LV_VDB_DOUBLE: Add double virtual display buffer. Needs test on real hardware

lv_conf_templ.h

@@ -17,18 +17,19 @@
 #define LV_HOR_RES          (320 * LV_DOWNSCALE)
 #define LV_VER_RES          (240 * LV_DOWNSCALE)
 #define LV_DPI              (80 * LV_DOWNSCALE)
-
-/* Buffered rendering: >= LV_DOWNSCALE * LV_HOR_RES or 0 to disable buffering*/
-#define LV_VDB_SIZE        (LV_HOR_RES * 30)
-
-/* Enable antialaiassing
+/* Enable anti-aliasing
  * If enabled everything will half-sized
- * Use LV_DOWNSCALE to compensate
- * the down scaling effect of antialiassing*/
+ * Use LV_DOWNSCALE to compensate he down scaling effect of anti-aliasing*/
 #define LV_ANTIALIAS        1
+#define LV_DOWNSCALE        (1 << LV_ANTIALIAS) /*Set the downscaling value*/
 
-/*Set the downscaling value*/
-#define LV_DOWNSCALE        (1 << LV_ANTIALIAS)
+/* Buffered rendering: >= LV_DOWNSCALE * LV_HOR_RES or 0 to disable buffering*/
+#define LV_VDB_SIZE         (LV_HOR_RES * LV_VER_RES / 20)
+#if LV_VDB_SIZE
+/* Double virtual buffering
+ * One for rendering another to transfer former rendered image to frame buffer in the background*/
+#define LV_VDB_DOUBLE       1
+#endif
 
 #define LV_REFR_PERIOD      40    /*Screen refresh period in milliseconds*/
 #define LV_INV_FIFO_SIZE    32    /*The average number of objects on a screen */

lv_obj/lv_refr.c

@@ -70,7 +70,6 @@ void lv_refr_init(void)
     ptask_t* task;
     task = ptask_create(lv_refr_task, LV_REFR_PERIOD, PTASK_PRIO_MID, NULL);
     dm_assert(task);
-    
 }
 
 /**
@@ -130,7 +129,7 @@ void lv_inv_area(const area_t * area_p)
  * @param cb pointer to a callback function (void my_refr_cb(uint32_t time_ms, uint32_t px_num))
  *           time_ms: refresh time in [ms]
  *           px_num: not the drawn pixels but the number of affected pixels of the screen
- *                   (more pixels are drawn with opacity areas)
+ *                   (more pixels are drawn because of overlapping objects)
  */
 void lv_refr_set_monitor_cb(void (*cb)(uint32_t, uint32_t))
 {
@@ -257,15 +256,8 @@ static void lv_refr_area_no_vdb(const area_t * area_p)
  */
 static void lv_refr_area_with_vdb(const area_t * area_p)
 {
-    lv_vdb_t * vdb_p = lv_vdb_get();
-    
-    /*Always use the full row*/
-    vdb_p->area.x1 = area_p->x1;
-    vdb_p->area.y1 = area_p->y1;
-    vdb_p->area.x2 = area_p->x2;
-
     /*Calculate the max row num*/
-    uint32_t max_row = (uint32_t) LV_VDB_SIZE / (vdb_p->area.x2 - vdb_p->area.x1 + 1);
+    uint32_t max_row = (uint32_t) LV_VDB_SIZE / (area_get_width(area_p));
     if(max_row > area_get_height(area_p)) max_row = area_get_height(area_p);
     
     /*Round the row number with downscale*/
@@ -273,20 +265,28 @@ static void lv_refr_area_with_vdb(const area_t * area_p)
     max_row &= (~0x1);
 #endif
 
-    /*Refresh all rows*/
-    cord_t row = area_p->y1;
-
+    /*Always use the full row*/
+    cord_t row;
+    cord_t row_last = 0;
     for(row = area_p->y1; row  + max_row - 1 <= area_p->y2; row += max_row)  {
+        lv_vdb_t * vdb_p = lv_vdb_get();
+
         /*Calc. the next y coordinates of VDB*/
+        vdb_p->area.x1 = area_p->x1;
+        vdb_p->area.x2 = area_p->x2;
         vdb_p->area.y1 = row;
         vdb_p->area.y2 = row + max_row - 1;
-
+        row_last = row + max_row - 1;
         lv_refr_area_part_vdb(area_p);
     }
     
     /*If the last y coordinates are not handled yet ...*/
-    if(area_p->y2 != vdb_p->area.y2) {
+    if(area_p->y2 != row_last) {
+        lv_vdb_t * vdb_p = lv_vdb_get();
+
         /*Calc. the next y coordinates of VDB*/
+        vdb_p->area.x1 = area_p->x1;
+        vdb_p->area.x2 = area_p->x2;
         vdb_p->area.y1 = row;
         vdb_p->area.y2 = area_p->y2;
 

lv_obj/lv_vdb.c

@@ -20,7 +20,13 @@
 /**********************
  *      TYPEDEFS
  **********************/
-
+#if LV_VDB_DOUBLE != 0
+typedef enum {
+    LV_VDB_STATE_FREE = 0,
+    LV_VDB_STATE_ACTIVE,
+    LV_VDB_STATE_FLUSH,
+} lv_vdb_state_t;
+#endif
 /**********************
  *  STATIC PROTOTYPES
  **********************/
@@ -28,7 +34,12 @@
 /**********************
  *  STATIC VARIABLES
  **********************/
+#if LV_VDB_DOUBLE == 0
 static lv_vdb_t vdb;
+#else
+static lv_vdb_t vdb[2];
+static volatile lv_vdb_state_t vdb_state[2] = {LV_VDB_STATE_FREE, LV_VDB_STATE_FREE};
+#endif
 
 /**********************
  *      MACROS
@@ -39,21 +50,53 @@ static lv_vdb_t vdb;
  **********************/
 
 /**
- * Get the vdb variable
- * @return pointer to the vdb variable
+ * Get the 'vdb' variable or allocate one in LV_VDB_DOUBLE mode
+ * @return pointer to the 'vdb' variable
  */
 lv_vdb_t * lv_vdb_get(void)
 {
+#if LV_VDB_DOUBLE == 0
     return &vdb;
+#else
+    /*If already there is an active do nothing*/
+    if(vdb_state[0] == LV_VDB_STATE_ACTIVE) return &vdb[0];
+    if(vdb_state[1] == LV_VDB_STATE_ACTIVE) return &vdb[1];
+
+    /*Try to allocate a free VDB*/
+    if(vdb_state[0] == LV_VDB_STATE_FREE) {
+        vdb_state[0] = LV_VDB_STATE_ACTIVE;
+        return &vdb[0];
+    }
+
+    if(vdb_state[1] == LV_VDB_STATE_FREE) {
+        vdb_state[1] = LV_VDB_STATE_ACTIVE;
+        return &vdb[1];
+    }
+
+    return NULL;   /*There wasn't free VDB (never happen)*/
+#endif
 }
 
 /**
- * Flush the content of the vdb
+ * Flush the content of the VDB
  */
 void lv_vdb_flush(void)
 {
+    lv_vdb_t * vdb_act = lv_vdb_get();
+    if(vdb_act == NULL) return;
+
+#if LV_VDB_DOUBLE != 0
+    /* Wait the pending flush before starting this one
+     * (Don't forget: 'lv_vdb_flush_ready' has to be called when flushing is ready)*/
+    while(vdb_state[0] == LV_VDB_STATE_FLUSH || vdb_state[1] == LV_VDB_STATE_FLUSH);
+
+    /*Turn the active VDB to flushing*/
+    if(vdb_state[0] == LV_VDB_STATE_ACTIVE) vdb_state[0] = LV_VDB_STATE_FLUSH;
+    if(vdb_state[1] == LV_VDB_STATE_ACTIVE) vdb_state[1] = LV_VDB_STATE_FLUSH;
+#endif
+
 #if LV_ANTIALIAS == 0
-	disp_map(vdb.area.x1, vdb.area.y1, vdb.area.x2, vdb.area.y2, vdb.buf);
+	disp_map(vdb_act->area.x1, vdb_act->area.y1, vdb_act->area.x2, vdb_act->area.y2, vdb_act->buf);
 #else
 	/* Get the average of 2x2 pixels and put the result back to the VDB
 	 * The reading goes much faster then the write back
@@ -68,12 +111,12 @@ void lv_vdb_flush(void)
 	 * */
 	cord_t x;
 	cord_t y;
-	cord_t w = area_get_width(&vdb.area);
-	color_t * in1_buf = vdb.buf;      /*Pointer to the first row*/
-    color_t * in2_buf = vdb.buf + w;  /*Pointer to the second row*/
-    color_t * out_buf = vdb.buf;      /*Store the result here*/
-	for(y = vdb.area.y1; y < vdb.area.y2; y += 2) {
-        for(x = vdb.area.x1; x < vdb.area.x2; x += 2) {
+	cord_t w = area_get_width(&vdb_act->area);
+	color_t * in1_buf = vdb_act->buf;      /*Pointer to the first row*/
+    color_t * in2_buf = vdb_act->buf + w;  /*Pointer to the second row*/
+    color_t * out_buf = vdb_act->buf;      /*Store the result here*/
+	for(y = vdb_act->area.y1; y < vdb_act->area.y2; y += 2) {
+        for(x = vdb_act->area.x1; x < vdb_act->area.x2; x += 2) {
         
             /*If the pixels are the same do not calculate the average */
             if(in1_buf->full == (in1_buf + 1)->full &&
@@ -103,7 +146,19 @@ void lv_vdb_flush(void)
 
 	/* Now the full the VDB is filtered and the result is stored in the first quarter of it
 	 * Write out the filtered map to the display*/
-    disp_map(vdb.area.x1 >> 1, vdb.area.y1 >> 1, vdb.area.x2 >> 1, vdb.area.y2 >> 1, vdb.buf);
+    disp_map(vdb_act->area.x1 >> 1, vdb_act->area.y1 >> 1, vdb_act->area.x2 >> 1, vdb_act->area.y2 >> 1, vdb_act->buf);
+#endif
+}
+
+/**
+ * In 'LV_VDB_DOUBLE' mode  has to be called when the 'disp_map'
+ * is ready with copying the map to a frame buffer.
+ */
+void lv_vdb_flush_ready(void)
+{
+#if LV_VDB_DOUBLE != 0
+    if(vdb_state[0] == LV_VDB_STATE_FLUSH)  vdb_state[0] = LV_VDB_STATE_FREE;
+    if(vdb_state[1] == LV_VDB_STATE_FLUSH)  vdb_state[1] = LV_VDB_STATE_FREE;
 #endif
 }
 

lv_obj/lv_vdb.h

@@ -34,15 +34,13 @@ typedef struct
     color_t buf[LV_VDB_SIZE];
 }lv_vdb_t;
 
-
-
 /**********************
  * GLOBAL PROTOTYPES
  **********************/
 
 /**
- * Get the vdb variable
- * @return pointer to the vdb variable
+ * Get the 'vdb' variable or allocate one in LV_VDB_DOUBLE mode
+ * @return pointer to the 'vdb' variable
  */
 lv_vdb_t * lv_vdb_get(void);
 
@@ -51,6 +49,13 @@ lv_vdb_t * lv_vdb_get(void);
  */
 void lv_vdb_flush(void);
 
+
+/**
+ * In 'LV_VDB_DOUBLE' mode  has to be called when 'disp_map()'
+ * is ready with copying the map to a frame buffer.
+ */
+void lv_vdb_flush_ready(void);
+
 /**********************
  *      MACROS
  **********************/