diff --git a/librashader-runtime-mtl/src/filter_chain.rs b/librashader-runtime-mtl/src/filter_chain.rs index d646db7..3de50e7 100644 --- a/librashader-runtime-mtl/src/filter_chain.rs +++ b/librashader-runtime-mtl/src/filter_chain.rs @@ -66,6 +66,14 @@ pub struct FilterChainMetal { output_framebuffers: Box<[OwnedTexture]>, feedback_framebuffers: Box<[OwnedTexture]>, history_framebuffers: VecDeque, + /// Metal does not allow us to push the input texture to history + /// before recording framebuffers, so we double-buffer it. + /// + /// First we swap OriginalHistory1 with the contents of this buffer (which were written to + /// in the previous frame) + /// + /// Then we blit the original to the buffer. + prev_frame_history_buffer: OwnedTexture, disable_mipmaps: bool, default_options: FrameOptionsMetal, } @@ -206,29 +214,38 @@ impl FilterChainMetal { cmd: &ProtocolObject, input: &ProtocolObject, ) -> error::Result<()> { - if let Some(mut back) = self.history_framebuffers.pop_back() { - let mipmapper = cmd - .blitCommandEncoder() - .ok_or(FilterChainError::FailedToCreateCommandBuffer)?; - if back.texture.height() != input.height() - || back.texture.width() != input.width() - || input.pixelFormat() != back.texture.pixelFormat() - { - let size = Size { - width: input.width() as u32, - height: input.height() as u32, - }; + // If there's no history, there's no need to do any of this. + let Some(mut back) = self.history_framebuffers.pop_back() else { + return Ok(()); + }; - let _old_back = std::mem::replace( - &mut back, - OwnedTexture::new(&self.common.device, size, 1, input.pixelFormat())?, - ); - } + // Push the previous frame as OriginalHistory1 + std::mem::swap(&mut back, &mut self.prev_frame_history_buffer); + self.history_framebuffers.push_front(back); - back.copy_from(&mipmapper, input)?; - mipmapper.endEncoding(); - self.history_framebuffers.push_front(back); + // Copy the current frame into prev_frame_history_buffer, which will be + // pushed to OriginalHistory1 in the next frame. + let back = &mut self.prev_frame_history_buffer; + let mipmapper = cmd + .blitCommandEncoder() + .ok_or(FilterChainError::FailedToCreateCommandBuffer)?; + if back.texture.height() != input.height() + || back.texture.width() != input.width() + || input.pixelFormat() != back.texture.pixelFormat() + { + let size = Size { + width: input.width() as u32, + height: input.height() as u32, + }; + + let _old_back = std::mem::replace( + back, + OwnedTexture::new(&self.common.device, size, 1, input.pixelFormat())?, + ); } + + back.copy_from(&mipmapper, input)?; + mipmapper.endEncoding(); Ok(()) } @@ -290,6 +307,8 @@ impl FilterChainMetal { // initialize history let (history_framebuffers, history_textures) = framebuffer_init.init_history()?; + let history_buffer = framebuffer_gen()?; + let draw_quad = DrawQuad::new(&device)?; Ok(FilterChainMetal { common: FilterCommon { @@ -306,6 +325,7 @@ impl FilterChainMetal { output_framebuffers, feedback_framebuffers, history_framebuffers, + prev_frame_history_buffer: history_buffer, disable_mipmaps: options.map(|f| f.force_no_mipmaps).unwrap_or(false), default_options: Default::default(), })