From ccf42c3614424ca66070722f848409df015aabdb Mon Sep 17 00:00:00 2001
From: Aaron Hill <aa1ronham@gmail.com>
Date: Sun, 27 Aug 2023 14:03:21 -0400
Subject: [PATCH] naga-pixelbender: Stub out Opcode::Loop

Some experimentation with Pixel Bender Studio shows
that Opcode::Loop has a 23-byte payload. I haven't tried to
figure out how to interpet the payload yet, but we can now
skip over the opcode instead of bailing out entirely.
---
 Cargo.lock                         |  1 +
 render/naga-pixelbender/Cargo.toml |  1 +
 render/naga-pixelbender/src/lib.rs |  5 ++++-
 render/src/pixel_bender.rs         | 10 ++++++++++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/Cargo.lock b/Cargo.lock
index dfdebc287..24805bf18 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2901,6 +2901,7 @@ dependencies = [
  "naga",
  "naga_oil",
  "ruffle_render",
+ "tracing",
 ]
 
 [[package]]
diff --git a/render/naga-pixelbender/Cargo.toml b/render/naga-pixelbender/Cargo.toml
index 3a736cb97..72adfd5eb 100644
--- a/render/naga-pixelbender/Cargo.toml
+++ b/render/naga-pixelbender/Cargo.toml
@@ -11,6 +11,7 @@ version.workspace = true
 ruffle_render = { path = "../" }
 naga = { workspace = true }
 naga_oil = { workspace = true }
+tracing = { workspace = true }
 anyhow = "1.0.75"
 bitflags = "2.4.0"
 
diff --git a/render/naga-pixelbender/src/lib.rs b/render/naga-pixelbender/src/lib.rs
index 3174b271d..ea92e09c2 100644
--- a/render/naga-pixelbender/src/lib.rs
+++ b/render/naga-pixelbender/src/lib.rs
@@ -1484,7 +1484,10 @@ impl<'a> ShaderBuilder<'a> {
                         }
                     }
                 }
-                _ => unimplemented!("Operation {op:?} not yet implemented"),
+                Operation::Loop { unknown } => {
+                    tracing::warn!("Unimplemented Loop opcode with data: {unknown:?}")
+                }
+                Operation::Nop => {}
             }
         }
         Ok(())
diff --git a/render/src/pixel_bender.rs b/render/src/pixel_bender.rs
index a4d67b430..e578648d6 100644
--- a/render/src/pixel_bender.rs
+++ b/render/src/pixel_bender.rs
@@ -244,6 +244,9 @@ pub enum Operation {
     },
     Else,
     EndIf,
+    Loop {
+        unknown: Box<[u8]>,
+    },
 }
 
 #[derive(Debug, Clone)]
@@ -564,6 +567,13 @@ fn read_op<R: Read>(
                 _ => unreachable!(),
             }
         }
+        Opcode::Loop => {
+            let mut unknown = vec![0u8; 23];
+            data.read_exact(&mut unknown)?;
+            shader.operations.push(Operation::Loop {
+                unknown: unknown.into(),
+            });
+        }
         _ => {
             let dst = data.read_u16::<LittleEndian>()?;
             let mut mask = data.read_u8()?;