Opt out of shadow casting for some lights (#2085)

Co-authored-by: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>

Resources/Shaders/Internal/light_shared.swsl

@@ -40,7 +40,7 @@ void fragment()
     highp vec2 diff = worldPosition - lightCenter;
 
     // Totally not hacky PCF on top of VSM.
-    highp float occlusion = createOcclusion(diff);
+    highp float occlusion = lightIndex < 0.0 ? 1.0 : createOcclusion(diff);
 
     if (occlusion == 0.0)
     {

Robust.Client/GameObjects/Components/Light/PointLightComponent.cs

@@ -120,6 +120,12 @@ namespace Robust.Client.GameObjects
             set => _visibleNested = value;
         }
 
+        /// <summary>
+        ///     Whether this pointlight should cast shadows
+        /// </summary>
+        [DataField("castShadows")]
+        public bool CastShadows = true;
+
         [DataField("nestedvisible")]
         private bool _visibleNested = true;
         [DataField("autoRot")]

Robust.Client/Graphics/Clyde/Clyde.LightRendering.cs

@@ -361,6 +361,8 @@ namespace Robust.Client.Graphics.Clyde
                     {
                         var (light, lightPos, _) = lights[i];
 
+                        if (!light.CastShadows) continue;
+
                         DrawOcclusionDepth(lightPos, ShadowMapSize, light.Radius, i);
                     }
                 }
@@ -459,7 +461,7 @@ namespace Robust.Client.Graphics.Clyde
                 }
 
                 lightShader.SetUniformMaybe("lightCenter", lightPos);
-                lightShader.SetUniformMaybe("lightIndex", (i + 0.5f) / ShadowTexture.Height);
+                lightShader.SetUniformMaybe("lightIndex", component.CastShadows ? (i + 0.5f) / ShadowTexture.Height : -1);
 
                 var offset = new Vector2(component.Radius, component.Radius);