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refactor: share lat/lon projection between radar and runway overlay #93

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20 changes: 20 additions & 0 deletions include/ui/radar_projection.h
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#pragma once

namespace ui::radar {

constexpr float kKmPerDeg = 111.0f;
constexpr float kDegToRad = 3.14159265f / 180.0f;

/** Offset of lat/lon from the radar center, in km. */
void offsetKmFromCenter(float lat, float lon, float* dx_km, float* dy_km,
float* dist_km);

/** Flat lat/lon as x/y: 1 deg ~ 111 km, north = screen up. */
void latLonToScreen(float lat, float lon, int* out_x, int* out_y);

int distSqFromCenter(int x, int y);

/** Pull (x1,y1) back along the segment from (x0,y0) until inside the ring. */
void clipPointToOuterRing(int x0, int y0, int* x1, int* y1);

} // namespace ui::radar
69 changes: 6 additions & 63 deletions src/ui/radar_display.cpp
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Expand Up @@ -11,6 +11,7 @@
#include "hardware/display_font.h"
#include "services/adsb_client.h"
#include "services/radar_location.h"
#include "ui/radar_projection.h"
#include "ui/radar_range.h"
#include "ui/radar_theme.h"
#include "ui/runway_overlay.h"
Expand All @@ -33,6 +34,11 @@ uint16_t kColorRunwayLabel = 0x7DFF;

namespace {

using radar::clipPointToOuterRing;
using radar::distSqFromCenter;
using radar::latLonToScreen;
using radar::offsetKmFromCenter;

bool s_label_metrics_ready = false;
bool s_cardinal_use_vlw = false;
bool s_scale_use_vlw = false;
Expand Down Expand Up @@ -197,51 +203,15 @@ void initPalette() {
radar::kRunwayLabelB);
}

constexpr float kKmPerDeg = 111.0f;
constexpr float kDegToRad = 3.14159265f / 180.0f;

void offsetKmFromCenter(float lat, float lon, float* dx_km, float* dy_km,
float* dist_km) {
// Longitude degrees shrink toward the poles; scale by cos(latitude) so
// east-west distance isn't overstated away from the equator.
const float center_lat_rad =
static_cast<float>(services::location::lat()) * kDegToRad;
*dx_km = static_cast<float>(lon - services::location::lon()) * kKmPerDeg *
cosf(center_lat_rad);
*dy_km =
static_cast<float>(lat - services::location::lat()) * kKmPerDeg;
*dist_km = sqrtf((*dx_km) * (*dx_km) + (*dy_km) * (*dy_km));
}

float innerRingMaxKm() {
const float outer_km = radar::rangeCurrent().outer_km;
return outer_km * (static_cast<float>(radar::kGridOuterRadius -
radar::kAircraftInsideRingInsetPx) /
static_cast<float>(radar::kGridOuterRadius));
}

/** Flat lat/lon as x/y: 1° ≈ 111 km, north = screen up. */
void latLonToScreen(float lat, float lon, int* out_x, int* out_y) {
const float outer_km = radar::rangeCurrent().outer_km;
const float px_per_km = static_cast<float>(radar::kGridOuterRadius) / outer_km;

float dx_km = 0.0f;
float dy_km = 0.0f;
float dist_km = 0.0f;
offsetKmFromCenter(lat, lon, &dx_km, &dy_km, &dist_km);

*out_x = radar::kCenterX + static_cast<int>(lroundf(dx_km * px_per_km));
*out_y = radar::kCenterY - static_cast<int>(lroundf(dy_km * px_per_km));
}

bool isInsideOuterRingKm(float dist_km) { return dist_km <= innerRingMaxKm(); }

int distSqFromCenter(int x, int y) {
const int dx = x - radar::kCenterX;
const int dy = y - radar::kCenterY;
return dx * dx + dy * dy;
}

bool isInsideOuterRing(int x, int y) {
const int max_r = radar::kGridOuterRadius - radar::kAircraftInsideRingInsetPx;
return distSqFromCenter(x, y) <= max_r * max_r;
Expand Down Expand Up @@ -275,33 +245,6 @@ void drawBeyondRingDot(int x, int y) {
radar::kColorAircraft);
}

void clipPointToOuterRing(int x0, int y0, int* x1, int* y1) {
const int max_r = radar::kGridOuterRadius;
const int max_r_sq = max_r * max_r;
if (distSqFromCenter(*x1, *y1) <= max_r_sq) {
return;
}

const int dx = *x1 - x0;
const int dy = *y1 - y0;
float t = 1.0f;
for (int step = 0; step < 20; ++step) {
const int px = x0 + static_cast<int>(lroundf(dx * t));
const int py = y0 + static_cast<int>(lroundf(dy * t));
if (distSqFromCenter(px, py) <= max_r_sq) {
*x1 = px;
*y1 = py;
return;
}
t -= 0.05f;
if (t <= 0.0f) {
*x1 = x0;
*y1 = y0;
return;
}
}
}

int speedLineLengthPx(float gs_knots) {
if (gs_knots <= 0.0f) {
return 0;
Expand Down
69 changes: 69 additions & 0 deletions src/ui/radar_projection.cpp
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@@ -0,0 +1,69 @@
#include "ui/radar_projection.h"

#include <cmath>

#include "services/radar_location.h"
#include "ui/radar_range.h"
#include "ui/radar_theme.h"

namespace ui::radar {

void offsetKmFromCenter(float lat, float lon, float* dx_km, float* dy_km,
float* dist_km) {
// Longitude degrees shrink toward the poles; scale by cos(latitude) so
// east-west distance isn't overstated away from the equator.
const float center_lat_rad =
static_cast<float>(services::location::lat()) * kDegToRad;
*dx_km = static_cast<float>(lon - services::location::lon()) * kKmPerDeg *
cosf(center_lat_rad);
*dy_km = static_cast<float>(lat - services::location::lat()) * kKmPerDeg;
*dist_km = sqrtf((*dx_km) * (*dx_km) + (*dy_km) * (*dy_km));
}

void latLonToScreen(float lat, float lon, int* out_x, int* out_y) {
const float outer_km = rangeCurrent().outer_km;
const float px_per_km = static_cast<float>(kGridOuterRadius) / outer_km;

float dx_km = 0.0f;
float dy_km = 0.0f;
float dist_km = 0.0f;
offsetKmFromCenter(lat, lon, &dx_km, &dy_km, &dist_km);

*out_x = kCenterX + static_cast<int>(lroundf(dx_km * px_per_km));
*out_y = kCenterY - static_cast<int>(lroundf(dy_km * px_per_km));
}

int distSqFromCenter(int x, int y) {
const int dx = x - kCenterX;
const int dy = y - kCenterY;
return dx * dx + dy * dy;
}

void clipPointToOuterRing(int x0, int y0, int* x1, int* y1) {
const int max_r = kGridOuterRadius;
const int max_r_sq = max_r * max_r;
if (distSqFromCenter(*x1, *y1) <= max_r_sq) {
return;
}

const int dx = *x1 - x0;
const int dy = *y1 - y0;
float t = 1.0f;
for (int step = 0; step < 20; ++step) {
const int px = x0 + static_cast<int>(lroundf(dx * t));
const int py = y0 + static_cast<int>(lroundf(dy * t));
if (distSqFromCenter(px, py) <= max_r_sq) {
*x1 = px;
*y1 = py;
return;
}
t -= 0.05f;
if (t <= 0.0f) {
*x1 = x0;
*y1 = y0;
return;
}
}
}

} // namespace ui::radar
68 changes: 6 additions & 62 deletions src/ui/runway_overlay.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8,14 +8,18 @@
#include "data/large_airports.h"
#include "hardware/display_font.h"
#include "services/radar_location.h"
#include "ui/radar_projection.h"
#include "ui/radar_range.h"
#include "ui/radar_theme.h"

namespace ui::runway {
namespace {

constexpr float kKmPerDeg = 111.0f;
constexpr float kDegToRad = 3.14159265f / 180.0f;
using radar::clipPointToOuterRing;
using radar::distSqFromCenter;
using radar::latLonToScreen;
using radar::offsetKmFromCenter;

constexpr size_t kMaxAirportLabels = 32;

bool s_in_range[data::large_airports::kAirportCount];
Expand Down Expand Up @@ -71,66 +75,6 @@ void applyRunwayLabelStyle(lgfx::LGFXBase& gfx) {

float e7ToDeg(int32_t e7) { return static_cast<float>(e7) * 1e-7f; }

void offsetKmFromCenter(float lat, float lon, float* dx_km, float* dy_km,
float* dist_km) {
// Longitude degrees shrink toward the poles; scale by cos(latitude) so
// east-west distance isn't overstated away from the equator.
const float center_lat_rad =
static_cast<float>(services::location::lat()) * kDegToRad;
*dx_km = static_cast<float>(lon - services::location::lon()) * kKmPerDeg *
cosf(center_lat_rad);
*dy_km =
static_cast<float>(lat - services::location::lat()) * kKmPerDeg;
*dist_km = sqrtf((*dx_km) * (*dx_km) + (*dy_km) * (*dy_km));
}

void latLonToScreen(float lat, float lon, int* out_x, int* out_y) {
const float outer_km = radar::rangeCurrent().outer_km;
const float px_per_km =
static_cast<float>(radar::kGridOuterRadius) / outer_km;

float dx_km = 0.0f;
float dy_km = 0.0f;
float dist_km = 0.0f;
offsetKmFromCenter(lat, lon, &dx_km, &dy_km, &dist_km);

*out_x = radar::kCenterX + static_cast<int>(lroundf(dx_km * px_per_km));
*out_y = radar::kCenterY - static_cast<int>(lroundf(dy_km * px_per_km));
}

int distSqFromCenter(int x, int y) {
const int dx = x - radar::kCenterX;
const int dy = y - radar::kCenterY;
return dx * dx + dy * dy;
}

void clipPointToOuterRing(int x0, int y0, int* x1, int* y1) {
const int max_r = radar::kGridOuterRadius;
const int max_r_sq = max_r * max_r;
if (distSqFromCenter(*x1, *y1) <= max_r_sq) {
return;
}

const int dx = *x1 - x0;
const int dy = *y1 - y0;
float t = 1.0f;
for (int step = 0; step < 20; ++step) {
const int px = x0 + static_cast<int>(lroundf(dx * t));
const int py = y0 + static_cast<int>(lroundf(dy * t));
if (distSqFromCenter(px, py) <= max_r_sq) {
*x1 = px;
*y1 = py;
return;
}
t -= 0.05f;
if (t <= 0.0f) {
*x1 = x0;
*y1 = y0;
return;
}
}
}

bool segmentIntersectsDisc(int x0, int y0, int x1, int y1) {
const int cx = radar::kCenterX;
const int cy = radar::kCenterY;
Expand Down