Merge #2071 #2164 #2166

2071: Remaping descriptor sets in the gl backend r=kvark a=ZeGentzy

I'll rebase off master when I'm done.

Uniforms in gl only have a bindings field, not a set one. This means that for shaders that use multiple sets to work, we must change where we are binding them.

See page 14 for what I mean: https://www.khronos.org/assets/uploads/developers/library/2016-vulkan-devday-uk/4-Using-spir-v-with-spirv-cross.pdf

PR checklist:
- [ ] `make` succeeds (on *nix)
- [ ] `make reftests` succeeds
- [ ] tested examples with the following backends:


2164: [mtl] Borrowed commands r=grovesNL a=kvark

PR checklist:
- [ ] `make` succeeds (on *nix)
- [x] `make reftests` succeeds
- [x] tested examples with the following backends:

r? @gfx-rs/metallists 

This PR attempts to have lightweight software commands that don't take any heap space or own ObjC objects. In most cases, where a command list is live-recorded and executed once, this should reduce the amount of work we do per command, which is especially important if those commands are thrown away (e.g. because we are not inside a render pass).

My expectation would be to see an improvement in #2161 due to us doing less work. The actual results are somewhat shocking: with v-sync enabled I'm getting the same 59-60 fps as usual. With v-sync OFF, I'm getting between 25 and 50 fps now (which is lower than the previous 50-70). Not sure what's going on, the instrumental profile doesn't give a clue. Please check out the code.

2166: Update example instructions in README.md r=kvark a=king6cong



Co-authored-by: Hal Gentz <[email protected]>
Co-authored-by: Dzmitry Malyshau <[email protected]>
Co-authored-by: king6cong <[email protected]>

README.md

@@ -36,8 +36,12 @@ To run an example, simply use `cargo run` and specify the backend with `--featur
 
 ```bash
 git clone https://github.com/gfx-rs/gfx
-cd gfx/examples/hal
+cd gfx/examples
+# macOS
+cargo run --bin quad --features metal
+# vulkan
 cargo run --bin quad --features vulkan
+# Windows
 cargo run --bin compute --features dx12 1 2 3 4
 ```
 

src/backend/gl/Cargo.toml

@@ -24,4 +24,4 @@ gfx_gl = "0.5"
 gfx-hal = { path = "../../hal", version = "0.1" }
 smallvec = "0.6"
 glutin = { version = "0.16", optional = true }
-spirv_cross = "0.8"
+spirv_cross = "0.9.2"

src/backend/gl/src/command.rs

@@ -108,6 +108,10 @@ pub enum Command {
     CopySurfaceToBuffer(n::Surface, n::RawBuffer, command::BufferImageCopy),
     CopyImageToTexture(n::ImageKind, n::Texture, command::ImageCopy),
     CopyImageToSurface(n::ImageKind, n::Surface, command::ImageCopy),
+
+    BindBufferRange(gl::types::GLenum, gl::types::GLuint, n::RawBuffer, gl::types::GLintptr, gl::types::GLsizeiptr),
+    BindTexture(gl::types::GLenum, n::Texture),
+    BindSampler(gl::types::GLuint, n::Texture),
 }
 
 pub type FrameBufferTarget = gl::types::GLenum;
@@ -862,17 +866,56 @@ impl command::RawCommandBuffer<Backend> for RawCommandBuffer {
 
     fn bind_graphics_descriptor_sets<I, J>(
         &mut self,
-        _layout: &n::PipelineLayout,
-        _first_set: usize,
-        _sets: I,
-        _offsets: J,
+        layout: &n::PipelineLayout,
+        first_set: usize,
+        sets: I,
+        offsets: J,
     ) where
         I: IntoIterator,
         I::Item: Borrow<n::DescriptorSet>,
         J: IntoIterator,
         J::Item: Borrow<command::DescriptorSetOffset>,
     {
-        // TODO
+        assert!(offsets.into_iter().next().is_none()); // TODO: offsets unsupported
+
+        let mut set = first_set as _;
+        let drd = &*layout.desc_remap_data.read().unwrap();
+
+        for desc_set in sets {
+            let desc_set = desc_set.borrow();
+            for new_binding in &*desc_set.bindings.lock().unwrap() {
+                match new_binding {
+                    n::DescSetBindings::Buffer {ty: btype, binding, buffer, offset, size} => {
+                        for binding in drd.get_binding(n::BindingTypes::UniformBuffers, set, *binding).unwrap() {
+                            self.push_cmd(Command::BindBufferRange(
+                                gl::UNIFORM_BUFFER,
+                                *binding,
+                                *buffer,
+                                *offset,
+                                *size,
+                            ))
+                        }
+                    }
+                    n::DescSetBindings::Texture(binding, texture) => {
+                        for binding in drd.get_binding(n::BindingTypes::Images, set, *binding).unwrap() {
+                            self.push_cmd(Command::BindTexture(
+                                *binding,
+                                *texture,
+                            ))
+                        }
+                    }
+                    n::DescSetBindings::Sampler(binding, sampler) => {
+                        for binding in drd.get_binding(n::BindingTypes::Images, set, *binding).unwrap() {
+                            self.push_cmd(Command::BindSampler(
+                                *binding,
+                                *sampler,
+                            ))
+                        }
+                    }
+                }
+            }
+            set += 1;
+        }
     }
 
     fn bind_compute_pipeline(&mut self, pipeline: &n::ComputePipeline) {