summaryrefslogtreecommitdiff
path: root/src/math.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/math.c')
-rw-r--r--src/math.c37
1 files changed, 29 insertions, 8 deletions
diff --git a/src/math.c b/src/math.c
index 0f48dd3..948ded8 100644
--- a/src/math.c
+++ b/src/math.c
@@ -19,7 +19,8 @@ c3_group_rel_t *get_group_relative(char *id) {
if(gr) return gr;
}
//if we got here, we need to make a new one.
- assert(gr=malloc(sizeof(c3_group_rel_t)));//just exit on malloc error? sure...
+ gr=malloc(sizeof(c3_group_rel_t));//just exit on malloc error? sure...
+ assert(gr && "failed to malloc something I don't want to figure out how to work around if it doesn't malloc.");
memset(gr,0,sizeof(c3_group_rel_t));
gr->s=(c3_t){1,1,1};//scale needs to be all 1s, since it is multiplied against the coordinates.
gr->id=strdup(id);//don't forget to free this when it gets deleted.
@@ -245,7 +246,7 @@ real distance3(c3_t p1,c3_t p2) {
// <0 for P2 right of the line
// See: Algorithm 1 "Area of Triangles and Polygons"
inline int
-isLeft( cs_t P0, cs_t P1, cs_t P2 )
+isLeft( c2_t P0, c2_t P1, c2_t P2 )
{
return ( (P1.x - P0.x) * (P2.y - P0.y)
- (P2.x - P0.x) * (P1.y - P0.y) );
@@ -256,20 +257,23 @@ isLeft( cs_t P0, cs_t P1, cs_t P2 )
// cn_PnPoly(): crossing number test for a point in a polygon
// Input: P = a point,
// V[] = vertex points of a polygon V[n+1] with V[n]=V[0]
+// hacked on by epoch to make the previous statement automatic. i+1 changed to i+1%n
// Return: 0 = outside, 1 = inside
// This code is patterned after [Franklin, 2000]
+
+//pretending like this will work fine with a real instead of an int... probably fine.
int
-cn_PnPoly( cs_t P, cs_t *V, int n )
+cn_PnPoly( c2_t P, c2_t *V, int n )
{
int cn = 0; // the crossing number counter
// loop through all edges of the polygon
for (int i=0; i<n; i++) { // edge from V[i] to V[i+1]
- if (((V[i].y <= P.y) && (V[i+1].y > P.y)) // an upward crossing
- || ((V[i].y > P.y) && (V[i+1].y <= P.y))) { // a downward crossing
+ if (((V[i].y <= P.y) && (V[i+1%n].y > P.y)) // an upward crossing
+ || ((V[i].y > P.y) && (V[i+1%n].y <= P.y))) { // a downward crossing
// compute the actual edge-ray intersect x-coordinate
- float vt = (float)(P.y - V[i].y) / (V[i+1].y - V[i].y);
- if (P.x < V[i].x + vt * (V[i+1].x - V[i].x)) // P.x < intersect
+ float vt = (float)(P.y - V[i].y) / (V[i+1%n].y - V[i].y);
+ if (P.x < V[i].x + vt * (V[i+1%n].x - V[i].x)) // P.x < intersect
++cn; // a valid crossing of y=P.y right of P.x
}
}
@@ -283,8 +287,9 @@ cn_PnPoly( cs_t P, cs_t *V, int n )
// Input: P = a point,
// V[] = vertex points of a polygon V[n+1] with V[n]=V[0]
// Return: wn = the winding number (=0 only when P is outside)
+
int
-wn_PnPoly( cs_t P, cs_t *V, int n )
+wn_PnPoly( c2_t P, c2_t *V, int n )
{
int wn = 0; // the winding number counter
@@ -304,3 +309,19 @@ wn_PnPoly( cs_t P, cs_t *V, int n )
return wn;
}
//===================================================================
+
+int epoch_PnPoly( c2_t P, c2_t *V, int n ) {
+ cs_t min,max;
+ int i;
+ min.x=V[0].x;
+ min.y=V[0].y;
+ max.x=V[0].x;
+ max.y=V[0].y;
+ for(i=0;i<n;i++) {
+ min.x=min(min.x,V[i].x);
+ max.x=max(max.x,V[i].x);
+ min.y=min(min.y,V[i].y);
+ max.y=max(max.y,V[i].y);
+ }
+ return (P.x <= max.x && P.x >= min.x && P.y >= min.y && P.y <= max.y);
+}