From: bones_was_here <bones_was_here@xonotic.au>
Date: Tue, 23 Jan 2024 01:00:01 +0000 (+1000)
Subject: r_shadow: work around a realtime world light crash
X-Git-Url: https://git.rm.cloudns.org/?a=commitdiff_plain;h=68fe6a551d9a8b5c2983d8b70bf16cf864fe7186;p=xonotic%2Fdarkplaces.git

r_shadow: work around a realtime world light crash

Fudges a bit more memory to support edge cases, prints a warn instead of
crashing if it's not enough.

see https://github.com/DarkPlacesEngine/darkplaces/issues/119
and 46964b3848eb7471d2f0e2284ae389b4b53337c1

Signed-off-by: bones_was_here <bones_was_here@xonotic.au>
---

diff --git a/gl_rsurf.c b/gl_rsurf.c
index 723e9fb4..a68daf5b 100644
--- a/gl_rsurf.c
+++ b/gl_rsurf.c
@@ -1295,7 +1295,10 @@ void R_Mod_CompileShadowMap(entity_render_t *ent, vec3_t relativelightorigin, ve
 	// exceeding the number of triangles in a single mesh) we have to make sure
 	// that we make only a single mesh - so over-estimate the size of the mesh
 	// to match the model.
-	r_shadow_compilingrtlight->static_meshchain_shadow_shadowmap = Mod_ShadowMesh_Begin(r_main_mempool, model->surfmesh.num_vertices, model->surfmesh.num_triangles);
+	// bones_was_here: +128 works around BUG https://github.com/DarkPlacesEngine/darkplaces/issues/119
+	// +64 was enough to start the map without triggering ASan, +96 was enough to also edit the light.
+	// See also: warning in Mod_ShadowMesh_AddMesh
+	r_shadow_compilingrtlight->static_meshchain_shadow_shadowmap = Mod_ShadowMesh_Begin(r_main_mempool, model->surfmesh.num_vertices, model->surfmesh.num_triangles + 128);
 	R_Shadow_PrepareShadowSides(model->surfmesh.num_triangles);
 	for (surfacelistindex = 0;surfacelistindex < numsurfaces;surfacelistindex++)
 	{
diff --git a/model_shared.c b/model_shared.c
index fd181f35..866ee56e 100644
--- a/model_shared.c
+++ b/model_shared.c
@@ -1044,6 +1044,12 @@ void Mod_ShadowMesh_AddMesh(shadowmesh_t *mesh, const float *vertex3f, int numtr
 
 	for (i = 0;i < numtris;i++)
 	{
+		if ((mesh->numtriangles * 3 + 2) * sizeof(int) + 1 >= ((memheader_t *)((unsigned char *)mesh->element3i - sizeof(memheader_t)))->size)
+		{
+			// FIXME: we didn't allocate enough space for all the tris, see R_Mod_CompileShadowMap
+			Con_Print(CON_WARN "Mod_ShadowMesh_AddMesh: insufficient memory allocated!\n");
+			return;
+		}
 		mesh->element3i[mesh->numtriangles * 3 + 0] = Mod_ShadowMesh_AddVertex(mesh, vertex3f + 3 * element3i[i * 3 + 0]);
 		mesh->element3i[mesh->numtriangles * 3 + 1] = Mod_ShadowMesh_AddVertex(mesh, vertex3f + 3 * element3i[i * 3 + 1]);
 		mesh->element3i[mesh->numtriangles * 3 + 2] = Mod_ShadowMesh_AddVertex(mesh, vertex3f + 3 * element3i[i * 3 + 2]);