From 04d50b8bbe324fdb7a8a1e724fbc59c4050862f0 Mon Sep 17 00:00:00 2001
From: rodri <rgl@antares-labs.eu>
Date: Sat, 13 Jul 2024 10:23:52 +0000
Subject: fix the geometry glitches when moving things around.

it's possible for interactive programs to keep updating
the geometry of the scene during rendering, which caused
primitives to look deformed or shattered in the final
image.

to avoid this we take a snapshot of the current state of
things (scene and camera), and render based on that copy.
---
 scene.c | 125 +++++++++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 92 insertions(+), 33 deletions(-)

(limited to 'scene.c')

diff --git a/scene.c b/scene.c
index ba30de9..95c6203 100644
--- a/scene.c
+++ b/scene.c
@@ -166,18 +166,12 @@ loadobjmodel(Model *m, OBJ *obj)
 
 			if(objmtl->map_Kd != nil){
 				mtl->diffusemap = alloctexture(sRGBTexture, nil);
-				mtl->diffusemap->image = allocmemimaged(objmtl->map_Kd->r, objmtl->map_Kd->chan, objmtl->map_Kd->data);
-				if(mtl->diffusemap->image == nil)
-					sysfatal("allocmemimaged: %r");
-				mtl->diffusemap->image->data->ref++;
+				mtl->diffusemap->image = dupmemimage(objmtl->map_Kd);
 			}
 
 			if(objmtl->norm != nil){
 				mtl->normalmap = alloctexture(RAWTexture, nil);
-				mtl->normalmap->image = allocmemimaged(objmtl->norm->r, objmtl->norm->chan, objmtl->norm->data);
-				if(mtl->normalmap->image == nil)
-					sysfatal("allocmemimaged: %r");
-				mtl->normalmap->image->data->ref++;
+				mtl->normalmap->image = dupmemimage(objmtl->norm);
 			}
 
 			addmtlmap(&mtlmap, objmtl, m->nmaterials-1);
@@ -318,29 +312,61 @@ newmodel(void)
 	return m;
 }
 
-void
-delmodel(Model *m)
+Model *
+dupmodel(Model *m)
 {
+	Model *nm;
+	int i;
+
 	if(m == nil)
-		return;
+		return nil;
+
+	nm = newmodel();
 	if(m->tex != nil)
-		freetexture(m->tex);
+		nm->tex = duptexture(m->tex);
 	if(m->nmaterials > 0){
-		while(m->nmaterials--){
-			freetexture(m->materials[m->nmaterials].diffusemap);
-			freetexture(m->materials[m->nmaterials].normalmap);
-			free(m->materials[m->nmaterials].name);
+		nm->nmaterials = m->nmaterials;
+		nm->materials = emalloc(nm->nmaterials*sizeof(*nm->materials));
+		for(i = 0; i < m->nmaterials; i++){
+			nm->materials[i] = m->materials[i];
+			nm->materials[i].diffusemap = duptexture(m->materials[i].diffusemap);
+			nm->materials[i].normalmap = duptexture(m->materials[i].normalmap);
+			nm->materials[i].name = strdup(m->materials[i].name);
+			if(nm->materials[i].name == nil)
+				sysfatal("strdup: %r");
 		}
-		free(m->materials);
 	}
-	if(m->nprims > 0)
-		free(m->prims);
-	memset(m, 0, sizeof *m);
+	if(m->nprims > 0){
+		nm->nprims = m->nprims;
+		nm->prims = emalloc(nm->nprims*sizeof(*nm->prims));
+		for(i = 0; i < m->nprims; i++){
+			nm->prims[i] = m->prims[i];
+			if(nm->nmaterials > 0 && m->prims[i].mtl != nil)
+				nm->prims[i].mtl = &nm->materials[m->prims[i].mtl - m->materials];
+		}
+	}
+	return nm;
+}
+
+void
+delmodel(Model *m)
+{
+	if(m == nil)
+		return;
+
+	freetexture(m->tex);
+	while(m->nmaterials--){
+		freetexture(m->materials[m->nmaterials].diffusemap);
+		freetexture(m->materials[m->nmaterials].normalmap);
+		free(m->materials[m->nmaterials].name);
+	}
+	free(m->materials);
+	free(m->prims);
 	free(m);
 }
 
 Entity *
-newentity(Model *m)
+newentity(char *name, Model *m)
 {
 	Entity *e;
 
@@ -349,19 +375,37 @@ newentity(Model *m)
 	e->bx = Vec3(1,0,0);
 	e->by = Vec3(0,1,0);
 	e->bz = Vec3(0,0,1);
+	e->name = name == nil? nil: strdup(name);
 	e->mdl = m;
 	e->prev = e->next = nil;
 	return e;
 }
 
+Entity *
+dupentity(Entity *e)
+{
+	Entity *ne;
+
+	if(e == nil)
+		return nil;
+
+	ne = newentity(nil, nil);
+	*ne = *e;
+	if(e->name != nil)
+		ne->name = strdup(e->name);
+	ne->mdl = dupmodel(e->mdl);
+	ne->prev = ne->next = nil;
+	return ne;
+}
+
 void
 delentity(Entity *e)
 {
 	if(e == nil)
 		return;
-	if(e->mdl != nil)
-		delmodel(e->mdl);
-	memset(e, 0, sizeof *e);
+
+	delmodel(e->mdl);
+	free(e->name);
 	free(e);
 }
 
@@ -399,15 +443,20 @@ newscene(char *name)
 	return s;
 }
 
-void
-delscene(Scene *s)
+Scene *
+dupscene(Scene *s)
 {
+	Scene *ns;
+	Entity *e;
+
 	if(s == nil)
-		return;
-	clearscene(s);
-	free(s->name);
-	memset(s, 0, sizeof *s);
-	free(s);
+		return nil;
+
+	ns = newscene(s->name);
+	if(s->nents > 0)
+		for(e = s->ents.next; e != &s->ents; e = e->next)
+			ns->addent(ns, dupentity(e));
+	return ns;
 }
 
 void
@@ -420,6 +469,16 @@ clearscene(Scene *s)
 		s->delent(s, e);
 		delentity(e);
 	}
-	if(s->skybox != nil)
-		freecubemap(s->skybox);
+	freecubemap(s->skybox);
+}
+
+void
+delscene(Scene *s)
+{
+	if(s == nil)
+		return;
+
+	clearscene(s);
+	free(s->name);
+	free(s);
 }
-- 
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