1 files changed, 79 insertions, 0 deletions
diff --git a/atari/redrawslots.c b/atari/redrawslots.c
new file mode 100644
index 000000000..f3969c283
--- /dev/null
+++ b/atari/redrawslots.c
@@ -0,0 +1,79 @@
+
+#include <stdbool.h>
+#include "windom.h"
+#include "utils/types.h"
+#include "atari/redrawslots.h"
+
+void redraw_slots_init(struct s_redrw_slots * slots, short size)
+{
+	slots->size = MIN( MAX_REDRW_SLOTS , size);
+	slots->areas_used = 0;
+}
+
+
+static inline bool rect_intersect( struct rect * box1, struct rect * box2 )
+{
+	if (box2->x1 < box1->x0)
+ 	       return false;
+
+	if (box2->y1 < box1->y0)
+        	return false;
+
+	if (box2->x0 > box1->x1)
+        	return false;
+
+	if (box2->y0 > box1->y1)
+        	return false;
+
+	return true;
+}
+/*
+	schedule a slots, coords are relative.
+*/
+void redraw_slot_schedule(struct s_redrw_slots * slots, short x0, short y0, short x1, short y1)
+{
+	int i;
+	struct rect area;
+
+	area.x0 = x0;
+	area.y0 = y0;
+	area.x1 = x1;
+	area.y1 = y1;
+
+	for( i=0; i<slots->areas_used; i++) {
+		if( slots->areas[i].x0 <= x0
+			&& slots->areas[i].x1 >= x1
+			&& slots->areas[i].y0 <= y0
+			&& slots->areas[i].y1 >= y1 ){
+			/* the area is already queued for redraw */
+			return;
+		} else {
+			if( rect_intersect(&slots->areas[i], &area ) ){
+				slots->areas[i].x0 = MIN(slots->areas[i].x0, x0);
+				slots->areas[i].y0 = MIN(slots->areas[i].y0, y0);
+				slots->areas[i].x1 = MAX(slots->areas[i].x1, x1);
+				slots->areas[i].y1 = MAX(slots->areas[i].y1, y1);
+				return;
+			}
+		}
+	}
+
+	if( slots->areas_used < slots->size ) {
+		slots->areas[slots->areas_used].x0 = x0;
+		slots->areas[slots->areas_used].x1 = x1;
+		slots->areas[slots->areas_used].y0 = y0;
+		slots->areas[slots->areas_used].y1 = y1;
+		slots->areas_used++;
+	} else {
+		/*
+			we are out of available slots, merge box with last slot
+			this is dumb... but also a very rare case.
+		*/
+		slots->areas[slots->size-1].x0 = MIN(slots->areas[i].x0, x0);
+		slots->areas[slots->size-1].y0 = MIN(slots->areas[i].y0, y0);
+		slots->areas[slots->size-1].x1 = MAX(slots->areas[i].x1, x1);
+		slots->areas[slots->size-1].y1 = MAX(slots->areas[i].y1, y1);
+	}
+done:
+	return;
+}