[dxvk] Add API for specialization constants

src/dxvk/dxvk_context.cpp

@@ -2142,6 +2142,16 @@ namespace dxvk {
     
     m_flags.set(DxvkContextFlag::GpDirtyPipelineState);
   }
+
+
+  void DxvkContext::setSpecConstant(
+          uint32_t            index,
+          uint32_t            value) {
+    if (m_state.gp.state.scSpecConstants[index] != value) {
+      m_state.gp.state.scSpecConstants[index] = value;
+      m_flags.set(DxvkContextFlag::GpDirtyPipelineState);
+    }
+  }
   
   
   void DxvkContext::setPredicate(

src/dxvk/dxvk_context.h

@@ -856,6 +856,19 @@ namespace dxvk {
             uint32_t            attachment,
       const DxvkBlendMode&      blendMode);
     
+    /**
+     * \brief Sets specialization constants
+     * 
+     * Replaces current specialization constants with
+     * the given list of constant entries. The specId
+     * in the shader can be computed with \c getSpecId.
+     * \param [in] index Constant index
+     * \param [in] value Constant value
+     */
+    void setSpecConstant(
+            uint32_t            index,
+            uint32_t            value);
+    
     /**
      * \brief Sets predicate
      *

src/dxvk/dxvk_graphics.cpp

@@ -205,6 +205,9 @@ namespace dxvk {
         specData.set(specId + 3, util::getComponentIndex(state.omComponentMapping[i].a, 3), 3u);
       }
     }
+
+    for (uint32_t i = 0; i < MaxNumSpecConstants; i++)
+      specData.set(getSpecId(i), state.scSpecConstants[i], 0u);
     
     VkSpecializationInfo specInfo = specData.getSpecInfo();
     

src/dxvk/dxvk_graphics.h

@@ -109,6 +109,8 @@ namespace dxvk {
     VkLogicOp                           omLogicOp;
     VkPipelineColorBlendAttachmentState omBlendAttachments[MaxNumRenderTargets];
     VkComponentMapping                  omComponentMapping[MaxNumRenderTargets];
+
+    uint32_t                            scSpecConstants[MaxNumSpecConstants];
   };
   
   

src/dxvk/dxvk_limits.h

@@ -15,6 +15,7 @@ namespace dxvk {
     MaxNumActiveBindings        =   128,
     MaxNumQueuedCommandBuffers  =     8,
     MaxNumQueryCountPerPool     =   128,
+    MaxNumSpecConstants         =     8,
     MaxUniformBufferSize        = 65536,
     MaxVertexBindingStride      =  2048,
     MaxPushConstantSize         =   128,

src/dxvk/dxvk_shader.h

@@ -30,7 +30,8 @@ namespace dxvk {
 
     // Specialization constants for pipeline state
     SpecConstantRangeStart      = ColorComponentMappings + MaxNumRenderTargets * 4,
-    RasterizerSampleCount       = SpecConstantRangeStart,
+    RasterizerSampleCount       = SpecConstantRangeStart + 0,
+    FirstPipelineConstant
   };
   
   

src/dxvk/dxvk_spec_const.h

@@ -4,6 +4,18 @@
 #include "dxvk_shader.h"
 
 namespace dxvk {
+
+  /**
+   * \briefS Specialization constant entry
+   * 
+   * Used to pass a list of user-defined
+   * specialization constants to shaders.
+   */
+  struct DxvkSpecConstant {
+    uint32_t specId;
+    uint32_t value;
+  };
+
   
   /**
    * \brief Specialization constant info
@@ -36,6 +48,18 @@ namespace dxvk {
         setAsUint32(specId, uint32_t(value));
     }
 
+    /**
+     * \brief Sets specialization constant value
+     *
+     * Always passes the constant value to the driver.
+     * \param [in] specId Specialization constant ID
+     * \param [in] value Specialization constant value
+     */
+    template<typename T>
+    void set(uint32_t specId, T value) {
+      setAsUint32(specId, uint32_t(value));
+    }
+
     /**
      * \brief Generates specialization info structure
      * \returns Specialization info for shader module
@@ -50,5 +74,18 @@ namespace dxvk {
     void setAsUint32(uint32_t specId, uint32_t value);
 
   };
+
+
+  /**
+   * \brief Computes specialization constant ID
+   * 
+   * Computest the specId to use within shaders
+   * for a given pipeline specialization constant.
+   * \param [in] index Spec constant index
+   * \returns Specialization constant ID
+   */
+  inline uint32_t getSpecId(uint32_t index) {
+    return uint32_t(DxvkSpecConstantId::FirstPipelineConstant) + index;
+  }
   
 }