************************* video

initial port 320x200 graphics and 640x400 text in a 640x480 window

GETPIXS(x,y)
PUTPIXS(x,y,c)

color depth
palette

vga_mode(0x13);
vgapalset();

clear_screen()


************************* text screen

gotoxy(text_x,text_y)
printf(......)
cprintf(......)
 textcolor(c)
 textbackground(c)

  emulate an 80x25 text screen
             80x50 ...

************************* timing
clock()
LOOPSPTICK
prevloopcts
smoothedloopcts[]
//system clock() ticks ~18.2 times a second


************************* keyboard
keyboardproc()
deinit_keyboard()


************************* standard c / in gcc ?
RAND_MAX	yes


************************* graphics screen resolution

screen resolution
 initial port 320x200 graphics and 640x400 text in a 640x480 window
 default 640x480
 options 320*200 640*480 800x600 1024x768 1280x1024 1280x720 ... 

yres(int y)

void squareproj(
   float ylet=133;

  graphical X_RES Y_RES X_RESM Y_RESM X_OFFS Y_OFFS
all projections
dpnsrerasering(
drawplayernsr(
drawshot(
drawplayer(
gridout()
gridin()
2.c eraseplayernsrte


************************* changes beyond porting

check/fix black hole absorbing players shots conservation physics
fix two small c errors noted in old hardcopy, one more in a text buffer sometime
put all radii in angular units (remove legacy pixel units)
separate player mass from player radius variable


************************* pixel-based units

p1rad
p2rad

shot radius
blackab.m

M_PI/Y_RES

  radius
dpnsrerasering(
drawplayernsr(
emergeshots(
wallcolliding(

  mass -- radius issues
playermoment(r1)
playerorbitmomentsphere(r1)
shoot(int player)
playerwallbouncel
shotplrcollisions(int shotkollangular, float dt)
p1p2bounce_sphere(float dist)
p1p2bounce_flat(float dist)
blackabgravity(float olon, float olat, float om, float *ov, float *oat, float dt, int real, int plrnotshot)
blackabgravitar(float dt)
baabsorbmomentum(float plon, float plat, float pm, float pv, float pat, int plrnotshot)
blackabcollisions(void)
    if(physdisp) 
2.c starblebounceflat