Matrix scrolling text animation (#283)

src/draw.h

@@ -19,6 +19,31 @@ struct box
 	uint32_t right;
 };
 
+struct matrix_dot
+{
+	int val;
+	bool is_head;
+};
+
+struct matrix_state
+{
+	struct matrix_dot** grid;
+	int* length;
+	int* spaces;
+	int* updates;
+};
+
+struct doom_state
+{
+	uint8_t* buf;
+};
+
+union anim_state
+{
+	struct doom_state* doom;
+	struct matrix_state* matrix;
+};
+
 struct term_buf
 {
 	uint16_t width;
@@ -34,7 +59,7 @@ struct term_buf
 	uint16_t box_width;
 	uint16_t box_height;
 
-	uint8_t* tmp_buf;
+	union anim_state astate;
 };
 
 void draw_init(struct term_buf* buf);