1 files changed, 148 insertions, 0 deletions
diff --git a/vertex.c b/vertex.c
new file mode 100644
index 0000000..0cd6ce7
--- /dev/null
+++ b/vertex.c
@@ -0,0 +1,148 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include <memdraw.h>
+#include <geometry.h>
+#include "libobj/obj.h"
+#include "graphics.h"
+#include "internal.h"
+
+static void
+_addvattr(Vertex *v, Vertexattr *va)
+{
+	int i;
+
+	for(i = 0; i < v->nattrs; i++)
+		if(strcmp(v->attrs[i].id, va->id) == 0){
+			v->attrs[i] = *va;
+			return;
+		}
+	v->attrs = erealloc(v->attrs, ++v->nattrs*sizeof(*va));
+	v->attrs[v->nattrs-1] = *va;
+}
+
+static void
+copyvattrs(Vertex *d, Vertex *s)
+{
+	int i;
+
+	for(i = 0; i < s->nattrs; i++)
+		_addvattr(d, &s->attrs[i]);
+}
+
+Vertex
+dupvertex(Vertex *v)
+{
+	Vertex nv;
+
+	nv = *v;
+	nv.attrs = nil;
+	nv.nattrs = 0;
+	copyvattrs(&nv, v);
+	return nv;
+}
+
+void
+lerpvertex(Vertex *v, Vertex *v0, Vertex *v1, double t)
+{
+	Vertexattr va;
+	int i;
+
+	v->p = lerp3(v0->p, v1->p, t);
+	v->n = lerp3(v0->n, v1->n, t);
+	v->c = lerp3(v0->c, v1->c, t);
+	v->uv = lerp2(v0->uv, v1->uv, t);
+	v->attrs = nil;
+	v->nattrs = 0;
+	for(i = 0; i < v0->nattrs; i++){
+		va.id = v0->attrs[i].id;
+		va.type = v0->attrs[i].type;
+		if(va.type == VAPoint)
+			va.p = lerp3(v0->attrs[i].p, v1->attrs[i].p, t);
+		else
+			va.n = flerp(v0->attrs[i].n, v1->attrs[i].n, t);
+		_addvattr(v, &va);
+	}
+}
+
+/*
+ * perspective-correct barycentric attribute interpolation
+ */
+void
+berpvertex(Vertex *v, Vertex *v0, Vertex *v1, Vertex *v2, Point3 bc)
+{
+	Vertexattr va;
+	int i;
+
+	v->n = addpt3(addpt3(
+		mulpt3(v0->n, bc.x),
+		mulpt3(v1->n, bc.y)),
+		mulpt3(v2->n, bc.z));
+	v->c = addpt3(addpt3(
+		mulpt3(v0->c, bc.x),
+		mulpt3(v1->c, bc.y)),
+		mulpt3(v2->c, bc.z));
+	v->uv = addpt2(addpt2(
+		mulpt2(v0->uv, bc.x),
+		mulpt2(v1->uv, bc.y)),
+		mulpt2(v2->uv, bc.z));
+	v->attrs = nil;
+	v->nattrs = 0;
+	for(i = 0; i < v0->nattrs; i++){
+		va.id = v0->attrs[i].id;
+		va.type = v0->attrs[i].type;
+		if(va.type == VAPoint)
+			va.p = addpt3(addpt3(
+				mulpt3(v0->attrs[i].p, bc.x),
+				mulpt3(v1->attrs[i].p, bc.y)),
+				mulpt3(v2->attrs[i].p, bc.z));
+		else
+			va.n = dotvec3(Vec3(v0->attrs[i].n, v1->attrs[i].n, v2->attrs[i].n), bc);
+		_addvattr(v, &va);
+	}
+}
+
+void
+addvattr(Vertex *v, char *id, int type, void *val)
+{
+	Vertexattr va;
+
+	va.id = id;
+	va.type = type;
+	switch(type){
+	case VAPoint: va.p = *(Point3*)val; break;
+	case VANumber: va.n = *(double*)val; break;
+	default: sysfatal("unknown vertex attribute type '%d'", type);
+	}
+	_addvattr(v, &va);
+}
+
+Vertexattr *
+getvattr(Vertex *v, char *id)
+{
+	int i;
+
+	for(i = 0; i < v->nattrs; i++)
+		if(strcmp(v->attrs[i].id, id) == 0)
+			return &v->attrs[i];
+	return nil;
+}
+
+void
+delvattrs(Vertex *v)
+{
+	free(v->attrs);
+	v->attrs= nil;
+	v->nattrs = 0;
+}
+
+void
+fprintvattrs(int fd, Vertex *v)
+{
+	int i;
+
+	for(i = 0; i < v->nattrs; i++)
+		fprint(fd, "id %s type %d v %g\n",
+			v->attrs[i].id, v->attrs[i].type, v->attrs[i].n);
+}