Remove unused depth tile calculations

The depth tile shaders calculated average and variance of the depth of
the pixels in the tile, storing these in the green and alpha channels.
Do not calculate these since they are not used.

Author: slipher

src/engine/renderer/glsl_source/depthtile1_fp.glsl

@@ -115,20 +115,9 @@ void	main()
 
     float maxDepth = max16( depth[0], depth[1], depth[2], depth[3] );
 
-    float avgDepth = dot( depth[0] + depth[1] + depth[2] + depth[3],
-			  vec4( samples ) );
-
-    depth[0] -= avgDepth * mask[0];
-    depth[1] -= avgDepth * mask[1];
-    depth[2] -= avgDepth * mask[2];
-    depth[3] -= avgDepth * mask[3];
-
-    float variance = dot( depth[0], depth[0] ) + dot( depth[1], depth[1] ) +
-      dot( depth[2], depth[2] ) + dot( depth[3], depth[3] );
-    variance *= samples;
-    outputColor = vec4( maxDepth, minDepth, avgDepth, sqrt( variance ) );
+    outputColor = vec4( maxDepth, minDepth, 0.0, 0.0 );
   } else {
     // found just sky pixels
-    outputColor = vec4( 99999.0, 99999.0, 99999.0, 0.0 );
+    outputColor = vec4( 99999.0, 99999.0, 0.0, 0.0 );
   }
 }

src/engine/renderer/glsl_source/depthtile2_fp.glsl

@@ -47,23 +47,16 @@ void	main()
   vec2 st = gl_FragCoord.st * r_tileStep;
   float x, y;
   vec4 accum = vec4( 0.0, 99999.0, 0.0, 0.0 );
-  float count = 0.0;
 
   for( x = -0.375; x < 0.5; x += 0.25 ) {
     for( y = -0.375; y < 0.5; y += 0.25 ) {
       vec4 data = texture2D( u_DepthTile1, st + vec2(x, y) * r_tileStep );
       if( data.y < 99999.0 ) {
 	accum.x = max( accum.x, data.x );
 	accum.y = min( accum.y, data.y );
-	accum.zw += data.zw;
-	count += 1.0;
       }
     }
   }
 
-  if( count >= 1.0 ) {
-    accum.zw *= 1.0 / count;
-  }
-
   outputColor = accum;
 }

src/engine/renderer/tr_image.cpp

@@ -2588,7 +2588,7 @@ static void R_CreateDepthRenderImage()
 		imageParams.wrapType = wrapTypeEnum_t::WT_ONE_CLAMP;
 
 		imageParams.bits = IF_NOPICMIP;
-		imageParams.bits |= r_highPrecisionRendering.Get() ? IF_RGBA32F : IF_RGBA16F;
+		imageParams.bits |= r_highPrecisionRendering.Get() ? IF_TWOCOMP32F : IF_TWOCOMP16F;
 
 		tr.depthtile1RenderImage = R_CreateImage( "_depthtile1Render", nullptr, w, h, 1, imageParams );