void Shape3D :: calc_face_normal(int face_index)
{
GLfloat* fn = new GLfloat[4];
// calculate face normal
GLfloat vector1[4], vector2[4];
vv_sub(verts[faces[face_index][0]], verts[faces[face_index][1]], vector1);
vv_sub(verts[faces[face_index][2]], verts[faces[face_index][1]], vector2);
vv_cross(vector2, vector1, fn);
normalize(fn);
// place into face normals array
f_norms[face_index] = fn;
}
void Cube :: make_face(int face_num, int v1, int v2, int v3)
{
// allocate new face
int* f = new int[3];
// allocate new face normal
GLfloat* fn = new GLfloat[4];
init_vector(fn);
// set face vertices
f[0] = v1;
f[1] = v2;
f[2] = v3;
// place into faces array
faces[face_num] = f;
// calculate face normal
GLfloat vector1[4], vector2[4];
vv_sub(verts[v2], verts[v1], vector1);
vv_sub(verts[v2], verts[v3], vector2);
vv_cross(vector1, vector2, fn);
normalize(fn);
// place into face normals array
f_norms[face_num] = fn;
}
int draw_3d_tri(
pVector v1p, Graph3dColor c1p, pVector n1p,
pVector v2p, Graph3dColor c2p, pVector n2p,
pVector v3p, Graph3dColor c3p, pVector n3p) {
int j;
int x1, x2, x3;
int y1, y2, y3;
// First, convert the colors to floats
Vector c1 = {
(float)c1p.r / 255.0,
(float)c1p.g / 255.0,
(float)c1p.b / 255.0,
1.0
};
Vector c2 = {
(float)c2p.r / 255.0,
(float)c2p.g / 255.0,
(float)c2p.b / 255.0,
1.0
};
Vector c3 = {
(float)c3p.r / 255.0,
(float)c3p.g / 255.0,
(float)c3p.b / 255.0,
1.0
};
Vector v1, v2, v3;
Vector n1, n2, n3;
Vector L1, L2, L3;
// Next, apply the modelview matrix to the triangle's vertices
vv_cpy(v1, v1p); vv_cpy(v2, v2p); vv_cpy(v3, v3p);
vm_mul(v1, modelview);
vm_mul(v2, modelview);
vm_mul(v3, modelview);
// And also to the normals
vv_cpy(n1, n1p); vv_cpy(n2, n2p); vv_cpy(n3, n3p);
vm_mul(n1, modelview);
vm_mul(n2, modelview);
vm_mul(n3, modelview);
// Find the distance for each point from the light
vv_cpy(L1, lightpos); vv_sub(L1, v1); v_norm(L1);
vv_cpy(L2, lightpos); vv_sub(L2, v2); v_norm(L2);
vv_cpy(L3, lightpos); vv_sub(L3, v3); v_norm(L3);
// Then, apply our lighting equations
// We assume that the triangle's ambient and diffuse values are the same
// We also assume that
for(j = 0; j < 4; j++) {
c1[j] = light_transform(c1[j], n1, L1, j);
c2[j] = light_transform(c2[j], n2, L2, j);
c2[j] = light_transform(c3[j], n3, L3, j);
}
// Convert the color values to values the graphics card will accept
// c1p et al were passed by value, so we can modify them
c1p.r = c1[0] * 255;
c1p.g = c1[1] * 255;
c1p.b = c1[2] * 255;
c2p.r = c2[0] * 255;
c2p.g = c2[1] * 255;
c2p.b = c2[2] * 255;
c3p.r = c3[0] * 255;
c3p.g = c3[1] * 255;
c3p.b = c3[2] * 255;
// Lastly, find the coordinates on the screen for each point,
// and draw the triangle
x1 = 800 * (depth/height) * (v1[0] / v1[2]);
y1 = 600 * (depth/height) * (v1[1] / v1[2]);
x2 = 800 * (depth/height) * (v2[0] / v2[2]);
y2 = 600 * (depth/height) * (v2[1] / v2[2]);
x3 = 800 * (depth/height) * (v3[0] / v3[2]);
y3 = 600 * (depth/height) * (v3[1] / v3[2]);
draw_2d_tri(x1, y1, c1p, x2, y2, c2p, x3, y3, c3p);
printf("v1: %f %f %f\n", v1[0], v1[1], v1[2]);
printf("v2: %f %f %f\n", v2[0], v2[1], v2[2]);
printf("v2: %f %f %f\n", v3[0], v3[1], v3[2]);
printf("%d %d; %d %d; %d %d\n", x1, y1, x2, y2, x3, y3);
return GRAPH3D_OK;
}
// modify_scene modifies the global variables g_projectiles and g_explosions
// during the course of an attack sequence. It takes a parameter dt which
// represents the amount of time between frames.
// Return: the number of items left to animate.
int modify_scene(float dt)
{
int i, j, num_impacted;
float t;
struct Projectile *p;
struct Explosion *e;
struct Tank *tank;
Vector v;
float d;
// Go through all the explosions and update them according to the
// amount of time passed.
for(j = 0; j < g_num_explosions; j++)
{
e = &g_explosions[j];
t = update_explosion(e, dt);
}
// Go through all the projectiles and handle the ones that have not yet
// been impacted.
for(j = 0, num_impacted = 0; j < g_num_projectiles; j++)
{
p = &g_projectiles[j];
if(p->o.state != STATE_IMPACTED)
{
t = update_projectile(p, dt);
if(p->o.state == STATE_IMPACTED)
{
printf("Projectile %d has impacted.\n", j);
// If the projectile has impacted, an explosion needs to be
// created which is appropriate to the projectile which has
// impacted, and which takes on properties of the former
// projectile.
e = new_explosion(p);
// Now, using the remaining time that did not get used on the
// projectile, update the new explosion.
t = update_explosion(e, dt - t);
// And play a sound to match
sx3_play_sound(SX3_AUDIO_EXPLOSION);
}
}
if(p->o.state == STATE_IMPACTED) num_impacted++;
}
// FIX ME!! These two checks don't work properly if we have a low
// framerate.
for(j = 0; j < g_num_explosions; j++)
{
e = &g_explosions[j];
for(i = 0; i < g_num_tanks; i++)
{
tank = &g_tanks[i];
// Don't check this tank if it's already been hit
// FIX ME!! This should be on a per-projectile/explosion basis
if(tank->s.temp_damage != 0.0) continue;
// Find the distance between the tank and the explosion, and test
vv_cpy(v, tank->o.props.position);
vv_sub(v, e->props.position);
d = v_mag(v);
if(d < tank->o.props.radius + e->props.radius)
{
// A tank has been hit!
sx3_play_sound(SX3_AUDIO_HIT);
printf("Tank %d hit by explosion %d\n", i, j);
// FIX ME!! This should not be constant damage.
tank->s.temp_damage = 20.0;
}
}
}
for(j = 0; j < g_num_projectiles; j++)
{
p = &g_projectiles[j];
if(p->o.state == STATE_IMPACTED) continue;
for(i = 0; i < g_num_tanks; i++)
{
tank = &g_tanks[i];
// Don't check this tank if it's already been hit
// FIX ME!! This should be on a per-projectile/explosion basis
if(tank->s.temp_damage != 0.0) continue;
// Find the distance between the tank and the projectiles, and test
vv_cpy(v, tank->o.props.position);
vv_sub(v, p->o.props.position);
d = v_mag(v);
if(d < tank->o.props.radius + p->o.props.radius)
{
// A tank has been hit!
sx3_play_sound(SX3_AUDIO_HIT);
printf("Tank %d hit by projectile %d\n", i, j);
// FIX ME!! This should not be constant damage.
tank->s.temp_damage = 40.0;
}
}
}
return g_num_explosions + g_num_projectiles - num_impacted;
}
