From aef0c7c2c4705b032b64eee7af8c95a8c9955bdd Mon Sep 17 00:00:00 2001
From: Kunal Mohan <kunalmohan99@gmail.com>
Date: Sun, 5 Apr 2020 11:16:50 +0530
Subject: [PATCH] Add check for bound pipeline fix #456 Validate that a
 pipeline is bound before issuing draw/dispatch call.

---
 wgpu-core/src/command/compute.rs | 10 ++++++++++
 wgpu-core/src/command/render.rs  |  7 +++++++
 2 files changed, 17 insertions(+)

diff --git a/wgpu-core/src/command/compute.rs b/wgpu-core/src/command/compute.rs
index 26b370e64c..e503b6bea7 100644
--- a/wgpu-core/src/command/compute.rs
+++ b/wgpu-core/src/command/compute.rs
@@ -19,6 +19,11 @@ use peek_poke::{Peek, PeekCopy, Poke};
 
 use std::iter;
 
+#[derive(Debug, PartialEq)]
+enum PipelineState {
+    Required,
+    Set,
+}
 
 #[derive(Clone, Copy, Debug, PeekCopy, Poke)]
 enum ComputeCommand {
@@ -76,6 +81,8 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
         let (buffer_guard, mut token) = hub.buffers.read(&mut token);
         let (texture_guard, _) = hub.textures.read(&mut token);
 
+        let mut pipeline_state = PipelineState::Required;
+
         let mut peeker = raw_data.as_ptr();
         let raw_data_end = unsafe {
             raw_data.as_ptr().add(raw_data.len())
@@ -142,6 +149,7 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                     }
                 }
                 ComputeCommand::SetPipeline(pipeline_id) => {
+                    pipeline_state = PipelineState::Set;
                     let pipeline = cmb.trackers
                         .compute_pipes
                         .use_extend(&*pipeline_guard, pipeline_id, (), ())
@@ -186,11 +194,13 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                     }
                 }
                 ComputeCommand::Dispatch(groups) => {
+                    assert_eq!(pipeline_state, PipelineState::Set, "Dispatch error: Pipeline is missing");
                     unsafe {
                         raw.dispatch(groups);
                     }
                 }
                 ComputeCommand::DispatchIndirect { buffer_id, offset } => {
+                    assert_eq!(pipeline_state, PipelineState::Set, "Dispatch error: Pipeline is missing");
                     let (src_buffer, src_pending) = cmb.trackers.buffers.use_replace(
                         &*buffer_guard,
                         buffer_id,
diff --git a/wgpu-core/src/command/render.rs b/wgpu-core/src/command/render.rs
index e6dde232eb..4d527193b0 100644
--- a/wgpu-core/src/command/render.rs
+++ b/wgpu-core/src/command/render.rs
@@ -182,6 +182,7 @@ impl OptionalState {
 enum DrawError {
     MissingBlendColor,
     MissingStencilReference,
+    MissingPipeline,
     IncompatibleBindGroup {
         index: u32,
         //expected: BindGroupLayoutId,
@@ -255,6 +256,7 @@ struct State {
     binder: Binder,
     blend_color: OptionalState,
     stencil_reference: OptionalState,
+    pipeline: OptionalState,
     index: IndexState,
     vertex: VertexState,
 }
@@ -269,6 +271,9 @@ impl State {
                 index: bind_mask.trailing_zeros(),
             });
         }
+        if self.pipeline == OptionalState::Required {
+            return Err(DrawError::MissingPipeline);
+        }
         if self.blend_color == OptionalState::Required {
             return Err(DrawError::MissingBlendColor);
         }
@@ -785,6 +790,7 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
             binder: Binder::new(cmb.features.max_bind_groups),
             blend_color: OptionalState::Unused,
             stencil_reference: OptionalState::Unused,
+            pipeline: OptionalState::Required,
             index: IndexState {
                 bound_buffer_view: None,
                 format: IndexFormat::Uint16,
@@ -852,6 +858,7 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                     };
                 }
                 RenderCommand::SetPipeline(pipeline_id) => {
+                    state.pipeline = OptionalState::Set;
                     let pipeline = trackers
                         .render_pipes
                         .use_extend(&*pipeline_guard, pipeline_id, (), ())