Add toggleable shadow debug overlay.

components/sceneutil/shadow.cpp

@@ -101,6 +101,11 @@ namespace SceneUtil
         else
             definesWithShadows["shadowMapsOverlap"] = "0";
 
+        if (Settings::Manager::getBool("enable debug overlay", "Shadows"))
+            definesWithShadows["useShadowDebugOverlay"] = "1";
+        else
+            definesWithShadows["useShadowDebugOverlay"] = "0";
+
         return definesWithShadows;
     }
 
@@ -112,6 +117,8 @@ namespace SceneUtil
 
         definesWithShadows["shadowMapsOverlap"] = "0";
 
+        definesWithShadows["useShadowDebugOverlay"] = "0";
+
         return definesWithShadows;
     }
     void ShadowManager::enableIndoorMode()

docs/source/reference/modding/settings/shadows.rst

@@ -49,6 +49,16 @@ enable debug hud
 Enable or disable the debug hud to see what the shadow map(s) contain.
 This setting is only recommended for developers, bug reporting and advanced users performing fine-tuning of shadow settings.
 
+enable debug overlay
+----------------
+
+:Type:		boolean
+:Range:		True/False
+:Default:	False
+
+Enable or disable the debug overlay to see the area covered by each shadow map.
+This setting is only recommended for developers, bug reporting and advanced users performing fine-tuning of shadow settings.
+
 compute tight scene bounds
 --------------------------
 

files/settings-default.cfg

@@ -530,6 +530,8 @@ split point uniform logarithmic ratio = 0.5
 split point bias = 0.0
 # Enable the debug hud to see what the shadow map(s) contain.
 enable debug hud = false
+# Enable the debug overlay to see where each shadow map affects.
+enable debug overlay = false
 # Attempt to better use the shadow map by making them cover a smaller area. Especially helpful when looking downwards with a high viewing distance. The performance impact of this may be very large.
 compute tight scene bounds = false
 # How large to make the shadow map(s). Higher values increase GPU load, but can produce better-looking results. Power-of-two values may turn out to be faster on some GPU/driver combinations.

files/shaders/objects_fragment.glsl

@@ -155,4 +155,6 @@ void main()
 
     float fogValue = clamp((depth - gl_Fog.start) * gl_Fog.scale, 0.0, 1.0);
     gl_FragData[0].xyz = mix(gl_FragData[0].xyz, gl_Fog.color.xyz, fogValue);
+
+    applyShadowDebugOverlay();
 }

files/shaders/shadows_fragment.glsl

@@ -34,3 +34,30 @@ float unshadowedLightRatio()
 #endif // SHADOWS
     return shadowing;
 }
+
+void applyShadowDebugOverlay()
+{
+#if SHADOWS && @useShadowDebugOverlay
+    bool doneOverlay = false;
+    float colourIndex = 0.0;
+    @foreach shadow_texture_unit_index @shadow_texture_unit_list
+        if (!doneOverlay)
+        {
+            vec2 shadowXY = shadowSpaceCoords@shadow_texture_unit_index.xy / shadowSpaceCoords@shadow_texture_unit_index.w;
+            if (all(lessThan(shadowXY, vec2(1.0, 1.0))) && all(greaterThan(shadowXY, vec2(0.0, 0.0))))
+            {
+                colourIndex = mod(@shadow_texture_unit_index.0, 3.0);
+		        if (colourIndex < 1.0)
+			        gl_FragData[0].x += 0.1;
+		        else if (colourIndex < 2.0)
+			        gl_FragData[0].y += 0.1;
+		        else
+			        gl_FragData[0].z += 0.1;
+
+                if (all(lessThan(shadowXY, vec2(0.95, 0.95))) && all(greaterThan(shadowXY, vec2(0.05, 0.05))))
+                    doneOverlay = true;
+            }
+        }
+    @endforeach
+#endif // SHADOWS
+}

files/shaders/terrain_fragment.glsl

@@ -86,4 +86,6 @@ void main()
 
     float fogValue = clamp((depth - gl_Fog.start) * gl_Fog.scale, 0.0, 1.0);
     gl_FragData[0].xyz = mix(gl_FragData[0].xyz, gl_Fog.color.xyz, fogValue);
+
+    applyShadowDebugOverlay();
 }

files/shaders/water_fragment.glsl

@@ -280,4 +280,6 @@ void main(void)
 #else
     gl_FragData[0].w = clamp(fresnel*6.0 + specular, 0.0, 1.0);     //clamp(fresnel*2.0 + specular, 0.0, 1.0);
 #endif
+
+    applyShadowDebugOverlay();
 }