ref: d3b995b6e6d02a4c2413313b34a1548a777f99f9
parent: 5c9a943eb609a0f2754753550effca8d8769c86f
author: rodri <rgl@antares-labs.eu>
date: Sat Feb 10 13:52:43 EST 2024
initial clipping implementation. (not fully working yet)
--- a/render.c
+++ b/render.c
@@ -114,13 +114,6 @@
ulong cap;
} Polygon;
-typedef struct
-{- ulong *idx;
- ulong nidx;
- ulong cap;
-} Cliplist;
-
static int
addvert(Polygon *p, Vertex v)
{@@ -130,37 +123,7 @@
return p->n;
}
-static void
-delvert(Polygon *p, ulong idx)
-{- if(--p->n > 1 && idx < p->cap-1)
- memmove(&p->v[idx], &p->v[idx+1], p->n);
-}
-
static int
-addidx(Cliplist *l, ulong idx)
-{- if(++l->nidx > l->cap)
- l->idx = erealloc(l->idx, (l->cap = l->nidx)*sizeof(*l->idx));
- l->idx[l->nidx-1] = idx;
- return l->nidx;
-}
-
-static int
-idxcmp(ulong *a, ulong *b)
-{- return *a - *b;
-}
-
-static void
-reapverts(Polygon *p, Cliplist *l)
-{- qsort(l->idx, l->nidx, sizeof(l->idx[0]), (int(*)(void*,void*))idxcmp);
- while(l->nidx--)
- delvert(p, l->idx[l->nidx]);
-}
-
-static int
cliptriangle(Triangle *t)
{/* TODO implement homogeneous clipping procedure */
@@ -182,40 +145,61 @@
0, 0, 1, 1,
0, 0, -1, 1,
}, sd0[6], sd1[6];
- Polygon V; /* new polygon verts */
- Cliplist D; /* verts to delete */
- Vertex v; /* new vertex (line-plane intersection) */
- int i, j;
+ double d0, d1;
+ Polygon Vout;
+ Vertex *v0, *v1, v; /* new vertex (line-plane intersection) */
+ int i, j, nt;
if(!isvisible(t[0][0].p) && !isvisible(t[0][1].p) && !isvisible(t[0][2].p))
return 0;
-// memset(&V, 0, sizeof V);
-// memset(&D, 0, sizeof D);
-// /* initialize with the original triangle */
-// for(i = 0; i < 3; i++)
-// addvert(&V, t[0][i]);
-//
-// for(i = 0; i < V.n-1; i++){-// memset(sd0, 0, sizeof sd0);
-// memset(sd1, 0, sizeof sd1);
-// mulsdm(sd0, sdm, V.v[i].p);
-// mulsdm(sd1, sdm, V.v[i+1].p);
-//
-// for(j = 0; j < 6; j++){-// if(sd0[i] < 0 && sd1[i] < 0){-// addidx(&D, i);
-// addidx(&D, i+1);
-// }else if(sd0[i] < 0){-// addidx(&D, i);
-// }else if(sd1[i] < 0){-// addidx(&D, i+1);
-// }
-// reapverts(&V, &D);
-// }
-// }
+ nt = 0;
+ memset(&Vout, 0, sizeof Vout);
- return 1;
+ for(i = 0; i < 3; i++){+ v0 = &t[0][i];
+ v1 = &t[0][(i+1) % 3];
+ memset(sd0, 0, sizeof sd0);
+ memset(sd1, 0, sizeof sd1);
+ mulsdm(sd0, sdm, v0->p);
+ mulsdm(sd1, sdm, v1->p);
+
+ for(j = 0; j < 6; j++){+ /*
+ * if both verts are outside any of the planes, they
+ * are not in the frustum, so no need to keep testing.
+ */
+ if(sd0[j] < 0 && sd1[j] < 0)
+ break;
+
+ if(sd0[j] >= 0 && sd1[j] >= 0)
+ goto allin;
+
+ /* keep the discarded vertex attributes */
+ v = sd0[j] < 0? *v0: *v1;
+
+ d0 = (j&1) == 0? sd0[j]: -sd0[j];
+ d1 = (j&1) == 0? sd1[j]: -sd1[j];
+ v.p = divpt3(subpt3(mulpt3(v0->p, d1), mulpt3(v1->p, d0)), d1-d0);
+ v.uv = divpt2(subpt2(mulpt2(v0->uv, d1), mulpt2(v1->uv, d0)), d1-d0);
+ addvert(&Vout, v);
+
+ if(sd1[j] >= 0){+allin:
+ addvert(&Vout, *v1);
+ }
+ }
+ }
+
+ /* triangulate */
+ for(i = 0; i < Vout.n-2; i++, nt++){+ t[nt][0] = Vout.v[0];
+ t[nt][1] = Vout.v[i+1];
+ t[nt][2] = Vout.v[i+2];
+ }
+ free(Vout.v);
+
+ return nt;
}
/*
@@ -422,7 +406,7 @@
OBJIndexArray *idxtab;
OBJElem **ep;
Point3 n; /* surface normal */
- Triangle t[7-2]; /* triangles to raster */
+ Triangle *t; /* triangles to raster */
int nt;
params = arg;
@@ -431,6 +415,7 @@
threadsetname("shader unit #%d", params->id);+ t = emalloc(sizeof(*t)*32);
verts = params->model->vertdata[OBJVGeometric].verts;
tverts = params->model->vertdata[OBJVTexture].verts;
nverts = params->model->vertdata[OBJVNormal].verts;
@@ -488,6 +473,7 @@
}
}
+ free(t);
freememimage(frag);
sendp(params->donec, nil);
free(params);