++

impeller/renderer/backend/gles/render_pass_gles.cc

@@ -450,25 +450,34 @@ struct RenderPassData {
     }
   }
 
-  // if (gl.DiscardFramebufferEXT.IsAvailable()) {
-  //   std::vector<GLenum> attachments;
-  //   if (pass_data.discard_color_attachment) {
-  //     attachments.push_back(is_default_fbo ? GL_COLOR_EXT
-  //                                          : GL_COLOR_ATTACHMENT0);
-  //   }
-  //   if (pass_data.discard_depth_attachment) {
-  //     attachments.push_back(is_default_fbo ? GL_DEPTH_EXT
-  //                                          : GL_DEPTH_ATTACHMENT);
-  //   }
-  //   if (pass_data.discard_stencil_attachment) {
-  //     attachments.push_back(is_default_fbo ? GL_STENCIL_EXT
-  //                                          : GL_STENCIL_ATTACHMENT);
-  //   }
-  //   gl.DiscardFramebufferEXT(GL_FRAMEBUFFER,      // target
-  //                            attachments.size(),  // attachments to discard
-  //                            attachments.data()   // size
-  //   );
-  // }
+  if (gl.DiscardFramebufferEXT.IsAvailable()) {
+    std::vector<GLenum> attachments;
+
+    if (pass_data.discard_color_attachment) {
+      attachments.push_back(is_default_fbo ? GL_COLOR_EXT
+                                           : GL_COLOR_ATTACHMENT0);
+    }
+    if (pass_data.discard_depth_attachment) {
+      attachments.push_back(is_default_fbo ? GL_DEPTH_EXT
+                                           : GL_DEPTH_ATTACHMENT);
+    }
+
+// TODO(jonahwilliams): discarding the stencil on the default fbo when running
+// on Windows. Causes Angle to discard the entire render target. Until we know
+// the reason, default to storing.
+#ifdef FML_OS_WIN
+    if (pass_data.discard_stencil_attachment && !is_default_fbo) {
+#else
+    if (pass_data.discard_stencil_attachment) {
+#endif
+      attachments.push_back(is_default_fbo ? GL_STENCIL_EXT
+                                           : GL_STENCIL_ATTACHMENT);
+    }
+    gl.DiscardFramebufferEXT(GL_FRAMEBUFFER,      // target
+                             attachments.size(),  // attachments to discard
+                             attachments.data()   // size
+    );
+  }
 
   return true;
 }