ardupilot/libraries/AP_Terrain/TerrainGCS.cpp
Peter Barker 541cfa022b AP_Terrain: fix bad prearms-pass-when-they-shouldn't issue
The squares surrounding the current location were only checked when we went to send a terrain request.  This means it was possible that:
 - the number of pending requests could go to zero
 - prearm checks would pass
 - vehicle arm is attempted by the user (or a script, or ....)
 - the code would call AP_Terrain::send_requests which would create more pending requests
 - the arming sequence would fail

It's also possible for the arming to succeed, and then we're flying in violation of the intended prearm checks.

Doing things in the update function has the additional advantage of making things more efficient as we can push out terrain requests more often.
2022-08-09 14:31:14 +10:00

328 lines
9.7 KiB
C++

/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
handle vehicle <-> GCS communications for terrain library
*/
#include "AP_Terrain.h"
#include <AP_AHRS/AP_AHRS.h>
#include <AP_HAL/AP_HAL.h>
#include <AP_Common/AP_Common.h>
#include <AP_Math/AP_Math.h>
#include <GCS_MAVLink/GCS_MAVLink.h>
#include <GCS_MAVLink/GCS.h>
#if AP_TERRAIN_AVAILABLE
#include <assert.h>
#include <stdio.h>
extern const AP_HAL::HAL& hal;
/*
request any missing 4x4 grids from a block, given a grid_cache
*/
bool AP_Terrain::request_missing(mavlink_channel_t chan, struct grid_cache &gcache)
{
struct grid_block &grid = gcache.grid;
if (options.get() & uint16_t(Options::DisableDownload)) {
return false;
}
if (grid.spacing != grid_spacing) {
// an invalid grid
return false;
}
// see if we are waiting for disk read
if (gcache.state == GRID_CACHE_DISKWAIT) {
// don't request data from the GCS till we know it's not on disk
return false;
}
// see if it is fully populated
if ((grid.bitmap & bitmap_mask) == bitmap_mask) {
// it is fully populated, nothing to do
return false;
}
if (!HAVE_PAYLOAD_SPACE(chan, TERRAIN_REQUEST)) {
// not enough buffer space
return false;
}
/*
ask the GCS to send a set of 4x4 grids
*/
mavlink_msg_terrain_request_send(chan, grid.lat, grid.lon, grid_spacing, bitmap_mask & ~grid.bitmap);
last_request_time_ms[chan] = AP_HAL::millis();
return true;
}
/*
request any missing 4x4 grids from a block
*/
bool AP_Terrain::request_missing(mavlink_channel_t chan, const struct grid_info &info)
{
// find the grid
struct grid_cache &gcache = find_grid_cache(info);
return request_missing(chan, gcache);
}
/*
send any pending cache requests
*/
bool AP_Terrain::send_cache_request(mavlink_channel_t chan)
{
for (uint16_t i=0; i<cache_size; i++) {
if (cache[i].state >= GRID_CACHE_VALID) {
if (request_missing(chan, cache[i])) {
return true;
}
}
}
return false;
}
/*
send any pending terrain request to the GCS
*/
void AP_Terrain::send_request(mavlink_channel_t chan)
{
if (!allocate()) {
// not enabled
return;
}
// see if we need to schedule some disk IO
schedule_disk_io();
Location loc;
if (!AP::ahrs().get_location(loc)) {
// we don't know where we are. Send a report and request any cached blocks.
// this allows for download of mission items when we have no GPS lock
loc = {};
send_terrain_report(chan, loc, true);
send_cache_request(chan);
return;
}
// always send a terrain report
send_terrain_report(chan, loc, true);
// did we request recently?
if (AP_HAL::millis() - last_request_time_ms[chan] < 2000) {
// too soon to request again
return;
}
// request any missing 4x4 blocks in the current grid
struct grid_info info;
calculate_grid_info(loc, info);
if (request_missing(chan, info)) {
return;
}
// check cache blocks that may have been setup by a TERRAIN_CHECK,
// mission items, rally items, squares surrounding our current
// location, favourite holiday destination, scripting, height
// reference location, ....
if (send_cache_request(chan)) {
return;
}
// request the current loc last to ensure it has highest last
// access time
if (request_missing(chan, info)) {
return;
}
}
/*
count bits in a uint64_t
*/
uint8_t AP_Terrain::bitcount64(uint64_t b) const
{
return __builtin_popcount((unsigned)(b&0xFFFFFFFF)) + __builtin_popcount((unsigned)(b>>32));
}
/*
get some statistics for TERRAIN_REPORT
*/
void AP_Terrain::get_statistics(uint16_t &pending, uint16_t &loaded) const
{
pending = 0;
loaded = 0;
for (uint16_t i=0; i<cache_size; i++) {
if (cache[i].grid.spacing != grid_spacing) {
continue;
}
if (cache[i].state == GRID_CACHE_INVALID) {
continue;
}
uint8_t maskbits = TERRAIN_GRID_BLOCK_MUL_X*TERRAIN_GRID_BLOCK_MUL_Y;
if (cache[i].state == GRID_CACHE_DISKWAIT) {
pending += maskbits;
continue;
}
if (cache[i].state == GRID_CACHE_DIRTY) {
// count dirty grids as a pending, so we know where there
// are disk writes pending
pending++;
}
uint8_t bitcount = bitcount64(cache[i].grid.bitmap);
pending += maskbits - bitcount;
loaded += bitcount;
}
}
/*
handle terrain messages from GCS
*/
void AP_Terrain::handle_data(mavlink_channel_t chan, const mavlink_message_t &msg)
{
if (msg.msgid == MAVLINK_MSG_ID_TERRAIN_DATA) {
handle_terrain_data(msg);
} else if (msg.msgid == MAVLINK_MSG_ID_TERRAIN_CHECK) {
handle_terrain_check(chan, msg);
}
}
/*
send a TERRAIN_REPORT for a location
*/
void AP_Terrain::send_terrain_report(mavlink_channel_t chan, const Location &loc, bool extrapolate)
{
float terrain_height = 0;
float home_terrain_height = 0;
uint16_t spacing = 0;
Location current_loc;
const AP_AHRS &ahrs = AP::ahrs();
if (ahrs.get_location(current_loc) &&
height_amsl(ahrs.get_home(), home_terrain_height) &&
height_amsl(loc, terrain_height)) {
// non-zero spacing indicates we have data
spacing = grid_spacing;
} else if (extrapolate && have_current_loc_height) {
// show the extrapolated height, so logs show what height is
// being used for navigation
terrain_height = last_current_loc_height;
} else {
// report terrain height if we can, but can't give current_height
height_amsl(loc, terrain_height);
}
uint16_t pending, loaded;
get_statistics(pending, loaded);
float current_height = 0.0f;
if (spacing == 0 && !(extrapolate && have_current_loc_height)) {
current_height = 0;
} else if (!current_loc.is_zero()) {
int32_t height_above_home_cm = 0;
UNUSED_RESULT(current_loc.get_alt_cm(Location::AltFrame::ABOVE_HOME, height_above_home_cm));
current_height = height_above_home_cm * 0.01f; // cm -> m
}
current_height += home_terrain_height - terrain_height;
if (HAVE_PAYLOAD_SPACE(chan, TERRAIN_REPORT)) {
mavlink_msg_terrain_report_send(chan, loc.lat, loc.lng, spacing,
terrain_height, current_height,
pending, loaded);
}
}
/*
handle TERRAIN_CHECK messages from GCS
*/
void AP_Terrain::handle_terrain_check(mavlink_channel_t chan, const mavlink_message_t &msg)
{
mavlink_terrain_check_t packet;
mavlink_msg_terrain_check_decode(&msg, &packet);
Location loc;
loc.lat = packet.lat;
loc.lng = packet.lon;
send_terrain_report(chan, loc, false);
}
/*
handle TERRAIN_DATA messages from GCS
*/
void AP_Terrain::handle_terrain_data(const mavlink_message_t &msg)
{
mavlink_terrain_data_t packet;
mavlink_msg_terrain_data_decode(&msg, &packet);
uint16_t i;
for (i=0; i<cache_size; i++) {
if (TERRAIN_LATLON_EQUAL(cache[i].grid.lat,packet.lat) &&
TERRAIN_LATLON_EQUAL(cache[i].grid.lon,packet.lon) &&
cache[i].grid.spacing == packet.grid_spacing &&
grid_spacing == packet.grid_spacing &&
packet.gridbit < 56) {
break;
}
}
if (i == cache_size) {
// we don't have that grid, ignore data
return;
}
struct grid_cache &gcache = cache[i];
struct grid_block &grid = gcache.grid;
uint8_t idx_x = (packet.gridbit / TERRAIN_GRID_BLOCK_MUL_Y) * TERRAIN_GRID_MAVLINK_SIZE;
uint8_t idx_y = (packet.gridbit % TERRAIN_GRID_BLOCK_MUL_Y) * TERRAIN_GRID_MAVLINK_SIZE;
ASSERT_RANGE(idx_x,0,(TERRAIN_GRID_BLOCK_MUL_X-1)*TERRAIN_GRID_MAVLINK_SIZE);
ASSERT_RANGE(idx_y,0,(TERRAIN_GRID_BLOCK_MUL_Y-1)*TERRAIN_GRID_MAVLINK_SIZE);
for (uint8_t x=0; x<TERRAIN_GRID_MAVLINK_SIZE; x++) {
for (uint8_t y=0; y<TERRAIN_GRID_MAVLINK_SIZE; y++) {
grid.height[idx_x+x][idx_y+y] = packet.data[x*TERRAIN_GRID_MAVLINK_SIZE+y];
}
}
gcache.grid.bitmap |= ((uint64_t)1) << packet.gridbit;
// mark dirty for disk IO
gcache.state = GRID_CACHE_DIRTY;
#if TERRAIN_DEBUG
hal.console->printf("Filled bit %u idx_x=%u idx_y=%u\n",
(unsigned)packet.gridbit, (unsigned)idx_x, (unsigned)idx_y);
if (gcache.grid.bitmap == bitmap_mask) {
hal.console->printf("--lat=%12.7f --lon=%12.7f %u\n",
grid.lat*1.0e-7f,
grid.lon*1.0e-7f,
grid.height[0][0]);
Location loc2;
loc2.lat = grid.lat;
loc2.lng = grid.lon;
loc2.offset(28*grid_spacing, 32*grid_spacing);
hal.console->printf("--lat=%12.7f --lon=%12.7f %u\n",
loc2.lat*1.0e-7f,
loc2.lng*1.0e-7f,
grid.height[27][31]);
}
#endif
// see if we need to schedule some disk IO
update();
}
#endif // AP_TERRAIN_AVAILABLE