Added int to switch between raymarching algorithm for testing purpose

ScriptableRenderPipeline/Core/CoreRP/ShaderLibrary/ScreenSpaceRaymarching.hlsl

 CBUFFER_START(ScreenSpaceRaymarching)
 int _SSRayMinLevel;
 int _SSRayMaxLevel;
+int _SSRayAlgorithm;
 CBUFFER_END
 
 struct ScreenSpaceHiZRaymarchInput

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Debug/DebugDisplay.cs

             list.Add(
                 new DebugUI.FloatField
                 {
-                    displayName = "SST Crossing Offset",
-                    getter = () => lightingDebugSettings.sstCrossingOffset,
-                    setter = value => lightingDebugSettings.sstCrossingOffset = value,
-                });
+                    displayName = "SSRayAlgorithm",
+                    getter = () => lightingDebugSettings.ssRayAlgorithm,
+                    setter = value => lightingDebugSettings.ssRayAlgorithm = value,
+                }
+            );
 
             list.Add(new DebugUI.EnumField { displayName = "Fullscreen Debug Mode", getter = () => (int)fullScreenDebugMode, setter = value => fullScreenDebugMode = (FullScreenDebugMode)value, enumNames = lightingFullScreenDebugStrings, enumValues = lightingFullScreenDebugValues, onValueChanged = RefreshLightingDebug });
             switch (fullScreenDebugMode)

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Debug/LightingDebug.cs

         }
 
         public DebugScreenSpaceTracing debugScreenSpaceTracingMode = DebugScreenSpaceTracing.None;
-        public float sstCrossingOffset;
+        public float ssRayAlgorithm;
         public DebugLightingMode    debugLightingMode = DebugLightingMode.None;
         public ShadowMapDebugMode   shadowDebugMode = ShadowMapDebugMode.None;
         public bool                 shadowDebugUseSelection = false;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs

 
         public void ApplyDebugDisplaySettings(HDCamera hdCamera, CommandBuffer cmd)
         {
+            cmd.SetGlobalInt(HDShaderIDs._SSRayAlgorithm, (int)m_CurrentDebugDisplaySettings.lightingDebugSettings.ssRayAlgorithm);
             if (m_CurrentDebugDisplaySettings.IsDebugDisplayEnabled() ||
                 m_CurrentDebugDisplaySettings.fullScreenDebugMode != FullScreenDebugMode.None ||
                 m_CurrentDebugDisplaySettings.colorPickerDebugSettings.colorPickerMode != ColorPickerDebugMode.None)

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDStringConstants.cs

 
         public static readonly int _SSRayMinLevel = Shader.PropertyToID("_SSRayMinLevel");
         public static readonly int _SSRayMaxLevel = Shader.PropertyToID("_SSRayMaxLevel");
+        public static readonly int _SSRayAlgorithm = Shader.PropertyToID("_SSRayAlgorithm");
     }
 }

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/Lit.hlsl

 
             uint2 depthSize = uint2(_PyramidDepthMipSize.xy);
 
-            ScreenSpaceLinearRaymarchInput ssInput;
-            ZERO_INITIALIZE(ScreenSpaceLinearRaymarchInput, ssInput);
+            ScreenSpaceRayHit hit;
+            ZERO_INITIALIZE(ScreenSpaceRayHit, hit);
-            //ScreenSpaceHiZRaymarchInput ssInput;
-            //ZERO_INITIALIZE(ScreenSpaceHiZRaymarchInput, ssInput);
+            bool hitSuccessful = false;
+            switch (_SSRayAlgorithm)
+            {
+            case 0:
+            {
+                ScreenSpaceHiZRaymarchInput ssInput;
+                ZERO_INITIALIZE(ScreenSpaceHiZRaymarchInput, ssInput);
+                ssInput.startPositionVS = positionVS;
+                ssInput.startLinearDepth = posInput.linearDepth;
+                ssInput.dirVS = transparentRefractVVS;
+                ssInput.projectionMatrix = UNITY_MATRIX_P;
+                ssInput.bufferSize = depthSize;
+                ssInput.minLevel = 0;
+                ssInput.maxLevel = int(_PyramidDepthMipSize.z);
+#ifdef DEBUG_DISPLAY
+                ssInput.writeStepDebug = !any(int2(_MouseClickPixelCoord.xy) - int2(posInput.positionSS));
+#endif
-            ScreenSpaceRayHit hit;
-            ZERO_INITIALIZE(ScreenSpaceRayHit, hit);
-            
-            ssInput.startPositionVS = positionVS;
-            ssInput.startLinearDepth = posInput.linearDepth;
-            ssInput.dirVS = transparentRefractVVS;
-            ssInput.projectionMatrix = UNITY_MATRIX_P;
-            ssInput.bufferSize = depthSize;
-            //ssInput.minLevel = 0;
-            //ssInput.maxLevel = int(_PyramidDepthMipSize.z);
+                hitSuccessful = ScreenSpaceHiZRaymarch(ssInput, hit);
+                break;
+            }
+            case 1:
+            {
+                ScreenSpaceLinearRaymarchInput ssInput;
+                ZERO_INITIALIZE(ScreenSpaceLinearRaymarchInput, ssInput);
+                ssInput.startPositionVS = positionVS;
+                ssInput.startLinearDepth = posInput.linearDepth;
+                ssInput.dirVS = transparentRefractVVS;
+                ssInput.projectionMatrix = UNITY_MATRIX_P;
+                ssInput.bufferSize = depthSize;
-            ssInput.writeStepDebug = !any(int2(_MouseClickPixelCoord.xy) - int2(posInput.positionSS));
+                ssInput.writeStepDebug = !any(int2(_MouseClickPixelCoord.xy) - int2(posInput.positionSS));
-            bool hitSuccessful = ScreenSpaceLinearRaymarch(ssInput, hit);
+                hitSuccessful = ScreenSpaceLinearRaymarch(ssInput, hit);
+                break;
+            }
+                
+            }
 
 #ifdef DEBUG_DISPLAY
             if (_DebugLightingMode == DEBUGLIGHTINGMODE_SCREEN_SPACE_TRACING_REFRACTION)