feat(rendering): add conditional shader compilation

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - SSAO resolution scale (#1423, **@tomas7770**).
+- Conditional shader compilation (#1406, **@tomas7770**).
 
 ### Changed
 

engine/CMakeLists.txt

@@ -150,6 +150,7 @@ set(CUBOS_ENGINE_SOURCE
 	"src/render/defaults/target.cpp"
 	"src/render/shader/plugin.cpp"
 	"src/render/shader/shader.cpp"
+	"src/render/shader/shader_builder.cpp"
 	"src/render/shader/bridge.cpp"
 	"src/render/g_buffer/plugin.cpp"
 	"src/render/g_buffer/g_buffer.cpp"

engine/include/cubos/engine/render/shader/shader.hpp

@@ -8,6 +8,7 @@
 #include <cubos/core/reflection/reflect.hpp>
 
 #include <cubos/engine/api.hpp>
+#include <cubos/engine/render/shader/shader_builder.hpp>
 
 namespace cubos::engine
 {
@@ -22,14 +23,24 @@ namespace cubos::engine
 
         /// @brief Constructs a shader from code.
         /// @param shaderStage Shader stage created from GLSL code.
-        Shader(cubos::core::gl::ShaderStage shaderStage)
-            : mShaderStage(std::move(shaderStage)){};
+        /// @param renderDevice Render device used to create the shader.
+        /// @param stage Shader stage to create.
+        /// @param contents Shader source code.
+        Shader(cubos::core::gl::ShaderStage shaderStage, cubos::core::gl::RenderDevice& renderDevice,
+               cubos::core::gl::Stage stage, const std::string& contents)
+            : mShaderStage(std::move(shaderStage))
+            , mBuilder(renderDevice, stage, contents){};
 
         /// @brief Returns the asset's shader stage.
         /// @return Shader stage.
         cubos::core::gl::ShaderStage shaderStage() const;
 
+        /// @brief Returns a shader builder to configure compile-time shader parameters.
+        /// @return Shader builder.
+        const ShaderBuilder& builder() const;
+
     private:
         cubos::core::gl::ShaderStage mShaderStage;
+        ShaderBuilder mBuilder;
     };
 } // namespace cubos::engine

engine/include/cubos/engine/render/shader/shader_builder.hpp

@@ -0,0 +1,60 @@
+/// @file
+/// @brief Class @ref cubos::engine::ShaderBuilder.
+/// @ingroup render-shader-plugin
+
+#pragma once
+
+#include <string>
+
+#include <cubos/core/gl/render_device.hpp>
+
+#include <cubos/engine/api.hpp>
+
+namespace cubos::engine
+{
+    class Shader;
+
+    /// @brief Configures compile-time shader parameters using #define macros.
+    /// @ingroup render-shader-plugin
+    class CUBOS_ENGINE_API ShaderBuilder final
+    {
+    public:
+        /// @brief Creates a shader builder.
+        /// @param renderDevice Render device used to create the shader.
+        /// @param stage Shader stage to create.
+        /// @param contents Shader source code.
+        ShaderBuilder(cubos::core::gl::RenderDevice& renderDevice, const cubos::core::gl::Stage stage,
+                      const std::string& contents)
+            : mRenderDevice(renderDevice)
+            , mStage(stage)
+            , mContents(contents){};
+
+        /// @brief Creates a shader builder, using the same render device and shader stage as another builder.
+        /// @param shaderBuilder Shader builder to copy parameters from.
+        /// @param contents Shader source code.
+        ShaderBuilder(const ShaderBuilder& shaderBuilder, const std::string& contents)
+            : mRenderDevice(shaderBuilder.mRenderDevice)
+            , mStage(shaderBuilder.mStage)
+            , mContents(contents){};
+
+        /// @brief Defines a parameter with no value.
+        /// @param defineName Parameter name to define.
+        /// @return New shader builder with the parameter defined.
+        ShaderBuilder with(const std::string& defineName) const;
+
+        /// @brief Defines a parameter with a value.
+        /// @param defineName Parameter name to define.
+        /// @param defineValue Parameter value.
+        /// @return New shader builder with the parameter defined.
+        ShaderBuilder with(const std::string& defineName, const std::string& defineValue) const;
+
+        /// @brief Compiles a shader from the source code stored in the builder.
+        /// @return Shader asset.
+        std::shared_ptr<Shader> build() const;
+
+    private:
+        cubos::core::gl::RenderDevice& mRenderDevice; ///< Render device used to create the shader.
+        const cubos::core::gl::Stage mStage;          ///< Shader stage type to create.
+        const std::string mContents;                  ///< Shader source code.
+    };
+} // namespace cubos::engine

engine/src/render/shader/bridge.cpp

@@ -20,7 +20,7 @@ bool ShaderBridge::loadFromFile(Assets& assets, const AnyAsset& handle, Stream&
     }
 
     // Store the asset's data.
-    assets.store(handle, Shader(shaderStage));
+    assets.store(handle, Shader(shaderStage, mRenderDevice, mStage, contents));
     return true;
 }
 

engine/src/render/shader/shader.cpp

@@ -19,3 +19,8 @@ cubos::core::gl::ShaderStage Shader::shaderStage() const
 {
     return mShaderStage;
 }
+
+const ShaderBuilder& Shader::builder() const
+{
+    return mBuilder;
+}

engine/src/render/shader/shader_builder.cpp

@@ -0,0 +1,30 @@
+#include <cubos/core/reflection/external/glm.hpp>
+#include <cubos/core/reflection/external/primitives.hpp>
+#include <cubos/core/reflection/traits/constructible.hpp>
+#include <cubos/core/reflection/type.hpp>
+
+#include <cubos/engine/render/shader/shader.hpp>
+#include <cubos/engine/render/shader/shader_builder.hpp>
+
+using namespace cubos::engine;
+
+ShaderBuilder ShaderBuilder::with(const std::string& defineName) const
+{
+    return ShaderBuilder(*this, "#define " + defineName + "\n" + mContents);
+}
+
+ShaderBuilder ShaderBuilder::with(const std::string& defineName, const std::string& defineValue) const
+{
+    return ShaderBuilder(*this, "#define " + defineName + " " + defineValue + "\n" + mContents);
+}
+
+std::shared_ptr<Shader> ShaderBuilder::build() const
+{
+    cubos::core::gl::ShaderStage shaderStage = mRenderDevice.createShaderStage(mStage, mContents.c_str());
+    if (shaderStage == nullptr)
+    {
+        CUBOS_ERROR("Shader asset stage creation failed");
+        return nullptr;
+    }
+    return std::make_shared<Shader>(shaderStage, mRenderDevice, mStage, mContents);
+}