1 files changed, 60 insertions, 0 deletions
diff --git a/counter.c b/counter.c
new file mode 100644
index 0000000..5a9913c
--- /dev/null
+++ b/counter.c
@@ -0,0 +1,60 @@
+#include <SDL.h>
+
+#include "digits.h"
+
+static SDL_Texture *get_font(SDL_Renderer *rend) {
+	static SDL_Texture *font = NULL;
+	if (!font) {
+		font = SDL_CreateTexture(rend,
+			SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STREAMING,
+			FONT_WIDTH, sizeof(digits) / FONT_WIDTH);
+		SDL_SetTextureBlendMode(font, SDL_BLENDMODE_BLEND);
+		SDL_assert(font);
+
+		int pitch;
+		void *out;
+		SDL_assert(SDL_LockTexture(font, NULL, &out, &pitch) >= 0);
+		SDL_Color *pixels = out;
+
+		for (int i = 0; i < sizeof(digits); i++) {
+			pixels[i] =
+				(SDL_Color) {0xFF, 0xFF, 0xFF, digits[i] ? 0xFF : 0x00};
+		}
+
+		SDL_UnlockTexture(font);
+	}
+	return font;
+}
+
+int draw_counter(SDL_Renderer *rend,
+		SDL_Point screen_pos, double size, SDL_Color color,
+		int number, int digits) {
+	double scale = size / FONT_HEIGHT;
+
+	SDL_Texture *font = get_font(rend);
+	SDL_SetTextureColorMod(font, color.r, color.g, color.b);
+
+	if (digits == 0) {
+		for (int n = number; n > 0; n /= DIGIT_BASE)
+			digits += 1;
+		digits = SDL_max(digits, 1);
+	}
+
+	int n = number;
+	for (int i = digits - 1; i >= 0; i--) {
+		int digit = n % DIGIT_BASE;
+
+		int width = SDL_round((double) FONT_WIDTH * scale);
+		int height = SDL_round((double) FONT_HEIGHT * scale);
+		int offset = SDL_round((double) FONT_WIDTH * scale * (double) i);
+		SDL_Rect draw = {screen_pos.x + offset, screen_pos.y, width, height};
+		SDL_Rect digit_rect = {
+			0, FONT_HEIGHT * digit, FONT_WIDTH, FONT_HEIGHT,
+		};
+		SDL_RenderCopy(rend, font, &digit_rect, &draw);
+
+		n /= DIGIT_BASE;
+	}
+
+	return SDL_round((double) FONT_WIDTH * scale * (double) digits);
+}