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ardupilot/libraries/AP_Terrain/AP_Terrain.cpp

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// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
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/>.
*/
#include <AP_HAL.h>
#include <AP_Common.h>
#include <AP_Math.h>
#include <GCS_MAVLink.h>
#include <GCS.h>
#include "AP_Terrain.h"
#if HAVE_AP_TERRAIN
#include <assert.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#define TERRAIN_DEBUG 0
extern const AP_HAL::HAL& hal;
// table of user settable parameters
const AP_Param::GroupInfo AP_Terrain::var_info[] PROGMEM = {
// @Param: ENABLE
// @DisplayName: Terrain following enable
// @Description: enable terrain following
// @Values: 0:Disable,1:Enable
AP_GROUPINFO("ENABLE", 0, AP_Terrain, enable, 0),
// @Param: SPACING
// @DisplayName: Terrain grid spacing
// @Description: distance between terrain grid points in meters
// @Units: meters
// @Increment: 1
AP_GROUPINFO("SPACING", 1, AP_Terrain, grid_spacing, 100),
AP_GROUPEND
};
// constructor
AP_Terrain::AP_Terrain(AP_AHRS &_ahrs) :
ahrs(_ahrs),
last_request_time_ms(0),
disk_io_state(DiskIoIdle),
fd(-1),
timer_setup(false),
file_lat_degrees(0),
file_lon_degrees(0),
io_failure(false),
directory_created(false)
{
AP_Param::setup_object_defaults(this, var_info);
}
#if TERRAIN_DEBUG
#define ASSERT_RANGE(v,minv,maxv) assert((v)<=(maxv)&&(v)>=(minv))
#else
#define ASSERT_RANGE(v,minv,maxv)
#endif
/*
calculate bit number in grid_block bitmap. This corresponds to a
bit representing a 4x4 mavlink transmitted block
*/
uint8_t AP_Terrain::grid_bitnum(uint8_t idx_x, uint8_t idx_y)
{
ASSERT_RANGE(idx_x,0,27);
ASSERT_RANGE(idx_y,0,31);
uint8_t subgrid_x = idx_x / TERRAIN_GRID_MAVLINK_SIZE;
uint8_t subgrid_y = idx_y / TERRAIN_GRID_MAVLINK_SIZE;
ASSERT_RANGE(subgrid_x,0,TERRAIN_GRID_BLOCK_MUL_X-1);
ASSERT_RANGE(subgrid_y,0,TERRAIN_GRID_BLOCK_MUL_Y-1);
return subgrid_y + TERRAIN_GRID_BLOCK_MUL_Y*subgrid_x;
}
/*
given a grid_info check that a given idx_x/idx_y is available (set
in the bitmap)
*/
bool AP_Terrain::check_bitmap(const struct grid_block &grid, uint8_t idx_x, uint8_t idx_y)
{
uint8_t bitnum = grid_bitnum(idx_x, idx_y);
return (grid.bitmap & (((uint64_t)1U)<<bitnum)) != 0;
}
/*
given a location, calculate the 32x28 grid SW corner, plus the
grid indices
*/
void AP_Terrain::calculate_grid_info(const Location &loc, struct grid_info &info) const
{
// grids start on integer degrees. This makes storing terrain data
// on the SD card a bit easier
info.lat_degrees = (loc.lat<0?(loc.lat-9999999L):loc.lat) / (10*1000*1000L);
info.lon_degrees = (loc.lng<0?(loc.lng-9999999L):loc.lng) / (10*1000*1000L);
// create reference position for this rounded degree position
Location ref;
ref.lat = info.lat_degrees*10*1000*1000L;
ref.lng = info.lon_degrees*10*1000*1000L;
// find offset from reference
Vector2f offset = location_diff(ref, loc);
// get indices in terms of grid_spacing elements
uint32_t idx_x = offset.x / grid_spacing;
uint32_t idx_y = offset.y / grid_spacing;
// find indexes into 32*28 grids for this degree reference. Note
// the use of TERRAIN_GRID_BLOCK_SPACING_{X,Y} which gives a one square
// overlap between grids
info.grid_idx_x = idx_x / TERRAIN_GRID_BLOCK_SPACING_X;
info.grid_idx_y = idx_y / TERRAIN_GRID_BLOCK_SPACING_Y;
// find the indices within the 32*28 grid
info.idx_x = idx_x % TERRAIN_GRID_BLOCK_SPACING_X;
info.idx_y = idx_y % TERRAIN_GRID_BLOCK_SPACING_Y;
// find the fraction (0..1) within the square
info.frac_x = (offset.x - idx_x * grid_spacing) / grid_spacing;
info.frac_y = (offset.y - idx_y * grid_spacing) / grid_spacing;
// calculate lat/lon of SW corner of 32*28 grid_block
location_offset(ref,
info.grid_idx_x * TERRAIN_GRID_BLOCK_SPACING_X * (float)grid_spacing,
info.grid_idx_y * TERRAIN_GRID_BLOCK_SPACING_Y * (float)grid_spacing);
info.grid_lat = ref.lat;
info.grid_lon = ref.lng;
ASSERT_RANGE(info.idx_x,0,TERRAIN_GRID_BLOCK_SPACING_X-1);
ASSERT_RANGE(info.idx_y,0,TERRAIN_GRID_BLOCK_SPACING_Y-1);
ASSERT_RANGE(info.frac_x,0,1);
ASSERT_RANGE(info.frac_y,0,1);
}
/*
find a grid structure given a grid_info
*/
AP_Terrain::grid_cache &AP_Terrain::find_grid(const struct grid_info &info)
{
uint16_t oldest_i = 0;
// see if we have that grid
for (uint16_t i=0; i<TERRAIN_GRID_BLOCK_CACHE_SIZE; i++) {
if (cache[i].grid.lat == info.grid_lat &&
cache[i].grid.lon == info.grid_lon &&
cache[i].grid.spacing == grid_spacing) {
cache[i].last_access_ms = hal.scheduler->millis();
return cache[i];
}
if (cache[i].last_access_ms < cache[oldest_i].last_access_ms) {
oldest_i = i;
}
}
// Not found. Use the oldest grid and make it this grid,
// initially unpopulated
struct grid_cache &grid = cache[oldest_i];
memset(&grid, 0, sizeof(grid));
grid.grid.lat = info.grid_lat;
grid.grid.lon = info.grid_lon;
grid.grid.spacing = grid_spacing;
grid.grid.grid_idx_x = info.grid_idx_x;
grid.grid.grid_idx_y = info.grid_idx_y;
grid.grid.lat_degrees = info.lat_degrees;
grid.grid.lon_degrees = info.lon_degrees;
grid.grid.version = TERRAIN_GRID_FORMAT_VERSION;
grid.last_access_ms = hal.scheduler->millis();
// mark as waiting for disk read
grid.state = GRID_CACHE_DISKWAIT;
return grid;
}
/*
return terrain height in meters above average sea level (WGS84) for
a given position
*/
bool AP_Terrain::height_amsl(const Location &loc, float &height)
{
if (!enable) {
return false;
}
struct grid_info info;
calculate_grid_info(loc, info);
// find the grid
const struct grid_block &grid = find_grid(info).grid;
/*
note that we rely on the one square overlap to ensure these
calculations don't go past the end of the arrays
*/
ASSERT_RANGE(info.idx_x, 0, TERRAIN_GRID_BLOCK_SIZE_X-2);
ASSERT_RANGE(info.idx_y, 0, TERRAIN_GRID_BLOCK_SIZE_Y-2);
// check we have all 4 required heights
if (!check_bitmap(grid, info.idx_x, info.idx_y) ||
!check_bitmap(grid, info.idx_x, info.idx_y+1) ||
!check_bitmap(grid, info.idx_x+1, info.idx_y) ||
!check_bitmap(grid, info.idx_x+1, info.idx_y+1)) {
return false;
}
// hXY are the heights of the 4 surrounding grid points
int16_t h00, h01, h10, h11;
h00 = grid.height[info.idx_x+0][info.idx_y+0];
h01 = grid.height[info.idx_x+0][info.idx_y+1];
h10 = grid.height[info.idx_x+1][info.idx_y+0];
h11 = grid.height[info.idx_x+1][info.idx_y+1];
float avg1 = (1.0f-info.frac_x) * h00 + info.frac_x * h10;
float avg2 = (1.0f-info.frac_x) * h01 + info.frac_x * h11;
float avg = (1.0f-info.frac_y) * avg1 + info.frac_y * avg2;
height = avg;
return true;
}
/*
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;
// see if we are waiting for disk read
if (gcache.state == GRID_CACHE_DISKWAIT) {
// don't request data from the GCS till we know its 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;
}
/*
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 = hal.scheduler->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(info);
return request_missing(chan, gcache);
}
/*
send any pending terrain request to the GCS
*/
void AP_Terrain::send_request(mavlink_channel_t chan)
{
if (enable == 0) {
// not enabled
return;
}
// see if we need to schedule some disk IO
update();
// did we request recently?
if (hal.scheduler->millis() - last_request_time_ms < 2000) {
// too soon to request again
return;
}
Location loc;
if (!ahrs.get_position(loc)) {
// we don't know where we are
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;
}
// also request a larger set of up to 9 grids
for (int8_t x=-1; x<=1; x++) {
for (int8_t y=-1; y<=1; y++) {
Location loc2 = loc;
location_offset(loc2,
x*TERRAIN_GRID_BLOCK_SIZE_X*0.7f*grid_spacing,
y*TERRAIN_GRID_BLOCK_SIZE_Y*0.7f*grid_spacing);
struct grid_info info2;
calculate_grid_info(loc2, info2);
if (request_missing(chan, info2)) {
return;
}
}
}
// check cache blocks that may have been setup by a TERRAIN_CHECK
for (uint16_t i=0; i<TERRAIN_GRID_BLOCK_CACHE_SIZE; i++) {
if (cache[i].state >= GRID_CACHE_VALID) {
if (request_missing(chan, cache[i])) {
return;
}
}
}
// request the current loc last to ensure it has highest last
// access time
if (request_missing(chan, info)) {
return;
}
// nothing to request, send a terrain report
send_terrain_report(chan, loc);
}
/*
count bits in a uint64_t
*/
uint8_t AP_Terrain::bitcount64(uint64_t b)
{
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)
{
pending = 0;
loaded = 0;
for (uint16_t i=0; i<TERRAIN_GRID_BLOCK_CACHE_SIZE; i++) {
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;
}
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, 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)
{
float height = 0;
uint16_t spacing = 0;
if (height_amsl(loc, height)) {
spacing = grid_spacing;
}
uint16_t pending, loaded;
get_statistics(pending, loaded);
if (comm_get_txspace(chan) >= MAVLINK_NUM_NON_PAYLOAD_BYTES + MAVLINK_MSG_ID_TERRAIN_REPORT_LEN) {
mavlink_msg_terrain_report_send(chan, loc.lat, loc.lng, spacing, height, pending, loaded);
}
}
/*
handle TERRAIN_CHECK messages from GCS
*/
void AP_Terrain::handle_terrain_check(mavlink_channel_t chan, 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);
}
/*
handle TERRAIN_DATA messages from GCS
*/
void AP_Terrain::handle_terrain_data(mavlink_message_t *msg)
{
mavlink_terrain_data_t packet;
mavlink_msg_terrain_data_decode(msg, &packet);
uint16_t i;
for (i=0; i<TERRAIN_GRID_BLOCK_CACHE_SIZE; i++) {
if (cache[i].grid.lat == packet.lat &&
cache[i].grid.lon == packet.lon &&
cache[i].grid.spacing == packet.grid_spacing &&
packet.gridbit < 56) {
break;
}
}
if (i == TERRAIN_GRID_BLOCK_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];
ASSERT_RANGE(grid.height[idx_x+x][idx_y+y], 1, 20000);
}
}
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;
location_offset(loc2, 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();
}
/*
find cache index of disk_block
*/
int16_t AP_Terrain::find_io_idx(enum GridCacheState state)
{
// try first with given state
for (uint16_t i=0; i<TERRAIN_GRID_BLOCK_CACHE_SIZE; i++) {
if (disk_block.block.lat == cache[i].grid.lat &&
disk_block.block.lon == cache[i].grid.lon &&
cache[i].state == state) {
return i;
}
}
// then any state
for (uint16_t i=0; i<TERRAIN_GRID_BLOCK_CACHE_SIZE; i++) {
if (disk_block.block.lat == cache[i].grid.lat &&
disk_block.block.lon == cache[i].grid.lon) {
return i;
}
}
return -1;
}
/*
check for blocks that need to be read from disk
*/
void AP_Terrain::check_disk_read(void)
{
for (uint16_t i=0; i<TERRAIN_GRID_BLOCK_CACHE_SIZE; i++) {
if (cache[i].state == GRID_CACHE_DISKWAIT) {
disk_block.block = cache[i].grid;
disk_io_state = DiskIoWaitRead;
return;
}
}
}
/*
check for blocks that need to be written to disk
*/
void AP_Terrain::check_disk_write(void)
{
for (uint16_t i=0; i<TERRAIN_GRID_BLOCK_CACHE_SIZE; i++) {
if (cache[i].state == GRID_CACHE_DIRTY) {
disk_block.block = cache[i].grid;
disk_io_state = DiskIoWaitWrite;
return;
}
}
}
/*
update terrain data. Check if we need to do disk IO for grids. This
should be called at around 1Hz
*/
void AP_Terrain::update(void)
{
if (enable == 0) {
return;
}
if (!timer_setup) {
timer_setup = true;
hal.scheduler->register_io_process(AP_HAL_MEMBERPROC(&AP_Terrain::io_timer));
}
switch (disk_io_state) {
case DiskIoIdle:
// look for a block that needs reading or writing
check_disk_read();
if (disk_io_state == DiskIoIdle) {
// still idle, check for writes
check_disk_write();
}
break;
case DiskIoDoneRead: {
// a read has completed
int16_t cache_idx = find_io_idx(GRID_CACHE_DISKWAIT);
if (cache_idx != -1) {
if (disk_block.block.bitmap != 0) {
// when bitmap is zero we read an empty block
cache[cache_idx].grid = disk_block.block;
}
cache[cache_idx].state = GRID_CACHE_VALID;
cache[cache_idx].last_access_ms = hal.scheduler->millis();
}
disk_io_state = DiskIoIdle;
break;
}
case DiskIoDoneWrite: {
// a write has completed
int16_t cache_idx = find_io_idx(GRID_CACHE_DIRTY);
if (cache_idx != -1) {
if (cache[cache_idx].grid.bitmap == disk_block.block.bitmap) {
// only mark valid if more grids haven't been added
cache[cache_idx].state = GRID_CACHE_VALID;
}
}
disk_io_state = DiskIoIdle;
break;
}
case DiskIoWaitWrite:
case DiskIoWaitRead:
// waiting for io_timer()
break;
}
Location loc;
if (!ahrs.get_position(loc)) {
// we don't know where we are
return;
}
#if TERRAIN_DEBUG
static uint32_t last_report_ms;
float height;
if (hal.scheduler->millis() - last_report_ms > 1000 && height_amsl(loc, height)) {
printf("height %.2f\n", height);
last_report_ms = hal.scheduler->millis();
}
#endif
}
/*
get CRC for a block
*/
uint16_t AP_Terrain::get_block_crc(struct grid_block &block)
{
uint16_t saved_crc = block.crc;
block.crc = 0;
uint16_t ret = crc16_ccitt((const uint8_t *)&block, sizeof(block), 0);
block.crc = saved_crc;
return ret;
}
/*
open the current degree file
*/
void AP_Terrain::open_file(void)
{
struct grid_block &block = disk_block.block;
if (fd != -1 &&
block.lat_degrees == file_lat_degrees &&
block.lon_degrees == file_lon_degrees) {
// already open on right file
return;
}
// build the pathname to the degree file
char path[] = HAL_BOARD_TERRAIN_DIRECTORY "/NxxExxx.DAT";
char *p = &path[strlen(HAL_BOARD_TERRAIN_DIRECTORY)+1];
snprintf(p, 12, "%c%02u%c%03u.DAT",
block.lat_degrees<0?'S':'N',
abs(block.lat_degrees),
block.lon_degrees<0?'W':'E',
abs(block.lon_degrees));
// create directory if need be
if (!directory_created) {
mkdir(HAL_BOARD_TERRAIN_DIRECTORY, 0755);
directory_created = true;
}
if (fd != -1) {
::close(fd);
}
fd = ::open(path, O_RDWR|O_CREAT, 0644);
if (fd == -1) {
#if TERRAIN_DEBUG
hal.console->printf("Open %s failed - %s\n",
path, strerror(errno));
#endif
io_failure = true;
return;
}
file_lat_degrees = block.lat_degrees;
file_lon_degrees = block.lon_degrees;
}
/*
seek to the right offset for disk_block
*/
void AP_Terrain::seek_offset(void)
{
struct grid_block &block = disk_block.block;
// work out how many longitude blocks there are at this latitude
Location loc1, loc2;
loc1.lat = block.lat_degrees*10*1000*1000L;
loc1.lng = block.lon_degrees*10*1000*1000L;
loc2.lat = block.lat_degrees*10*1000*1000L;
loc2.lng = (block.lon_degrees+1)*10*1000*1000L;
// shift another two blocks east to ensure room is available
location_offset(loc2, 0, 2*grid_spacing*TERRAIN_GRID_BLOCK_SIZE_Y);
Vector2f offset = location_diff(loc1, loc2);
uint16_t east_blocks = offset.y / (grid_spacing*TERRAIN_GRID_BLOCK_SIZE_Y);
uint32_t file_offset = (east_blocks * block.grid_idx_x +
block.grid_idx_y) * sizeof(union grid_io_block);
if (::lseek(fd, file_offset, SEEK_SET) != file_offset) {
#if TERRAIN_DEBUG
hal.console->printf("Seek %lu failed - %s\n",
(unsigned long)file_offset, strerror(errno));
#endif
::close(fd);
fd = -1;
io_failure = true;
}
}
/*
write out disk_block
*/
void AP_Terrain::write_block(void)
{
seek_offset();
if (io_failure) {
return;
}
disk_block.block.crc = get_block_crc(disk_block.block);
ssize_t ret = ::write(fd, &disk_block, sizeof(disk_block));
if (ret != sizeof(disk_block)) {
#if TERRAIN_DEBUG
hal.console->printf("write failed - %s\n", strerror(errno));
#endif
::close(fd);
fd = -1;
io_failure = true;
} else {
::fsync(fd);
#if TERRAIN_DEBUG
printf("wrote block at %ld %ld ret=%d mask=%07llx\n",
(long)disk_block.block.lat,
(long)disk_block.block.lon,
(int)ret,
(unsigned long long)disk_block.block.bitmap);
#endif
}
disk_io_state = DiskIoDoneWrite;
}
/*
read in disk_block
*/
void AP_Terrain::read_block(void)
{
seek_offset();
if (io_failure) {
return;
}
int32_t lat = disk_block.block.lat;
int32_t lon = disk_block.block.lon;
ssize_t ret = ::read(fd, &disk_block, sizeof(disk_block));
if (ret != sizeof(disk_block) ||
disk_block.block.lat != lat ||
disk_block.block.lon != lon ||
disk_block.block.bitmap == 0 ||
disk_block.block.spacing != grid_spacing ||
disk_block.block.version != TERRAIN_GRID_FORMAT_VERSION ||
disk_block.block.crc != get_block_crc(disk_block.block)) {
#if TERRAIN_DEBUG
printf("read empty block at %ld %ld ret=%d\n",
(long)lat,
(long)lon,
(int)ret);
#endif
// a short read or bad data is not an IO failure, just a
// missing block on disk
memset(&disk_block, 0, sizeof(disk_block));
disk_block.block.lat = lat;
disk_block.block.lon = lon;
disk_block.block.bitmap = 0;
} else {
#if TERRAIN_DEBUG
printf("read block at %ld %ld ret=%d mask=%07llx\n",
(long)lat,
(long)lon,
(int)ret,
(unsigned long long)disk_block.block.bitmap);
#endif
}
disk_io_state = DiskIoDoneRead;
}
/*
timer called to do disk IO
*/
void AP_Terrain::io_timer(void)
{
if (io_failure) {
// don't keep trying io, so we don't thrash the filesystem
// code while flying
return;
}
switch (disk_io_state) {
case DiskIoIdle:
case DiskIoDoneRead:
case DiskIoDoneWrite:
// nothing to do
break;
case DiskIoWaitWrite:
// need to write out the block
open_file();
if (fd == -1) {
return;
}
write_block();
break;
case DiskIoWaitRead:
// need to read in the block
open_file();
if (fd == -1) {
return;
}
read_block();
break;
}
}
#endif // HAVE_AP_TERRAIN
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