[modules] dc: add dc_distance function

- use dc_gps_count in distance mode
- cleanup some variables

conf/modules/digital_cam.xml

@@ -14,6 +14,7 @@
 
     <define name="DC_AUTOSHOOT_QUARTERSEC_PERIOD" value="6" description="quarter_second"/>
     <define name="DC_AUTOSHOOT_DISTANCE_INTERVAL" value="50" description="distance interval for DC_AUTOSHOOT_DISTANCE in meters"/>
+    <define name="DC_AUTOSHOOT_SURVEY_INTERVAL" value="50" description="distance interval for DC_AUTOSHOOT_SURVEY in meters"/>
     <define name="DC_SHOT_SYNC_SEND" value="TRUE|FALSE" description="send DC_SHOT message when photo was taken (default: TRUE)"/>
   </doc>
   <settings>
@@ -33,9 +34,9 @@
         </dl_setting>
 
         <dl_setting max="255" min="1" step="1" var="dc_autoshoot_quartersec_period" shortname="Periodic" param="DC_AUTOSHOOT_QUARTERSEC_PERIOD" unit="quarter-sec"/>
-        <dl_setting max="255" min="0" step="1" var="dc_autoshoot_distance_interval" shortname="dist" param="DC_AUTOSHOOT_DISTANCE_INTERVAL" unit="meter"/>
+        <dl_setting max="255" min="0" step="1" var="dc_distance_interval" shortname="dist" param="DC_AUTOSHOOT_DISTANCE_INTERVAL" unit="meter"/>
 
-        <dl_setting max="250" min="0" step="5" module="digital_cam/dc" var="dc_gps_dist" handler="Survey" shortname="Linear-Interval"/>
+        <dl_setting max="250" min="0" step="5" module="digital_cam/dc" var="dc_survey_interval" handler="Survey" shortname="Survey-Interval"/>
         <dl_setting max="90" min="5" step="5" module="digital_cam/dc" var="dc_circle_interval" handler="Circle" shortname="Circle-Interval"/>
         <dl_setting max="1" min="0" step="1" var="dc_cam_tracing" shortname="Cam-Tracing"/>
       </dl_settings>

sw/airborne/modules/digital_cam/dc.c

@@ -46,11 +46,16 @@
 #define DC_AUTOSHOOT_QUARTERSEC_PERIOD 2
 #endif
 
-/** default distance interval 50m */
+/** default distance interval for distance mode: 50m */
 #ifndef DC_AUTOSHOOT_DISTANCE_INTERVAL
 #define DC_AUTOSHOOT_DISTANCE_INTERVAL 50
 #endif
 
+/** default distance interval for survey mode: 50m */
+#ifndef DC_AUTOSHOOT_SURVEY_INTERVAL
+#define DC_AUTOSHOOT_SURVEY_INTERVAL 50
+#endif
+
 // Variables with boot defaults
 dc_autoshoot_type dc_autoshoot = DC_AUTOSHOOT_STOP;
 uint16_t dc_gps_count = 0;
@@ -62,12 +67,14 @@ float dc_circle_start_angle = 0;
 float dc_circle_last_block = 0;
 float dc_circle_max_blocks = 0;
 
-float dc_gps_dist = 50;
+float dc_survey_interval = DC_AUTOSHOOT_SURVEY_INTERVAL;
 float dc_gps_next_dist = 0;
 float dc_gps_x = 0;
 float dc_gps_y = 0;
 
-uint8_t dc_autoshoot_distance_interval;
+static struct FloatVect2 last_shot_pos = {0.0, 0.0};
+float dc_distance_interval;
+
 uint8_t dc_autoshoot_quartersec_period;
 
 /** by default send DC_SHOT message when photo was taken */
@@ -121,7 +128,7 @@ void dc_init(void)
 {
   dc_autoshoot = DC_AUTOSHOOT_STOP;
   dc_autoshoot_quartersec_period = DC_AUTOSHOOT_QUARTERSEC_PERIOD;
-  dc_autoshoot_distance_interval = DC_AUTOSHOOT_DISTANCE_INTERVAL;
+  dc_distance_interval = DC_AUTOSHOOT_DISTANCE_INTERVAL;
 }
 
 uint8_t dc_info(void) {
@@ -135,7 +142,7 @@ uint8_t dc_info(void) {
                         &stateGetPositionLla_i()->alt,
                         &course,
                         &dc_photo_nr,
-                        &dc_gps_dist,
+                        &dc_survey_interval,
                         &dc_gps_next_dist,
                         &dc_gps_x,
                         &dc_gps_y,
@@ -148,6 +155,18 @@ uint8_t dc_info(void) {
   return 0;
 }
 
+/* shoot on distance */
+uint8_t dc_distance(float interval) {
+  dc_autoshoot = DC_AUTOSHOOT_DISTANCE;
+  dc_gps_count = 0;
+  dc_distance_interval = interval;
+  last_shot_pos.x = 0;
+  last_shot_pos.y = 0;
+
+  dc_info();
+  return 0;
+}
+
 /* shoot on circle */
 uint8_t dc_circle(float interval, float start) {
   dc_autoshoot = DC_AUTOSHOOT_CIRCLE;
@@ -172,7 +191,7 @@ uint8_t dc_circle(float interval, float start) {
 uint8_t dc_survey(float interval, float x, float y) {
   dc_autoshoot = DC_AUTOSHOOT_SURVEY;
   dc_gps_count = 0;
-  dc_gps_dist = interval;
+  dc_survey_interval = interval;
 
   if (x == DC_IGNORE && y == DC_IGNORE) {
     dc_gps_x = stateGetPositionEnu_f()->x;
@@ -222,14 +241,14 @@ void dc_periodic_4Hz(void)
 
     case DC_AUTOSHOOT_DISTANCE:
       {
-        static struct FloatVect2 last_shot_pos = {0.0, 0.0};
         struct FloatVect2 cur_pos;
         cur_pos.x = stateGetPositionEnu_f()->x;
         cur_pos.y = stateGetPositionEnu_f()->y;
         struct FloatVect2 delta_pos;
         VECT2_DIFF(delta_pos, cur_pos, last_shot_pos);
         float dist_to_last_shot = float_vect2_norm(&delta_pos);
-        if (dist_to_last_shot > dc_autoshoot_distance_interval) {
+        if (dist_to_last_shot > dc_distance_interval) {
+          dc_gps_count++;
           dc_send_command(DC_SHOOT);
           VECT2_COPY(last_shot_pos, cur_pos);
         }
@@ -257,7 +276,7 @@ void dc_periodic_4Hz(void)
         float dist_y = dc_gps_y - stateGetPositionEnu_f()->y;
 
         if (dist_x*dist_x + dist_y*dist_y >= dc_gps_next_dist*dc_gps_next_dist) {
-          dc_gps_next_dist += dc_gps_dist;
+          dc_gps_next_dist += dc_survey_interval;
           dc_gps_count++;
           dc_send_command(DC_SHOOT);
         }

sw/airborne/modules/digital_cam/dc.h

@@ -42,30 +42,52 @@
 #include "generated/airframe.h"
 #include "subsystems/gps.h"
 
+/** export the number of the last photo */
+extern uint16_t dc_photo_nr;
+
 /** number of images taken since the last change of dc_mode */
 extern uint16_t dc_gps_count;
 
-/** export the number of the last photo */
-extern uint16_t dc_photo_nr;
 
+/*
+ * Variables for PERIODIC mode.
+ */
+/** AutoShoot photos every X quarter_second */
+extern uint8_t dc_autoshoot_quartersec_period;
+
+
+/*
+ * Variables for DISTANCE mode.
+ */
+/** AutoShoot photos on distance to last shot in meters */
+extern float dc_distance_interval;
+
+
+/*
+ * Variables for SURVEY mode.
+ */
 /** distance between dc shots in meters */
-extern float dc_gps_dist;
+extern float dc_survey_interval;
+
+/** point of reference for the survey mode */
+extern float dc_gps_x, dc_gps_y;
 
 extern float dc_gps_next_dist;
 
+
+/*
+ * Variables for CIRCLE mode.
+ */
 /** angle a where first image will be taken at a + delta */
 extern float dc_circle_start_angle;
 
-/*' angle between dc shots in degree */
+/** angle between dc shots in degree */
 extern float dc_circle_interval;
 
 extern float dc_circle_max_blocks;
-
-/** point of reference for the distance based mode */
-extern float dc_gps_x, dc_gps_y;
-
 extern float dc_circle_last_block;
 
+
 /** camera angle */
 extern float dc_cam_angle;
 extern uint8_t dc_cam_tracing;
@@ -109,12 +131,6 @@ typedef enum {
 } dc_autoshoot_type;
 extern dc_autoshoot_type dc_autoshoot;
 
-/** AutoShoot photos every X quarter_second */
-extern uint8_t dc_autoshoot_quartersec_period;
-
-/** AutoShoot photos on distance to last shot in meters */
-extern uint8_t dc_autoshoot_distance_interval;
-
 /** Send Down the coordinates of where the photo was taken */
 void dc_send_shot_position(void);
 
@@ -138,6 +154,19 @@ extern void dc_init(void);
 /** periodic 4Hz function */
 extern void dc_periodic_4Hz(void);
 
+/**
+ * Sets the dc control in distance mode.
+ *
+ * Shoot the next pic if distance to last saved shot position
+ * is greater than @a interval.
+ *
+ * The first picture is taken at after @a interval.
+ *
+ * @param interval minimum distance between shots in m
+ * @return zero
+ */
+extern uint8_t dc_distance(float interval);
+
 /**
  * Sets the dc control in circle mode.
  *