From 3e136b9a3152d408469e7314eb231ccc0732af0f Mon Sep 17 00:00:00 2001
From: codereader <greebo@angua.at>
Date: Sun, 14 Mar 2021 10:04:55 +0100
Subject: [PATCH] #5532: Migrating texgen param expressions to use the
 expression slots

---
 include/ishaderlayer.h                   |  6 ++++++
 radiantcore/shaders/Doom3ShaderLayer.cpp |  1 -
 radiantcore/shaders/Doom3ShaderLayer.h   | 15 +++++++--------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/include/ishaderlayer.h b/include/ishaderlayer.h
index 936548f5d0..72a281a493 100644
--- a/include/ishaderlayer.h
+++ b/include/ishaderlayer.h
@@ -105,6 +105,9 @@ class IShaderLayer
         enum Slot
         {
             AlphaTest = 0,
+            TexGenParam1,
+            TexGenParam2,
+            TexGenParam3,
             NumExpressionSlots
         };
     };
@@ -136,6 +139,9 @@ class IShaderLayer
 	 */
 	virtual void evaluateExpressions(std::size_t time, const IRenderEntity& entity) = 0;
 
+    // Returns the requested expression
+    virtual shaders::IShaderExpression::Ptr getExpression(Expression::Slot slot) = 0;
+
 	/**
 	 * The flags set on this stage.
 	 */
diff --git a/radiantcore/shaders/Doom3ShaderLayer.cpp b/radiantcore/shaders/Doom3ShaderLayer.cpp
index 2a993b824b..ecb135f8c5 100644
--- a/radiantcore/shaders/Doom3ShaderLayer.cpp
+++ b/radiantcore/shaders/Doom3ShaderLayer.cpp
@@ -85,7 +85,6 @@ void ExpressionSlots::assign(IShaderLayer::Expression::Slot slot, const IShaderE
     if (!newExpression)
     {
         expressionSlot.expression.reset();
-        expressionSlot.expressionIndex = ExpressionSlot::Unused;
         expressionSlot.registerIndex = defaultRegisterIndex;
         return;
     }
diff --git a/radiantcore/shaders/Doom3ShaderLayer.h b/radiantcore/shaders/Doom3ShaderLayer.h
index dc5a08b558..50cb31f9c7 100644
--- a/radiantcore/shaders/Doom3ShaderLayer.h
+++ b/radiantcore/shaders/Doom3ShaderLayer.h
@@ -21,17 +21,11 @@ struct ExpressionSlot
     // The register holding the evaluated float
     std::size_t registerIndex;
 
-    // The index of this expression in the slots array
-    std::size_t expressionIndex;
-
-    // The expression itself
+    // The expression itself (empty if unused)
     IShaderExpression::Ptr expression;
 
-    static const std::size_t Unused = std::numeric_limits<std::size_t>::max();
-
     ExpressionSlot() :
-        registerIndex(REG_ZERO),
-        expressionIndex(Unused)
+        registerIndex(REG_ZERO)
     {}
 };
 
@@ -252,6 +246,11 @@ class Doom3ShaderLayer :
         }
     }
 
+    shaders::IShaderExpression::Ptr getExpression(Expression::Slot slot) override
+    {
+        return _expressionSlots[slot].expression;
+    }
+
     /**
      * \brief
      * Set the bindable texture object.