ref: fe1eb39db7ae6904924f3ab1f6f9b34416f2eb1b
dir: /sys/src/games/turtle.c/
#include <u.h> #include <libc.h> #include <bio.h> #include <draw.h> #include <event.h> #include <keyboard.h> Biobuf *bin; double px, py; double θ; double *stack; int sp; int stacksize; double *lines; int lp; int *frames; int fp; int curframe; double minx = -10, maxx = 10, miny = -10, maxy = 10; Point cvt(double x, double y) { return Pt((x - minx) * Dx(screen->r) / (maxx - minx) + screen->r.min.x, (maxy - y) * Dy(screen->r) / (maxy - miny) + screen->r.min.y); } void opdraw(int, char **argv) { double npx, npy, l; l = atof(argv[1]); npx = px + sin(θ * PI / 180) * l; npy = py + cos(θ * PI / 180) * l; lines = realloc(lines, (lp + 4) * sizeof(double)); lines[lp++] = px; lines[lp++] = py; lines[lp++] = npx; lines[lp++] = npy; px = npx; py = npy; } void opturn(int, char **argv) { θ += atof(argv[1]); } void oppush(int, char **) { if(sp + 3 > stacksize){ stack = realloc(stack, (stacksize + 3) * sizeof(double)); stacksize += 3; } stack[sp++] = px; stack[sp++] = py; stack[sp++] = θ; } void oppop(int, char **) { if(sp == 0) sysfatal("stack underflow"); θ = stack[--sp]; py = stack[--sp]; px = stack[--sp]; } void opend(int, char **) { θ = 0; px = 0; py = 0; frames = realloc(frames, (fp + 1) * sizeof(int)); frames[fp++] = lp; } typedef struct Cmd Cmd; struct Cmd { char *name; int nargs; void (*op)(int, char**); }; Cmd cmdtab[] = { "draw", 1, opdraw, "turn", 1, opturn, "push", 0, oppush, "pop", 0, oppop, "end", 0, opend, }; void runline(char *s) { char *f[10]; int nf; Cmd *p; nf = tokenize(s, f, nelem(f)); if(nf == 0) return; for(p = cmdtab; p < cmdtab + nelem(cmdtab); p++) if(strcmp(p->name, f[0]) == 0){ if(nf != p->nargs + 1 && p->nargs >= 0) sysfatal("wrong number of arguments for %s", f[0]); p->op(nf, f); return; } sysfatal("unknown command %s", f[0]); } void redraw(void) { int i; minx = maxx = lines[frames[curframe]]; miny = maxy = lines[frames[curframe]+1]; for(i = frames[curframe]; i < frames[curframe + 1]; i += 2){ if(lines[i] < minx) minx = lines[i]; if(lines[i] > maxx) maxx = lines[i]; if(lines[i+1] < miny) miny = lines[i+1]; if(lines[i+1] > maxy) maxy = lines[i+1]; } maxx += (maxx - minx) * 0.05; minx -= (maxx - minx) * 0.05; maxy += (maxy - miny) * 0.05; miny -= (maxy - miny) * 0.05; if(minx == maxx){ minx -= 0.05; maxx += 0.05; } if(miny == maxy){ miny -= 0.05; maxy += 0.05; } draw(screen, screen->r, display->white, nil, ZP); for(i = frames[curframe]; i < frames[curframe + 1]; i += 4) line(screen, cvt(lines[i], lines[i+1]), cvt(lines[i+2], lines[i+3]), 0, 0, 0, display->black, ZP); flushimage(display, 1); } void eresized(int new) { if(new && getwindow(display, Refnone) < 0){ fprint(2, "colors: can't reattach to window: %r\n"); exits("resized"); } redraw(); } void main() { char *s; bin = Bfdopen(0, OREAD); if(bin == nil) sysfatal("Bfdopen: %r"); frames = malloc(sizeof(int)); frames[fp++] = 0; for(;;){ s = Brdstr(bin, '\n', 1); if(s == nil) break; runline(s); } if(lines == nil) exits(nil); if(initdraw(nil, nil, nil) < 0) sysfatal("initdraw: %r"); einit(Emouse | Ekeyboard); redraw(); for(;;){ switch(ekbd()){ case Khome: curframe = 0; break; case Kend: curframe = fp - 2; break; case Kup: case Kleft: if(curframe > 0) curframe--; break; case ' ': case Kdown: case Kright: if(curframe < fp - 2) curframe++; break; case 'q': case Kdel: exits(nil); } redraw(); } }