(#4) Prettify counter a bit

Makefile

@@ -1,6 +1,6 @@
 PKGS=x11 sdl2
 CFLAGS=-Wall -Wextra -std=c11 -pedantic `pkg-config --cflags $(PKGS)`
-LIBS=`pkg-config --libs $(PKGS)`
+LIBS=`pkg-config --libs $(PKGS)` -lm
 
 voidf: main.c
 	$(CC) $(CFLAGS) -o voidf main.c $(LIBS)

main.c

@@ -65,10 +65,16 @@ Bitmap_Font bitmap_font_from_file(SDL_Renderer *renderer, const char *file_path)
     return result;
 }
 
+void bitmap_font_text_size(const char *cstr, int sw, int sh, int *w, int *h)
+{
+    *w = strlen(cstr) * BITMAP_FONT_CHAR_WIDTH * sw;
+    *h = BITMAP_FONT_CHAR_HEIGHT * sh;
+}
+
 void bitmap_font_render(Bitmap_Font *font,
                         SDL_Renderer *renderer,
                         int x, int y,
-                        int w, int h,
+                        int sw, int sh,
                         SDL_Color color,
                         const char *cstr)
 {
@@ -80,10 +86,10 @@ void bitmap_font_render(Bitmap_Font *font,
     for (int col = 0; (size_t) col < n; ++col) {
         const SDL_Rect src_rect = bitmap_font_char_rect(font, cstr[col]);
         const SDL_Rect dest_rect = {
-            x + BITMAP_FONT_CHAR_WIDTH  * col * w,
-            y + BITMAP_FONT_CHAR_HEIGHT       * h,
-            src_rect.w * w,
-            src_rect.h * h
+            x + BITMAP_FONT_CHAR_WIDTH  * col * sw,
+            y,
+            src_rect.w * sw,
+            src_rect.h * sh
         };
         SDL_RenderCopy(renderer, font->bitmap, &src_rect, &dest_rect);
     }
@@ -146,6 +152,68 @@ size_t scan_devices(Device *devices, size_t capacity)
 #define DEVICES_CAPACITY 256
 Device devices[DEVICES_CAPACITY];
 
+#define SCREEN_WIDTH 800
+#define SCREEN_HEIGHT 600
+#define FPS 60
+#define DELTA_TIME (1.0f / FPS)
+
+typedef struct {
+    char text[256];
+    float a;
+} Popup;
+
+#define POPUPS_CAPACITY 32
+Popup popups[POPUPS_CAPACITY] = {0};
+
+#define POPUP_FADEOUT_RATE 1.5f
+#define POPUP_FADEOUT_DISTANCE 150
+#define POPUP_SWIDTH 20
+#define POPUP_SHEIGHT 20
+#define POPUP_COLOR ((SDL_Color) {255, 255, 255, 255})
+
+void popups_render(SDL_Renderer *renderer, Bitmap_Font *font)
+{
+    for (size_t i = 0; i < POPUPS_CAPACITY; ++i) {
+        if (popups[i].a > 0.0) {
+            int w = 0;
+            int h = 0;
+            bitmap_font_text_size(popups[i].text, POPUP_SWIDTH, POPUP_SHEIGHT, &w, &h);
+            const int x = SCREEN_WIDTH / 2 - w / 2;
+            const int y = SCREEN_HEIGHT / 2 - h / 2 - (int) floorf((1.0 - popups[i].a) * POPUP_FADEOUT_DISTANCE);
+
+            SDL_Color color = POPUP_COLOR;
+            color.a = (Uint8) floorf(255.0f * popups[i].a);
+            bitmap_font_render(
+                    font,
+                    renderer,
+                    x, y,
+                    POPUP_SWIDTH, POPUP_SHEIGHT,
+                    color,
+                    popups[i].text);
+        }
+    }
+}
+
+void popups_update(float dt)
+{
+    for (size_t i = 0; i < POPUPS_CAPACITY; ++i) {
+        if (popups[i].a > 0) {
+            popups[i].a -= dt * POPUP_FADEOUT_RATE;
+        }
+    }
+}
+
+void popups_new(const char *text)
+{
+    for (size_t i = 0; i < POPUPS_CAPACITY; ++i) {
+        if (popups[i].a <= 0) {
+            snprintf(popups[i].text, sizeof(popups[i].text), "%s", text);
+            popups[i].a = 1.0f;
+            return;
+        }
+    }
+}
+
 int main()
 {
     const size_t devices_size = scan_devices(devices, DEVICES_CAPACITY);
@@ -198,7 +266,8 @@ int main()
     SDL_Window * const window = SDL_CreateWindow(
         "V̳͙̥̹̟͗̀̎̓͌͐́O̘̞͇̞̣͇͕͂͠I͙̋͐̍͂̀D̶͕̩̦̲͙F̟̖̮ͩ̏ͥ̂ͨ͠ ͍̰̫̯͙̯ͨ̉ͤ̈̿ͭI̤͍̲̯ͤ̎̀͝S̴̻͇̳̗̩ͧ̆ ̭̘̦ͭ͒Ĉ̸̰̼̤̖̲O̹̭̞̺̻͚̣̒M̪͓̗̤͋͢Ĩ͔̗̣̻̄̏̏̏̚N̳̦̂ͯ̅͂̓̈́G͈̣",
         0, 0,
-        800, 600, SDL_WINDOW_RESIZABLE);
+        SCREEN_WIDTH, SCREEN_HEIGHT, 
+        SDL_WINDOW_RESIZABLE);
     if (window == NULL) {
         fprintf(stderr, "ERROR: Could not initialize SDL: %s\n", SDL_GetError());
         exit(1);
@@ -211,6 +280,10 @@ int main()
         exit(1);
     }
 
+    SDL_RenderSetLogicalSize(renderer,
+            (int) SCREEN_WIDTH,
+            (int) SCREEN_HEIGHT);
+
     // TODO(#3): charmap-oldschool.bmp should be baked into the executable
     Bitmap_Font font = bitmap_font_from_file(renderer, "./charmap-oldschool.bmp");
 
@@ -239,25 +312,37 @@ int main()
                     if(is_voidf(&cursor, ev[i].code)) {
                         printf("VOIDF IS COMING\n");
                         voidf_count += 1;
+                        // TODO(#6): quake-style combo message
+                        popups_new("voidf");
                     }
                 }
             }
         }
 
-        SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0);
+        popups_update(DELTA_TIME);
+
+        SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
         SDL_RenderClear(renderer);
 
         snprintf(voidf_buffer, sizeof(voidf_buffer), "%d", voidf_count);
 
-        // TODO(#4): voidf counter is ugly
+        const int sw = 10 * 3;
+        const int sh = 10 * 3;
+        int w = 0;
+        int h = 0;
+        bitmap_font_text_size(voidf_buffer, sw, sh, &w, &h);
+        const int x = SCREEN_WIDTH / 2 - w / 2;
+        const int y = SCREEN_HEIGHT / 2 - h / 2;
         bitmap_font_render(&font,
                            renderer,
-                           0, 0,
-                           10, 10,
+                           x, y,
+                           sw, sh,
                            (SDL_Color) {255, 255, 255, 255},
                            voidf_buffer);
 
-        SDL_Delay(10);
+        popups_render(renderer, &font);
+
+        SDL_Delay((int) floorf(DELTA_TIME * 1000.0f));
         SDL_RenderPresent(renderer);
     }