Add Vulkan Host-Shader compilation

Compiles Vulkan Host shaders into spirv binary files and embeds them
into the application's virtual file-system.

CMakeLists.txt

@@ -251,10 +251,30 @@ if(ENABLE_VULKAN)
     set(HEADER_FILES ${HEADER_FILES} ${RENDERER_VK_INCLUDE_FILES})
     source_group("Source Files\\Core\\Vulkan Renderer" FILES ${RENDERER_VK_SOURCE_FILES})
 
+
+	set(RENDERER_VK_HOST_SHADERS_SOURCE
+		"src/host_shaders/vulkan_display.frag"
+		"src/host_shaders/vulkan_display.vert"
+	)
+
+foreach( HOST_SHADER_SOURCE ${RENDERER_VK_HOST_SHADERS_SOURCE} )
+	get_filename_component( FILE_NAME ${HOST_SHADER_SOURCE} NAME )
+	set( HOST_SHADER_SPIRV "${PROJECT_BINARY_DIR}/host_shaders/${FILE_NAME}.spv" )
+	add_custom_command(
+		OUTPUT ${HOST_SHADER_SPIRV}
+		COMMAND ${CMAKE_COMMAND} -E make_directory "${PROJECT_BINARY_DIR}/host_shaders/"
+		COMMAND Vulkan::glslangValidator -t --target-env vulkan1.1 -g -V "${PROJECT_SOURCE_DIR}/${HOST_SHADER_SOURCE}" -o ${HOST_SHADER_SPIRV}
+		#COMMAND ${SPIRV_OPT} -O ${HOST_SHADER_SPIRV} -o ${HOST_SHADER_SPIRV}
+		DEPENDS ${HOST_SHADER_SOURCE}
+	)
+	list( APPEND RENDERER_VK_HOST_SHADERS_SPIRV ${HOST_SHADER_SPIRV} )
+endforeach()
+
 	cmrc_add_resource_library(
 		resources_renderer_vk
 		NAMESPACE RendererVK
-		WHENCE "src/host_shaders/"
+		WHENCE "${PROJECT_BINARY_DIR}/host_shaders/"
+		${RENDERER_VK_HOST_SHADERS_SPIRV}
 	)
 endif()
 

src/host_shaders/vulkan_display.frag

@@ -0,0 +1,7 @@
+#version 460 core
+layout(location = 0) in vec2 UV;
+layout(location = 0) out vec4 FragColor;
+
+layout(binding = 0) uniform sampler2D u_texture;
+
+void main() { FragColor = texture(u_texture, UV); }

src/host_shaders/vulkan_display.vert

@@ -0,0 +1,23 @@
+#version 460 core
+layout(location = 0) out vec2 UV;
+
+void main() {
+	const vec4 positions[4] = vec4[](
+		vec4(-1.0, 1.0, 1.0, 1.0),   // Top-left
+		vec4(1.0, 1.0, 1.0, 1.0),    // Top-right
+		vec4(-1.0, -1.0, 1.0, 1.0),  // Bottom-left
+		vec4(1.0, -1.0, 1.0, 1.0)    // Bottom-right
+	);
+
+	// The 3DS displays both screens' framebuffer rotated 90 deg counter clockwise
+	// So we adjust our texcoords accordingly
+	const vec2 texcoords[4] = vec2[](
+		vec2(1.0, 1.0),  // Top-right
+		vec2(1.0, 0.0),  // Bottom-right
+		vec2(0.0, 1.0),  // Top-left
+		vec2(0.0, 0.0)   // Bottom-left
+	);
+
+	gl_Position = positions[gl_VertexIndex];
+	UV = texcoords[gl_VertexIndex];
+}