#include <stdio.h>
#include <math.h>
#include <allegro.h>
#ifndef M_PI
#define M_PI 3.14159
#endif
/* display di una scacchiera reticolata 8x8 */
#define GRID_SIZE 8
/* converte i radianti in gradi */
#define DEG(n) ((n) * 180.0 / M_PI)
/* quanto volte in un secondo i FPS vengono calcolati */
#define FPS_INT 2
/* decommentare per disattivare l'attesa per vsync */
/* #define DISABLE_VSYNC */
/* parametri che controllano lo stato della telecamera */
int viewport_w = 320;
int viewport_h = 240;
int fov = 48;
float aspect = 1.33f;
float xpos = 0;
float ypos = -2;
float zpos = -4;
float heading = 0;
float pitch = 0;
float roll = 0;
int fps;
int framecount;
/* fa il render di una mattonella del reticolato */
void draw_square(BITMAP *bmp, MATRIX_f *camera, int x, int z)
{
V3D_f _v[4], _vout[8], _vtmp[8];
V3D_f *v[4], *vout[8], *vtmp[8];
int flags[4], out[8];
int c, vc;
for (c=0; c<4; c++)
v[c] = &_v[c];
for (c=0; c<8; c++) {
vout[c] = &_vout[c];
vtmp[c] = &_vtmp[c];
}
/* setta quattro vertici con la posizione della mattonella */
v[0]->x = x - GRID_SIZE/2;
v[0]->y = 0;
v[0]->z = z - GRID_SIZE/2;
v[1]->x = x - GRID_SIZE/2 + 1;
v[1]->y = 0;
v[1]->z = z - GRID_SIZE/2;
v[2]->x = x - GRID_SIZE/2 + 1;
v[2]->y = 0;
v[2]->z = z - GRID_SIZE/2 + 1;
v[3]->x = x - GRID_SIZE/2;
v[3]->y = 0;
v[3]->z = z - GRID_SIZE/2 + 1;
/* applica la camera_matrix */
for (c=0; c<4; c++) {
apply_matrix_f(camera, v[c]->x, v[c]->y, v[c]->z,
&v[c]->x, &v[c]->y, &v[c]->z);
flags[c] = 0;
/* setta flags se questo vertice è fuori dal bordo dello schermo */
if (v[c]->x < -v[c]->z)
flags[c] |= 1;
else if (v[c]->x > v[c]->z)
flags[c] |= 2;
if (v[c]->y < -v[c]->z)
flags[c] |= 4;
else if (v[c]->y > v[c]->z)
flags[c] |= 8;
if (v[c]->z < 0.1)
flags[c] |= 16;
}
/* esce se tutti i vertici sono fuori da bordo dello schermo */
if (flags[0] & flags[1] & flags[2] & flags[3])
return;
if (flags[0] | flags[1] | flags[2] | flags[3]) {
/* spiana se alcuni vertici sono fuori dallo schermo */
vc = clip3d_f(POLYTYPE_FLAT, 0.1, 0.1, 4, (AL_CONST V3D_f **)v,
vout, vtmp, out);
if (vc <= 0)
return;
}
else {
vout[0] = v[0];
vout[1] = v[1];
vout[2] = v[2];
vout[3] = v[3];
vc = 4;
}
/* visuale */
for (c=0; c<vc; c++)
persp_project_f(vout[c]->x, vout[c]->y, vout[c]->z,
&vout[c]->x, &vout[c]->y);
/* setta il colore */
vout[0]->c = ((x + z) & 1) ? makecol(0, 255, 0) : makecol(255, 255, 0);
/* render del poligono */
polygon3d_f(bmp, POLYTYPE_FLAT, NULL, vc, vout);
}
/* scrive tutto */
void render(BITMAP *bmp)
{
MATRIX_f roller, camera;
int x, y, w, h;
float xfront, yfront, zfront;
float xup, yup, zup;
/* cancella lo sfondo */
clear_to_color(bmp, makecol(255, 255, 255));
/* setta la regione visiva */
x = (SCREEN_W - viewport_w) / 2;
y = (SCREEN_H - viewport_h) / 2;
w = viewport_w;
h = viewport_h;
set_projection_viewport(x, y, w, h);
rect(bmp, x-1, y-1, x+w, y+h, makecol(255, 0, 0));
set_clip_rect(bmp, x, y, x+w-1, y+h-1);
/* calcola il vettore davanti */
xfront = sin(heading) * cos(pitch);
yfront = sin(pitch);
zfront = cos(heading) * cos(pitch);
/* ruota il vettore superiore intorno al vettore davanti dall'angolo spianato */
get_vector_rotation_matrix_f(&roller, xfront, yfront, zfront,
roll*128.0/M_PI);
apply_matrix_f(&roller, 0, -1, 0, &xup, &yup, &zup);
/* costruisce la camera_matrix */
get_camera_matrix_f(&camera,
xpos, ypos, zpos, /* posizione della camera */
xfront, yfront, zfront, /* vettore davanti */
xup, yup, zup, /* vettore superiore */
fov, /* campo di visualizzazione */
aspect); /* rapporto dell'aspetto (aspect ratio) */
/* disegna il reticolato dei quadrati */
for (x=0; x<GRID_SIZE; x++)
for (y=0; y<GRID_SIZE; y++)
draw_square(bmp, &camera, x, y);
/* mostra i testi */
set_clip_rect(bmp, 0, 0, bmp->w, bmp->h);
textprintf_ex(bmp, font, 0, 0, makecol(0, 0, 0), -1,
"Viewport width: %d (w/W changes)", viewport_w);
textprintf_ex(bmp, font, 0, 8, makecol(0, 0, 0), -1,
"Viewport height: %d (h/H changes)", viewport_h);
textprintf_ex(bmp, font, 0, 16, makecol(0, 0, 0), -1,
"Field of view: %d (f/F changes)", fov);
textprintf_ex(bmp, font, 0, 24, makecol(0, 0, 0), -1,
"Aspect ratio: %.2f (a/A changes)", aspect);
textprintf_ex(bmp, font, 0, 32, makecol(0, 0, 0), -1,
"X position: %.2f (x/X changes)", xpos);
textprintf_ex(bmp, font, 0, 40, makecol(0, 0, 0), -1,
"Y position: %.2f (y/Y changes)", ypos);
textprintf_ex(bmp, font, 0, 48, makecol(0, 0, 0), -1,
"Z position: %.2f (z/Z changes)", zpos);
textprintf_ex(bmp, font, 0, 56, makecol(0, 0, 0), -1,
"Heading: %.2f deg (left/right changes)", DEG(heading));
textprintf_ex(bmp, font, 0, 64, makecol(0, 0, 0), -1,
"Pitch: %.2f deg (pgup/pgdn changes)", DEG(pitch));
textprintf_ex(bmp, font, 0, 72, makecol(0, 0, 0), -1,
"Roll: %.2f deg (r/R changes)", DEG(roll));
textprintf_ex(bmp, font, 0, 80, makecol(0, 0, 0), -1,
"Front vector: %.2f, %.2f, %.2f", xfront, yfront, zfront);
textprintf_ex(bmp, font, 0, 88, makecol(0, 0, 0), -1,
"Up vector: %.2f, %.2f, %.2f", xup, yup, zup);
textprintf_ex(bmp, font, 0, 96, makecol(0, 0, 0), -1,
"Frames per second: %d", fps);
}
/* accordo con l'utente */
void process_input(void)
{
double frac, iptr;
poll_keyboard();
if (key[KEY_W]) {
if (key_shifts & KB_SHIFT_FLAG) {
if (viewport_w < SCREEN_W)
viewport_w += 8;
}
else {
if (viewport_w > 16)
viewport_w -= 8;
}
}
if (key[KEY_H]) {
if (key_shifts & KB_SHIFT_FLAG) {
if (viewport_h < SCREEN_H)
viewport_h += 8;
}
else {
if (viewport_h > 16)
viewport_h -= 8;
}
}
if (key[KEY_F]) {
if (key_shifts & KB_SHIFT_FLAG) {
if (fov < 96)
fov++;
}
else {
if (fov > 16)
fov--;
}
}
if (key[KEY_A]) {
frac = modf(aspect*10.0, &iptr);
if (key_shifts & KB_SHIFT_FLAG) {
if ((frac>0.59) && (frac<0.61))
aspect += 0.04f;
else
aspect += 0.03f;
if (aspect > 2)
aspect = 2;
}
else {
if ((frac>0.99) || (frac<0.01))
aspect -= 0.04f;
else
aspect -= 0.03f;
if (aspect < .1)
aspect = .1;
}
}
if (key[KEY_X]) {
if (key_shifts & KB_SHIFT_FLAG)
xpos += 0.05;
else
xpos -= 0.05;
}
if (key[KEY_Y]) {
if (key_shifts & KB_SHIFT_FLAG)
ypos += 0.05;
else
ypos -= 0.05;
}
if (key[KEY_Z]) {
if (key_shifts & KB_SHIFT_FLAG)
zpos += 0.05;
else
zpos -= 0.05;
}
if (key[KEY_LEFT])
heading -= 0.05;
if (key[KEY_RIGHT])
heading += 0.05;
if (key[KEY_PGUP])
if (pitch > -M_PI/4)
pitch -= 0.05;
if (key[KEY_PGDN])
if (pitch < M_PI/4)
pitch += 0.05;
if (key[KEY_R]) {
if (key_shifts & KB_SHIFT_FLAG) {
if (roll < M_PI/4)
roll += 0.05;
}
else {
if (roll > -M_PI/4)
roll -= 0.05;
}
}
if (key[KEY_UP]) {
xpos += sin(heading) / 4;
zpos += cos(heading) / 4;
}
if (key[KEY_DOWN]) {
xpos -= sin(heading) / 4;
zpos -= cos(heading) / 4;
}
}
void fps_check(void)
{
fps = framecount*FPS_INT;
framecount = 0;
}
int main(void)
{
BITMAP *buffer;
if (allegro_init() != 0)
return 1;
install_keyboard();
install_timer();
if (set_gfx_mode(GFX_AUTODETECT, 640, 480, 0, 0) != 0) {
if (set_gfx_mode(GFX_SAFE, 640, 480, 0, 0) != 0) {
set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
allegro_message("Inabilitato al settaggio della grafican%sn",
allegro_error);
return 1;
}
}
set_palette(desktop_palette);
buffer = create_bitmap(SCREEN_W, SCREEN_H);
install_int_ex(fps_check, BPS_TO_TIMER(FPS_INT));
while (!key[KEY_ESC]) {
render(buffer);
#ifndef DISABLE_VSYNC
vsync();
#endif
blit(buffer, screen, 0, 0, 0, 0, SCREEN_W, SCREEN_H);
framecount++;
process_input();
}
destroy_bitmap(buffer);
return 0;
}
END_OF_MAIN()
