From cc0955f12d3d124a61a5fa435265ecba3864168c Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Tue, 25 Oct 2016 10:28:45 -0700
Subject: [PATCH] webgl: Unbind deleted objects from the GL side, not just our
 side.

Once FBOs are allowed, we were running into testcases that deleted the
active FBO, and expected the following ReadPixels to come from the
default framebuffer.
---
 .../script/dom/webglrenderingcontext.rs       | 32 ++++++++++++++-----
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/components/script/dom/webglrenderingcontext.rs b/components/script/dom/webglrenderingcontext.rs
index 2d4e26fd05f8..1926bdf8a8d0 100644
--- a/components/script/dom/webglrenderingcontext.rs
+++ b/components/script/dom/webglrenderingcontext.rs
@@ -74,11 +74,17 @@ macro_rules! handle_potential_webgl_error {
 //
 // and similar text occurs for other object types.
 macro_rules! handle_object_deletion {
-    ($binding:expr, $object:ident) => {
+    ($self_:expr, $binding:expr, $object:ident, $unbind_command:expr) => {
         if let Some(bound_object) = $binding.get() {
             if bound_object.id() == $object.id() {
                 $binding.set(None);
             }
+
+            if let Some(command) = $unbind_command {
+                $self_.ipc_renderer
+                    .send(CanvasMsg::WebGL(command))
+                    .unwrap();
+            }
         }
     };
 }
@@ -1251,8 +1257,10 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.5
     fn DeleteBuffer(&self, buffer: Option<&WebGLBuffer>) {
         if let Some(buffer) = buffer {
-            handle_object_deletion!(self.bound_buffer_array, buffer);
-            handle_object_deletion!(self.bound_buffer_element_array, buffer);
+            handle_object_deletion!(self, self.bound_buffer_array, buffer,
+                                    Some(WebGLCommand::BindBuffer(constants::ARRAY_BUFFER, None)));
+            handle_object_deletion!(self, self.bound_buffer_element_array, buffer,
+                                    Some(WebGLCommand::BindBuffer(constants::ELEMENT_ARRAY_BUFFER, None)));
             buffer.delete()
         }
     }
@@ -1260,7 +1268,9 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.6
     fn DeleteFramebuffer(&self, framebuffer: Option<&WebGLFramebuffer>) {
         if let Some(framebuffer) = framebuffer {
-            handle_object_deletion!(self.bound_framebuffer, framebuffer);
+            handle_object_deletion!(self, self.bound_framebuffer, framebuffer,
+                                    Some(WebGLCommand::BindFramebuffer(constants::FRAMEBUFFER,
+                                                                       WebGLFramebufferBindingRequest::Default)));
             framebuffer.delete()
         }
     }
@@ -1268,7 +1278,8 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.7
     fn DeleteRenderbuffer(&self, renderbuffer: Option<&WebGLRenderbuffer>) {
         if let Some(renderbuffer) = renderbuffer {
-            handle_object_deletion!(self.bound_renderbuffer, renderbuffer);
+            handle_object_deletion!(self, self.bound_renderbuffer, renderbuffer,
+                                    Some(WebGLCommand::BindRenderbuffer(constants::RENDERBUFFER, None)));
             renderbuffer.delete()
         }
     }
@@ -1276,8 +1287,10 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.8
     fn DeleteTexture(&self, texture: Option<&WebGLTexture>) {
         if let Some(texture) = texture {
-            handle_object_deletion!(self.bound_texture_2d, texture);
-            handle_object_deletion!(self.bound_texture_cube_map, texture);
+            handle_object_deletion!(self, self.bound_texture_2d, texture,
+                                    Some(WebGLCommand::BindTexture(constants::TEXTURE_2D, None)));
+            handle_object_deletion!(self, self.bound_texture_cube_map, texture,
+                                    Some(WebGLCommand::BindTexture(constants::TEXTURE_CUBE_MAP, None)));
             texture.delete()
         }
     }
@@ -1285,7 +1298,10 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
     fn DeleteProgram(&self, program: Option<&WebGLProgram>) {
         if let Some(program) = program {
-            handle_object_deletion!(self.current_program, program);
+            // FIXME: We should call glUseProgram(0), but
+            // WebGLCommand::UseProgram() doesn't take an Option
+            // currently.  This is also a problem for useProgram(null)
+            handle_object_deletion!(self, self.current_program, program, None);
             program.delete()
         }
     }