From: John Tsiombikas <nuclear@member.fsf.org>
Date: Fri, 3 Feb 2023 16:18:42 +0000 (+0200)
Subject: foo
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=meshfrac;a=commitdiff_plain;h=82bf18c392447827912146ba65145500c9c25385

foo
---

diff --git a/src/frac.c b/src/frac.c
index 071b5c2..93cb963 100644
--- a/src/frac.c
+++ b/src/frac.c
@@ -118,29 +118,68 @@ int frac_build_cells(struct fracture *frac)
 
 static int build_cell(struct fracture *frac, int cellidx)
 {
-	int i, j, num;
-	struct plane plane, *pptr;
+	int i, j, num, clipres;
+	struct plane plane;
 	struct frac_cell *cell = frac->cells + cellidx;
+	struct poly poly, clipped, *polys, *pptr;
+	float bsize;
+
+	if(!(polys = dynarr_alloc(0, sizeof *polys))) {
+		return -1;
+	}
+
+	cmesh_bsphere(frac->mesh, 0, &bsize);
+	size *= 2;
 
 	num = dynarr_size(frac->cells);
 	for(i=0; i<num; i++) {
 		if(i == cellidx) continue;
 		midplane(&plane, &cell->pt, &frac->cells[i].pt);
-		if(!(pptr = dynarr_push(cell->planes, &plane))) {
+		plane_poly(&plane, &poly, bsize);
+		if(!(pptr = dynarr_push(polys, &poly))) {
 			return -1;
 		}
-		cell->planes = pptr;
+		polys = pptr;
 	}
 
+	num = dynarr_size(polys);
+	valid_planes = alloca(num * sizeof *valid_planes);
+	memset(valid_planes, 0xff, num * sizeof *valid_planes);
+
 	/* clip all planes against each other to end up with a convex cell */
-	num = dynarr_size(cell->planes);
+	cell->num_polys = num;
 	for(i=0; i<num; i++) {
 		for(j=0; j<num; j++) {
-			if(i == j) continue;
+			if(i == j || !valid_planes[j]) {
+				continue;
+			}
+
+			/* clip plane polygon i with plane j */
+			poly_plane(polys + j, &plane);
+			init_poly(&clipped);
+			if((clipres = clip_poly(&clipped, polys + i, &plane)) < 0) {
+				/* completely clipped, mark it for removal */
+				valid_planes[i] = 0;
+				cell->num_polys--;
+				break;
+			}
+		}
+	}
 
-			clip_poly...
+	if(!(cell->polys = malloc(cell->num_polys * sizeof *cell->polys))) {
+		return -1;
+	}
+	pptr = cell->polys;
+	for(i=0; i<num; i++) {
+		if(valid_planes[i]) {
+			assert(pptr - cell->polys < cell->num_polys);
+			*pptr++ = polys[i];
+		} else {
+			destroy_poly(polys + i);
 		}
 	}
+	darr_free(polys);
+	return 0;
 }
 
 int frac_build_shell(struct fracture *frac)
diff --git a/src/frac.h b/src/frac.h
index 72192b7..8a7e022 100644
--- a/src/frac.h
+++ b/src/frac.h
@@ -7,8 +7,8 @@
 
 struct frac_cell {
 	cgm_vec3 pt;
-	struct cmesh *mesh;
-	struct plane *planes;			/* dynarr */
+	struct poly *polys;
+	int num_polys;
 };
 
 struct fracture {
diff --git a/src/geom.c b/src/geom.c
index 81e9df4..4e30628 100644
--- a/src/geom.c
+++ b/src/geom.c
@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <assert.h>
 #include "geom.h"
 #include "dynarr.h"
 
@@ -130,6 +131,12 @@ float ray_poly(const cgm_ray *ray, const struct poly *poly)
 	return t;
 }
 
+int init_poly(struct poly *p)
+{
+	p->verts = dynarr_alloc(0, sizeof *p->verts);
+	assert(p->verts);
+	return p->verts ? 0 : -1;
+}
 
 /* returns:
  *  1 -> both inside
diff --git a/src/geom.h b/src/geom.h
index ebb6659..19c10ff 100644
--- a/src/geom.h
+++ b/src/geom.h
@@ -27,6 +27,8 @@ int plane_poly(const struct plane *plane, struct poly *poly, float size);
 float ray_plane(const cgm_ray *ray, const struct plane *plane);
 float ray_poly(const cgm_ray *ray, const struct poly *poly);
 
+int init_poly(struct poly *p);
+void destroy_poly(struct poly *p);
 int clip_poly(struct poly *pout, const struct poly *pin, const struct plane *plane);
 
 #endif	/* GEOM_H_ */