source/renderer/backend/PipelineState.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_RENDERER_BACKEND_PIPELINESTATE
  19 #define INCLUDED_RENDERER_BACKEND_PIPELINESTATE
  20
  21 #include "graphics/Color.h"
  22 #include "renderer/backend/CompareOp.h"
  23 #include "renderer/backend/IDeviceObject.h"
  24 #include "renderer/backend/IShaderProgram.h"
  25
  26 class CStr;
  27
  28 namespace Renderer
  29 {
  30
  31 namespace Backend
  32 {
  33
  34 enum class StencilOp
  35 {
  36         // Keeps the current value.
  37         KEEP,
  38         // Sets the value to zero.
  39         ZERO,
  40         // Sets the value to reference.
  41         REPLACE,
  42         // Increments the value and clamps to the maximum representable unsigned
  43         // value.
  44         INCREMENT_AND_CLAMP,
  45         // Decrements the value and clamps to zero.
  46         DECREMENT_AND_CLAMP,
  47         // Bitwise inverts the value.
  48         INVERT,
  49         // Increments the value and wraps it to zero when incrementing the maximum
  50         // representable unsigned value.
  51         INCREMENT_AND_WRAP,
  52         // Decrements the value and wraps it to the maximum representable unsigned
  53         // value when decrementing zero.
  54         DECREMENT_AND_WRAP
  55 };
  56
  57 struct SStencilOpState
  58 {
  59         StencilOp failOp;
  60         StencilOp passOp;
  61         StencilOp depthFailOp;
  62         CompareOp compareOp;
  63 };
  64
  65 struct SDepthStencilStateDesc
  66 {
  67         bool depthTestEnabled;
  68         CompareOp depthCompareOp;
  69         bool depthWriteEnabled;
  70         bool stencilTestEnabled;
  71         uint32_t stencilReadMask;
  72         uint32_t stencilWriteMask;
  73         uint32_t stencilReference;
  74         SStencilOpState stencilFrontFace;
  75         SStencilOpState stencilBackFace;
  76 };
  77
  78 // TODO: add per constant description.
  79
  80 enum class BlendFactor
  81 {
  82         ZERO,
  83         ONE,
  84         SRC_COLOR,
  85         ONE_MINUS_SRC_COLOR,
  86         DST_COLOR,
  87         ONE_MINUS_DST_COLOR,
  88         SRC_ALPHA,
  89         ONE_MINUS_SRC_ALPHA,
  90         DST_ALPHA,
  91         ONE_MINUS_DST_ALPHA,
  92         CONSTANT_COLOR,
  93         ONE_MINUS_CONSTANT_COLOR,
  94         CONSTANT_ALPHA,
  95         ONE_MINUS_CONSTANT_ALPHA,
  96         SRC_ALPHA_SATURATE,
  97         SRC1_COLOR,
  98         ONE_MINUS_SRC1_COLOR,
  99         SRC1_ALPHA,
 100         ONE_MINUS_SRC1_ALPHA,
 101 };
 102
 103 enum class BlendOp
 104 {
 105         ADD,
 106         SUBTRACT,
 107         REVERSE_SUBTRACT,
 108         MIN,
 109         MAX
 110 };
 111
 112 // Using a namespace instead of a enum allows using the same syntax while
 113 // avoiding adding operator overrides and additional checks on casts.
 114 namespace ColorWriteMask
 115 {
 116 constexpr uint8_t RED = 0x01;
 117 constexpr uint8_t GREEN = 0x02;
 118 constexpr uint8_t BLUE = 0x04;
 119 constexpr uint8_t ALPHA = 0x08;
 120 } // namespace ColorWriteMask
 121
 122 struct SBlendStateDesc
 123 {
 124         bool enabled;
 125         BlendFactor srcColorBlendFactor;
 126         BlendFactor dstColorBlendFactor;
 127         BlendOp colorBlendOp;
 128         BlendFactor srcAlphaBlendFactor;
 129         BlendFactor dstAlphaBlendFactor;
 130         BlendOp alphaBlendOp;
 131         CColor constant;
 132         uint8_t colorWriteMask;
 133 };
 134
 135 enum class PolygonMode
 136 {
 137         FILL,
 138         LINE
 139 };
 140
 141 enum class CullMode
 142 {
 143         NONE,
 144         FRONT,
 145         BACK
 146 };
 147
 148 enum class FrontFace
 149 {
 150         COUNTER_CLOCKWISE,
 151         CLOCKWISE
 152 };
 153
 154 struct SRasterizationStateDesc
 155 {
 156         PolygonMode polygonMode;
 157         CullMode cullMode;
 158         FrontFace frontFace;
 159         bool depthBiasEnabled;
 160         float depthBiasConstantFactor;
 161         float depthBiasSlopeFactor;
 162 };
 163
 164 struct SGraphicsPipelineStateDesc
 165 {
 166         // It's a backend client reponsibility to keep the shader program alive
 167         // while it's bound.
 168         IShaderProgram* shaderProgram;
 169         SDepthStencilStateDesc depthStencilState;
 170         SBlendStateDesc blendState;
 171         SRasterizationStateDesc rasterizationState;
 172 };
 173
 174 // We don't provide additional helpers intentionally because all custom states
 175 // should be described with a related shader and should be switched together.
 176 SGraphicsPipelineStateDesc MakeDefaultGraphicsPipelineStateDesc();
 177
 178 StencilOp ParseStencilOp(const CStr& str);
 179
 180 BlendFactor ParseBlendFactor(const CStr& str);
 181 BlendOp ParseBlendOp(const CStr& str);
 182
 183 PolygonMode ParsePolygonMode(const CStr& str);
 184 CullMode ParseCullMode(const CStr& str);
 185 FrontFace ParseFrontFace(const CStr& str);
 186
 187 /**
 188  * A holder for precompiled graphics pipeline description.
 189  */
 190 class IGraphicsPipelineState : public IDeviceObject<IGraphicsPipelineState>
 191 {
 192 public:
 193         virtual IShaderProgram* GetShaderProgram() const = 0;
 194 };
 195
 196 } // namespace Backend
 197
 198 } // namespace Renderer
 199
 200 #endif // INCLUDED_RENDERER_BACKEND_PIPELINESTATE