Mask off sky depth after drawing skyrooms, to avoid nasty surprises. Also don't get confused by the viewmodel's depthhack.

quakespasm/Quake/gl_rmain.c

@@ -22,6 +22,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 // r_main.c
 
 #include "quakedef.h"
+#include "glquake.h"
 
 qboolean	r_cache_thrash;		// compatability
 
@@ -727,7 +728,7 @@ R_DrawViewModel -- johnfitz -- gutted
 */
 void R_DrawViewModel (void)
 {
-	if (!r_drawviewmodel.value || !r_drawentities.value || chase_active.value)
+	if (!r_drawviewmodel.value || !r_drawentities.value || chase_active.value || skyroom_drawing/*silly depthrange*/)
 		return;
 
 	if (cl.items & IT_INVISIBILITY || cl.stats[STAT_HEALTH] <= 0)
@@ -1208,6 +1209,7 @@ void R_RenderView (void)
 			VectorAngles(axis[0], axis[2], r_refdef.viewangles);
 		}
 
+		skyroom_drawing = true;
 		R_SetupView ();
 		//note: sky boxes are generally considered an 'infinite' distance away such that you'd not see paralax.
 		//that's my excuse for not handling r_stereo here, and I'm sticking to it.
@@ -1217,6 +1219,7 @@ void R_RenderView (void)
 		VectorCopy(viewang, r_refdef.viewangles);
 		skyroom_drawn = true;	//disable glClear(GL_COLOR_BUFFER_BIT)
 	}
+	skyroom_drawing = false;
 	//skyroom end
 
 	R_SetupView (); //johnfitz -- this does everything that should be done once per frame

quakespasm/Quake/gl_sky.c

@@ -35,6 +35,7 @@ extern	int rs_skypasses; //for r_speeds readout
 float	skyflatcolor[3];
 float	skymins[2][6], skymaxs[2][6];
 
+qboolean skyroom_drawing;
 qboolean skyroom_drawn;
 qboolean skyroom_enabled;
 vec4_t skyroom_origin;
@@ -1068,9 +1069,39 @@ void Sky_DrawSky (void)
 	int				i;
 
 	//in these special render modes, the sky faces are handled in the normal world/brush renderer
-	if (r_drawflat_cheatsafe || r_lightmap_cheatsafe || skyroom_drawn)
+	if (r_drawflat_cheatsafe || r_lightmap_cheatsafe)
 		return;
 
+	if (skyroom_drawn)
+	{	//Spike: We already drew a skyroom underneath. If we draw an actual sky now then we'll have wasted all that effort.
+		//however, if we fiddle with stuff, we can make sure that other surfaces don't draw over it either.
+
+		int			i;
+		msurface_t	*s;
+		texture_t	*t;
+
+		glColorMask(false,false,false,false);
+		glDisable (GL_TEXTURE_2D);
+		for (i=0 ; i<cl.worldmodel->numtextures ; i++)
+		{
+			t = cl.worldmodel->textures[i];
+
+			if (!t || !t->texturechains[chain_world] || !(t->texturechains[chain_world]->flags & SURF_DRAWSKY))
+				continue;
+
+			for (s = t->texturechains[chain_world]; s; s = s->texturechain)
+				if (!s->culled)
+				{
+					DrawGLPoly(s->polys);
+					rs_brushpasses++;
+					Sky_ProcessPoly (s->polys);
+				}
+		}
+		glEnable (GL_TEXTURE_2D);
+		glColorMask(true,true,true,true);
+		return;
+	}
+
 	//
 	// reset sky bounds
 	//

quakespasm/Quake/glquake.h

@@ -440,7 +440,7 @@ void Sky_DrawSky (void);
 void Sky_NewMap (void);
 void Sky_LoadTexture (texture_t *mt, enum srcformat fmt, unsigned int width, unsigned int height);
 void Sky_LoadSkyBox (const char *name);
-extern qboolean skyroom_drawn;		//we draw a skyroom this frame
+extern qboolean skyroom_drawn, skyroom_drawing;		//we draw a skyroom this frame
 extern qboolean skyroom_enabled;	//we know where the skyroom is ...
 extern vec4_t skyroom_origin;		//... and it is here. [3] is paralax scale
 extern vec4_t skyroom_orientation;