Fixed opaque & non-opaque sprite sorting (#3660)

Author: antopilo

engine/Sandbox.Engine/Scene/GameObjectSystems/SceneSpriteSystem.cs

@@ -231,6 +231,11 @@ private static RenderGroupKey GetRenderGroupKey( ISpriteRenderGroup component, G
 			flags |= InstanceGroupFlags.Additive;
 		}
 
+		if ( component.Opaque )
+		{
+			flags |= InstanceGroupFlags.Opaque;
+		}
+
 		RenderGroupKey renderGroupKey = new()
 		{
 			GroupFlags = flags,
@@ -281,6 +286,7 @@ private SpriteBatchSceneObject CreateRenderGroup( RenderGroupKey renderGroupKey
 		renderGroupObject.Flags.ExcludeGameLayer = (renderGroupKey.GroupFlags & InstanceGroupFlags.CastOnlyShadow) != 0;
 		renderGroupObject.Sorted = (renderGroupKey.GroupFlags & InstanceGroupFlags.Transparent) != 0;
 		renderGroupObject.Additive = (renderGroupKey.GroupFlags & InstanceGroupFlags.Additive) != 0;
+		renderGroupObject.Opaque = (renderGroupKey.GroupFlags & InstanceGroupFlags.Opaque) != 0;
 		renderGroupObject.Tags.SetFrom( new TagSet( renderGroupKey.Tags ) );
 		renderGroupKey.RenderLayer.Apply( renderGroupObject );
 
@@ -362,6 +368,7 @@ internal enum InstanceGroupFlags
 		CastShadow = 1 << 0,
 		CastOnlyShadow = 1 << 1,
 		Transparent = 1 << 2,
-		Additive = 1 << 3
+		Additive = 1 << 3,
+		Opaque = 1 << 4
 	}
 }

engine/Sandbox.Engine/Systems/SceneSystem/SpriteBatchSceneObject.cs

@@ -13,6 +13,7 @@ internal sealed class SpriteBatchSceneObject : SceneCustomObject
 	public bool Sorted { get; set; } = false;
 	public bool Filtered { get; set; } = false;
 	public bool Additive { get; set; } = false;
+	public bool Opaque { get; set; } = false;
 
 	internal Dictionary<Guid, SpriteRenderer> Components = new();
 
@@ -512,6 +513,7 @@ public override void RenderSceneObject()
 		Graphics.ResourceBarrierTransition( SpriteBufferOut, ResourceState.Common );
 
 		Graphics.Attributes.SetCombo( "D_BLEND", Additive ? 1 : 0 );
+		Graphics.Attributes.SetCombo( "D_OPAQUE", Opaque ? 1 : 0 );
 
 		// Sort
 		if ( Sorted )

game/addons/base/Assets/shaders/sprite/sprite_ps.shader

@@ -230,16 +230,15 @@ PS
 		RenderState( SrcBlend, SRC_ALPHA );
 		RenderState( DstBlend, ONE );
 		RenderState( DepthWriteEnable, false );
-	#else 
-		RenderState( BlendEnable, true);
-		RenderState( DepthWriteEnable, S_MODE_DEPTH == 1 );
+	#else
+		RenderState( BlendEnable, true );
 		RenderState( SrcBlend, SRC_ALPHA );
 		RenderState( DstBlend, INV_SRC_ALPHA );
 		RenderState( BlendOp, ADD );
 		RenderState( SrcBlendAlpha, ONE );
 		RenderState( DstBlendAlpha, INV_SRC_ALPHA );
-		RenderState( AlphaToCoverageEnable, S_MODE_DEPTH == 1);
-		
+		RenderState( DepthWriteEnable, D_OPAQUE || S_MODE_DEPTH == 1 );
+		RenderState( AlphaToCoverageEnable, S_MODE_DEPTH == 1 );
 	#endif
 
 	RenderState( CullMode, NONE );
@@ -290,6 +289,7 @@ PS
 	int CurrentBufferSize < Attribute("SpriteCount"); >;
 
 	DynamicCombo( D_BLEND, 0..1, Sys( ALL ) );
+	DynamicCombo( D_OPAQUE, 0..1, Sys( ALL ) );
 
 	float g_FogStrength < Attribute( "g_FogStrength" ); >;