Implement shader caching

* Shader compilation is now cached. Subsequent loads take less than a millisecond.
* Improved game, editor and project manager startup time.
* Editor uses .godot/shader_cache to store shaders.
* Game uses user://shader_cache
* Project manager uses $config_dir/shader_cache
* Options to tweak shader caching in project settings.
* Editor path configuration moved from EditorSettings to new class, EditorPaths, so it can be available early on (before shaders are compiled).
* Reworked ShaderCompilerRD to ensure deterministic shader code creation (else shader may change and cache will be invalidated).
* Added shader compression with SMOLV: https://github.com/aras-p/smol-v

1 files changed, 4 insertions, 0 deletions

diff --git a/servers/rendering/rendering_device.h b/servers/rendering/rendering_device.h
index 27bded9810..4dcb9b963e 100644
--- a/servers/rendering/rendering_device.h
+++ b/servers/rendering/rendering_device.h
@@ -103,12 +103,14 @@ public:
 		bool supports_multiview = false; // If true this device supports multiview options
 	};
 
+	typedef String (*ShaderGetCacheKeyFunction)(const Capabilities *p_capabilities);
 	typedef Vector<uint8_t> (*ShaderCompileFunction)(ShaderStage p_stage, const String &p_source_code, ShaderLanguage p_language, String *r_error, const Capabilities *p_capabilities);
 	typedef Vector<uint8_t> (*ShaderCacheFunction)(ShaderStage p_stage, const String &p_source_code, ShaderLanguage p_language);
 
 private:
 	static ShaderCompileFunction compile_function;
 	static ShaderCacheFunction cache_function;
+	static ShaderGetCacheKeyFunction get_cache_key_function;
 
 	static RenderingDevice *singleton;
 
@@ -635,9 +637,11 @@ public:
 	const Capabilities *get_device_capabilities() const { return &device_capabilities; };
 
 	virtual Vector<uint8_t> shader_compile_from_source(ShaderStage p_stage, const String &p_source_code, ShaderLanguage p_language = SHADER_LANGUAGE_GLSL, String *r_error = nullptr, bool p_allow_cache = true);
+	virtual String shader_get_cache_key() const;
 
 	static void shader_set_compile_function(ShaderCompileFunction p_function);
 	static void shader_set_cache_function(ShaderCacheFunction p_function);
+	static void shader_set_get_cache_key_function(ShaderGetCacheKeyFunction p_function);
 
 	struct ShaderStageData {
 		ShaderStage shader_stage;