//+------------------------------------------------------------------+
//|                                                     DXShader.mqh |
//|                             Copyright 2000-2025, MetaQuotes Ltd. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#include "DXHandle.mqh"
#include "DXInput.mqh"
#include "DXTexture.mqh"
//+------------------------------------------------------------------+
//| Maximum inputs count for shaders                                 |
//| D3D11_COMMONSHADER_CONSTANT_BUFFER_API_SLOT_COUNT in DX11        |
//+------------------------------------------------------------------+
#define DX_SHADER_INPUTS_MAX 14
//+------------------------------------------------------------------+
//| Class CDXShader                                                  |
//+------------------------------------------------------------------+
class CDXShader : public CDXHandleShared
  {
protected:
   //--- shader type
   ENUM_DX_SHADER_TYPE m_type;
   //--- input data
   CDXInput*           m_inputs[];
   CDXTexture*         m_textures[];

public:
   //+------------------------------------------------------------------+
   //| Destructor                                                       |
   //+------------------------------------------------------------------+
   virtual          ~CDXShader(void)
     {
      Shutdown();
     }
   //+------------------------------------------------------------------+
   //| Create a new shader from source code                             |
   //+------------------------------------------------------------------+
   bool              Create(int context,ENUM_DX_SHADER_TYPE shader_type,string source,string entry_point)
     {
      //--- shutdown shader
      Shutdown();
      //--- save new context
      m_context=context;
      //--- check context
      if(m_context==INVALID_HANDLE)
         return(false);
      //--- save shader type;
      m_type=shader_type;
      //--- compile shader
      string error="";
      m_handle=DXShaderCreate(m_context,m_type,source,entry_point,error);
      if(m_handle==INVALID_HANDLE)
         return(false);
      //--- success
      return(true);
     }
   //+------------------------------------------------------------------+
   //| Set vertex shader vertices layout                                |
   //+------------------------------------------------------------------+
   template<typename TVertex>
   bool              LayoutSet(void)
     {
      //--- check shader handle
      if(m_handle==INVALID_HANDLE)
         return(false);
      //--- layout is available only for vertex shaders
      if(m_type!=DX_SHADER_VERTEX)
         return(false);
      //--- set layout
      return(DXShaderSetLayout(m_handle,TVertex::s_layout));
     }
   //+------------------------------------------------------------------+
   //| Set input buffer at specified index                              |
   //+------------------------------------------------------------------+
   bool              InputSet(int index,CDXInput* dx_input)
     {
      //---
      if(index>=DX_SHADER_INPUTS_MAX || CheckPointer(dx_input)==POINTER_INVALID || dx_input.Handle()==INVALID_HANDLE)
         return(false);
      //--- check if input is the same
      int count=ArraySize(m_inputs);
      if(index<count && CheckPointer(m_inputs[index])!=POINTER_INVALID && m_inputs[index].Handle()==dx_input.Handle())
         return(true);
      //--- allocate array for new inputs
      if(index>=count)
         ArrayResize(m_inputs,index+1);
      for(int i=count; i<=index; i++)
         m_inputs[i]=NULL;
      //--- release previous input buffer
      if(m_inputs[index])
         m_inputs[index].Release();
      //--- set new input buffer
      m_inputs[index]=dx_input;
      dx_input.AddRef();
      //--- successed
      return(true);
     }
   //+------------------------------------------------------------------+
   //| Set texture at specified index                                   |
   //+------------------------------------------------------------------+
   bool              TextureSet(int index,CDXTexture* texture)
     {
      //---
      if(m_type!=DX_SHADER_PIXEL || index>=DX_SHADER_INPUTS_MAX || CheckPointer(texture)==POINTER_INVALID || texture.Handle()==INVALID_HANDLE)
         return(false);
      //--- check if texture is the same
      int count=ArraySize(m_textures);
      if(index<count && CheckPointer(m_textures[index])!=POINTER_INVALID && m_textures[index].Handle()==texture.Handle())
         return(true);
      //--- allocate array for new inputs
      if(index>=count)
         ArrayResize(m_textures,index+1);
      for(int i=count; i<=index; i++)
         m_textures[i]=NULL;
      //--- release previous input buffer
      if(m_textures[index])
         m_textures[index].Release();
      //--- set new input buffer
      m_textures[index]=texture;
      texture.AddRef();
      //--- successed
      return(true);
     }
   //+------------------------------------------------------------------+
   //| Set texture at specified index                                   |
   //+------------------------------------------------------------------+
   void              TexturesClear()
     {
      //--- release textures
      for(int i=0; i<ArraySize(m_textures); i++)
         if(m_textures[i])
            m_textures[i].Release();
      ArrayFree(m_textures);
     }
   //+------------------------------------------------------------------+
   //| Put shader into render queue                                     |
   //+------------------------------------------------------------------+
   virtual bool      Render(void)
     {
      //--- check handles
      if(m_context==INVALID_HANDLE || m_handle==INVALID_HANDLE)
         return(false);
      //--- update shader inputs
      if(!UpdateInputs())
         return(false);
      //--- set shader
      return(DXShaderSet(m_context,m_handle));
     }
   //+------------------------------------------------------------------+
   //| Shutdown                                                         |
   //+------------------------------------------------------------------+
   virtual void      Shutdown(void)
     {
      //--- relase handle
      if(m_handle!=INVALID_HANDLE)
         DXRelease(m_handle);
      m_handle=INVALID_HANDLE;
      //--- release input buffers
      for(int i=0; i<ArraySize(m_inputs); i++)
         if(m_inputs[i])
            m_inputs[i].Release();
      //--- release textures
      for(int i=0; i<ArraySize(m_textures); i++)
         if(m_textures[i])
            m_textures[i].Release();
      ArrayFree(m_textures);
     }

private:
   //+------------------------------------------------------------------+
   //| Shutdown                                                         |
   //+------------------------------------------------------------------+
   bool              UpdateInputs(void)
     {
      int handles[];
      //--- set inputs handles
      int count=ArraySize(m_inputs);
      if(count>0)
        {
         ArrayResize(handles,count);
         //--- copy inputs handles
         for(int i=0; i<count; i++)
            if(m_inputs[i])
               handles[i]=m_inputs[i].Handle();
            else
               handles[i]=INVALID_HANDLE;
        }
      else
         ArrayFree(handles);
      //--- set input handles
      if(!DXShaderInputsSet(m_handle,handles))
         return(false);
      //--- set textures handles
      if(m_type==DX_SHADER_PIXEL)
        {
         count=ArraySize(m_textures);
         if(count>0)
           {
            ArrayResize(handles,count);
            //--- copy inputs handles
            for(int i=0; i<count; i++)
               if(m_textures[i])
                  handles[i]=m_textures[i].Handle();
               else
                  handles[i]=INVALID_HANDLE;
           }
         else
            ArrayFree(handles);
         ResetLastError();
         //--- set taxtures handles
         if(!DXShaderTexturesSet(m_handle,handles))
            return(false);
        }
      //--- succes
      return(true);
     }
  };
//+------------------------------------------------------------------+