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

3 files changed, 14 insertions, 0 deletions

diff --git a/core/SCsub b/core/SCsub
index bdf8544840..e3ba46be02 100644
--- a/core/SCsub
+++ b/core/SCsub
@@ -59,6 +59,7 @@ thirdparty_misc_sources = [
     "pcg.cpp",
     "polypartition.cpp",
     "clipper.cpp",
+    "smolv.cpp",
 ]
 thirdparty_misc_sources = [thirdparty_misc_dir + file for file in thirdparty_misc_sources]
 env_thirdparty.add_source_files(thirdparty_obj, thirdparty_misc_sources)
diff --git a/core/config/engine.cpp b/core/config/engine.cpp
index 2360d66438..c43e32868c 100644
--- a/core/config/engine.cpp
+++ b/core/config/engine.cpp
@@ -31,6 +31,7 @@
 #include "engine.h"
 
 #include "core/authors.gen.h"
+#include "core/config/project_settings.h"
 #include "core/donors.gen.h"
 #include "core/license.gen.h"
 #include "core/version.h"
@@ -210,6 +211,13 @@ void Engine::get_singletons(List<Singleton> *p_singletons) {
 	}
 }
 
+void Engine::set_shader_cache_path(const String &p_path) {
+	shader_cache_path = p_path;
+}
+String Engine::get_shader_cache_path() const {
+	return shader_cache_path;
+}
+
 Engine *Engine::singleton = nullptr;
 
 Engine *Engine::get_singleton() {
diff --git a/core/config/engine.h b/core/config/engine.h
index a9080e3dfd..276da1c7ea 100644
--- a/core/config/engine.h
+++ b/core/config/engine.h
@@ -72,6 +72,8 @@ private:
 
 	static Engine *singleton;
 
+	String shader_cache_path;
+
 public:
 	static Engine *get_singleton();
 
@@ -121,6 +123,9 @@ public:
 	Dictionary get_license_info() const;
 	String get_license_text() const;
 
+	void set_shader_cache_path(const String &p_path);
+	String get_shader_cache_path() const;
+
 	bool is_abort_on_gpu_errors_enabled() const;
 	bool is_validation_layers_enabled() const;