82.4 KB