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working links, fixed crucial type error at update_point

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Ole Morud
2022-06-08 18:25:18 +02:00
parent 8b74e263f0
commit ecd1d2469e
1 changed files with 20 additions and 37 deletions
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57
physics.c
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@@ -55,7 +55,7 @@ int main(){
// Add 4 points, link them, and add points and links to respective arrays // Add 4 points, link them, and add points and links to respective arrays
Point a = { 10.0, 10.0, Point a = { 10.0, 10.0,
10.0, 10.0, 11.0, 10.0,
0.0, GRAVITY/FRAMERATE}; 0.0, GRAVITY/FRAMERATE};
Point b = { 20.0, 10.0, Point b = { 20.0, 10.0,
@@ -63,7 +63,7 @@ int main(){
0.0, GRAVITY/FRAMERATE}; 0.0, GRAVITY/FRAMERATE};
Point c = { 20.0, 20.0, Point c = { 20.0, 20.0,
20.0, 20.0, 19.0, 20.0,
0.0, GRAVITY/FRAMERATE}; 0.0, GRAVITY/FRAMERATE};
Point d = { 10.0, 20.0, Point d = { 10.0, 20.0,
@@ -74,9 +74,11 @@ int main(){
Link *l_bc = link_points(&b, &c); Link *l_bc = link_points(&b, &c);
Link *l_cd = link_points(&c, &d); Link *l_cd = link_points(&c, &d);
Link *l_ad = link_points(&a, &d); Link *l_ad = link_points(&a, &d);
Link *l_ac = link_points(&a, &c);
Link *l_bd = link_points(&b, &d);
Point *points[] = {&a, &b, &c, &d}; Point *points[] = {&a, &b, &c, &d};
Link *links[] = {l_ab, l_bc, l_cd, l_ad}; Link *links[] = {l_ab, l_bc, l_cd, l_ad, l_ac, l_bd};
while(1){ while(1){
@@ -84,17 +86,16 @@ int main(){
memset(cnv.data, '.', cnv.x * cnv.y); memset(cnv.data, '.', cnv.x * cnv.y);
for(int i=0; i<4; i++) for(int i=0; i<6; i++)
draw_link(&cnv, links[i]); draw_link(&cnv, links[i]);
for(int i=0; i<4; i++){ for(int i=0; i<4; i++){
update_point(points[i]); update_point(points[i]);
} }
// This function doesn't work for(int i=0; i<6; i++){
//for(int i=0; i<4; i++){ update_link(links[i]);
// update_link(links[i]); }
//}
// then render and wait // then render and wait
render(&cnv); render(&cnv);
@@ -142,46 +143,28 @@ void draw_link(Canvas* c, Link* l){
* and the forces acting upon it (fx,fy) * and the forces acting upon it (fx,fy)
*/ */
void update_point(Point* p){ void update_point(Point* p){
uint tempx = p->x; double tempx = p->x;
uint tempy = p->y; double tempy = p->y;
p->x += (p->x - p->px) + p->fx; p->x += (p->x - p->px) + p->fx;
p->y += (p->y - p->py) + p->fy; p->y += (p->y - p->py) + p->fy;
p->px = tempx; p->px = tempx;
p->py = tempy; p->py = tempy;
} }
/* /*
* Returns vector of length 1 in direction from a to b
* - probably a million ways to optimize this
*/
Point* unit_vec(Point* a, Point* b){
Point* vec = malloc(sizeof(Point));
vec->x = b->x - a->x;
vec->y = b->y - a->y;
Point origin = {0, 0};
double dist = distance(&origin, vec);
vec->x /= dist;
vec->y /= dist;
//printf("<%f, %f>, distance:%f", vec->x, vec->y, distance(&origin, vec));
return vec;
}
/* TODO
* Moves points in link l such that their distance becomes l.length * Moves points in link l such that their distance becomes l.length
*/ */
void update_link(Link* l){ void update_link(Link* l){
double cur_dist = distance(l->a, l->b); double cur_dist = distance(l->a, l->b);
double delta = l->length - cur_dist; double delta = (l->length - cur_dist)/2.0f;
double nx = (l->b->x - l->a->x)/cur_dist;
double ny = (l->b->y - l->a->y)/cur_dist;
Point* uvec = unit_vec(l->a, l->b); l->a->x -= nx * delta;
l->a->x += uvec->x * delta; l->a->y -= ny * delta;
l->a->y += uvec->y * delta; l->b->x += nx * delta;
l->b->x -= uvec->x * delta; l->b->y += ny * delta;
l->b->y -= uvec->y * delta;
} }