Added sdl version to exmplify extension of the main engine

src/engine.c

@@ -270,7 +270,6 @@ int gamestate_tick(struct gfx_state *s, struct gamestate *g, int d, void (*callb
 {
     /* Reset move. Altered by gravitate and merge if we do move */
     g->moved = 0;
-    printf("%d\n", d);
     gravitate(s, g, d, callback);
     merge(s, g, d, callback);
     gravitate(s, g, d, callback);

src/gfx_sdl.c

@@ -0,0 +1,181 @@
+#include <stdlib.h>
+#include <SDL.h>
+#include <SDL_ttf.h>
+#include "gfx.h"
+
+/* Side length of a 'pixel' in pixels */
+#define TTF_FONT_PATH "res/Anonymous Pro.ttf"
+#define TTF_FONT_PT 32
+
+#define iterate(n, expression)\
+    do {\
+        int i;\
+        for (i = 0; i < n; ++i) { expression; }\
+    } while (0)
+
+struct gfx_state {
+    SDL_Window *window;
+    SDL_Surface *surface;
+    TTF_Font *font;
+    int side_length;
+    int window_height;
+    int window_width;
+};
+
+struct gfx_state* gfx_init(struct gamestate *g)
+{
+    struct gfx_state *s = malloc(sizeof(struct gfx_state));
+
+    SDL_Init(SDL_INIT_VIDEO);
+    TTF_Init();
+    s->font = TTF_OpenFont(TTF_FONT_PATH, TTF_FONT_PT);
+
+    s->side_length   = TTF_FontLineSkip(s->font);
+    s->window_height = g->opts->grid_height * (g->print_width + 2) + 3;
+    s->window_width  = g->opts->grid_width * (g->print_width + 2) + 1;
+    s->window = SDL_CreateWindow(
+                "2048",
+                SDL_WINDOWPOS_UNDEFINED,
+                SDL_WINDOWPOS_UNDEFINED,
+
+                /* Spacing is inconsistent right now. Need to find width and
+                 * height spacing to accurately resize window */
+                s->window_width * TTF_FONT_PT * 0.7,
+                s->window_height * s->side_length * 0.35,
+                SDL_WINDOW_OPENGL | SDL_WINDOW_ALLOW_HIGHDPI
+            );
+
+    s->surface = SDL_GetWindowSurface(s->window);
+
+    return s;
+}
+
+#define rect_set(r, xv, yv, wv, hv)\
+    do {\
+        r.x = xv; r.y = yv; r.w = wv; r.h = hv;\
+    } while (0)
+
+
+void gfx_draw(struct gfx_state *s, struct gamestate *g)
+{
+    /* This shouldn't ever overflow. Max width effectively is determined by the size
+     * of two integers' text representation */
+    const int buffer_length = 64;
+    char string_buffer[buffer_length];
+
+    /* Set up text object so we can write to sdl window */
+    SDL_Surface *text;
+    SDL_Color text_color = {255, 255, 255, 0};
+    SDL_Rect rect;
+
+    /* Clear screen */
+    SDL_FillRect(s->surface, NULL, SDL_MapRGB(s->surface->format, 0, 0, 0));
+
+    if (g->score_last)
+        snprintf(string_buffer, buffer_length, "Score: %ld (+%ld)", g->score, g->score_last);
+    else
+        snprintf(string_buffer, buffer_length, "Score: %ld", g->score);
+
+    rect_set(rect, 0, 0, 0, 0);
+    text = TTF_RenderText_Solid(s->font, string_buffer, text_color);
+    SDL_BlitSurface(text, NULL, s->surface, &rect);
+
+    snprintf(string_buffer, buffer_length, "   Hi: %ld", g->score_high);
+    rect_set(rect, 0, s->side_length * 1, 0, 0);
+    text = TTF_RenderText_Solid(s->font, string_buffer, text_color);
+    SDL_BlitSurface(text, NULL, s->surface, &rect);
+
+    int i;
+    for (i = 0; i < g->opts->grid_width * (g->print_width + 2) + 1; ++i)
+        string_buffer[i] = '-';
+    string_buffer[i] = '\0';
+
+    rect_set(rect, 0, s->side_length * 2, 0, 0);
+    text = TTF_RenderText_Solid(s->font, string_buffer, text_color);
+    SDL_BlitSurface(text, NULL, s->surface, &rect);
+
+    int x, y;
+    char line_buffer[buffer_length];
+    for (y = 0; y < g->opts->grid_height; ++y) {
+        int line_index = 0;
+        line_buffer[line_index++] = '|';
+
+        for (x = 0; x < g->opts->grid_width; ++x) {
+            if (g->grid[x][y]) {
+                snprintf(string_buffer, buffer_length, "%*ld |", g->print_width, g->grid[x][y]);
+                strncpy(line_buffer + line_index, string_buffer, buffer_length - line_index);
+                line_index += strlen(string_buffer);
+            }
+            else {
+                snprintf(string_buffer, buffer_length, "%*s |", g->print_width, "");
+                strncpy(line_buffer + line_index, string_buffer, buffer_length - line_index);
+                line_index += strlen(string_buffer);
+            }
+        }
+
+        line_buffer[line_index] = 0;
+        rect_set(rect, 0, s->side_length * (y + 3), 0, 0);
+        text = TTF_RenderText_Solid(s->font, line_buffer, text_color);
+        SDL_BlitSurface(text, NULL, s->surface, &rect);
+    }
+
+    for (i = 0; i < g->opts->grid_height * (g->print_width + 2) + 1; ++i)
+        string_buffer[i] = '-';
+    string_buffer[i] = '\0';
+
+    rect_set(rect, 0, s->side_length * (y + 3), 0, 0);
+    text = TTF_RenderText_Solid(s->font, string_buffer, text_color);
+    SDL_BlitSurface(text, NULL, s->surface, &rect);
+    SDL_UpdateWindowSurface(s->window);
+}
+
+/* This getch we parse here, and we just return when we get an appropriate
+ * event */
+int gfx_getch(struct gfx_state *s)
+{
+    (void)s; /* Supress unused warning */
+    SDL_Event event;
+
+    while (1) {
+        while (SDL_WaitEvent(&event)) {
+            switch (event.type) {
+            case SDL_QUIT:
+                return 'q';
+            case SDL_KEYDOWN:
+            switch (event.key.keysym.sym) {
+                case SDLK_q:
+                    return 'q';
+                case SDLK_UP:
+                case SDLK_w:
+                    return 'w';
+                case SDLK_DOWN:
+                case SDLK_s:
+                    return 's';
+                case SDLK_LEFT:
+                case SDLK_a:
+                    return 'a';
+                case SDLK_RIGHT:
+                case SDLK_d:
+                    return 'd';
+                default:
+                     break;
+            }
+                break;
+            default:
+                break;
+            }
+        }
+    }
+}
+
+void gfx_sleep(int ms)
+{
+    SDL_Delay(ms);
+}
+
+void gfx_destroy(struct gfx_state *s)
+{
+    SDL_DestroyWindow(s->window);
+    TTF_Quit();
+    SDL_Quit();
+}