Removed external SDL2 dependency

Author: YaLTeR

README.md

@@ -15,7 +15,6 @@ hl-capture is designed to be **fast** and **convenient**. Video and sound are en
 
 ## Requirements
 - 32-bit FFMpeg libraries.
-- 32-bit SDL2.
 - 32-bit OpenCL (look for something like ocl-icd).
 
 ## Usage

src/hooks/hw.rs

@@ -64,6 +64,7 @@ struct Functions {
 /// Pointers to all used hw variables.
 struct Pointers {
     cls: *mut client_static_t,
+    game: *mut *mut CGame,
     host_frametime: *mut c_double,
     paintbuffer: *mut portable_samplepair_t, // [1026]
     paintedtime: *mut c_int,
@@ -191,6 +192,12 @@ struct dma_t {
     buffer: *mut c_uchar,
 }
 
+#[repr(C)]
+struct CGame {
+    stuff: [u8; 0xC],
+    m_hSDLGLContext: c_uint,
+}
+
 /// The "main" function of hw.so, called inside `CEngineAPI::Run()`.
 ///
 /// The game runs within this function and shortly after it exits hw.so is unloaded.
@@ -506,6 +513,7 @@ fn refresh_pointers(_: &Engine) -> Result<()> {
 
         POINTERS = Some(Pointers {
                             cls: find!(hw, "cls"),
+                            game: find!(hw, "game"),
                             host_frametime: find!(hw, "host_frametime"),
                             paintbuffer: find!(hw, "paintbuffer"),
                             paintedtime: find!(hw, "paintedtime"),
@@ -652,7 +660,7 @@ pub fn get_pro_que(engine: &Engine) -> Option<&mut ocl::ProQue> {
             engine.data().pro_que = Some(None);
         } else {
             let context = ocl::Context::builder()
-                .gl_context(sdl::get_current_context())
+                .gl_context(get_opengl_context(engine))
                 .glx_display(unsafe { glx::GetCurrentDisplay() } as _)
                 .build()
                 .chain_err(|| "error building ocl::Context");
@@ -897,5 +905,10 @@ fn read_pixels(_: &Engine, (w, h): (u32, u32), buf: &mut [u8]) {
     }
 }
 
+/// Retrieves the current OpenGL context.
+fn get_opengl_context(_: &Engine) -> u32 {
+    unsafe { (**ptr!(game)).m_hSDLGLContext }
+}
+
 cvar!(cap_allow_tabbing_out_in_demos, "1");
 cvar!(cap_playdemostop, "1");

src/sdl.rs

@@ -7,8 +7,3 @@ pub fn get_proc_address(name: &str) -> *const c_void {
     let cstring = CString::new(name).expect("could not convert name to a CString");
     unsafe { sdl2_sys::SDL_GL_GetProcAddress(cstring.as_ptr()) }
 }
-
-#[inline]
-pub fn get_current_context() -> u32 {
-    unsafe { sdl2_sys::SDL_GL_GetCurrentContext() as u32 }
-}