Initial OpenGL core support

mmmmmm, this really is NOT as clean as I want it to be, but here it is!

Cargo.lock

@@ -191,6 +191,26 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "gl"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a94edab108827d67608095e269cf862e60d920f144a5026d3dbcfd8b877fb404"
+dependencies = [
+ "gl_generator",
+]
+
+[[package]]
+name = "gl_generator"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a95dfc23a2b4a9a2f5ab41d194f8bfda3cabec42af4e39f08c339eb2a0c124d"
+dependencies = [
+ "khronos_api",
+ "log",
+ "xml-rs",
+]
+
 [[package]]
 name = "glob"
 version = "0.3.1"
@@ -237,6 +257,12 @@ dependencies = [
  "either",
 ]
 
+[[package]]
+name = "khronos_api"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2db585e1d738fc771bf08a151420d3ed193d9d895a36df7f6f8a9456b911ddc"
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -433,6 +459,8 @@ dependencies = [
  "anyhow",
  "cc",
  "clap",
+ "gl",
+ "gl_generator",
  "libvnc-sys",
  "retro_frontend",
  "tracing",
@@ -785,3 +813,9 @@ checksum = "68a9bda4691f099d435ad181000724da8e5899daa10713c2d432552b9ccd3a6f"
 dependencies = [
  "memchr",
 ]
+
+[[package]]
+name = "xml-rs"
+version = "0.8.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "791978798f0597cfc70478424c2b4fdc2b7a8024aaff78497ef00f24ef674193"

crates/retro_frontend/src/frontend.rs

@@ -21,11 +21,22 @@ use tracing::{error, info};
 /// Only one instance of Frontend can be active in an application.
 pub(crate) static mut FRONTEND: *mut Frontend = std::ptr::null_mut();
 
+/// A "Generalized" type for OpenGL's "getProcAddress" idiom
+pub type GlGetProcAddress = *mut unsafe extern "C" fn(name: *const i8) -> unsafe extern "C" fn();
+
+/// Initalization data for HW OpenGL cores.
+pub struct HwGlInitData {
+	pub get_proc_address: GlGetProcAddress,
+}
+
 /// Interface for the frontend to call to user code.
 pub trait FrontendInterface {
 	/// Called when video is updated.
 	fn video_update(&mut self, slice: &[u32], pitch: u32);
 
+	/// Called when video is updated and the core is using HW OpenGL rendering.
+	fn video_update_gl(&mut self);
+
 	/// Called when resize occurs.
 	fn video_resize(&mut self, width: u32, height: u32);
 
@@ -36,10 +47,8 @@ pub trait FrontendInterface {
 	/// Called to poll input
 	fn input_poll(&mut self);
 
-	// TODO(lily): Provide APIs for gathering a GL context/fbo.
+	/// Initalize hardware accelerated rendering using OpenGL.
-	// This should be abstracted so if a frontend written on top of retro_frontend
+	fn hw_gl_init(&mut self) -> HwGlInitData;
-	// wants to give a FBO from a GLX/WGL/windowed whatever context, it can,
-	// but a headless frontend can itself provide a headless EGL context just the same.
 }
 
 /// Per-core settings
@@ -73,6 +82,9 @@ pub struct Frontend {
 	pub(crate) fb_height: u32,
 	pub(crate) fb_pitch: u32,
 
+	// HW OpenGL FBO id.
+	pub(crate) gl_fbo_id: u32,
+
 	/// The "system" directory. Used for BIOS roms.
 	pub(crate) system_directory: CString,
 
@@ -109,6 +121,7 @@ impl Frontend {
 			fb_width: 0,
 			fb_height: 0,
 			fb_pitch: 0,
+			gl_fbo_id: 0,
 
 			// TODO: We should let callers set these, probably.
 			// For now, this is probably fine.
@@ -431,6 +444,10 @@ impl Frontend {
 		(self.fb_width, self.fb_height)
 	}
 
+	pub fn set_gl_fbo(&mut self, id: u32) {
+		self.gl_fbo_id = id;
+	}
+
 	pub fn reset(&mut self) {
 		let core_api = self.core_api.as_ref().unwrap();
 

crates/retro_frontend/src/libretro_callbacks.rs

@@ -8,6 +8,11 @@ use std::ffi;
 
 use tracing::{debug, error, info};
 
+/// This function is used with HW OpenGL cores to transfer the current FBO's ID.
+unsafe extern "C" fn hw_gl_get_framebuffer() -> usize {
+	(*FRONTEND).gl_fbo_id as usize
+}
+
 pub(crate) unsafe extern "C" fn environment_callback(
 	environment_command: u32,
 	data: *mut ffi::c_void,
@@ -99,6 +104,33 @@ pub(crate) unsafe extern "C" fn environment_callback(
 			return true;
 		}
 
+		ENVIRONMENT_SET_HW_RENDER => {
+			let hw_render = (data as *mut HwRenderCallback).as_mut().unwrap();
+
+			let hw_render_context_type =
+				HwContextType::from_uint(hw_render.context_type).expect("FUCK");
+
+			if hw_render_context_type != HwContextType::OpenGL && hw_render_context_type != HwContextType::OpenGLCore {
+				error!(
+					"Core is trying to request an context type we don't support ({:?})",
+					hw_render_context_type
+				);
+				return false;
+			}
+
+			info!("Core requesting context type {:?}", hw_render_context_type);
+
+			let init_data = (*(*FRONTEND).interface).hw_gl_init();
+
+			hw_render.get_current_framebuffer = hw_gl_get_framebuffer;
+			hw_render.get_proc_address = std::mem::transmute(init_data.get_proc_address);
+
+			// reset context
+			(hw_render.context_reset)();
+
+			return true;
+		}
+
 		ENVIRONMENT_GET_VARIABLE => {
 			// Make sure the core actually is giving us a pointer to a *Variable
 			// so we can fill it in.
@@ -179,9 +211,19 @@ pub(crate) unsafe extern "C" fn video_refresh_callback(
 
 	//info!("Video refresh called, {width}, {height}, {pitch}");
 
+	if (*FRONTEND).fb_width != width || (*FRONTEND).fb_height != height {
+		(*(*FRONTEND).interface).video_resize(width, height);
+	}
+
 	// bleh
 	(*FRONTEND).fb_width = width;
 	(*FRONTEND).fb_height = height;
+
+	if pixels == (-1i64 as *const ffi::c_void) {
+		(*(*FRONTEND).interface).video_update_gl();
+		return;
+	}
+
 	(*FRONTEND).fb_pitch =
 		pitch as u32 / util::bytes_per_pixel_from_libretro((*FRONTEND).pixel_format);
 
@@ -200,9 +242,6 @@ pub(crate) unsafe extern "C" fn video_refresh_callback(
 				(*FRONTEND)
 					.converted_pixel_buffer
 					.resize((pitch * height as usize) as usize, 0);
-
-				// some cores are stupid
-				(*(*FRONTEND).interface).video_resize(width, height);
 			}
 
 			// TODO: Make this convert from weird pitches to native resolution where possible.
@@ -217,7 +256,8 @@ pub(crate) unsafe extern "C" fn video_refresh_callback(
 				}
 			}
 
-			(*(*FRONTEND).interface).video_update(&(*FRONTEND).converted_pixel_buffer[..], pitch as u32);
+			(*(*FRONTEND).interface)
+				.video_update(&(*FRONTEND).converted_pixel_buffer[..], pitch as u32);
 		}
 		_ => {
 			let pixel_data_slice = std::slice::from_raw_parts(

crates/retrovnc/Cargo.toml

@@ -7,6 +7,7 @@ publish = false
 [dependencies]
 anyhow = "1.0.86"
 clap = { version = "4.5.6", features = ["cargo"] }
+gl = "0.14.0"
 libvnc-sys = "0.1.4"
 retro_frontend = { path = "../retro_frontend" }
 tracing = "0.1.40"
@@ -14,3 +15,4 @@ tracing-subscriber = "0.3.18"
 
 [build-dependencies]
 cc = "1.0.99"
+gl_generator = "0.14.0"

crates/retrovnc/build.rs

@@ -1,8 +1,33 @@
 use cc;
 
-fn main() {
+use gl_generator::{Api, Fallbacks, Profile, Registry, StaticGenerator};
-	let mut build = cc::Build::new();
+use std::env;
+use std::fs::File;
+use std::path::Path;
 
+
+fn main() {
+	// EGL
+
+	let dest = env::var("OUT_DIR").unwrap();
+    let mut file = File::create(&Path::new(&dest).join("egl_bindings.rs")).unwrap();
+
+    Registry::new(Api::Egl, (1, 5), Profile::Core, Fallbacks::All, [
+		"EGL_EXT_platform_base",
+		"EGL_EXT_device_base",
+		
+		// This allows getting OpenGL APIs via eglGetProcAddress()
+		"EGL_KHR_get_all_proc_addresses",
+		"EGL_KHR_client_get_all_proc_addresses",
+
+		"EGL_EXT_platform_device"
+
+	])
+        .write_bindings(StaticGenerator, &mut file)
+        .unwrap();
+
+	// C++
+	let mut build = cc::Build::new();
 	build
 		.emit_rerun_if_env_changed(true)
 		.cpp(true)

crates/retrovnc/src/egl.rs

@@ -0,0 +1,34 @@
+#[allow(non_camel_case_types)]
+mod egl_impl {
+	pub type khronos_utime_nanoseconds_t = khronos_uint64_t;
+	pub type khronos_uint64_t = u64;
+	pub type khronos_ssize_t = std::ffi::c_long;
+	pub type EGLint = i32;
+	pub type EGLNativeDisplayType = *const std::ffi::c_void;
+	pub type EGLNativePixmapType = *const std::ffi::c_void;
+	pub type EGLNativeWindowType = *const std::ffi::c_void;
+
+	pub type NativeDisplayType = EGLNativeDisplayType;
+	pub type NativePixmapType = EGLNativePixmapType;
+	pub type NativeWindowType = EGLNativeWindowType;
+
+	include!(concat!(env!("OUT_DIR"), "/egl_bindings.rs"));
+
+	pub type GetPlatformDisplayExt = unsafe extern "C" fn(
+		platform: types::EGLenum,
+		native_display: *const std::ffi::c_void,
+		attrib_list: *const types::EGLint,
+	) -> types::EGLDisplay;
+
+	pub type QueryDevicesExt = unsafe extern "C" fn(
+		max_devices: self::types::EGLint,
+		devices: *mut self::types::EGLDeviceEXT,
+		devices: *mut EGLint,
+	) -> types::EGLBoolean;
+
+	// link EGL as a library dependency
+	#[link(name = "EGL")]
+	extern "C" {}
+}
+
+pub use egl_impl::*;

crates/retrovnc/src/main.rs

@@ -1,9 +1,9 @@
-use std::{net::Ipv4Addr, path::Path};
+use std::{net::Ipv4Addr, path::Path, ptr::addr_of_mut};
 
 use anyhow::Result;
 
 use retro_frontend::{
-	frontend::{Frontend, FrontendInterface},
+	frontend::{Frontend, FrontendInterface, HwGlInitData},
 	input_devices::{InputDevice, RetroPad},
 };
 use tracing::Level;
@@ -11,6 +11,32 @@ use tracing_subscriber::FmtSubscriber;
 
 use clap::{arg, command, value_parser};
 
+
+
+extern "system" fn opengl_message_callback(
+	source: gl::types::GLenum,
+	_type: gl::types::GLenum,
+	id: gl::types::GLuint,
+	severity: gl::types::GLenum,
+	length: gl::types::GLsizei,
+	message: *const gl::types::GLchar,
+	user: *mut std::ffi::c_void,
+) {
+	unsafe {
+		let message = std::ffi::CStr::from_ptr(message);
+		if _type == gl::DEBUG_TYPE_ERROR {
+			tracing::error!(
+				"OpenGL error: {:?} (res {:08x}, id = {:08x}, source = {:08x})",
+				message,
+				_type,
+				id,
+				source
+			);
+		}
+	}
+}
+
+mod egl;
 mod rfb;
 use rfb::*;
 
@@ -18,6 +44,15 @@ struct App {
 	frontend: Option<Box<Frontend>>,
 	rfb_server: Box<RfbServer>,
 	pad: RetroPad,
+
+	hw_render: bool,
+
+	// opengl state shits
+	texture_id: gl::types::GLuint,
+	renderbuffer_id: gl::types::GLuint,
+	fbo_id: gl::types::GLuint,
+
+	readback_buffer: Vec<u32>,
 }
 
 impl App {
@@ -26,6 +61,11 @@ impl App {
 			frontend: None,
 			rfb_server: RfbServer::new(rfb_config)?,
 			pad: RetroPad::new(),
+			hw_render: false,
+			texture_id: 0,
+			renderbuffer_id: 0,
+			fbo_id: 0,
+			readback_buffer: Vec::new(),
 		});
 
 		// Very very nasty, but honestly it works.
@@ -80,6 +120,81 @@ impl App {
 		Ok(())
 	}
 
+	fn hw_gl_resize(&mut self, width: u32, height: u32) {
+		// TODO: if requested, add depth renderbuffer.
+		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);
+			}
+
+			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::TexImage2D(
+				gl::TEXTURE_2D,
+				0,
+				gl::RGBA8 as i32,
+				width as i32,
+				height as i32,
+				0,
+				gl::RGBA,
+				gl::UNSIGNED_BYTE,
+				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);
+				gl::RenderbufferStorage(
+					gl::RENDERBUFFER,
+					gl::DEPTH_COMPONENT,
+					width as i32,
+					height as i32,
+				);
+			}
+
+			gl::FramebufferTexture2D(
+				gl::FRAMEBUFFER,
+				gl::COLOR_ATTACHMENT0,
+				gl::TEXTURE_2D,
+				self.texture_id,
+				0,
+			);
+
+			gl::BindTexture(gl::TEXTURE_2D, 0);
+
+			gl::FramebufferRenderbuffer(
+				gl::FRAMEBUFFER,
+				gl::DEPTH_ATTACHMENT,
+				gl::RENDERBUFFER,
+				self.renderbuffer_id,
+			);
+
+			gl::BindRenderbuffer(gl::RENDERBUFFER, 0);
+
+			gl::Viewport(0, 0, width as i32, height as i32);
+
+			gl::BindFramebuffer(gl::FRAMEBUFFER, 0);
+
+			let id = self.fbo_id;
+			self.get_frontend().set_gl_fbo(id);
+
+			self.readback_buffer.resize((width * height) as usize, 0);
+		}
+	}
+
 	// Main loop
 	fn main_loop(&mut self) -> ! {
 		let frontend = self.get_frontend();
@@ -101,13 +216,41 @@ impl FrontendInterface for App {
 		//let height = height * 2;
 
 		tracing::info!("Resized to {width}x{height}");
+
+		// Resize OpenGL
+		if self.hw_render {
+			self.hw_gl_resize(width, height);
+		}
+
 		self.rfb_server.resize(width as u16, height as u16);
 	}
 
 	fn video_update(&mut self, slice: &[u32], pitch: u32) {
 		//let framebuffer_size = self.get_frontend().get_size();
-		self.rfb_server
+		self.rfb_server.update_buffer(&slice, pitch, false);
-			.update_buffer(&slice, pitch);
+	}
+
+	fn video_update_gl(&mut self) {
+		let dimensions = self.get_frontend().get_size();
+
+		unsafe {
+			gl::BindFramebuffer(gl::FRAMEBUFFER, self.fbo_id);
+
+			// I know this sucks but hey
+			gl::ReadPixels(
+				0,
+				0,
+				dimensions.0 as i32,
+				dimensions.1 as i32,
+				gl::RGBA,
+				gl::UNSIGNED_BYTE,
+				self.readback_buffer.as_mut_ptr() as *mut std::ffi::c_void,
+			);
+
+			self.rfb_server.update_buffer(&self.readback_buffer[..], dimensions.0, true);
+
+			gl::BindFramebuffer(gl::FRAMEBUFFER, 0);
+		}
 	}
 
 	fn audio_sample(&mut self, _slice: &[i16], _size: usize) {}
@@ -123,6 +266,112 @@ impl FrontendInterface for App {
 			}
 		}
 	}
+
+	fn hw_gl_init(&mut self) -> HwGlInitData {
+		if self.hw_render {
+			panic!("Nope!");
+		}
+
+		let display = unsafe {
+			const NR_DEVICES_MAX: usize = 16;
+			let mut devices: [egl::types::EGLDeviceEXT; NR_DEVICES_MAX] =
+				[std::ptr::null(); NR_DEVICES_MAX];
+
+			let mut nr_devices_real: egl::EGLint = 0;
+
+			let query_devices_ext: egl::QueryDevicesExt = std::mem::transmute(egl::GetProcAddress(
+				b"eglQueryDevicesEXT\0".as_ptr() as *const i8,
+			));
+			let get_platform_display_ext: egl::GetPlatformDisplayExt = std::mem::transmute(
+				egl::GetProcAddress(b"eglGetPlatformDisplayEXT\0".as_ptr() as *const i8),
+			);
+
+			// load OpenGL functions (using EGL loader. We should probably check the one extension exists)
+			gl::load_with(|s| {
+				let str = std::ffi::CString::new(s).expect("you MOTHERFUCKER");
+				std::mem::transmute(egl::GetProcAddress(str.as_ptr()))
+			});
+
+			tracing::info!("before query devices");
+
+			(query_devices_ext)(
+				NR_DEVICES_MAX as i32,
+				devices.as_mut_ptr(),
+				std::ptr::addr_of_mut!(nr_devices_real),
+			);
+
+			tracing::info!("after query devices");
+			(get_platform_display_ext)(egl::PLATFORM_DEVICE_EXT, devices[0], std::ptr::null())
+		};
+
+		tracing::info!("made EGL display");
+
+		let context = unsafe {
+			const EGL_CONFIG_ATTRIBUTES: [egl::types::EGLenum; 13] = [
+				egl::SURFACE_TYPE,
+				egl::PBUFFER_BIT,
+				egl::BLUE_SIZE,
+				8,
+				egl::RED_SIZE,
+				8,
+				egl::BLUE_SIZE,
+				8,
+				egl::DEPTH_SIZE,
+				8,
+				egl::RENDERABLE_TYPE,
+				egl::OPENGL_BIT,
+				egl::NONE,
+			];
+			let mut egl_major: egl::EGLint = 0;
+			let mut egl_minor: egl::EGLint = 0;
+
+			let mut egl_config_count: egl::EGLint = 0;
+
+			let mut config: egl::types::EGLConfig = std::ptr::null();
+
+			egl::Initialize(
+				display,
+				std::ptr::addr_of_mut!(egl_major),
+				std::ptr::addr_of_mut!(egl_minor),
+			);
+
+			egl::ChooseConfig(
+				display,
+				EGL_CONFIG_ATTRIBUTES.as_ptr() as *const egl::EGLint,
+				std::ptr::addr_of_mut!(config),
+				1,
+				std::ptr::addr_of_mut!(egl_config_count),
+			);
+
+			egl::BindAPI(egl::OPENGL_API);
+
+			egl::CreateContext(display, config, egl::NO_CONTEXT, std::ptr::null())
+		};
+
+		unsafe {
+			egl::MakeCurrent(display, egl::NO_SURFACE, egl::NO_SURFACE, context);
+
+			gl::Enable(gl::DEBUG_OUTPUT);
+			gl::DebugMessageCallback(Some(opengl_message_callback), std::ptr::null());
+
+			let dimensions = self.get_frontend().get_size();
+
+			self.hw_gl_resize(dimensions.0, dimensions.1);
+
+			gl::BindFramebuffer(gl::FRAMEBUFFER, 0);
+		}
+
+		self.hw_render = true;
+
+		return unsafe {
+			HwGlInitData {
+				get_proc_address: std::mem::transmute::<
+					_,
+					retro_frontend::frontend::GlGetProcAddress,
+				>(egl::GetProcAddress as usize),
+			}
+		};
+	}
 }
 
 fn main() -> Result<()> {
@@ -170,7 +419,6 @@ fn main() -> Result<()> {
 
 	app.load_core(core_path)?;
 
-
 	if let Some(rom_path) = matches.get_one::<String>("rom") {
 		app.load_game(rom_path)?
 	}

crates/retrovnc/src/rfb.rs

@@ -20,7 +20,7 @@ pub struct RfbServer {
 	buttons: [bool; 32],
 
 	width: u16,
-	height: u16
+	height: u16,
 }
 
 impl RfbServer {
@@ -57,7 +57,7 @@ impl RfbServer {
 				framebuffer: Vec::new(),
 				buttons: [false; 32],
 				width: config.width,
-				height: config.height
+				height: config.height,
 			});
 
 			// Disable the normal libvnc cursor (it's annoying)
@@ -99,8 +99,7 @@ impl RfbServer {
 		}
 	}
 
-	pub fn update_buffer(&mut self, slice: &[u32], pitch: u32) {
+	pub fn update_buffer(&mut self, slice: &[u32], pitch: u32, flipped: bool) {
-
 		//self.framebuffer.copy_from_slice(&slice);
 
 		let has_disconnected_pitch = pitch != self.width as u32;
@@ -110,6 +109,31 @@ impl RfbServer {
 		//}
 
 		// copy a line at a time (test)
+
+		if flipped {
+			let mut scanlines: Vec<&[u32]> = Vec::with_capacity(self.height as usize);
+
+			for y in (0..self.height).rev() {
+				let src_line_off = (y as u32 * pitch) as usize;
+				let src_slice = &slice[src_line_off..src_line_off + self.width as usize];
+				scanlines.push(src_slice);
+			}
+
+			for y in (0..self.height) {
+				let src_line_off = (y as u32 * pitch) as usize;
+				let mut dest_line_off = src_line_off;
+
+				// copy only
+				if has_disconnected_pitch {
+					dest_line_off = (y * self.width) as usize;
+				}
+
+				let dest_slice =
+					&mut self.framebuffer[dest_line_off..dest_line_off + self.width as usize];
+
+				dest_slice.copy_from_slice(scanlines[y as usize]);
+			}
+		} else {
 			for y in 0..self.height {
 				let src_line_off = (y as u32 * pitch) as usize;
 				let mut dest_line_off = src_line_off;
@@ -121,10 +145,12 @@ impl RfbServer {
 
 				// Create slices repressenting each part
 				let src_slice = &slice[src_line_off..src_line_off + self.width as usize];
-			let dest_slice = &mut self.framebuffer[dest_line_off..dest_line_off + self.width as usize];
+				let dest_slice =
+					&mut self.framebuffer[dest_line_off..dest_line_off + self.width as usize];
 
 				dest_slice.copy_from_slice(src_slice);
 			}
+		}
 
 		unsafe {
 			rfb::bindings::rfbMarkRectAsModified(