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, 42 insertions, 0 deletions

diff --git a/servers/rendering/renderer_rd/renderer_compositor_rd.cpp b/servers/rendering/renderer_rd/renderer_compositor_rd.cpp
index 0012ba9c27..1337d36762 100644
--- a/servers/rendering/renderer_rd/renderer_compositor_rd.cpp
+++ b/servers/rendering/renderer_rd/renderer_compositor_rd.cpp
@@ -31,6 +31,7 @@
 #include "renderer_compositor_rd.h"
 
 #include "core/config/project_settings.h"
+#include "core/os/dir_access.h"
 
 void RendererCompositorRD::prepare_for_blitting_render_targets() {
 	RD::get_singleton()->prepare_screen_for_drawing();
@@ -155,6 +156,43 @@ void RendererCompositorRD::finalize() {
 RendererCompositorRD *RendererCompositorRD::singleton = nullptr;
 
 RendererCompositorRD::RendererCompositorRD() {
+	{
+		String shader_cache_dir = Engine::get_singleton()->get_shader_cache_path();
+		if (shader_cache_dir == String()) {
+			shader_cache_dir = "user://";
+		}
+		DirAccessRef da = DirAccess::open(shader_cache_dir);
+		if (!da) {
+			ERR_PRINT("Can't create shader cache folder, no shader caching will happen: " + shader_cache_dir);
+		} else {
+			Error err = da->change_dir("shader_cache");
+			if (err != OK) {
+				err = da->make_dir("shader_cache");
+			}
+			if (err != OK) {
+				ERR_PRINT("Can't create shader cache folder, no shader caching will happen: " + shader_cache_dir);
+			} else {
+				shader_cache_dir = shader_cache_dir.plus_file("shader_cache");
+
+				bool shader_cache_enabled = GLOBAL_GET("rendering/shader_compiler/shader_cache/enabled");
+				if (!Engine::get_singleton()->is_editor_hint() && !shader_cache_enabled) {
+					shader_cache_dir = String(); //disable only if not editor
+				}
+
+				if (shader_cache_dir != String()) {
+					bool compress = GLOBAL_GET("rendering/shader_compiler/shader_cache/compress");
+					bool use_zstd = GLOBAL_GET("rendering/shader_compiler/shader_cache/use_zstd_compression");
+					bool strip_debug = GLOBAL_GET("rendering/shader_compiler/shader_cache/strip_debug");
+
+					ShaderRD::set_shader_cache_dir(shader_cache_dir);
+					ShaderRD::set_shader_cache_save_compressed(compress);
+					ShaderRD::set_shader_cache_save_compressed_zstd(use_zstd);
+					ShaderRD::set_shader_cache_save_debug(!strip_debug);
+				}
+			}
+		}
+	}
+
 	singleton = this;
 	time = 0;
 
@@ -171,3 +209,7 @@ RendererCompositorRD::RendererCompositorRD() {
 		scene = memnew(RendererSceneRenderImplementation::RenderForwardClustered(storage));
 	}
 }
+
+RendererCompositorRD::~RendererCompositorRD() {
+	ShaderRD::set_shader_cache_dir(String());
+}