Create Render struct

Separate coarse and fine stages as separate methods of Render struct.

src/render.rs

@@ -9,6 +9,34 @@ use crate::{
     Scene,
 };
 
+/// State for a render in progress.
+pub struct Render {
+    /// Size of binning and info combined buffer in u32 units
+    binning_info_size: u32,
+    /// Size of tiles buf in tiles
+    tiles_size: u32,
+    /// Size of segments buf in segments
+    segments_size: u32,
+    /// Size of per-tile command list in u32 units
+    ptcl_size: u32,
+    width_in_tiles: u32,
+    height_in_tiles: u32,
+    fine: Option<FineResources>,
+}
+
+/// Resources produced by pipeline, needed for fine rasterization.
+struct FineResources {
+    config_buf: ResourceProxy,
+    bump_buf: ResourceProxy,
+    tile_buf: ResourceProxy,
+    segments_buf: ResourceProxy,
+    ptcl_buf: ResourceProxy,
+    gradient_image: ResourceProxy,
+    info_bin_data_buf: ResourceProxy,
+
+    out_image: ImageProxy,
+}
+
 const TAG_MONOID_SIZE: u64 = 12;
 const TAG_MONOID_FULL_SIZE: u64 = 20;
 const PATH_BBOX_SIZE: u64 = 24;
@@ -157,12 +185,49 @@ pub fn render_full(
     render_encoding_full(scene.data(), shaders, width, height)
 }
 
+/// Create a single recording with both coarse and fine render stages.
+///
+/// This function is not recommended when the scene can be complex, as it does not
+/// implement robust dynamic memory.
 pub fn render_encoding_full(
     encoding: &Encoding,
     shaders: &FullShaders,
     width: u32,
     height: u32,
 ) -> (Recording, ResourceProxy) {
+    let mut render = Render::new();
+    let mut recording = render.render_encoding_coarse(encoding, shaders, width, height);
+    let out_image = render.out_image();
+    render.record_fine(shaders, &mut recording);
+    (recording, out_image.into())
+}
+
+pub fn align_up(len: usize, alignment: u32) -> usize {
+    len + (len.wrapping_neg() & (alignment as usize - 1))
+}
+
+impl Render {
+    pub fn new() -> Self {
+        // These sizes are adequate for paris-30k but should probably be dialed down.
+        Render {
+            binning_info_size: (1 << 20) / 4,
+            tiles_size: (1 << 24) / TILE_SIZE as u32,
+            segments_size: (1 << 26) / SEGMENT_SIZE as u32,
+            ptcl_size: (1 << 25) / 4 as u32,
+            width_in_tiles: 0,
+            height_in_tiles: 0,
+            fine: None,
+        }
+    }
+
+    /// Prepare a recording for the coarse rasterization phase.
+    pub fn render_encoding_coarse(
+        &mut self,
+        encoding: &Encoding,
+        shaders: &FullShaders,
+        width: u32,
+        height: u32,
+    ) -> Recording {
         use crate::encoding::{resource::ResourceCache, PackedEncoding};
         let mut recording = Recording::default();
         let mut resources = ResourceCache::new();
@@ -196,10 +261,10 @@ pub fn render_encoding_full(
             height_in_tiles: new_height / 16,
             target_width: width,
             target_height: height,
-        binning_size: ((1 << 20) / 4) - info_size,
-        tiles_size: (1 << 24) / TILE_SIZE as u32,
-        segments_size: (1 << 26) / SEGMENT_SIZE as u32,
-        ptcl_size: (1 << 25) / 4,
+            binning_size: self.binning_info_size - info_size,
+            tiles_size: self.tiles_size,
+            segments_size: self.segments_size,
+            ptcl_size: self.ptcl_size,
             layout: packed.layout,
         };
         // println!("{:?}", config);
@@ -274,7 +339,8 @@ pub fn render_encoding_full(
             recording.free_resource(reduced_scan);
         }
         let drawobj_wgs = (n_drawobj + shaders::PATH_BBOX_WG - 1) / shaders::PATH_BBOX_WG;
-    let path_bbox_buf = ResourceProxy::new_buf(n_paths as u64 * PATH_BBOX_SIZE, "path_bbox_buf");
+        let path_bbox_buf =
+            ResourceProxy::new_buf(n_paths as u64 * PATH_BBOX_SIZE, "path_bbox_buf");
         recording.dispatch(
             shaders.bbox_clear,
             (drawobj_wgs, 1, 1),
@@ -319,7 +385,8 @@ pub fn render_encoding_full(
             ],
         );
         recording.free_resource(draw_reduced_buf);
-    let clip_el_buf = ResourceProxy::new_buf(encoding.n_clips as u64 * CLIP_EL_SIZE, "clip_el_buf");
+        let clip_el_buf =
+            ResourceProxy::new_buf(encoding.n_clips as u64 * CLIP_EL_SIZE, "clip_el_buf");
         let clip_bic_buf = ResourceProxy::new_buf(
             (n_clip / shaders::CLIP_REDUCE_WG) as u64 * CLIP_BIC_SIZE,
             "clip_bic_buf",
@@ -358,7 +425,8 @@ pub fn render_encoding_full(
         recording.free_resource(clip_inp_buf);
         recording.free_resource(clip_bic_buf);
         recording.free_resource(clip_el_buf);
-    let draw_bbox_buf = ResourceProxy::new_buf(n_paths as u64 * DRAW_BBOX_SIZE, "draw_bbox_buf");
+        let draw_bbox_buf =
+            ResourceProxy::new_buf(n_paths as u64 * DRAW_BBOX_SIZE, "draw_bbox_buf");
         let bump_buf = BufProxy::new(BUMP_SIZE, "bump_buf");
         let width_in_bins = (config.width_in_tiles + 15) / 16;
         let height_in_bins = (config.height_in_tiles + 15) / 16;
@@ -443,31 +511,52 @@ pub fn render_encoding_full(
         recording.free_resource(draw_monoid_buf);
         recording.free_resource(bin_header_buf);
         recording.free_resource(path_buf);
-    // TODO: bump_buf is special
-    recording.free_resource(bump_buf);
         let out_image = ImageProxy::new(width, height, ImageFormat::Rgba8);
-    recording.dispatch(
-        shaders.fine,
-        (config.width_in_tiles, config.height_in_tiles, 1),
-        [
+        self.width_in_tiles = config.width_in_tiles;
+        self.height_in_tiles = config.height_in_tiles;
+        self.fine = Some(FineResources {
             config_buf,
+            bump_buf,
             tile_buf,
             segments_buf,
-            ResourceProxy::Image(out_image),
             ptcl_buf,
             gradient_image,
             info_bin_data_buf,
-        ],
-    );
-    recording.free_resource(config_buf);
-    recording.free_resource(tile_buf);
-    recording.free_resource(segments_buf);
-    recording.free_resource(ptcl_buf);
-    recording.free_resource(gradient_image);
-    recording.free_resource(info_bin_data_buf);
-    (recording, ResourceProxy::Image(out_image))
+            out_image,
+        });
+        recording
     }
 
-pub fn align_up(len: usize, alignment: u32) -> usize {
-    len + (len.wrapping_neg() & (alignment as usize - 1))
+    /// Run fine rasterization assuming the coarse phase succeeded.
+    pub fn record_fine(&mut self, shaders: &FullShaders, recording: &mut Recording) {
+        let fine = self.fine.take().unwrap();
+        recording.free_resource(fine.bump_buf);
+        recording.dispatch(
+            shaders.fine,
+            (self.width_in_tiles, self.height_in_tiles, 1),
+            [
+                fine.config_buf,
+                fine.tile_buf,
+                fine.segments_buf,
+                ResourceProxy::Image(fine.out_image),
+                fine.ptcl_buf,
+                fine.gradient_image,
+                fine.info_bin_data_buf,
+            ],
+        );
+        recording.free_resource(fine.config_buf);
+        recording.free_resource(fine.tile_buf);
+        recording.free_resource(fine.segments_buf);
+        recording.free_resource(fine.ptcl_buf);
+        recording.free_resource(fine.gradient_image);
+        recording.free_resource(fine.info_bin_data_buf);
+    }
+
+    /// Get the output image.
+    ///
+    /// This is going away, as the caller will add the output image to the bind
+    /// map.
+    pub fn out_image(&self) -> ImageProxy {
+        self.fine.as_ref().unwrap().out_image
+    }
 }