Draw the skybox in a deferred subpass (fixes #162)

.github/workflows/build.yml

@@ -64,7 +64,7 @@ jobs:
         run: |
           sudo apt-get update -qq
           sudo apt-get install -y --no-install-recommends \
-            ninja-build pkg-config \
+            ninja-build pkg-config binutils \
             xorg-dev libx11-dev libwayland-dev libxkbcommon-dev libglu1-mesa-dev \
             libvulkan-dev
 
@@ -208,6 +208,42 @@ jobs:
         if: runner.os == 'Windows'
         run: ctest --test-dir build -C Debug --output-on-failure --no-tests=error --timeout 300
 
+  # Build with the Vulkan SDK, then run Sandbox where libvulkan.so.1 cannot be
+  # loaded. The windowed run must exit 2 and log the missing-runtime line.
+  # --null-render must still exit 0, because it does not open the loader.
+  # The mount namespace hides the host copies. It does not uninstall packages
+  # and it does not change the other jobs.
+  no-vulkan-runtime:
+    name: Linux no Vulkan runtime
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          submodules: recursive
+
+      - name: Install Linux dependencies
+        run: |
+          sudo apt-get update -qq
+          sudo apt-get install -y --no-install-recommends \
+            ninja-build pkg-config \
+            xorg-dev libx11-dev libwayland-dev libxkbcommon-dev libglu1-mesa-dev \
+            libvulkan-dev
+
+      - name: Build and install Catch2
+        run: |
+          cmake -DFLING_INIT_CONFIGS=Release \
+            -DFLING_INIT_SKIP_SUBMODULES=ON -DFLING_INIT_SKIP_CONFIGURE=ON \
+            -P scripts/init.cmake
+
+      - name: Configure
+        run: cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
+
+      - name: Build Sandbox
+        run: cmake --build build --target Sandbox --parallel
+
+      - name: Run with the loader hidden
+        run: bash FlingTests/VulkanLoad/RunWithoutVulkanLoader.sh build/Sandbox/bin/Sandbox
+
   # Doc-comment conventions for first-party sources (see Skills/coding-style.md / issue #166).
   # clang-format cannot enforce comment *content*; this script does.
   comment-style:

Assets/Shaders/Deferred/deferred.frag

@@ -40,7 +40,16 @@ layout (binding = 7) uniform UBO
 void main() 
 {
 	// Get G-Buffer values
-	vec3 fragPos = texture(samplerposition, inUV).rgb;
+	vec4 position = texture(samplerposition, inUV);
+
+	// The offscreen pass writes alpha 1 for geometry and clears to 0. Keep what is
+	// already in the frame (the skybox, if there is one) where there is no geometry.
+	if (position.a == 0.0)
+	{
+		discard;
+	}
+
+	vec3 fragPos = position.rgb;
 	vec3 normal = normalize(texture(samplerNormal, inUV).rgb);
 	vec4 albedo = texture(samplerAlbedo, inUV);
 	float roughness = texture(samplerRoughness, inUV).x;

Assets/Shaders/skybox/skybox.frag

@@ -1,12 +1,22 @@
 #version 450
 
+// Inverse of projection * view, with the camera translation removed. @see SkyboxSubpass.cpp
+layout (binding = 0) uniform UBO
+{
+	mat4 invViewProjection;
+} ubo;
+
 layout (binding = 1) uniform samplerCube samplerCubeMap;
 
-layout (location = 0) in vec3 inUVW;
+layout (location = 0) in vec2 inNDC;
 
 layout (location = 0) out vec4 outFragColor;
 
-void main() 
+void main()
 {
-	outFragColor = texture(samplerCubeMap, inUVW);
-}
+	// Change the pixel back to a world space direction from the camera
+	vec4 farPoint = ubo.invViewProjection * vec4(inNDC, 1.0, 1.0);
+	vec3 direction = normalize(farPoint.xyz / farPoint.w);
+
+	outFragColor = vec4(texture(samplerCubeMap, direction).rgb, 1.0);
+}

Assets/Shaders/skybox/skybox.vert

@@ -1,25 +1,18 @@
 #version 450
 
-layout (location = 0) in vec3 inPos;
-layout(location = 1) in vec3 inColor;
-layout(location = 2) in vec2 inTexCoord;
+// Normalized device coordinates of this pixel, for the fragment shader to make a view ray
+layout (location = 0) out vec2 outNDC;
 
-layout (binding = 0) uniform UBO 
-{
-	mat4 projection;
-	mat4 modelView;
-} ubo;
-
-layout (location = 0) out vec3 outUVW;
-
-out gl_PerVertex 
+out gl_PerVertex
 {
 	vec4 gl_Position;
 };
 
-void main() 
+void main()
 {
-	vec3 position = mat3(ubo.modelView) * inPos.xyz;
-	gl_Position = (ubo.projection * vec4(position, 0.0)).xyzz;
-	outUVW = inPos.xyz;
+	// One triangle that covers the full screen, made from the vertex index with no vertex buffer
+	// @see https://www.saschawillems.de/blog/2016/08/13/vulkan-tutorial-on-rendering-a-fullscreen-quad-without-buffers/
+	vec2 uv = vec2((gl_VertexIndex << 1) & 2, gl_VertexIndex & 2);
+	outNDC = uv * 2.0 - 1.0;
+	gl_Position = vec4(outNDC, 1.0, 1.0);
 }

Config/EngineConf.ini

@@ -21,6 +21,11 @@ WindowIconImage=FlingEngineLogo.png
 EnableValidationLayers=false
 #EnableValidationLayers=true
 
+[Graphics]
+; Cube map folder for the skybox, relative to the Assets directory. Leave empty for no skybox.
+; @see Cubemap.h for the face file names
+Skybox=Textures/Skybox/Garden
+
 [Camera]
 MoveSpeed=10
 RotationSpeed=700

FlingEngine/Application/src/Engine.cpp

@@ -128,7 +128,7 @@ namespace Fling
 		else
 		{
 			VulkanApp::Get().Init(
-				static_cast<PipelineFlags>(PipelineFlags::DEFERRED | PipelineFlags::IMGUI),
+				static_cast<PipelineFlags>(PipelineFlags::DEFERRED | PipelineFlags::CUBEMAP | PipelineFlags::IMGUI),
 				g_Registry,
 				m_DebugUI
 			);

FlingEngine/Core/CMakeLists.txt

@@ -13,6 +13,14 @@ fling_add_module(Core
 		FlingExt::json	# Input recording files are JSON Lines, hidden in InputRecording.cpp
 )
 
+# DynamicLibrary is the only dlopen caller. Older glibc keeps it in libdl.
+target_link_libraries(Core PRIVATE ${CMAKE_DL_LIBS})
+
+# DynamicLibrary calls WinVerifyTrust before LoadLibraryExW.
+if(WIN32)
+	target_link_libraries(Core PRIVATE wintrust)
+endif()
+
 # Feature flags are read from Core headers (FlingTypes.h) and from every module
 # that links Core, so they live here and propagate to everything.
 target_compile_definitions(Core PUBLIC

FlingEngine/Core/inc/DynamicLibrary.h

@@ -0,0 +1,91 @@
+#pragma once
+
+#include "CoreAPI.h"
+
+#include <span>
+#include <string>
+#include <string_view>
+
+namespace Fling
+{
+    /**
+     * Load and unload one shared library.
+     *
+     * This is the only Fling type that calls LoadLibrary or dlopen.
+     * Move a DynamicLibrary. Do not copy it.
+     *
+     * Open loads a library with the platform search path.
+     * It does not check a signature. Use it for game modules and plugins.
+     * OpenSigned is the strict open. On Windows it checks Authenticode
+     * before the load. Linux has no Authenticode check, so OpenSigned
+     * calls Open there.
+     */
+    class CORE_API DynamicLibrary
+    {
+    public:
+        DynamicLibrary() = default;
+
+        /** Unload the library when this object is still open. */
+        ~DynamicLibrary();
+
+        DynamicLibrary(const DynamicLibrary&) = delete;
+        DynamicLibrary& operator=(const DynamicLibrary&) = delete;
+
+        DynamicLibrary(DynamicLibrary&& t_Other) noexcept;
+        DynamicLibrary& operator=(DynamicLibrary&& t_Other) noexcept;
+
+        /**
+         * Open the shared library t_Name.
+         *
+         * An empty object means that the load failed. When t_Error is not
+         * null, write the platform message there on failure. Clear t_Error
+         * on success.
+         */
+        static DynamicLibrary Open(std::string_view t_Name, std::string* t_Error = nullptr);
+
+        /**
+         * Open t_Name only when Windows trusts its Authenticode signature.
+         *
+         * A valid signature is embedded or catalog. A bare name is resolved
+         * in System32, then in the executable directory. The current
+         * directory and PATH are not searched. An explicit path contains a
+         * slash, a backslash, or a drive prefix. That path is verified and
+         * loaded alone. A missing file sets "The shared library was not found".
+         * On Linux this calls Open.
+         */
+        static DynamicLibrary OpenSigned(std::string_view t_Name, std::string* t_Error = nullptr);
+
+        /**
+         * Open the first library in t_Names that loads.
+         *
+         * When every name fails and t_Error is not null, write the last
+         * platform message.
+         */
+        static DynamicLibrary OpenFirst(std::span<const std::string_view> t_Names, std::string* t_Error = nullptr);
+
+        /** True when a library is open. */
+        explicit operator bool() const;
+
+        /**
+         * Return the address of t_Name.
+         * Return null when the library is closed or the symbol is missing.
+         */
+        void* Symbol(std::string_view t_Name) const;
+
+        /**
+         * Return the address of t_Name as T_Fn.
+         * Return null when the library is closed or the symbol is missing.
+         */
+        template <typename T_Fn>
+        T_Fn SymbolAs(std::string_view t_Name) const
+        {
+            return reinterpret_cast<T_Fn>(Symbol(t_Name));
+        }
+
+        /** Close the library. A second call does nothing. */
+        void Close();
+
+    private:
+        void* m_Handle = nullptr;
+    };
+} // namespace Fling