mirror of
https://github.com/acemod/ACE3.git
synced 2024-08-30 18:23:18 +00:00
Advanced Ballistics - More advanced drag update routine
* Handles greater 'simulationIntervals' much better: * 'simulationInterval=0.00' -> Error (at 2km): 0.004 MILs * 'simulationInterval=0.05' -> Error (at 2km): 0.030 MILs * 'simulationInterval=0.10' -> Error (at 2km): 0.070 MILs * Almost completely FPS invariant
This commit is contained in:
ulteq
parent
502648fae3
commit
1997edb62e
@ -8,7 +8,8 @@
|
||||
#include <cmath>
|
||||
#include <sstream>
|
||||
|
||||
#define DELTA_T 0.02f
|
||||
#define DT_ZERO 0.02
|
||||
#define DT_SIMULATION 0.005
|
||||
#define GRAVITY 9.80665f
|
||||
#define DEGREES(X) (X * 180 / M_PI)
|
||||
#define ABSOLUTE_ZERO_IN_CELSIUS -273.15f
|
||||
@ -180,14 +181,14 @@ double calculateVanillaZeroAngle(double zeroRange, double muzzleVelocity, double
|
||||
ax += gx;
|
||||
ay += gy;
|
||||
|
||||
px += vx * DELTA_T * 0.5;
|
||||
py += vy * DELTA_T * 0.5;
|
||||
vx += ax * DELTA_T;
|
||||
vy += ay * DELTA_T;
|
||||
px += vx * DELTA_T * 0.5;
|
||||
py += vy * DELTA_T * 0.5;
|
||||
px += vx * DT_ZERO * 0.5;
|
||||
py += vy * DT_ZERO * 0.5;
|
||||
vx += ax * DT_ZERO;
|
||||
vy += ay * DT_ZERO;
|
||||
px += vx * DT_ZERO * 0.5;
|
||||
py += vy * DT_ZERO * 0.5;
|
||||
|
||||
tof += DELTA_T;
|
||||
tof += DT_ZERO;
|
||||
}
|
||||
|
||||
double y = ly + (zeroRange - lx) * (py - ly) / (px - lx);
|
||||
@ -235,14 +236,14 @@ double calculateZeroAngle(double zeroRange, double muzzleVelocity, double boreHe
|
||||
ax += gx;
|
||||
ay += gy;
|
||||
|
||||
px += vx * DELTA_T * 0.5;
|
||||
py += vy * DELTA_T * 0.5;
|
||||
vx += ax * DELTA_T;
|
||||
vy += ay * DELTA_T;
|
||||
px += vx * DELTA_T * 0.5;
|
||||
py += vy * DELTA_T * 0.5;
|
||||
px += vx * DT_ZERO * 0.5;
|
||||
py += vy * DT_ZERO * 0.5;
|
||||
vx += ax * DT_ZERO;
|
||||
vy += ay * DT_ZERO;
|
||||
px += vx * DT_ZERO * 0.5;
|
||||
py += vy * DT_ZERO * 0.5;
|
||||
|
||||
tof += DELTA_T;
|
||||
tof += DT_ZERO;
|
||||
}
|
||||
|
||||
double y = ly + (zeroRange - lx) * (py - ly) / (px - lx);
|
||||
@ -414,7 +415,20 @@ void __stdcall RVExtension(char *output, int outputSize, const char *function)
|
||||
bulletDatabase[index].overcast = overcast;
|
||||
bulletDatabase[index].startTime = tickTime;
|
||||
bulletDatabase[index].lastFrame = tickTime;
|
||||
bulletDatabase[index].randSeed = 0;
|
||||
|
||||
int angle = (int)round(atan2(bulletDatabase[index].bulletVelocity[0], bulletDatabase[index].bulletVelocity[1]) * 360 / M_PI);
|
||||
bulletDatabase[index].randSeed = (unsigned)(720 + angle) % 720;
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)round(abs(bulletDatabase[index].bulletVelocity[2]) / 2);
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)round(abs(bulletDatabase[index].origin[0] / 2));
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)round(abs(bulletDatabase[index].origin[1] / 2));
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)abs(bulletDatabase[index].temperature) * 10;
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)abs(bulletDatabase[index].humidity) * 10;
|
||||
bulletDatabase[index].randGenerator.seed(bulletDatabase[index].randSeed);
|
||||
|
||||
strncpy_s(output, outputSize, "", _TRUNCATE);
|
||||
EXTENSION_RETURN();
|
||||
@ -452,22 +466,6 @@ void __stdcall RVExtension(char *output, int outputSize, const char *function)
|
||||
heightAGL = strtod(strtok_s(NULL, ":", &next_token), NULL);
|
||||
tickTime = strtod(strtok_s(NULL, ":", &next_token), NULL);
|
||||
|
||||
if (bulletDatabase[index].randSeed == 0) {
|
||||
int angle = (int)round(atan2(velocity[0], velocity[1]) * 360 / M_PI);
|
||||
bulletDatabase[index].randSeed = (unsigned)(720 + angle) % 720;
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)round(abs(velocity[2]) / 2);
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)round(abs(bulletDatabase[index].origin[0] / 2));
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)round(abs(bulletDatabase[index].origin[1] / 2));
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)abs(bulletDatabase[index].temperature) * 10;
|
||||
bulletDatabase[index].randSeed *= 3;
|
||||
bulletDatabase[index].randSeed += (unsigned)abs(bulletDatabase[index].humidity) * 10;
|
||||
bulletDatabase[index].randGenerator.seed(bulletDatabase[index].randSeed);
|
||||
}
|
||||
|
||||
double ballisticCoefficient = 1.0;
|
||||
double dragRef = 0.0;
|
||||
double drag = 0.0;
|
||||
@ -482,7 +480,6 @@ void __stdcall RVExtension(char *output, int outputSize, const char *function)
|
||||
double windSpeed = 0.0;
|
||||
double windAttenuation = 1.0;
|
||||
double velocityOffset[3] = { 0.0, 0.0, 0.0 };
|
||||
double bulletSpeed = sqrt(pow(bulletDatabase[index].bulletVelocity[0], 2) + pow(bulletDatabase[index].bulletVelocity[1], 2) + pow(bulletDatabase[index].bulletVelocity[2], 2));
|
||||
|
||||
bulletDatabase[index].lastFrame = tickTime;
|
||||
|
||||
@ -528,80 +525,122 @@ void __stdcall RVExtension(char *output, int outputSize, const char *function)
|
||||
windSpeed = sqrt(pow(wind[0], 2) + pow(wind[1], 2) + pow(wind[2], 2));
|
||||
}
|
||||
|
||||
trueVelocity[0] = bulletDatabase[index].bulletVelocity[0] - wind[0];
|
||||
trueVelocity[1] = bulletDatabase[index].bulletVelocity[1] - wind[1];
|
||||
trueVelocity[2] = bulletDatabase[index].bulletVelocity[2] - wind[2];
|
||||
trueSpeed = sqrt(pow(trueVelocity[0], 2) + pow(trueVelocity[1], 2) + pow(trueVelocity[2], 2));
|
||||
std::vector<double> bulletVelocity = bulletDatabase[index].bulletVelocity;
|
||||
double time = 0.0;
|
||||
|
||||
if (bulletDatabase[index].transonicStabilityCoef < 1.0f && trueSpeed - 60 < SPEED_OF_SOUND(temperature) && trueSpeed > SPEED_OF_SOUND(temperature)) {
|
||||
std::uniform_real_distribution<double> distribution(-10.0, 10.0);
|
||||
double coef = 1.0f - bulletDatabase[index].transonicStabilityCoef;
|
||||
while (time < deltaT) {
|
||||
double dt = std::min(deltaT - time, DT_SIMULATION);
|
||||
|
||||
trueVelocity[0] += distribution(bulletDatabase[index].randGenerator) * coef;
|
||||
trueVelocity[1] += distribution(bulletDatabase[index].randGenerator) * coef;
|
||||
trueVelocity[2] += distribution(bulletDatabase[index].randGenerator) * coef;
|
||||
double speed = sqrt(pow(trueVelocity[0], 2) + pow(trueVelocity[1], 2) + pow(trueVelocity[2], 2));
|
||||
double bulletSpeed = sqrt(pow(bulletVelocity[0], 2) + pow(bulletVelocity[1], 2) + pow(bulletVelocity[2], 2));
|
||||
|
||||
trueVelocity[0] *= trueSpeed / speed;
|
||||
trueVelocity[1] *= trueSpeed / speed;
|
||||
trueVelocity[2] *= trueSpeed / speed;
|
||||
};
|
||||
dragRef = -bulletDatabase[index].airFriction * bulletSpeed * bulletSpeed;
|
||||
|
||||
dragRef = -bulletDatabase[index].airFriction * bulletSpeed * bulletSpeed;
|
||||
accelRef[0] = (bulletVelocity[0] / bulletSpeed) * dragRef;
|
||||
accelRef[1] = (bulletVelocity[1] / bulletSpeed) * dragRef;
|
||||
accelRef[2] = (bulletVelocity[2] / bulletSpeed) * dragRef;
|
||||
|
||||
accelRef[0] = (bulletDatabase[index].bulletVelocity[0] / bulletSpeed) * dragRef;
|
||||
accelRef[1] = (bulletDatabase[index].bulletVelocity[1] / bulletSpeed) * dragRef;
|
||||
accelRef[2] = (bulletDatabase[index].bulletVelocity[2] / bulletSpeed) * dragRef;
|
||||
velocityOffset[0] += accelRef[0] * dt;
|
||||
velocityOffset[1] += accelRef[1] * dt;
|
||||
velocityOffset[2] += accelRef[2] * dt;
|
||||
|
||||
velocityOffset[0] += accelRef[0] * deltaT;
|
||||
velocityOffset[1] += accelRef[1] * deltaT;
|
||||
velocityOffset[2] += accelRef[2] * deltaT;
|
||||
bulletVelocity[0] -= accelRef[0] * dt;
|
||||
bulletVelocity[1] -= accelRef[1] * dt;
|
||||
bulletVelocity[2] -= accelRef[2] * dt + GRAVITY * dt;
|
||||
|
||||
if (bulletDatabase[index].ballisticCoefficients.size() == bulletDatabase[index].velocityBoundaries.size() + 1) {
|
||||
ballisticCoefficient = bulletDatabase[index].ballisticCoefficients[0];
|
||||
for (int i = (int)bulletDatabase[index].velocityBoundaries.size() - 1; i >= 0; i = i - 1) {
|
||||
if (trueSpeed < bulletDatabase[index].velocityBoundaries[i]) {
|
||||
ballisticCoefficient = bulletDatabase[index].ballisticCoefficients[i + 1];
|
||||
break;
|
||||
time += dt;
|
||||
}
|
||||
|
||||
bulletVelocity = bulletDatabase[index].bulletVelocity;
|
||||
time = 0.0;
|
||||
TOF -= deltaT;
|
||||
|
||||
while (time < deltaT) {
|
||||
double dt = std::min(deltaT - time, DT_SIMULATION * 2);
|
||||
|
||||
trueVelocity[0] = bulletVelocity[0] - wind[0];
|
||||
trueVelocity[1] = bulletVelocity[1] - wind[1];
|
||||
trueVelocity[2] = bulletVelocity[2] - wind[2];
|
||||
trueSpeed = sqrt(pow(trueVelocity[0], 2) + pow(trueVelocity[1], 2) + pow(trueVelocity[2], 2));
|
||||
|
||||
if (bulletDatabase[index].transonicStabilityCoef < 1.0f && trueSpeed < 1.2 * SPEED_OF_SOUND(temperature) && trueSpeed > SPEED_OF_SOUND(temperature)) {
|
||||
std::uniform_real_distribution<double> distribution(-10.0, 10.0);
|
||||
double coef = 1.0f - bulletDatabase[index].transonicStabilityCoef;
|
||||
|
||||
trueVelocity[0] += distribution(bulletDatabase[index].randGenerator) * coef;
|
||||
trueVelocity[1] += distribution(bulletDatabase[index].randGenerator) * coef;
|
||||
trueVelocity[2] += distribution(bulletDatabase[index].randGenerator) * coef;
|
||||
|
||||
double speed = sqrt(pow(trueVelocity[0], 2) + pow(trueVelocity[1], 2) + pow(trueVelocity[2], 2));
|
||||
|
||||
trueVelocity[0] *= trueSpeed / speed;
|
||||
trueVelocity[1] *= trueSpeed / speed;
|
||||
trueVelocity[2] *= trueSpeed / speed;
|
||||
};
|
||||
|
||||
if (bulletDatabase[index].ballisticCoefficients.size() == bulletDatabase[index].velocityBoundaries.size() + 1) {
|
||||
ballisticCoefficient = bulletDatabase[index].ballisticCoefficients[0];
|
||||
for (int i = (int)bulletDatabase[index].velocityBoundaries.size() - 1; i >= 0; i = i - 1) {
|
||||
if (trueSpeed < bulletDatabase[index].velocityBoundaries[i]) {
|
||||
ballisticCoefficient = bulletDatabase[index].ballisticCoefficients[i + 1];
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
ballisticCoefficient = calculateAtmosphericCorrection(ballisticCoefficient, temperature, pressure, bulletDatabase[index].humidity, bulletDatabase[index].atmosphereModel);
|
||||
|
||||
drag = calculateRetard(bulletDatabase[index].dragModel, ballisticCoefficient, trueSpeed, SPEED_OF_SOUND(temperature));
|
||||
}
|
||||
else {
|
||||
double airDensity = calculateAirDensity(temperature, pressure, bulletDatabase[index].humidity);
|
||||
double airFriction = bulletDatabase[index].airFriction * airDensity / STD_AIR_DENSITY_ICAO;
|
||||
|
||||
drag = -airFriction * trueSpeed * trueSpeed;
|
||||
}
|
||||
|
||||
ballisticCoefficient = calculateAtmosphericCorrection(ballisticCoefficient, temperature, pressure, bulletDatabase[index].humidity, bulletDatabase[index].atmosphereModel);
|
||||
accel[0] = (trueVelocity[0] / trueSpeed) * drag;
|
||||
accel[1] = (trueVelocity[1] / trueSpeed) * drag;
|
||||
accel[2] = (trueVelocity[2] / trueSpeed) * drag;
|
||||
|
||||
drag = calculateRetard(bulletDatabase[index].dragModel, ballisticCoefficient, trueSpeed, SPEED_OF_SOUND(temperature));
|
||||
} else {
|
||||
double airDensity = calculateAirDensity(temperature, pressure, bulletDatabase[index].humidity);
|
||||
double airFriction = bulletDatabase[index].airFriction * airDensity / STD_AIR_DENSITY_ICAO;
|
||||
velocityOffset[0] -= accel[0] * dt;
|
||||
velocityOffset[1] -= accel[1] * dt;
|
||||
velocityOffset[2] -= accel[2] * dt;
|
||||
|
||||
drag = -airFriction * trueSpeed * trueSpeed;
|
||||
bulletVelocity[0] -= accel[0] * dt;
|
||||
bulletVelocity[1] -= accel[1] * dt;
|
||||
bulletVelocity[2] -= accel[2] * dt;
|
||||
|
||||
if (TOF > 0) {
|
||||
double bulletDir = atan2(bulletVelocity[0], bulletVelocity[1]);
|
||||
double driftAccel = bulletDatabase[index].twistDirection * (0.0482251 * (bulletDatabase[index].stabilityFactor + 1.2)) / pow(TOF, 0.17);
|
||||
double driftVelocity = 0.0581025 *(bulletDatabase[index].stabilityFactor + 1.2) * pow(TOF, 0.83);
|
||||
double dragCorrection = (driftVelocity / trueSpeed) * drag;
|
||||
double velocityOffsetX = sin(bulletDir + M_PI / 2) * (driftAccel + dragCorrection) * dt;
|
||||
double velocityOffsetY = cos(bulletDir + M_PI / 2) * (driftAccel + dragCorrection) * dt;
|
||||
|
||||
velocityOffset[0] += velocityOffsetX;
|
||||
velocityOffset[1] += velocityOffsetY;
|
||||
|
||||
bulletVelocity[0] += velocityOffsetX;
|
||||
bulletVelocity[1] += velocityOffsetY;
|
||||
}
|
||||
|
||||
double lat = bulletDatabase[index].latitude;
|
||||
accel[0] = 2 * EARTH_ANGULAR_SPEED * +(bulletVelocity[1] * sin(lat) - bulletVelocity[2] * cos(lat));
|
||||
accel[1] = 2 * EARTH_ANGULAR_SPEED * -(bulletVelocity[0] * sin(lat));
|
||||
accel[2] = 2 * EARTH_ANGULAR_SPEED * +(bulletVelocity[0] * cos(lat));
|
||||
|
||||
velocityOffset[0] += accel[0] * dt;
|
||||
velocityOffset[1] += accel[1] * dt;
|
||||
velocityOffset[2] += accel[2] * dt;
|
||||
|
||||
bulletVelocity[0] += accel[0] * dt;
|
||||
bulletVelocity[1] += accel[1] * dt;
|
||||
bulletVelocity[2] += accel[2] * dt - GRAVITY * dt;
|
||||
|
||||
TOF += dt;
|
||||
time += dt;
|
||||
}
|
||||
|
||||
accel[0] = (trueVelocity[0] / trueSpeed) * drag;
|
||||
accel[1] = (trueVelocity[1] / trueSpeed) * drag;
|
||||
accel[2] = (trueVelocity[2] / trueSpeed) * drag;
|
||||
|
||||
velocityOffset[0] -= accel[0] * deltaT;
|
||||
velocityOffset[1] -= accel[1] * deltaT;
|
||||
velocityOffset[2] -= accel[2] * deltaT;
|
||||
|
||||
if (TOF > 0) {
|
||||
double bulletDir = atan2(bulletDatabase[index].bulletVelocity[0], bulletDatabase[index].bulletVelocity[1]);
|
||||
double driftAccel = bulletDatabase[index].twistDirection * (0.0482251 * (bulletDatabase[index].stabilityFactor + 1.2)) / pow(TOF, 0.17);
|
||||
double driftVelocity = 0.0581025 *(bulletDatabase[index].stabilityFactor + 1.2) * pow(TOF, 0.83);
|
||||
double dragCorrection = (driftVelocity / trueSpeed) * drag * deltaT;
|
||||
velocityOffset[0] += sin(bulletDir + M_PI / 2) * (driftAccel * deltaT + dragCorrection);
|
||||
velocityOffset[1] += cos(bulletDir + M_PI / 2) * (driftAccel * deltaT + dragCorrection);
|
||||
}
|
||||
|
||||
double lat = bulletDatabase[index].latitude;
|
||||
accel[0] = 2 * EARTH_ANGULAR_SPEED * +(bulletDatabase[index].bulletVelocity[1] * sin(lat) - bulletDatabase[index].bulletVelocity[2] * cos(lat));
|
||||
accel[1] = 2 * EARTH_ANGULAR_SPEED * -(bulletDatabase[index].bulletVelocity[0] * sin(lat));
|
||||
accel[2] = 2 * EARTH_ANGULAR_SPEED * +(bulletDatabase[index].bulletVelocity[0] * cos(lat));
|
||||
|
||||
velocityOffset[0] += accel[0] * deltaT;
|
||||
velocityOffset[1] += accel[1] * deltaT;
|
||||
velocityOffset[2] += accel[2] * deltaT;
|
||||
|
||||
bulletDatabase[index].bulletVelocity[0] = velocity[0] + velocityOffset[0];
|
||||
bulletDatabase[index].bulletVelocity[1] = velocity[1] + velocityOffset[1];
|
||||
bulletDatabase[index].bulletVelocity[2] = velocity[2] + velocityOffset[2];
|
||||
|
||||
Loading…
Reference in New Issue
Block a user