Struct glium::backend::Context
[−]
[src]
pub struct Context {
// some fields omitted
}Stores the state and information required for glium to execute commands. Most public glium
functions require passing a Rc<Context>.
Methods
impl Context
unsafe fn new<B, E>(backend: B, check_current_context: bool, callback_behavior: DebugCallbackBehavior) -> Result<Rc<Context>, GliumCreationError<E>> where B: Backend + 'static
Builds a new context.
The check_current_context parameter tells the context whether it should check
if the backend's OpenGL context is the current one before each OpenGL operation.
If you pass false, you must ensure that no other OpenGL context is going to be made
current in the same thread as this context. Passing true makes things safe but
is slightly slower.
The OpenGL context must be newly-created. If you make modifications to the context before passing it to this function, glium's state cache may mismatch the actual one.
fn get_framebuffer_dimensions(&self) -> (u32, u32)
Calls get_framebuffer_dimensions on the backend object stored by this context.
unsafe fn rebuild<B, E>(&self, new_backend: B) -> Result<(), GliumCreationError<E>> where B: Backend + 'static
Changes the OpenGL context associated with this context.
The new context must have lists shared with the old one.
fn swap_buffers(&self) -> Result<(), SwapBuffersError>
Swaps the buffers in the backend.
fn get_version(&self) -> &Version
DEPRECATED. Use get_opengl_version instead.
fn get_opengl_version(&self) -> &Version
Returns the OpenGL version detected by this context.
fn get_supported_glsl_version(&self) -> Version
Returns the GLSL version guaranteed to be supported.
fn is_glsl_version_supported(&self, version: &Version) -> bool
Returns true if the given GLSL version is supported.
fn is_robust(&self) -> bool
Returns true if out-of-bound buffer access from the GPU side (inside a program) cannot result in a crash.
You should take extra care if is_robust returns false.
fn is_context_loss_possible(&self) -> bool
Returns true if a context loss is possible.
fn is_context_lost(&self) -> bool
Returns true if the context has been lost and needs to be recreated.
Implementation
If it has been determined that the context has been lost before, then the function
immediatly returns true. Otherwise, calls glGetGraphicsResetStatus. If this function
is not available, returns false.
fn get_release_behavior(&self) -> ReleaseBehavior
Returns the behavior when the current OpenGL context is changed.
The most common value is Flush. In order to get None you must explicitely request it
during creation.
fn get_max_anisotropy_support(&self) -> Option<u16>
Returns the maximum value that can be used for anisotropic filtering, or None
if the hardware doesn't support it.
fn get_max_viewport_dimensions(&self) -> (u32, u32)
Returns the maximum dimensions of the viewport.
Glium will panic if you request a larger viewport than this when drawing.
fn release_shader_compiler(&self)
Releases the shader compiler, indicating that no new programs will be created for a while.
This method is a no-op if it's not available in the implementation.
fn get_free_video_memory(&self) -> Option<usize>
Returns an estimate of the amount of video memory available in bytes.
Returns None if no estimate is available.
fn read_front_buffer<T>(&self) -> T where T: Texture2dDataSink<(u8, u8, u8, u8)>
Reads the content of the front buffer.
You will only see the data that has finished being drawn.
This function can return any type that implements Texture2dData.
Example
let pixels: Vec<Vec<(u8, u8, u8, u8)>> = display.read_front_buffer();
unsafe fn exec_in_context<'a, T, F>(&self, action: F) -> T where T: Send + 'static, F: FnOnce() -> T + 'a
Execute an arbitrary closure with the OpenGL context active. Useful if another component needs to directly manipulate OpenGL state.
If action manipulates any OpenGL state, it must be restored before action
completes.
fn assert_no_error(&self, user_msg: Option<&str>)
Asserts that there are no OpenGL errors pending.
This function should be used in tests.
fn synchronize(&self)
DEPRECATED. Renamed finish.
fn finish(&self)
Calls glFinish(). This waits until all the previously issued commands have finished
being executed.
When you execute OpenGL functions, they are not executed immediately. Instead they are put in a queue. This function flushes this queue, then waits until all commands have finished being executed.
You normally don't need to call this function manually, except for debugging purposes.
fn flush(&self)
Calls glFlush(). This starts executing the commands that you have issued if it is not
yet the case.
When you execute OpenGL functions, they are not executed immediately. Instead they are put in a queue. This function flushes this queue so that commands start being executed.
You normally don't need to call this function manually. Swapping buffers automatically flushes the queue. This function can be useful if you want to benchmark the time it takes from your OpenGL driver to process commands.
fn insert_debug_marker(&self, marker: &str) -> Result<(), ()>
Inserts a debugging string in the commands queue. If you use an OpenGL debugger, you will be able to see that string.
This is helpful to understand where you are when you have big applications.
Returns Err if the backend doesn't support this functionnality. You can choose whether
to call .unwrap() if you want to make sure that it works, or .ok() if you don't care.
fn debug_insert_debug_marker(&self, marker: &str) -> Result<(), ()>
Same as insert_debug_marker, except that if you don't compile with debug_assertions
it is a no-op and returns Ok.