Use std430 for all storage buffers

This commit changes the used layout for storage buffers
to std430. Previously, only storage buffers defined as function
inputs of compute shaders would use this layout. Storage
buffers defined via UniformScope would not use any layout
and thus lead to implementation dependent behavior.

src/Libs/FShade.GLSL/Assembler.fs

@@ -1438,8 +1438,13 @@ module Assembler =
             | Some fmt -> fmt
             | _ -> t.Name
 
-    let private uniformLayout (isUniformBuffer : bool) (decorations : list<UniformDecoration>) (set : int) (binding : int) =
+    // For some reason we use std430 for storage buffers but std140 for uniform buffers
+    type private Layout =
+        | None = 0
+        | Std140 = 1
+        | Std430 = 2
 
+    let private uniformLayout (layout : Layout) (decorations : list<UniformDecoration>) (set : int) (binding : int) =
         let decorations =
             decorations |> List.choose (fun d ->
                 match d with
@@ -1458,8 +1463,13 @@ module Assembler =
             else decorations
 
         let decorations =
-            if isUniformBuffer then "std140" :: decorations
-            else decorations
+            let layout =
+                match layout with
+                | Layout.Std430 -> ["std430"]
+                | Layout.Std140 -> ["std140"]
+                | _ -> []
+
+            layout @ decorations
 
         match decorations with
             | [] -> ""
@@ -1529,7 +1539,7 @@ module Assembler =
                                     fields |> List.mapS (fun field ->
                                         state {
                                             let! binding = getBinding InputKind.StorageBuffer 1 [field]
-                                            let prefix = uniformLayout false [] set binding
+                                            let prefix = uniformLayout Layout.Std430 [] set binding
                                             let name = checkName field.cUniformName
 
                                             match field.cUniformType with
@@ -1559,7 +1569,7 @@ module Assembler =
                             | Some bufferName when config.createUniformBuffers ->
                                 let bufferName = checkName bufferName
                                 let! binding = getBinding InputKind.UniformBuffer 1 fields
-                                let prefix = uniformLayout true [] set binding
+                                let prefix = uniformLayout Layout.Std140 [] set binding
 
                                 let fieldStr = 
                                     fields |> List.map (fun u -> 
@@ -1588,7 +1598,7 @@ module Assembler =
                                                 match t with
                                                     | GLSLTextureType.GLSLSampler samplerType -> 
                                                         let! binding = getBinding InputKind.Sampler cnt [u]
-                                                        prefix <- uniformLayout false u.cUniformDecorations set binding
+                                                        prefix <- uniformLayout Layout.None u.cUniformDecorations set binding
 
                                                         do! Interface.addSampler { 
                                                             samplerSet = set
@@ -1601,7 +1611,7 @@ module Assembler =
 
                                                     | GLSLTextureType.GLSLImage imageType ->
                                                         let! binding = getBinding InputKind.Image cnt [u]
-                                                        prefix <- uniformLayout false u.cUniformDecorations set binding
+                                                        prefix <- uniformLayout Layout.None u.cUniformDecorations set binding
 
                                                         do! Interface.addImage { 
                                                             imageSet = set
@@ -1612,7 +1622,7 @@ module Assembler =
 
                                             | CAccelerationStructure ->
                                                 let! binding = getBinding InputKind.AccelerationStructure 1 [u]
-                                                prefix <- uniformLayout false u.cUniformDecorations set binding
+                                                prefix <- uniformLayout Layout.None u.cUniformDecorations set binding
 
                                                 do! Interface.addAccelerationStructure {
                                                     accelSet = set
@@ -1622,7 +1632,7 @@ module Assembler =
 
                                             | _ ->
                                                 let! binding = getBinding InputKind.UniformBuffer 1 [u]
-                                                prefix <- uniformLayout false u.cUniformDecorations set binding
+                                                prefix <- uniformLayout Layout.None u.cUniformDecorations set binding
 
                                                 ()
 

src/Tests/FShade.GLSL.Tests/SimpleTests.fs

@@ -1234,4 +1234,35 @@ let ``Uniform alias with mismatching scope``() =
             e.Shaders |> ignore
         )
 
-    Assert.That(exn.Message, Does.Contain "has conflicting values")
+    Assert.That(exn.Message, Does.Contain "has conflicting values")
+
+[<Test>]
+let ``Uniform and storage buffers use std140 and std430 layout``() =
+    Setup.Run()
+
+    let fs (v : Vertex) =
+        fragment {
+            return uniform.RegionBuffer.[0]
+        }
+
+    let fsu (v : Vertex) =
+        fragment {
+            return uniform.SomeUniformArr.[0]
+        }
+
+    let cs (mybuffer : int[]) =
+        compute {
+            let id = getGlobalId().XY
+            mybuffer.[id.X] <- id.Y
+        }
+
+    GLSL.shouldCompileAndContainRegex [ Effect.ofFunction fs ] [ "std430" ]
+    GLSL.shouldCompileAndContainRegex [ Effect.ofFunction fsu ] [ "std140" ]
+
+    let glsl =
+        cs
+        |> ComputeShader.ofFunction (V3i(128,128,128))
+        |> ComputeShader.toModule
+        |> ModuleCompiler.compileGLSL430
+
+    GLSL.shouldContainRegex glsl [ "std430", None ]