Working on exposing the doubles-sided flag outside the Opacity property group.

Before, the only way to set the double-sided flag was to enable a non-opaque mode, because the flag was hidden. We are moving the double-sided flag to the general property group instead of the opacity property group, so it is always available. In this particular commit, we just add the general.doubleSided property so we don't break existing data. In an upcoming commit I will remove opacity.doubleSided, once we have the material backward compatibility system ready.

I also added another "default" texture map to the Common/Feature gem that is directional, so better for understanding UV/tangent space. These were copied from the AtomLyIntegration gem. This is being used for a screenshot test in AtomSampleViewer with the new 009_Opacity_Opaque_DoubleSided.material.

Signed-off-by: santorac <55155825+santorac@users.noreply.github.com>

Gems/Atom/Feature/Common/Assets/Materials/Types/EnhancedPBR.materialtype

@@ -92,6 +92,12 @@
         ],
         "properties": {
             "general": [
+                {
+                    "id": "doubleSided",
+                    "displayName": "Double-sided",
+                    "description": "Whether to render back-faces or just front-faces.",
+                    "type": "Bool"
+                },
                 {
                     "id": "applySpecularAA",
                     "displayName": "Apply Specular AA",

Gems/Atom/Feature/Common/Assets/Materials/Types/StandardPBR.materialtype

@@ -72,6 +72,12 @@
         ],
         "properties": {
             "general": [
+                {
+                    "id": "doubleSided",
+                    "displayName": "Double-sided",
+                    "description": "Whether to render back-faces or just front-faces.",
+                    "type": "Bool"
+                },
                 {
                     "id": "applySpecularAA",
                     "displayName": "Apply Specular AA",

Gems/Atom/Feature/Common/Assets/Materials/Types/StandardPBR_HandleOpacityDoubleSided.lua

@@ -10,17 +10,19 @@
 ----------------------------------------------------------------------------------------------------
 
 function GetMaterialPropertyDependencies()
-    return {"opacity.doubleSided"}
+    return {"general.doubleSided", "opacity.doubleSided", "opacity.mode"}
 end
  
 ForwardPassIndex = 0
 ForwardPassEdsIndex = 1
 
 function Process(context)
-    local doubleSided = context:GetMaterialPropertyValue_bool("opacity.doubleSided")
+    local doubleSided = context:GetMaterialPropertyValue_bool("general.doubleSided")
+    local opacityDoubleSided = context:GetMaterialPropertyValue_bool("opacity.doubleSided")
+    local opacityMode = context:GetMaterialPropertyValue_enum("opacity.mode")
     local lastShader = context:GetShaderCount() - 1;
 
-    if(doubleSided) then
+    if(doubleSided or (opacityDoubleSided and opacityMode ~= 0)) then
         for i=0,lastShader do
             context:GetShader(i):GetRenderStatesOverride():SetCullMode(CullMode_None)
         end

Gems/Atom/Feature/Common/Assets/Textures/Default/checker_basecolor.tif

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:57d6744696768f9fb8a5fe5fee9aa36fee1eb87a9dbc1e60d4a35ed3c39d68e6
+size 810620

Gems/Atom/Feature/Common/Assets/Textures/Default/checker_uv_basecolor.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:513f47f6fea5105f603170a8881b7e3b1cd2c4258636d64a6399c725032b500d
+size 38689

Gems/Atom/TestData/TestData/Materials/StandardPbrTestCases/009_Opacity_Opaque_DoubleSided.material

@@ -0,0 +1,14 @@
+{
+    "description": "",
+    "materialType": "Materials/Types/StandardPBR.materialtype",
+    "parentMaterial": "",
+    "propertyLayoutVersion": 3,
+    "properties": {
+        "baseColor": {
+            "textureMap": "Textures/Default/checker_uv_basecolor.png"
+        },
+        "general": {
+            "doubleSided": true
+        }
+    }
+}

Gems/Atom/TestData/TestData/Objects/tube.fbx

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b2ecc32cd3052f3cb5836c8be7bf5cba54d98f46e6a0eeac95aaef00a123411a
+size 27340