From: havoc <havoc@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Tue, 5 Apr 2011 07:51:52 +0000 (+0000)
Subject: added backface culling optimization to cl_decals_newsystem, this helps
X-Git-Tag: xonotic-v0.5.0~303
X-Git-Url: https://git.xonotic.org/?a=commitdiff_plain;h=83ca53c995879fb81105426a1766ac17eaa575f5;hp=1b31df6b230b39e9b0eed0f3f4707486e7d71c47;p=xonotic%2Fdarkplaces.git

added backface culling optimization to cl_decals_newsystem, this helps
in many cases

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@11023 d7cf8633-e32d-0410-b094-e92efae38249
::stable-branch::merge=2d5c40b14b6bdba99443bd22b68e3dcddc345801
---

diff --git a/client.h b/client.h
index 909a5e22..af413434 100644
--- a/client.h
+++ b/client.h
@@ -35,6 +35,7 @@ typedef struct tridecal_s
 	float			texcoord2f[3][2];
 	float			vertex3f[3][3];
 	float			color4f[3][4];
+	float			plane[4]; // backface culling
 	// how long this decal has lived so far (the actual fade begins at cl_decals_time)
 	float			lived;
 	// if >= 0 this indicates the decal should follow an animated triangle
diff --git a/gl_rmain.c b/gl_rmain.c
index 0fbb9ad7..758673f6 100644
--- a/gl_rmain.c
+++ b/gl_rmain.c
@@ -10404,6 +10404,9 @@ static void R_DecalSystem_SpawnTriangle(decalsystem_t *decalsystem, const float
 	decal->texcoord2f[1][1] = t1[1];
 	decal->texcoord2f[2][0] = t2[0];
 	decal->texcoord2f[2][1] = t2[1];
+	TriangleNormal(v0, v1, v2, decal->plane);
+	VectorNormalize(decal->plane);
+	decal->plane[3] = DotProduct(v0, decal->plane);
 }
 
 extern cvar_t cl_decals_bias;
@@ -10857,6 +10860,10 @@ static void R_DrawModelDecals_Entity(entity_render_t *ent)
 		if (surfacevisible && !surfacevisible[decal->surfaceindex])
 			continue;
 
+		// skip backfaces
+		if (decal->triangleindex < 0 && DotProduct(r_refdef.view.origin, decal->plane) < decal->plane[3])
+			continue;
+
 		// update color values for fading decals
 		if (decal->lived >= cl_decals_time.value)
 			alpha = 1 - faderate * (decal->lived - cl_decals_time.value);