/* Compile: gcc -o cubbi-cube cubbi-cube.c -lvgagl -lvga Exit: Ctrl-C (c) 1999 Sergey Zubkov */ #include #include #include #include #include /* the mode I will use */ #define VGAMODE G320x200x256 /* try this one for 640x480 */ // #define VGAMODE G640x480x256 /* note that the cube rotates slower in high-res not because of lower FPS, but * because the rotation is done by frame change, not by time. If you want to * run it faster in 640x480 - increase a,b,c in rotatecube() or calculate them * using current time */ /* fps-related variables */ int framecount; clock_t frameclock; float framerate; /* we need two contexts - one for actual output */ GraphicsContext *physicalscreen; /* and one to draw our lines and letters in */ GraphicsContext *backscreen; /* If you want to combine several layers in your picture, like background and * foreground - you will need more contexts */ /* Not really *cube* - just 8 3D-points */ struct { struct {float x; float y; float z;} c1; struct {float x; float y; float z;} c2; struct {float x; float y; float z;} c3; struct {float x; float y; float z;} c4; struct {float x; float y; float z;} c5; struct {float x; float y; float z;} c6; struct {float x; float y; float z;} c7; struct {float x; float y; float z;} c8; } cube; /* draw the cube, X-Y projection */ void drawcube(void) { /* actually here I just draw 12 lines connecting our 8 dots, with a * WIDTH/2,HEIGHT/2 bias to put them closer to the center of the screen */ gl_line(WIDTH/2+cube.c1.x, HEIGHT/2+cube.c1.y, WIDTH/2+cube.c2.x, HEIGHT/2+cube.c2.y, 1); gl_line(WIDTH/2+cube.c2.x, HEIGHT/2+cube.c2.y, WIDTH/2+cube.c3.x, HEIGHT/2+cube.c3.y, 1); gl_line(WIDTH/2+cube.c3.x, HEIGHT/2+cube.c3.y, WIDTH/2+cube.c4.x, HEIGHT/2+cube.c4.y, 1); gl_line(WIDTH/2+cube.c4.x, HEIGHT/2+cube.c4.y, WIDTH/2+cube.c1.x, HEIGHT/2+cube.c1.y, 1); gl_line(WIDTH/2+cube.c1.x, HEIGHT/2+cube.c1.y, WIDTH/2+cube.c7.x, HEIGHT/2+cube.c7.y, 2); gl_line(WIDTH/2+cube.c2.x, HEIGHT/2+cube.c2.y, WIDTH/2+cube.c8.x, HEIGHT/2+cube.c8.y, 2); gl_line(WIDTH/2+cube.c3.x, HEIGHT/2+cube.c3.y, WIDTH/2+cube.c5.x, HEIGHT/2+cube.c5.y, 2); gl_line(WIDTH/2+cube.c4.x, HEIGHT/2+cube.c4.y, WIDTH/2+cube.c6.x, HEIGHT/2+cube.c6.y, 2); gl_line(WIDTH/2+cube.c5.x, HEIGHT/2+cube.c5.y, WIDTH/2+cube.c6.x, HEIGHT/2+cube.c6.y, 3); gl_line(WIDTH/2+cube.c6.x, HEIGHT/2+cube.c6.y, WIDTH/2+cube.c7.x, HEIGHT/2+cube.c7.y, 3); gl_line(WIDTH/2+cube.c7.x, HEIGHT/2+cube.c7.y, WIDTH/2+cube.c8.x, HEIGHT/2+cube.c8.y, 3); gl_line(WIDTH/2+cube.c8.x, HEIGHT/2+cube.c8.y, WIDTH/2+cube.c5.x, HEIGHT/2+cube.c5.y, 3); } /* rotate one 3D point */ void rotatedot(float *x,float *y,float *z,float a,float b,float c) { float tmp_x,tmp_y,tmp_z; /* stupid imperative C */ tmp_x=*x; tmp_y=*y; tmp_z=*z; /* This is NOT Euler 3D rotation transform - this is the version of it used in air and space: a is the Tilt angle, b is the Tangage angle, c is the Slide angle (not sure about english names for those words) But you can take a math textbook and use Euler just as well. */ *x=cos(b)*cos(c)*tmp_x -cos(b)*sin(c)*tmp_y +sin(b)*tmp_z; *y=(sin(a)*sin(b)*sin(c)+cos(a)*sin(c))*tmp_x +(-sin(a)*sin(b)*sin(c)+cos(a)*cos(c))*tmp_y -sin(a)*cos(b)*tmp_z; *z=(-cos(a)*sin(b)*cos(c)+sin(a)*sin(c))*tmp_x +(cos(a)*sin(b)*sin(c)+sin(a)*cos(c))*tmp_y +cos(a)*cos(b)*tmp_z; } /* rotate the cube */ void rotatecube(void) { float a,b,c; /* rotation angles */ /* every frame the cube is rotated by : */ a=0.007; /* 0.007 radian around x axis */ b=0.003; /* 0.003 radian around y axis */ c=0.005; /* 0.005 radian around z axis */ /* CHANGE these to change the speed of rotation as well as the * directions. It would be fun to make each of these angular speeds * change with time, getting faster and slower. */ /* apply rotation rules to every vertix separately */ rotatedot(&cube.c1.x,&cube.c1.y,&cube.c1.z,a,b,c); rotatedot(&cube.c2.x,&cube.c2.y,&cube.c2.z,a,b,c); rotatedot(&cube.c3.x,&cube.c3.y,&cube.c3.z,a,b,c); rotatedot(&cube.c4.x,&cube.c4.y,&cube.c4.z,a,b,c); rotatedot(&cube.c5.x,&cube.c5.y,&cube.c5.z,a,b,c); rotatedot(&cube.c6.x,&cube.c6.y,&cube.c6.z,a,b,c); rotatedot(&cube.c7.x,&cube.c7.y,&cube.c7.z,a,b,c); rotatedot(&cube.c8.x,&cube.c8.y,&cube.c8.z,a,b,c); } /* create and draw next frame on the screen */ void drawscreen(void) { int i; char s[50]; /* From this command all gl_* functions will draw the objects in * backscreen. */ gl_setcontext(backscreen); /* clear frame */ gl_clearscreen(0); /* change the cube's coordinates by rotation */ rotatecube(); /* output the current cube into our "backscreen" buffer */ drawcube(); /* Output current frame and last second's FPS into backscreen */ sprintf(s, "Frame: %3d FPS: %g",framecount,framerate); gl_setwritemode(WRITEMODE_OVERWRITE); gl_write(0, HEIGHT-8, s); /* Copy backscreen to physical screen (this is actual output!) */ gl_copyscreen(physicalscreen); } int main(void) { void *font; /* init and switch to graphics */ vga_init(); vga_setmode(VGAMODE); /* set up the screen buffer */ gl_setcontextvga(VGAMODE); physicalscreen = gl_allocatecontext(); gl_getcontext(physicalscreen); /* allocate and set up font for display of frame rate */ font = (void*)malloc(256 * 8 * 8 * BYTESPERPIXEL); gl_expandfont(8, 8, 1, gl_font8x8, font); gl_setfont(8, 8, font); /* Initial cube position and size is set here */ /* It doesn't really *have* to be a cube - it's simply 8 dots in space, * connected with lines - try changing any of the following coordinates * at will. Remember that rotation will be aroung the 0,0,0 dot in * these coordinates (try setting all positive) */ cube.c1.x=cube.c1.y=cube.c1.z=-10; cube.c2.y=cube.c2.z=-10; cube.c2.x=20; cube.c3.x=cube.c3.y=20; cube.c3.z=-10; cube.c4.x=cube.c4.z=-10; cube.c4.y=20; cube.c5.x=cube.c5.y=cube.c5.z=20; cube.c6.y=cube.c6.z=20; cube.c6.x=-10; cube.c7.x=cube.c7.y=-10; cube.c7.z=20; cube.c8.x=cube.c8.z=20; cube.c8.y=-10; /* set up the virtual buffer for drawing in */ gl_setcontextvgavirtual(VGAMODE); backscreen = gl_allocatecontext(); gl_getcontext(backscreen); /* main display loop */ framerate = 0; framecount = 0; frameclock = clock(); for (;;) { /* draw next frame */ drawscreen(); /* update frame counter */ framecount++; /* if a second passed - update frame rate (see man clock) */ if (clock()-frameclock >= CLOCKS_PER_SEC) { framerate = (float)framecount*CLOCKS_PER_SEC / (float)(clock()-frameclock); framecount = 0; frameclock = clock(); } } /* exit (never reached in this program) */ vga_setmode(TEXT); return 0; }