Add a Framebuffer cache

Adds a FramebufferCache singletion that operates the same way as UniformSetCache.

Allows creating framebuffers on the fly (and keep them cached if re-requested) such as:

```C++
RID fb = FramebufferCache::get_singleton()->get_cache(texture1,texture2);
```

2 files changed, 32 insertions, 7 deletions

diff --git a/drivers/vulkan/rendering_device_vulkan.cpp b/drivers/vulkan/rendering_device_vulkan.cpp
index 0979ae9e16..45e114b130 100644
--- a/drivers/vulkan/rendering_device_vulkan.cpp
+++ b/drivers/vulkan/rendering_device_vulkan.cpp
@@ -3971,7 +3971,7 @@ RenderingDevice::FramebufferFormatID RenderingDeviceVulkan::framebuffer_format_c
 	passes.push_back(pass);
 	return framebuffer_format_create_multipass(p_format, passes, p_view_count);
 }
-RenderingDevice::FramebufferFormatID RenderingDeviceVulkan::framebuffer_format_create_multipass(const Vector<AttachmentFormat> &p_attachments, Vector<FramebufferPass> &p_passes, uint32_t p_view_count) {
+RenderingDevice::FramebufferFormatID RenderingDeviceVulkan::framebuffer_format_create_multipass(const Vector<AttachmentFormat> &p_attachments, const Vector<FramebufferPass> &p_passes, uint32_t p_view_count) {
 	_THREAD_SAFE_METHOD_
 
 	FramebufferFormatKey key;
@@ -4110,7 +4110,7 @@ RID RenderingDeviceVulkan::framebuffer_create(const Vector<RID> &p_texture_attac
 	return framebuffer_create_multipass(p_texture_attachments, passes, p_format_check, p_view_count);
 }
 
-RID RenderingDeviceVulkan::framebuffer_create_multipass(const Vector<RID> &p_texture_attachments, Vector<FramebufferPass> &p_passes, FramebufferFormatID p_format_check, uint32_t p_view_count) {
+RID RenderingDeviceVulkan::framebuffer_create_multipass(const Vector<RID> &p_texture_attachments, const Vector<FramebufferPass> &p_passes, FramebufferFormatID p_format_check, uint32_t p_view_count) {
 	_THREAD_SAFE_METHOD_
 
 	Vector<AttachmentFormat> attachments;
@@ -4181,6 +4181,22 @@ RenderingDevice::FramebufferFormatID RenderingDeviceVulkan::framebuffer_get_form
 	return framebuffer->format_id;
 }
 
+bool RenderingDeviceVulkan::framebuffer_is_valid(RID p_framebuffer) const {
+	_THREAD_SAFE_METHOD_
+
+	return framebuffer_owner.owns(p_framebuffer);
+}
+
+void RenderingDeviceVulkan::framebuffer_set_invalidation_callback(RID p_framebuffer, InvalidationCallback p_callback, void *p_userdata) {
+	_THREAD_SAFE_METHOD_
+
+	Framebuffer *framebuffer = framebuffer_owner.get_or_null(p_framebuffer);
+	ERR_FAIL_COND(!framebuffer);
+
+	framebuffer->invalidated_callback = p_callback;
+	framebuffer->invalidated_callback_userdata = p_userdata;
+}
+
 /*****************/
 /**** SAMPLER ****/
 /*****************/
@@ -6218,7 +6234,7 @@ bool RenderingDeviceVulkan::uniform_set_is_valid(RID p_uniform_set) {
 	return uniform_set_owner.owns(p_uniform_set);
 }
 
-void RenderingDeviceVulkan::uniform_set_set_invalidation_callback(RID p_uniform_set, UniformSetInvalidatedCallback p_callback, void *p_userdata) {
+void RenderingDeviceVulkan::uniform_set_set_invalidation_callback(RID p_uniform_set, InvalidationCallback p_callback, void *p_userdata) {
 	UniformSet *us = uniform_set_owner.get_or_null(p_uniform_set);
 	ERR_FAIL_COND(!us);
 	us->invalidated_callback = p_callback;
@@ -8685,6 +8701,11 @@ void RenderingDeviceVulkan::_free_internal(RID p_id) {
 	} else if (framebuffer_owner.owns(p_id)) {
 		Framebuffer *framebuffer = framebuffer_owner.get_or_null(p_id);
 		frames[frame].framebuffers_to_dispose_of.push_back(*framebuffer);
+
+		if (framebuffer->invalidated_callback != nullptr) {
+			framebuffer->invalidated_callback(framebuffer->invalidated_callback_userdata);
+		}
+
 		framebuffer_owner.free(p_id);
 	} else if (sampler_owner.owns(p_id)) {
 		VkSampler *sampler = sampler_owner.get_or_null(p_id);
diff --git a/drivers/vulkan/rendering_device_vulkan.h b/drivers/vulkan/rendering_device_vulkan.h
index 7c8021251f..d98ac1114b 100644
--- a/drivers/vulkan/rendering_device_vulkan.h
+++ b/drivers/vulkan/rendering_device_vulkan.h
@@ -392,6 +392,8 @@ class RenderingDeviceVulkan : public RenderingDevice {
 
 		uint32_t storage_mask = 0;
 		Vector<RID> texture_ids;
+		InvalidationCallback invalidated_callback = nullptr;
+		void *invalidated_callback_userdata = nullptr;
 
 		struct Version {
 			VkFramebuffer framebuffer = VK_NULL_HANDLE;
@@ -747,7 +749,7 @@ class RenderingDeviceVulkan : public RenderingDevice {
 		LocalVector<AttachableTexture> attachable_textures; //used for validation
 		Vector<Texture *> mutable_sampled_textures; //used for layout change
 		Vector<Texture *> mutable_storage_textures; //used for layout change
-		UniformSetInvalidatedCallback invalidated_callback = nullptr;
+		InvalidationCallback invalidated_callback = nullptr;
 		void *invalidated_callback_userdata = nullptr;
 	};
 
@@ -1059,13 +1061,15 @@ public:
 	/*********************/
 
 	virtual FramebufferFormatID framebuffer_format_create(const Vector<AttachmentFormat> &p_format, uint32_t p_view_count = 1);
-	virtual FramebufferFormatID framebuffer_format_create_multipass(const Vector<AttachmentFormat> &p_attachments, Vector<FramebufferPass> &p_passes, uint32_t p_view_count = 1);
+	virtual FramebufferFormatID framebuffer_format_create_multipass(const Vector<AttachmentFormat> &p_attachments, const Vector<FramebufferPass> &p_passes, uint32_t p_view_count = 1);
 	virtual FramebufferFormatID framebuffer_format_create_empty(TextureSamples p_samples = TEXTURE_SAMPLES_1);
 	virtual TextureSamples framebuffer_format_get_texture_samples(FramebufferFormatID p_format, uint32_t p_pass = 0);
 
 	virtual RID framebuffer_create(const Vector<RID> &p_texture_attachments, FramebufferFormatID p_format_check = INVALID_ID, uint32_t p_view_count = 1);
-	virtual RID framebuffer_create_multipass(const Vector<RID> &p_texture_attachments, Vector<FramebufferPass> &p_passes, FramebufferFormatID p_format_check = INVALID_ID, uint32_t p_view_count = 1);
+	virtual RID framebuffer_create_multipass(const Vector<RID> &p_texture_attachments, const Vector<FramebufferPass> &p_passes, FramebufferFormatID p_format_check = INVALID_ID, uint32_t p_view_count = 1);
 	virtual RID framebuffer_create_empty(const Size2i &p_size, TextureSamples p_samples = TEXTURE_SAMPLES_1, FramebufferFormatID p_format_check = INVALID_ID);
+	virtual bool framebuffer_is_valid(RID p_framebuffer) const;
+	virtual void framebuffer_set_invalidation_callback(RID p_framebuffer, InvalidationCallback p_callback, void *p_userdata);
 
 	virtual FramebufferFormatID framebuffer_get_format(RID p_framebuffer);
 
@@ -1110,7 +1114,7 @@ public:
 
 	virtual RID uniform_set_create(const Vector<Uniform> &p_uniforms, RID p_shader, uint32_t p_shader_set);
 	virtual bool uniform_set_is_valid(RID p_uniform_set);
-	virtual void uniform_set_set_invalidation_callback(RID p_uniform_set, UniformSetInvalidatedCallback p_callback, void *p_userdata);
+	virtual void uniform_set_set_invalidation_callback(RID p_uniform_set, InvalidationCallback p_callback, void *p_userdata);
 
 	virtual Error buffer_update(RID p_buffer, uint32_t p_offset, uint32_t p_size, const void *p_data, uint32_t p_post_barrier = BARRIER_MASK_ALL); //works for any buffer
 	virtual Error buffer_clear(RID p_buffer, uint32_t p_offset, uint32_t p_size, uint32_t p_post_barrier = BARRIER_MASK_ALL);