source/graphics/ShaderTechnique.h

   1 /* Copyright (C) 2022 Wildfire Games.
   2  * This file is part of 0 A.D.
   3  *
   4  * 0 A.D. is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * 0 A.D. is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #ifndef INCLUDED_SHADERTECHNIQUE
  19 #define INCLUDED_SHADERTECHNIQUE
  20
  21 #include "graphics/ShaderDefines.h"
  22 #include "graphics/ShaderProgram.h"
  23 #include "graphics/ShaderTechniquePtr.h"
  24 #include "lib/code_annotation.h"
  25 #include "lib/file/vfs/vfs_path.h"
  26 #include "renderer/backend/PipelineState.h"
  27
  28 #include <functional>
  29 #include <memory>
  30 #include <vector>
  31
  32 /**
  33  * Implements a render pass consisting of a pipeline state and a shader,
  34  * used by CShaderTechnique.
  35  */
  36 class CShaderPass
  37 {
  38 public:
  39         CShaderPass(
  40                 std::unique_ptr<Renderer::Backend::IGraphicsPipelineState> pipelineState,
  41                 const CShaderProgramPtr& shader);
  42         MOVABLE(CShaderPass);
  43
  44         const CShaderProgramPtr& GetShaderProgram() const noexcept { return m_Shader; }
  45
  46         Renderer::Backend::IGraphicsPipelineState*
  47         GetPipelineState() const noexcept { return m_PipelineState.get(); }
  48
  49 private:
  50         CShaderProgramPtr m_Shader;
  51
  52         std::unique_ptr<Renderer::Backend::IGraphicsPipelineState> m_PipelineState;
  53 };
  54
  55 /**
  56  * Implements a render technique consisting of a sequence of passes.
  57  * CShaderManager loads these from shader effect XML files.
  58  */
  59 class CShaderTechnique
  60 {
  61 public:
  62         using PipelineStateDescCallback =
  63                 std::function<void(Renderer::Backend::SGraphicsPipelineStateDesc& pipelineStateDesc)>;
  64
  65         CShaderTechnique(const VfsPath& path, const CShaderDefines& defines, const PipelineStateDescCallback& callback);
  66
  67         void SetPasses(std::vector<CShaderPass>&& passes);
  68
  69         int GetNumPasses() const;
  70
  71         Renderer::Backend::IShaderProgram* GetShader(int pass = 0) const;
  72
  73         Renderer::Backend::IGraphicsPipelineState*
  74         GetGraphicsPipelineState(int pass = 0) const;
  75
  76         /**
  77          * Whether this technique uses alpha blending that requires objects to be
  78          * drawn from furthest to nearest.
  79          */
  80         bool GetSortByDistance() const;
  81
  82         void SetSortByDistance(bool enable);
  83
  84         const VfsPath& GetPath() { return m_Path; }
  85
  86         const CShaderDefines& GetShaderDefines() { return m_Defines; }
  87
  88         const PipelineStateDescCallback& GetPipelineStateDescCallback() const { return m_PipelineStateDescCallback; };
  89
  90 private:
  91         std::vector<CShaderPass> m_Passes;
  92
  93         bool m_SortByDistance = false;
  94
  95         // We need additional data to reload the technique.
  96         VfsPath m_Path;
  97         CShaderDefines m_Defines;
  98
  99         PipelineStateDescCallback m_PipelineStateDescCallback;
 100 };
 101
 102 #endif // INCLUDED_SHADERTECHNIQUE