313159 2026-04-23 12:29:41 -0700 WebGPU doesn't show result with direct texture usage and multisampled resolve 2026-04-24 03:45:53 -0700 1 1 1 Unclassified WebKit WebGPU Safari Technology Preview Mac (Apple Silicon) macOS 26 RESOLVED FIXED InRadar P2 Normal --- 1 gman mwyrzykowski mwyrzykowski tzagallo webkit-bug-importer oldest_to_newest 2203816 0 479272 gman 2026-04-23 12:29:41 -0700 Created attachment 479272 repo Run the attached sample. You should see a flashing red screen. Works in Firefox and Chrome,not in Safari. There are no validation errors The sample uses direct texture vs texture views. In other words encoder.beginPass({ colorAttachments: [ { view: someMultiSampledTexture, // Not a GPUTextureView resolveTarget: someTexture, // Not a GPUTextureView ... }, ], }); 2203841 1 mwyrzykowski 2026-04-23 13:37:44 -0700 _MTLDebugValidateRenderPassDescriptorAndTrackAttachments:370: failed assertion `RenderPass Descriptor Validation MTLRenderPassAttachmentDescriptor resolveTexture must have storeAction of MTLStoreActionMultisampleResolve, MTLStoreActionStoreAndMultisampleResolve or MTLStoreActionUnknown 2203843 2 mwyrzykowski 2026-04-23 13:40:49 -0700 Thank you for the repro Gregg 2203844 3 webkit-bug-importer 2026-04-23 13:40:55 -0700 <rdar://problem/175452924> 2203854 4 mwyrzykowski 2026-04-23 13:51:10 -0700 Pull request: https://github.com/WebKit/WebKit/pull/63459 2204095 5 ews-feeder 2026-04-24 03:45:51 -0700 Committed 311938@main (626105188e7e): <https://commits.webkit.org/311938@main> Reviewed commits have been landed. Closing PR #63459 and removing active labels. 479272 2026-04-23 12:29:41 -0700 2026-04-23 12:29:41 -0700 repo webgpu-resolve-to-canvas-direct-texture.html text/html 2945 gman PCFET0NUWVBFIGh0bWw+CjxodG1sPgogIDxoZWFkPgogICAgPG1ldGEgY2hhcnNldD0idXRmLTgi IC8+CiAgICA8bWV0YSBuYW1lPSJ2aWV3cG9ydCIgY29udGVudD0id2lkdGg9ZGV2aWNlLXdpZHRo LCBpbml0aWFsLXNjYWxlPTEiIC8+CiAgICA8dGl0bGU+V2ViR1BVOiByQUYgbG9vcCB3aXRoIGdl dEN1cnJlbnRUZXh0dXJlIGFuZCBubyBHUFVUZXh0dXJlVmlldzwvdGl0bGU+CiAgICA8c3R5bGU+ Cmh0bWwsIGJvZHkgewogIG1hcmdpbjogMDsgICAgICAgLyogcmVtb3ZlIHRoZSBkZWZhdWx0IG1h cmdpbiAgICAgICAgICAqLwogIGhlaWdodDogMTAwJTsgICAgLyogbWFrZSB0aGUgaHRtbCxib2R5 IGZpbGwgdGhlIHBhZ2UgICAqLwp9CmNhbnZhcyB7CiAgZGlzcGxheTogYmxvY2s7ICAvKiBtYWtl IHRoZSBjYW52YXMgYWN0IGxpa2UgYSBibG9jayAgICovCiAgd2lkdGg6IDEwMCU7ICAgICAvKiBt YWtlIHRoZSBjYW52YXMgZmlsbCBpdHMgY29udGFpbmVyICovCiAgaGVpZ2h0OiAxMDAlOwp9Cgog ICAgPC9zdHlsZT4KICA8L2hlYWQ+CiAgPGJvZHk+CjxjYW52YXM+PC9jYW52YXM+CiAgPC9ib2R5 PgogIDxzY3JpcHQgdHlwZT0ibW9kdWxlIj4KYXN5bmMgZnVuY3Rpb24gbWFpbigpIHsKICBjb25z dCBhZGFwdGVyID0gYXdhaXQgbmF2aWdhdG9yLmdwdT8ucmVxdWVzdEFkYXB0ZXIoKTsKICBjb25z dCBkZXZpY2UgPSBhd2FpdCBhZGFwdGVyPy5yZXF1ZXN0RGV2aWNlKCk7CiAgaWYgKCFkZXZpY2Up IHsKICAgIGZhaWwoJ25lZWQgYSBicm93c2VyIHRoYXQgc3VwcG9ydHMgV2ViR1BVJyk7CiAgICBy ZXR1cm47CiAgfQoKICAvLyBHZXQgYSBXZWJHUFUgY29udGV4dCBmcm9tIHRoZSBjYW52YXMgYW5k IGNvbmZpZ3VyZSBpdAogIGNvbnN0IGNhbnZhcyA9IGRvY3VtZW50LnF1ZXJ5U2VsZWN0b3IoJ2Nh bnZhcycpOwogIGNvbnN0IGNvbnRleHQgPSBjYW52YXMuZ2V0Q29udGV4dCgnd2ViZ3B1Jyk7CiAg Y29uc3QgcHJlc2VudGF0aW9uRm9ybWF0ID0gbmF2aWdhdG9yLmdwdS5nZXRQcmVmZXJyZWRDYW52 YXNGb3JtYXQoKTsKICBjb250ZXh0LmNvbmZpZ3VyZSh7CiAgICBkZXZpY2UsCiAgICBmb3JtYXQ6 IHByZXNlbnRhdGlvbkZvcm1hdCwKICB9KTsKCiAgY29uc3QgcmVuZGVyUGFzc0Rlc2NyaXB0b3Ig PSB7CiAgICBsYWJlbDogJ291ciBiYXNpYyBjYW52YXMgcmVuZGVyUGFzcycsCiAgICBjb2xvckF0 dGFjaG1lbnRzOiBbCiAgICAgIHsKICAgICAgICAvLyB2aWV3OiA8LSB0byBiZSBmaWxsZWQgb3V0 IHdoZW4gd2UgcmVuZGVyCiAgICAgICAgY2xlYXJWYWx1ZTogWzAuMywgMC4zLCAwLjMsIDFdLAog ICAgICAgIGxvYWRPcDogJ2NsZWFyJywKICAgICAgICBzdG9yZU9wOiAnc3RvcmUnLAogICAgICB9 LAogICAgXSwKICB9OwoKICBsZXQgcmVuZGVyVGFyZ2V0OwoKICBmdW5jdGlvbiByZW5kZXIoKSB7 CiAgICBjb25zdCBjYW52YXNUZXh0dXJlID0gY29udGV4dC5nZXRDdXJyZW50VGV4dHVyZSgpOwog ICAgY29uc3QgeyB3aWR0aCwgaGVpZ2h0IH0gPSBjYW52YXNUZXh0dXJlOwogICAgaWYgKHJlbmRl clRhcmdldD8ud2lkdGggIT09IHdpZHRoIHx8IHJlbmRlclRhcmdldD8uaGVpZ2h0ICE9PSBoZWln aHQpIHsKICAgICAgcmVuZGVyVGFyZ2V0Py5kZXN0cm95KCk7CiAgICAgIHJlbmRlclRhcmdldCA9 IGRldmljZS5jcmVhdGVUZXh0dXJlKHsKICAgICAgICBzaXplOiBbd2lkdGgsIGhlaWdodF0sCiAg ICAgICAgZm9ybWF0OiBwcmVzZW50YXRpb25Gb3JtYXQsCiAgICAgICAgdXNhZ2U6IEdQVVRleHR1 cmVVc2FnZS5SRU5ERVJfQVRUQUNITUVOVCwKICAgICAgICBzYW1wbGVDb3VudDogNCwKICAgICAg fSk7CiAgICB9CgogICAgcmVuZGVyUGFzc0Rlc2NyaXB0b3IuY29sb3JBdHRhY2htZW50c1swXS52 aWV3ID0gcmVuZGVyVGFyZ2V0OwogICAgcmVuZGVyUGFzc0Rlc2NyaXB0b3IuY29sb3JBdHRhY2ht ZW50c1swXS5yZXNvbHZlVGFyZ2V0ID0gY2FudmFzVGV4dHVyZTsKICAgIHJlbmRlclBhc3NEZXNj cmlwdG9yLmNvbG9yQXR0YWNobWVudHNbMF0uY2xlYXJWYWx1ZVswXSA9IHBlcmZvcm1hbmNlLm5v dygpIC8gMTAwMCAlIDE7CgogICAgY29uc3QgZW5jb2RlciA9IGRldmljZS5jcmVhdGVDb21tYW5k RW5jb2Rlcih7IGxhYmVsOiAnb3VyIGVuY29kZXInIH0pOwogICAgY29uc3QgcGFzcyA9IGVuY29k ZXIuYmVnaW5SZW5kZXJQYXNzKHJlbmRlclBhc3NEZXNjcmlwdG9yKTsKICAgIHBhc3MuZW5kKCk7 CgogICAgY29uc3QgY29tbWFuZEJ1ZmZlciA9IGVuY29kZXIuZmluaXNoKCk7CiAgICBkZXZpY2Uu cXVldWUuc3VibWl0KFtjb21tYW5kQnVmZmVyXSk7CgogICAgcmVxdWVzdEFuaW1hdGlvbkZyYW1l KHJlbmRlcik7CiAgfQogIHJlcXVlc3RBbmltYXRpb25GcmFtZShyZW5kZXIpOwoKICBjb25zdCBv YnNlcnZlciA9IG5ldyBSZXNpemVPYnNlcnZlcihlbnRyaWVzID0+IHsKICAgIGZvciAoY29uc3Qg ZW50cnkgb2YgZW50cmllcykgewogICAgICBjb25zdCBjYW52YXMgPSBlbnRyeS50YXJnZXQ7CiAg ICAgIGNvbnN0IHdpZHRoID0gZW50cnkuY29udGVudEJveFNpemVbMF0uaW5saW5lU2l6ZTsKICAg ICAgY29uc3QgaGVpZ2h0ID0gZW50cnkuY29udGVudEJveFNpemVbMF0uYmxvY2tTaXplOwogICAg ICBjYW52YXMud2lkdGggPSBNYXRoLm1heCgxLCBNYXRoLm1pbih3aWR0aCwgZGV2aWNlLmxpbWl0 cy5tYXhUZXh0dXJlRGltZW5zaW9uMkQpKTsKICAgICAgY2FudmFzLmhlaWdodCA9IE1hdGgubWF4 KDEsIE1hdGgubWluKGhlaWdodCwgZGV2aWNlLmxpbWl0cy5tYXhUZXh0dXJlRGltZW5zaW9uMkQp KTsKICAgIH0KICB9KTsKICBvYnNlcnZlci5vYnNlcnZlKGNhbnZhcyk7Cn0KCmZ1bmN0aW9uIGZh aWwobXNnKSB7CiAgLy8gZXNsaW50LWRpc2FibGUtbmV4dC1saW5lIG5vLWFsZXJ0CiAgYWxlcnQo bXNnKTsKfQoKbWFpbigpOwoKICA8L3NjcmlwdD4KPC9odG1sPgo=