Add Graphics.TestValue general purpose utility for A/B testing features and perf in shaders during development

Source/Engine/Graphics/Graphics.cpp

@@ -29,6 +29,9 @@ bool Graphics::GICascadesBlending = false;
 PostProcessSettings Graphics::PostProcessSettings;
 bool Graphics::GammaColorSpace = true;
 bool Graphics::SpreadWorkload = true;
+#if !BUILD_RELEASE && !USE_EDITOR
+float Graphics::TestValue = 0.0f;
+#endif
 bool Graphics::PostProcessing::ColorGradingVolumeLUT = true;
 
 #if GRAPHICS_API_NULL

Source/Engine/Graphics/Graphics.h

@@ -90,6 +90,16 @@ public:
     /// </summary>
     API_FIELD() static bool SpreadWorkload;
 
+#if BUILD_RELEASE && !USE_EDITOR
+    /// <summary>Unused.</summary>
+    API_FIELD() static constexpr float TestValue = 0.0f;
+#else
+    /// <summary>
+    /// Debug utility to control visual or rendering features during development. For example, can be used to branch different code paths in shaders for A/B testing (perf or quality).
+    /// </summary>
+    API_FIELD() static float TestValue;
+#endif
+
 public:
     // Post Processing effects rendering configuration.
     API_CLASS(Static, Attributes = "DebugCommand") class FLAXENGINE_API PostProcessing

Source/Engine/Graphics/Materials/MaterialShader.cpp

@@ -5,6 +5,7 @@
 #include "Engine/Serialization/MemoryReadStream.h"
 #include "Engine/Level/LargeWorlds.h"
 #include "Engine/Renderer/RenderList.h"
+#include "Engine/Graphics/Graphics.h"
 #include "Engine/Graphics/RenderTask.h"
 #include "Engine/Graphics/GPUDevice.h"
 #include "Engine/Graphics/GPUContext.h"
@@ -38,6 +39,7 @@ GPU_CB_STRUCT(MaterialShaderDataPerView {
     Float3 LargeWorldsChunkIndex;
     float LargeWorldsChunkSize;
     Float3 ViewPadding0;
+    float TestValue;
     float ScaledTimeParam;
     });
 
@@ -89,6 +91,7 @@ void IMaterial::BindParameters::BindViewData()
     cb.TemporalAAJitter = view.TemporalAAJitter;
     cb.LargeWorldsChunkIndex = LargeWorlds::Enable ? (Float3)Int3(view.Origin / LargeWorlds::ChunkSize) : Float3::Zero;
     cb.LargeWorldsChunkSize = LargeWorlds::ChunkSize;
+    cb.TestValue = Graphics::TestValue;
 
     // Update constants
     GPUContext->UpdateCB(PerViewConstants, &cb);