From 91dee22da5d644806287e8423ccf2ba6d19a309c Mon Sep 17 00:00:00 2001
From: modeco80 <lily.modeco80@protonmail.ch>
Date: Mon, 5 Aug 2024 22:23:41 -0400
Subject: [PATCH] cleanup OpenGL FBO creation/deletion

---
 crates/retrovnc/src/main.rs | 63 +++++++++++++++++++------------------
 1 file changed, 33 insertions(+), 30 deletions(-)

diff --git a/crates/retrovnc/src/main.rs b/crates/retrovnc/src/main.rs
index 1543169..0d85f1d 100644
--- a/crates/retrovnc/src/main.rs
+++ b/crates/retrovnc/src/main.rs
@@ -182,34 +182,42 @@ impl App {
 	/// Destroys EGL resources.
 	unsafe fn hw_gl_egl_exit(&mut self) {
 		// Release the EGL context we created before destroying it
-		egl::MakeCurrent(self.egl_display, egl::NO_SURFACE, egl::NO_SURFACE, egl::NO_CONTEXT);
+		egl::MakeCurrent(
+			self.egl_display,
+			egl::NO_SURFACE,
+			egl::NO_SURFACE,
+			egl::NO_CONTEXT,
+		);
 		egl::DestroyContext(self.egl_display, self.egl_context);
 		egl::Terminate(self.egl_display);
 		self.egl_display = std::ptr::null();
 		self.egl_context = std::ptr::null();
 	}
 
-	fn hw_gl_resize_fbo(&mut self, width: u32, height: u32) {
-		// TODO: cleanup "delete" codepaths so we aren't duplicating as much.
-		// (we should probably just have a "create" and "delete" FBO pair.)
+	fn hw_gl_delete_fbo(&mut self) {
 		unsafe {
-			if self.fbo_id == 0 {
-				gl::GenFramebuffers(1, std::ptr::addr_of_mut!(self.fbo_id));
-				gl::BindFramebuffer(gl::FRAMEBUFFER, self.fbo_id);
-			} else {
-				gl::DeleteFramebuffers(1, std::ptr::addr_of_mut!(self.fbo_id));
-				gl::GenFramebuffers(1, std::ptr::addr_of_mut!(self.fbo_id));
-				gl::BindFramebuffer(gl::FRAMEBUFFER, self.fbo_id);
+			gl::DeleteFramebuffers(1, std::ptr::addr_of_mut!(self.fbo_id));
+			self.fbo_id = 0;
+
+			gl::DeleteTextures(1, std::ptr::addr_of_mut!(self.texture_id));
+			self.texture_id = 0;
+
+			gl::DeleteRenderbuffers(1, std::ptr::addr_of_mut!(self.renderbuffer_id));
+			self.renderbuffer_id = 0;
+		}
+	}
+
+	fn hw_gl_create_fbo(&mut self, width: u32, height: u32) {
+		unsafe {
+			if self.fbo_id != 0 {
+				self.hw_gl_delete_fbo();
 			}
 
-			if self.texture_id == 0 {
-				gl::GenTextures(1, std::ptr::addr_of_mut!(self.texture_id));
-				gl::BindTexture(gl::TEXTURE_2D, self.texture_id);
-			} else {
-				gl::DeleteTextures(1, std::ptr::addr_of_mut!(self.texture_id));
-				gl::GenTextures(1, std::ptr::addr_of_mut!(self.texture_id));
-				gl::BindTexture(gl::TEXTURE_2D, self.texture_id);
-			}
+			gl::GenFramebuffers(1, std::ptr::addr_of_mut!(self.fbo_id));
+			gl::BindFramebuffer(gl::FRAMEBUFFER, self.fbo_id);
+
+			gl::GenTextures(1, std::ptr::addr_of_mut!(self.texture_id));
+			gl::BindTexture(gl::TEXTURE_2D, self.texture_id);
 
 			gl::TexImage2D(
 				gl::TEXTURE_2D,
@@ -223,14 +231,8 @@ impl App {
 				std::ptr::null(),
 			);
 
-			if self.renderbuffer_id == 0 {
-				gl::GenRenderbuffers(1, std::ptr::addr_of_mut!(self.renderbuffer_id));
-				gl::BindRenderbuffer(gl::RENDERBUFFER, self.renderbuffer_id);
-			} else {
-				gl::DeleteRenderbuffers(1, std::ptr::addr_of_mut!(self.renderbuffer_id));
-				gl::GenRenderbuffers(1, std::ptr::addr_of_mut!(self.renderbuffer_id));
-				gl::BindRenderbuffer(gl::RENDERBUFFER, self.renderbuffer_id);
-			}
+			gl::GenRenderbuffers(1, std::ptr::addr_of_mut!(self.renderbuffer_id));
+			gl::BindRenderbuffer(gl::RENDERBUFFER, self.renderbuffer_id);
 
 			gl::RenderbufferStorage(
 				gl::RENDERBUFFER,
@@ -262,6 +264,7 @@ impl App {
 
 			gl::BindFramebuffer(gl::FRAMEBUFFER, 0);
 
+			// Notify the frontend layer about the new FBO
 			let id = self.fbo_id;
 			self.get_frontend().set_gl_fbo(id);
 
@@ -292,7 +295,7 @@ impl FrontendInterface for App {
 
 		// Resize OpenGL resources if we need to.
 		if self.hw_render {
-			self.hw_gl_resize_fbo(width, height);
+			self.hw_gl_create_fbo(width, height);
 		}
 
 		self.rfb_server.resize(width as u16, height as u16);
@@ -360,9 +363,9 @@ impl FrontendInterface for App {
 			gl::Enable(gl::DEBUG_OUTPUT);
 			gl::DebugMessageCallback(Some(opengl_message_callback), std::ptr::null());
 
-			// Resize to initial dimensions (this will create an FBO as well)
+			// Create the initial FBO for the core to render to
 			let dimensions = self.get_frontend().get_size();
-			self.hw_gl_resize_fbo(dimensions.0, dimensions.1);
+			self.hw_gl_create_fbo(dimensions.0, dimensions.1);
 		}
 
 		self.hw_render = true;