2048-homework/src/gui.c

#include "gui.h"
#include <SDL.h>
#include <SDL_image.h>
#include <SDL_ttf.h>
#include <stdbool.h>

const SCREEN_WIDTH = 800;
const SCREEN_HEIGHT = 920;

// these are meant to be immutable like in Rust
// unfortunately, C does not allow that
SDL_Window *window = NULL;
// SDL_Surface* screenSurface = NULL;
SDL_Renderer *window_renderer = NULL;
SDL_Texture *tile_textures[13];
SDL_Rect tile_size;
SDL_Texture *game_over_texture = NULL;
SDL_Texture *you_won_texture = NULL;
TTF_Font *Sans = NULL;
SDL_Color Black = { 0, 0, 0 };

SDL_Texture *texture_from_png(char *n) {
    SDL_Surface *s = IMG_Load(n);
    SDL_Texture *t = SDL_CreateTextureFromSurface(window_renderer, s);
    SDL_FreeSurface(s);
    return t;
}

void gui_init() {

    // Initialize SDL
    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        printf("SDL could not initialize! SDL_Error: %s\n", SDL_GetError());
    }

    window = SDL_CreateWindow("2048", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
    if (window == NULL) {
        printf("Window could not be created! SDL_Error: %s\n", SDL_GetError());
    }

    TTF_Init();
    // screenSurface = SDL_GetWindowSurface(window);
    // SDL_FillRect(screenSurface, NULL, SDL_MapRGB(screenSurface->format, 255, 255, 255));

    // create renderer and render white window
    window_renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
    SDL_SetRenderDrawColor(window_renderer, 0xFF, 0xFF, 0xFF, 0xFF);
    SDL_RenderClear(window_renderer);
    SDL_RenderPresent(window_renderer);
    // SDL_UpdateWindowSurface(window);

    // load up textures
    tile_textures[0] = texture_from_png("res/tile.png");
    tile_textures[1] = texture_from_png("res/1.png");
    tile_textures[2] = texture_from_png("res/2.png");
    tile_textures[3] = texture_from_png("res/4.png");
    tile_textures[4] = texture_from_png("res/8.png");
    tile_textures[5] = texture_from_png("res/16.png");
    tile_textures[6] = texture_from_png("res/32.png");
    tile_textures[7] = texture_from_png("res/64.png");
    tile_textures[8] = texture_from_png("res/128.png");
    tile_textures[9] = texture_from_png("res/256.png");
    tile_textures[10] = texture_from_png("res/512.png");
    tile_textures[11] = texture_from_png("res/1024.png");
    tile_textures[12] = texture_from_png("res/2048.png");
    tile_size.x = 0;
    tile_size.y = 0;
    SDL_QueryTexture(tile_textures[0], NULL, NULL, &tile_size.w, &tile_size.h);

    game_over_texture = texture_from_png("res/game_over.png");
    you_won_texture = texture_from_png("res/you_won.png");

    Sans = TTF_OpenFont("res/LiberationSerif-Regular.ttf", 92);
}

void gui_destroy() {
    // Destroy window
    SDL_DestroyWindow(window);
    window = NULL;
    SDL_DestroyRenderer(window_renderer);
    window_renderer = NULL;
    for (int i = 0; i < 13; i++) {
        SDL_DestroyTexture(tile_textures[i]);
        tile_textures[i] = NULL;
    }
    SDL_DestroyTexture(game_over_texture);
    game_over_texture = NULL;
    SDL_DestroyTexture(you_won_texture);
    you_won_texture = NULL;

    TTF_Quit();
    // Quit SDL subsystems
    SDL_Quit();
}

void gui_loop(Game *game) {
    bool quit = false;
    bool needs_redraw = true; // there's no need to redraw window when nothing's changed. will be set to false later. first run has to be always done
    SDL_Event e;

    while (!quit) {
        while (SDL_PollEvent(&e) != 0) {
            switch (e.type) {
            /* Keyboard event */
            /* Pass the event data onto PrintKeyInfo() */
            case SDL_KEYDOWN:
                switch (e.key.keysym.sym) {
                case SDLK_h:
                case SDLK_LEFT:
                case SDLK_4:
                    needs_redraw = true;
                    game_move(game, Left);
                    break;
                case SDLK_l:
                case SDLK_RIGHT:
                case SDLK_6:
                    needs_redraw = true;
                    game_move(game, Right);
                    break;
                case SDLK_j:
                case SDLK_DOWN:
                case SDLK_2:
                    needs_redraw = true;
                    game_move(game, Down);
                    break;
                case SDLK_k:
                case SDLK_UP:
                case SDLK_8:
                    needs_redraw = true;
                    game_move(game, Up);
                    break;
                }
                break;
            case SDL_QUIT:
                quit = 1;
                break;
            case SDL_WINDOWEVENT_SHOWN:
            case SDL_WINDOWEVENT_EXPOSED:
                needs_redraw = true;
                break;
            }
        }

        if (needs_redraw) {
            SDL_RenderClear(window_renderer);
            SDL_Rect tile_rect = tile_size;
            for (int i = 0; i < game->field_size_x; i++) {
                tile_rect.x = i * (700 / game->field_size_x) + 50;
                for (int j = 0; j < game->field_size_y; j++) {
                    tile_rect.y = j * (700 / game->field_size_y) + 150;

                    // get texture index from  value
                    for (int k = 0; k < 13; k++) {
                        if (!(game->field[j][i] >> k)) {
                            SDL_RenderCopy(window_renderer, tile_textures[k], NULL, &tile_rect);
                            break;
                        }
                    }
                }
            }

            // score - I am too lazy to optimize this further
            char label_text[24] = "Score: 0x";
            char value[16];
            SDL_itoa(game->score, value, 16);
            strncat(label_text, value, strlen(value));
            SDL_Surface *score_label = TTF_RenderText_Blended(Sans, label_text, Black);
            SDL_Texture *score_label_texture = SDL_CreateTextureFromSurface(window_renderer, score_label);
            SDL_Rect score_label_rect;
            SDL_QueryTexture(score_label_texture, NULL, NULL, &score_label_rect.w, &score_label_rect.h);
            score_label_rect.x = (SCREEN_WIDTH - score_label_rect.w) / 2;
            score_label_rect.y = 25;
            SDL_RenderCopy(window_renderer, score_label_texture, NULL, &score_label_rect);
            SDL_FreeSurface(score_label);
            SDL_DestroyTexture(score_label_texture);

            if (game->game_over) {
                // render game over screen
                SDL_RenderCopy(window_renderer, game_over_texture, NULL, NULL);
            }
            else if (game->won) {
                SDL_RenderCopy(window_renderer, you_won_texture, NULL, NULL);
            }

            SDL_RenderPresent(window_renderer);
            needs_redraw = false;
        }
    }
}