mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-12-26 11:30:12 +00:00
366 lines
8.3 KiB
C
366 lines
8.3 KiB
C
#include <stdio.h>
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#include <math.h>
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/* http://wiki.kerbalspaceprogram.com/wiki/Tutorial:Advanced_Rocket_Design */
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/* Also, high school physics (thanks Mr. Brennen) */
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#define PI 3.14159265358979323846264338327
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static double sin_degrees(double degrees) {
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return sin(degrees*PI/180);
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}
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static double cos_degrees(double degrees) {
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return cos(degrees*PI/180);
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}
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static double vector_magnitude(double a,double b) {
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return sqrt(a*a+b*b);
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}
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static void home(void) {
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printf("%c[2J%c[1;1H",27,27);
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}
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static void htabvtab(int x,int y) {
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printf("%c[%d;%dH",27,y,x);
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}
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#define KERBIN_RADIUS 600000.0
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int autopilot(double fuel_left, double altitude, double *angle) {
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if (fuel_left>25.0) {
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*angle=45.0;
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return 1;
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}
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if (altitude>KERBIN_RADIUS+40000) {
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*angle=100.0; /* actually want tanegent to surface */
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return 1;
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}
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return 0;
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}
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int main(int argc, char **argv) {
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FILE *logfile,*vlogfile;
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double angle=0;
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double capsule_mass=1.0;
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// double engines=3;
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double engine_isp=270.0; /* s */
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// double engine_mass=(1.5)*engines; /* tons */
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// double engine_thrust=(168.0)*engines; /* kN */
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// double fuel_flow_rate;
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// double tanks=6;
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// double tank_mass=(0.5)*tanks; /* tons */
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// double fuel_mass=(4.0)*tanks; /* tons */
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// double total_fuel=fuel_mass;
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double fuel_left=100.0;
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double gravity=-9.8; /* m/s^2 */
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double gravity_x=0.0;
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double gravity_y=-9.8;
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double gravity_angle=0.0;
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/* Kerbin radius = 600km */
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double rocket_velocity=0.0;
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double rocket_velocity_x=0.0; /* m/s */
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double rocket_velocity_y=0.0; /* m/s */
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double rocket_acceleration_x=0.0; /* m/s^2 */
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double rocket_acceleration_y=0.0; /* m/s^2 */
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double rocket_x=0;
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double rocket_y=KERBIN_RADIUS+10;
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double rocket_altitude=KERBIN_RADIUS; /* m */
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double v0_x,v0_y;
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double time=0.0; /* s */
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double deltat=1.0;
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/* atmospheric pressure */
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double pressure=101325; /* Pascals */
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double pressure0=101325;
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double density=0; /* kg/m^3 */
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double temperature=273; /* K */
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double drag=0.0,drag_a=0.0;
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int parachutes_deployed=0;
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int parachutes=3;
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int stage=2;
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int log_step=0;
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char input;
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int thrusting=1,i,j;
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int stages=3;
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int engines[3],stacks[3],tanks[3];
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double stage_empty_mass[3],stage_full_mass[3],total_mass[3],thrust[3];
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double fuel_mass[3],stage_fuel_total[3];
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double deltav[3],twr[3],fuel_flow[3];
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logfile=fopen("log.jgr","w");
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vlogfile=fopen("vlog.jgr","w");
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engines[0]=1; stacks[0]=1; tanks[0]=1;
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engines[1]=2; stacks[1]=2; tanks[1]=1;
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engines[2]=3; stacks[2]=3; tanks[2]=1;
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/* 1000 */
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for(i=0;i<stages;i++) {
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stage_empty_mass[i]=(engines[i]*1.5)+(stacks[i]*tanks[i]*0.5);
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if (i==0) stage_empty_mass[i]+=capsule_mass;/* tons */
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fuel_mass[i]=(stacks[i]*tanks[i]*4.0);
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stage_fuel_total[i]=fuel_mass[i];
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stage_full_mass[i]=stage_empty_mass[i]+fuel_mass[i];
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/* 1020 */
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total_mass[i]=0.0;
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for(j=i;j>=0;j--) {
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total_mass[i]+=stage_full_mass[j];
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}
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thrust[i]=engines[i]*168.0; /* kN */
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deltav[i]=engine_isp*-gravity*log(total_mass[i]/(total_mass[i]-fuel_mass[i]));
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twr[i]=thrust[i]/(total_mass[i]*-gravity);
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fuel_flow[i]=(thrust[i])/(engine_isp*-gravity);
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printf("Stage %d\n",i+1);
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printf("\ttanks=%d engines=%d\n",stacks[i]*tanks[i],engines[i]);
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printf("\tstage mass=%lf total_mass=%lf\n",stage_full_mass[i],
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total_mass[i]);
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printf("\tdeltaV=%lf\n",deltav[i]);
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printf("\tTWR=%lf\n",twr[i]);
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}
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// printf("Fuel flow rate=%lf, time=%lfs\n",
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// fuel_flow_rate,fuel_mass/fuel_flow_rate);
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scanf("%c",&input);
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/* 4000 */
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while(1) {
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/* 4010 */
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fuel_left=fuel_mass[stage]*100.0/stage_fuel_total[stage];
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//thrusting=1;//autopilot(fuel_left, rocket_altitude,&angle);
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if (thrusting) {
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if (fuel_mass[stage]<0.1) {
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fuel_mass[stage]=0.0;
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rocket_acceleration_x=0;
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rocket_acceleration_y=0;
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}
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else {
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rocket_acceleration_x=(thrust[stage]/total_mass[stage])*sin_degrees(angle);
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rocket_acceleration_y=(thrust[stage]/total_mass[stage])*cos_degrees(angle);
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fuel_mass[stage]=fuel_mass[stage]-fuel_flow[stage];
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total_mass[stage]=total_mass[stage]-fuel_flow[stage];
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}
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}
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else {
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rocket_acceleration_x=0.0;
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rocket_acceleration_y=0.0;
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}
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/* 4060 */
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gravity_angle=atan(rocket_x/rocket_y);
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if (rocket_y<0) gravity_angle+=PI;
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/* 4070 */
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gravity_y=cos(gravity_angle)*gravity;
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gravity_x=sin(gravity_angle)*gravity;
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/* 4080 */
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rocket_acceleration_y+=gravity_y;
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rocket_acceleration_x+=gravity_x;
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/* Adjust pressure */
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pressure=pressure0*exp(-(rocket_altitude-KERBIN_RADIUS)/5600);
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density=pressure/(287*temperature);
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/* 0.5*rho*v^2*d*A */
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/* d=coefficient of drag, A=surface area */
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/* d=1.05 for cube (wikipedia) */
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/* d=0.8 for long cylinder */
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/* d=0.5 for long cone */
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if (parachutes_deployed) {
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drag=0.5*density*rocket_velocity*rocket_velocity*1.5*1000.0*parachutes;
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}
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else {
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drag=0.5*density*rocket_velocity*rocket_velocity*0.5*1.0;
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}
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drag_a=drag/(total_mass[stage]*1000);
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if (rocket_velocity_y>0) drag_a=-drag_a;
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rocket_acceleration_y+=drag_a;
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/* v=v0+at */
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v0_x=rocket_velocity_x;
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v0_y=rocket_velocity_y;
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rocket_velocity_y=v0_y+rocket_acceleration_y*deltat;
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rocket_velocity_x=v0_x+rocket_acceleration_x*deltat;
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rocket_velocity=vector_magnitude(rocket_velocity_x,rocket_velocity_y),
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/* deltaX=1/2 (v+v0)t */
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/* could also use deltax=v0t+(1/2)*a*t*t */
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rocket_y=rocket_y+0.5*(v0_y+rocket_velocity_y)*deltat;
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rocket_x=rocket_x+0.5*(v0_x+rocket_velocity_x)*deltat;
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rocket_altitude=vector_magnitude(rocket_x,rocket_y);
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/* 5020 */
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if (rocket_altitude<KERBIN_RADIUS) {
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if (rocket_velocity<20.0) {
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printf("LANDED!\n");
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}
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else {
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printf("CRASHED!\n");
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}
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break;
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}
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/* 5030 */
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/* Adjust gravity */
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gravity=-9.8/(
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((rocket_altitude)/KERBIN_RADIUS)*
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((rocket_altitude)/KERBIN_RADIUS));
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home();
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htabvtab(1,21);
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printf("Time: %lf\n",time);
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printf("ALT: %lf km\tg=%lf\n",(rocket_altitude-KERBIN_RADIUS)/1000.0,
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gravity);
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printf("VEL: %lf m/s\tStage: %d\n",
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rocket_velocity,
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stage);
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printf("ACCEL: %lf g\tFuel: %lf%%",
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vector_magnitude(rocket_acceleration_x,rocket_acceleration_y)/9.8,
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fuel_left);
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htabvtab(30,21);
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printf("ZURGTROYD");
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htabvtab(30,20);
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if ((angle>90) && (angle<270)) printf("SCREAM");
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else if (rocket_velocity_y>100) printf("SMILE");
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else if (rocket_acceleration_y<0) printf("FROWN");
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else printf("NEUTRAL");
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htabvtab(20,14);
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printf("pressure=%lf density=%lf drag=%lf drag_a=%lf\n",
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pressure,density,drag,drag_a);
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htabvtab(20,13);
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printf("grav angle=%lf\n",gravity_angle*180.0/PI);
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htabvtab(20,12);
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printf("x=%lf y=%lf\n",rocket_x,rocket_y);
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htabvtab(20,11);
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printf("vx=%lf vy=%lf ax=%lf ay=%lf\n",
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rocket_velocity_x,rocket_velocity_y,
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rocket_acceleration_x,rocket_acceleration_y);
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htabvtab(20,10);
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printf("angle=%lf\n",angle);
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htabvtab(20,9);
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if (angle<22.5) printf("^");
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else if (angle<67.5) printf("/");
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else if (angle<112.5) printf(">");
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else if (angle<157.5) printf("\\");
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else if (angle<205.5) printf("V");
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else if (angle<250.5) printf("/");
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else if (angle<295.5) printf("<");
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else if (angle<340.5) printf("\\");
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else printf("^");
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scanf("%c",&input);
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if (input==' ') {
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if (stage>0) stage--;
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else parachutes_deployed=1;
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}
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if (input=='d') {
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angle+=45.0;
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if (angle>=360) angle=0.0;
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}
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if (input=='a') {
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angle-=45.0;
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if (angle<0.0) angle+=360.0;
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}
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if (input=='z') {
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/* no thrusting while fast-forwarding */
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if (deltat<1.5) thrusting=1;
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}
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if (input=='x') {
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thrusting=0;
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}
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if (input=='q') {
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break;
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}
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if (input=='>') {
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/* no fast-forwarding while thrusting */
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if (!thrusting) deltat+=1.0;
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}
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if (input=='<') {
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deltat-=1.0;
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if (deltat<1.0) deltat=1.0;
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}
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time+=deltat;
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if (log_step==0) {
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if (logfile) {
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fprintf(logfile,"%lf %lf\n",rocket_x/1000.0,rocket_y/1000.0);
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}
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if (vlogfile) {
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fprintf(vlogfile,
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"t=%lf h=%lf v=%lf g=%lf d=%lf ray=%lf\n",
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time,rocket_altitude-KERBIN_RADIUS,rocket_velocity,
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gravity_y,drag_a,rocket_acceleration_y);
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}
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}
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log_step++;
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if (log_step>10) {
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log_step=0;
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}
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}
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if (logfile) fclose(logfile);
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if (vlogfile) fclose(vlogfile);
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return 0;
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}
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/* Notes */
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/* Once altitude above 100m stop drawing ground */
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/* Once above 20k no more drag? */
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/* Once above 2100m/s sideways, orbit? */
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/* Once above 40k draw stars? */
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/* Kerbal neutral 0-1G, smiles 1-2G, frowns > 2G or -velocity? */
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