133636 2014-06-08 23:07:54 -0700 iOS WebGL getParameter hardcoded limits 2016-03-25 13:30:39 -0700 1 1 1 Unclassified WebKit WebGL 528+ (Nightly build) iPhone / iPad Unspecified RESOLVED INVALID https://bugs.webkit.org/show_bug.cgi?id=133745 http://codeflow.org/entries/2014/jun/08/some-issues-with-apples-ios-webgl-implementation/ P2 Normal --- 1 pyalot achristensen achristensen bfulgham commit-queue dino jonlee kondapallykalyan noam pyalot roger_fong shaffstall oldest_to_newest 1014069 0 pyalot 2014-06-08 23:07:54 -0700 Several capabilities seem to exhibit hardcoded limits, namely: - MAX_COMBINED_TEXTURE_IMAGE_UNITS (WebGL=8, iPad mini retina native=32) - MAX_TEXTURE_IMAGE_UNITS (WebGL=8, iPad mini retina native=16) - MAX_VERTEX_TEXTURE_IMAGE_UNITS (WebGL=8, iPad mini retina native=16) - MAX_FRAGMENT_UNIFORM_VECTORS (WebGL=64, iPad mini retina native=224) - MAX_VERTEX_UNIFORM_VECTORS (WebGL=128, iPad mini retina native=512) - MAX_VARYING_VECTORS (WebGL=8, iPad mini retina native=15) These limits match iPod touch 5th gen limitations, but they are still reported back when running WebGL on an iPad mini retina, which has higher limits natively. 1014176 1 shaffstall 2014-06-09 12:30:11 -0700 The low number of available vertex shader uniform vectors is the most surprising restriction to me, and probably the hardest to work with. Having access to only 128 uniform vectors implies that GPU skinning is severely limited to a small number of bone transforms. It would make a world of difference if at least 250 uniform vectors were supported on most iOS devices. As you can see on the WebGL stats page, 99.6% of WebGL enabled browsers support at least 250, so it's become a reliable vector count to use. 1014524 2 achristensen 2014-06-10 14:20:58 -0700 (In reply to comment #0) These native values you are reporting indicate that you are using OpenGL ES 3.0. Many devices cannot use OpenGL ES 3.0 according to https://developer.apple.com/library/ios/documentation/DeviceInformation/Reference/iOSDeviceCompatibility/OpenGLESPlatforms/OpenGLESPlatforms.html I'm not sure what else this will give access to or what this will do to the extensions, but here is a patch that gives access to the additional vertex uniform vectors, etc. 1014532 3 232816 achristensen 2014-06-10 14:28:32 -0700 Created attachment 232816 Patch 1014548 4 achristensen 2014-06-10 14:50:43 -0700 This patch does not change the behavior of an iPhone5, but it significantly changes the behavior of an iPhone5s. For example, GL_OES_texture_float is no longer in the string returned by ::glGetString(GL_EXTENSIONS) so our extensions detection thinks that we no longer have OES_texture_float. This is true with the other GLES2 extensions that are standard to GLES3. What do we want to do about this? 1014582 5 232828 achristensen 2014-06-10 16:34:24 -0700 Created attachment 232828 Patch 1014583 6 achristensen 2014-06-10 16:38:24 -0700 This patch feels pretty hacky, but it's necessary to maintain the same behavior as OpenGL ES 2. This is especially necessary with people querying the extensions through JavaScript. Maybe this should be specifically mentioned in the WebGL 2.0 spec, which claims that "WebGL 2 is backwards compatible with WebGL 1: existing content will run in WebGL 2 without modification." Also, maybe this is getting too close to WebGL 2.0 behavior to be included in WebGL 1.0. 1014648 7 pyalot 2014-06-10 20:43:41 -0700 I was under the impression that things like usable texture units, uniforms and so forth should reflect the limitations of the machine, rather than limitations of the revision of API in use. Afaik that's how the parameters are handled by most other drivers. In that case, the fault would seem to lie rather with the driver, because the limits imposed upon the iPod touch 5th gen seem rather severe given the fact that they're far exceeded by even Nexus 4 hardware, which should be somewhat weaker hardware than the iPod 5g ones. Regarding using OpenGL ES 3.0 as the backend, I don't think that should be an essential problem. However, I did notice that the ES 3.0 context on iOS does seem to forgo extensions which where present in ES 2.0, in case that they would be available as part of ES 3.0 core functionality. These extensions would seem to be: - OES_texture_float - OES_texture_half_float - OES_depth_texture - OES_element_index_uint - EXT_draw_buffers - EXT_instanced_arrays - OES_texture_float_linear - OES_texture_half_float_linear - EXT_color_buffer_float - EXT_frag_depth - EXT_sRGB - EXT_blend_minmax - EXT_shader_texture_lod I think that this means that if you switch to an ES3 context on iOS, that you'll have to provide the corresponding WebGL1 (ES2) extensions, you'll need to emulate the extensions above using ES3 core functionality on iOS, lest you'll want to lose that functionality on ES3 compatible devices. 1014774 8 achristensen 2014-06-11 09:29:57 -0700 I think this might be prematurely jumping into WebGL 2.0 functionality. The "problem" is correctly following Apple's specified behavior using GLES2, and the workaround would need more extensive specification and testing. I think this should wait until the WebGL 2 spec is more complete so we know what to do with GLES3 stuff. 1014790 9 bfulgham 2014-06-11 10:07:17 -0700 The hardcoded limits are expected and documented behavior, since WebKit is currently backed by an OpenGL ES 2.0 context. See https://developer.apple.com/library/ios/documentation/DeviceInformation/Reference/iOSDeviceCompatibility/OpenGLESPlatforms/OpenGLESPlatforms.html for details. I think we should close this bug as "INVALID", and open a new bug that tracks progress to move WebKit's WebGL implementation to GLES3 on the backend. 1014793 10 achristensen 2014-06-11 10:21:51 -0700 Done. https://bugs.webkit.org/show_bug.cgi?id=133745 <rdar://problem/17242741> 232816 2014-06-10 14:28:32 -0700 2014-06-10 16:34:21 -0700 Patch bug-133636-20140610142808.patch text/plain 1548 achristensen SW5kZXg6IFNvdXJjZS9XZWJDb3JlL0NoYW5nZUxvZwo9PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09Ci0tLSBTb3VyY2UvV2Vi Q29yZS9DaGFuZ2VMb2cJKHJldmlzaW9uIDE2OTc2MykKKysrIFNvdXJjZS9XZWJDb3JlL0NoYW5n ZUxvZwkod29ya2luZyBjb3B5KQpAQCAtMSwzICsxLDE0IEBACisyMDE0LTA2LTEwICBBbGV4IENo cmlzdGVuc2VuICA8YWNocmlzdGVuc2VuQHdlYmtpdC5vcmc+CisKKyAgICAgICAgW2lPUyBXZWJH TF0gR2l2ZSBXZWJHTCBhY2Nlc3MgdG8gbGVzcy1yZXN0cmljdGl2ZSBPcGVuR0wgRVMgMy4wIGhh cmR3YXJlIGxpbWl0cy4KKyAgICAgICAgaHR0cHM6Ly9idWdzLndlYmtpdC5vcmcvc2hvd19idWcu Y2dpP2lkPTEzMzYzNgorCisgICAgICAgIFJldmlld2VkIGJ5IE5PQk9EWSAoT09QUyEpLgorCisg ICAgICAgICogcGxhdGZvcm0vZ3JhcGhpY3MvbWFjL0dyYXBoaWNzQ29udGV4dDNETWFjLm1tOgor ICAgICAgICAoV2ViQ29yZTo6R3JhcGhpY3NDb250ZXh0M0Q6OkdyYXBoaWNzQ29udGV4dDNEKToK KyAgICAgICAgVHJ5IHVzaW5nIHRoZSBHTEVTMyBBUEkgaWYgaXQgaXMgYXZhaWxhYmxlIHRvIGxl dCBXZWJHTCB1c2UgdGhlIGZ1bGwgcG93ZXIgb2YgdGhlIEE3IEdQVS4KKwogMjAxNC0wNi0xMCAg QW50dGkgS29pdmlzdG8gIDxhbnR0aUBhcHBsZS5jb20+CiAKICAgICAgICAgU2VyaWFsaXplIFJl c291cmNlUmVxdWVzdHMgd2l0aG91dCBwbGF0Zm9ybSByZXF1ZXN0CkluZGV4OiBTb3VyY2UvV2Vi Q29yZS9wbGF0Zm9ybS9ncmFwaGljcy9tYWMvR3JhcGhpY3NDb250ZXh0M0RNYWMubW0KPT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09 PT09PQotLS0gU291cmNlL1dlYkNvcmUvcGxhdGZvcm0vZ3JhcGhpY3MvbWFjL0dyYXBoaWNzQ29u dGV4dDNETWFjLm1tCShyZXZpc2lvbiAxNjk2OTcpCisrKyBTb3VyY2UvV2ViQ29yZS9wbGF0Zm9y bS9ncmFwaGljcy9tYWMvR3JhcGhpY3NDb250ZXh0M0RNYWMubW0JKHdvcmtpbmcgY29weSkKQEAg LTE1MCw3ICsxNTAsOSBAQCBHcmFwaGljc0NvbnRleHQzRDo6R3JhcGhpY3NDb250ZXh0M0QoR3Jh CiAgICAgVU5VU0VEX1BBUkFNKHJlbmRlclN0eWxlKTsKIAogI2lmIFBMQVRGT1JNKElPUykKLSAg ICBtX2NvbnRleHRPYmogPSBbW0VBR0xDb250ZXh0IGFsbG9jXSBpbml0V2l0aEFQSTprRUFHTFJl bmRlcmluZ0FQSU9wZW5HTEVTMl07CisgICAgbV9jb250ZXh0T2JqID0gW1tFQUdMQ29udGV4dCBh bGxvY10gaW5pdFdpdGhBUEk6a0VBR0xSZW5kZXJpbmdBUElPcGVuR0xFUzNdOworICAgIGlmICgh bV9jb250ZXh0T2JqKQorICAgICAgICBtX2NvbnRleHRPYmogPSBbW0VBR0xDb250ZXh0IGFsbG9j XSBpbml0V2l0aEFQSTprRUFHTFJlbmRlcmluZ0FQSU9wZW5HTEVTMl07CiAgICAgbWFrZUNvbnRl eHRDdXJyZW50KCk7CiAjZWxzZQogICAgIFZlY3RvcjxDR0xQaXhlbEZvcm1hdEF0dHJpYnV0ZT4g YXR0cmliczsK 232828 2014-06-10 16:34:24 -0700 2014-06-11 10:00:29 -0700 Patch bug-133636-20140610163359.patch text/plain 4397 achristensen SW5kZXg6IFNvdXJjZS9XZWJDb3JlL0NoYW5nZUxvZwo9PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09Ci0tLSBTb3VyY2UvV2Vi Q29yZS9DaGFuZ2VMb2cJKHJldmlzaW9uIDE2OTc4MCkKKysrIFNvdXJjZS9XZWJDb3JlL0NoYW5n ZUxvZwkod29ya2luZyBjb3B5KQpAQCAtMSwzICsxLDIwIEBACisyMDE0LTA2LTEwICBBbGV4IENo cmlzdGVuc2VuICA8YWNocmlzdGVuc2VuQHdlYmtpdC5vcmc+CisKKyAgICAgICAgW2lPUyBXZWJH TF0gR2l2ZSBXZWJHTCBhY2Nlc3MgdG8gbGVzcy1yZXN0cmljdGl2ZSBPcGVuR0wgRVMgMy4wIGhh cmR3YXJlIGxpbWl0cy4KKyAgICAgICAgaHR0cHM6Ly9idWdzLndlYmtpdC5vcmcvc2hvd19idWcu Y2dpP2lkPTEzMzYzNgorCisgICAgICAgIFJldmlld2VkIGJ5IE5PQk9EWSAoT09QUyEpLgorCisg ICAgICAgICogcGxhdGZvcm0vZ3JhcGhpY3MvR3JhcGhpY3NDb250ZXh0M0QuaDoKKyAgICAgICAg KFdlYkNvcmU6OkdyYXBoaWNzQ29udGV4dDNEOjp1c2VzR0xFUzMpOgorICAgICAgICBBZGRlZCBj aGVjayBmb3IgdXNpbmcgT3BlbkdMIEVTIDMuMC4KKyAgICAgICAgKiBwbGF0Zm9ybS9ncmFwaGlj cy9tYWMvR3JhcGhpY3NDb250ZXh0M0RNYWMubW06CisgICAgICAgIChXZWJDb3JlOjpHcmFwaGlj c0NvbnRleHQzRDo6R3JhcGhpY3NDb250ZXh0M0QpOgorICAgICAgICBUcnkgdXNpbmcgdGhlIEdM RVMzIEFQSSBpZiBpdCBpcyBhdmFpbGFibGUgdG8gbGV0IFdlYkdMIHVzZSB0aGUgZnVsbCBwb3dl ciBvZiB0aGUgQTcgR1BVLgorICAgICAgICAqIHBsYXRmb3JtL2dyYXBoaWNzL29wZW5nbC9FeHRl bnNpb25zM0RPcGVuR0wuY3BwOgorICAgICAgICAoV2ViQ29yZTo6RXh0ZW5zaW9uczNET3BlbkdM OjpnZXRFeHRlbnNpb25zKToKKyAgICAgICAgQWRkZWQgbGlzdCBvZiBHTEVTMiBleHRlbnNpb25z IHRoYXQgYXJlIGVuYWJsZWQgYnkgZGVmYXVsdCB3aGVuIHVzaW5nIEdMRVMzIHRvIG1hdGNoIGJl aGF2aW9yIG9mIFdlYkdMIDEuCisKIDIwMTQtMDYtMTAgIE15bGVzIEMuIE1heGZpZWxkICA8bW1h eGZpZWxkQGFwcGxlLmNvbT4KIAogICAgICAgICBKYXBhbmVzZSB0ZXh0IGluIEdvb2dsZSBzZWFy Y2ggaXMgcmVuZGVyZWQgdG9vIGxvdyBhbmQgY2xpcHBlZApJbmRleDogU291cmNlL1dlYkNvcmUv cGxhdGZvcm0vZ3JhcGhpY3MvR3JhcGhpY3NDb250ZXh0M0QuaAo9PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09Ci0tLSBTb3Vy Y2UvV2ViQ29yZS9wbGF0Zm9ybS9ncmFwaGljcy9HcmFwaGljc0NvbnRleHQzRC5oCShyZXZpc2lv biAxNjk3NDYpCisrKyBTb3VyY2UvV2ViQ29yZS9wbGF0Zm9ybS9ncmFwaGljcy9HcmFwaGljc0Nv bnRleHQzRC5oCSh3b3JraW5nIGNvcHkpCkBAIC04NDcsNiArODQ3LDcgQEAgcHVibGljOgogICAg IGJvb2wgcGFpbnRDb21wb3NpdGVkUmVzdWx0c1RvQ2FudmFzKEltYWdlQnVmZmVyKik7CiAKICNp ZiBQTEFURk9STShJT1MpCisgICAgYm9vbCB1c2VzR0xFUzMoKSB7IHJldHVybiBtX3VzZXNHTEVT MzsgfQogICAgIHZvaWQgZW5kUGFpbnQoKTsKICNlbmRpZgogCkBAIC0xMTI2LDYgKzExMjcsNyBA QCBwcml2YXRlOgogICAgIEdDM0R1aW50IG1fZGVwdGhTdGVuY2lsQnVmZmVyOwogCiAgICAgYm9v bCBtX2xheWVyQ29tcG9zaXRlZDsKKyAgICBib29sIG1fdXNlc0dMRVMzOwogICAgIEdDM0R1aW50 IG1faW50ZXJuYWxDb2xvckZvcm1hdDsKIAogICAgIHN0cnVjdCBHcmFwaGljc0NvbnRleHQzRFN0 YXRlIHsKSW5kZXg6IFNvdXJjZS9XZWJDb3JlL3BsYXRmb3JtL2dyYXBoaWNzL21hYy9HcmFwaGlj c0NvbnRleHQzRE1hYy5tbQo9PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09Ci0tLSBTb3VyY2UvV2ViQ29yZS9wbGF0Zm9ybS9n cmFwaGljcy9tYWMvR3JhcGhpY3NDb250ZXh0M0RNYWMubW0JKHJldmlzaW9uIDE2OTc0NikKKysr IFNvdXJjZS9XZWJDb3JlL3BsYXRmb3JtL2dyYXBoaWNzL21hYy9HcmFwaGljc0NvbnRleHQzRE1h Yy5tbQkod29ya2luZyBjb3B5KQpAQCAtMTQwLDYgKzE0MCw3IEBAIEdyYXBoaWNzQ29udGV4dDNE OjpHcmFwaGljc0NvbnRleHQzRChHcmEKICAgICAsIG1fZmJvKDApCiAgICAgLCBtX2RlcHRoU3Rl bmNpbEJ1ZmZlcigwKQogICAgICwgbV9sYXllckNvbXBvc2l0ZWQoZmFsc2UpCisgICAgLCBtX3Vz ZXNHTEVTMyhmYWxzZSkKICAgICAsIG1faW50ZXJuYWxDb2xvckZvcm1hdCgwKQogICAgICwgbV9t dWx0aXNhbXBsZUZCTygwKQogICAgICwgbV9tdWx0aXNhbXBsZURlcHRoU3RlbmNpbEJ1ZmZlcigw KQpAQCAtMTUwLDcgKzE1MSwxMSBAQCBHcmFwaGljc0NvbnRleHQzRDo6R3JhcGhpY3NDb250ZXh0 M0QoR3JhCiAgICAgVU5VU0VEX1BBUkFNKHJlbmRlclN0eWxlKTsKIAogI2lmIFBMQVRGT1JNKElP UykKLSAgICBtX2NvbnRleHRPYmogPSBbW0VBR0xDb250ZXh0IGFsbG9jXSBpbml0V2l0aEFQSTpr RUFHTFJlbmRlcmluZ0FQSU9wZW5HTEVTMl07CisgICAgbV9jb250ZXh0T2JqID0gW1tFQUdMQ29u dGV4dCBhbGxvY10gaW5pdFdpdGhBUEk6a0VBR0xSZW5kZXJpbmdBUElPcGVuR0xFUzNdOworICAg IGlmIChtX2NvbnRleHRPYmopCisgICAgICAgIG1fdXNlc0dMRVMzID0gdHJ1ZTsKKyAgICBlbHNl CisgICAgICAgIG1fY29udGV4dE9iaiA9IFtbRUFHTENvbnRleHQgYWxsb2NdIGluaXRXaXRoQVBJ OmtFQUdMUmVuZGVyaW5nQVBJT3BlbkdMRVMyXTsKICAgICBtYWtlQ29udGV4dEN1cnJlbnQoKTsK ICNlbHNlCiAgICAgVmVjdG9yPENHTFBpeGVsRm9ybWF0QXR0cmlidXRlPiBhdHRyaWJzOwpJbmRl eDogU291cmNlL1dlYkNvcmUvcGxhdGZvcm0vZ3JhcGhpY3Mvb3BlbmdsL0V4dGVuc2lvbnMzRE9w ZW5HTC5jcHAKPT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PQotLS0gU291cmNlL1dlYkNvcmUvcGxhdGZvcm0vZ3JhcGhpY3Mv b3BlbmdsL0V4dGVuc2lvbnMzRE9wZW5HTC5jcHAJKHJldmlzaW9uIDE2OTc0NikKKysrIFNvdXJj ZS9XZWJDb3JlL3BsYXRmb3JtL2dyYXBoaWNzL29wZW5nbC9FeHRlbnNpb25zM0RPcGVuR0wuY3Bw CSh3b3JraW5nIGNvcHkpCkBAIC0yNzksNiArMjc5LDEzIEBAIHZvaWQgRXh0ZW5zaW9uczNET3Bl bkdMOjp2ZXJ0ZXhBdHRyaWJEaXYKIAogU3RyaW5nIEV4dGVuc2lvbnMzRE9wZW5HTDo6Z2V0RXh0 ZW5zaW9ucygpCiB7CisjaWYgUExBVEZPUk0oSU9TKQorICAgIGlmIChtX2NvbnRleHQtPnVzZXNH TEVTMygpKSB7CisgICAgICAgIC8vIFRoZXNlIGFyZSBleHRlbnNpb25zIGluIEdMRVMyIGJ1dCBz dXBwb3J0ZWQgYnkgZGVmYXVsdCBpbiBHTEVTMyBhbmQgbm90IHJldHVybmVkIGJ5IGdsR2V0U3Ry aW5nLgorICAgICAgICAvLyBTZWUgaHR0cHM6Ly9kZXZlbG9wZXIuYXBwbGUuY29tL2xpYnJhcnkv aW9zL2RvY3VtZW50YXRpb24vRGV2aWNlSW5mb3JtYXRpb24vUmVmZXJlbmNlL2lPU0RldmljZUNv bXBhdGliaWxpdHkvT3BlbkdMRVNQbGF0Zm9ybXMvT3BlbkdMRVNQbGF0Zm9ybXMuaHRtbAorICAg ICAgICByZXR1cm4gU3RyaW5nKHJlaW50ZXJwcmV0X2Nhc3Q8Y29uc3QgY2hhcio+KDo6Z2xHZXRT dHJpbmcoR0xfRVhURU5TSU9OUykpKSArICIgR0xfT0VTX2RlcHRoX3RleHR1cmUgR0xfT0VTX2Rl cHRoMjQgR0xfT0VTX2VsZW1lbnRfaW5kZXhfdWludCBHTF9PRVNfZmJvX3JlbmRlcl9taXBtYXAg R0xfT0VTX21hcGJ1ZmZlciBHTF9PRVNfcGFja2VkX2RlcHRoX3N0ZW5jaWwgR0xfT0VTX3JnYjhf cmdiYTggR0xfT0VTX3RleHR1cmVfZmxvYXQgR0xfT0VTX3RleHR1cmVfaGFsZl9mbG9hdCBHTF9P RVNfdGV4dHVyZV9oYWxmX2Zsb2F0X2xpbmVhciBHTF9PRVNfdmVydGV4X2FycmF5X29iamVjdCBH TF9FWFRfYmxlbmRfbWlubWF4IEdMX0VYVF9kaXNjYXJkX2ZyYW1lYnVmZmVyIEdMX0VYVF9kcmF3 X2luc3RhbmNlZCBHTF9FWFRfaW5zdGFuY2VkX2FycmF5cyBHTF9FWFRfbWFwX2J1ZmZlcl9yYW5n ZSBHTF9FWFRfb2NjbHVzaW9uX3F1ZXJ5X2Jvb2xlYW4gR0xfRVhUX3NSR0IgR0xfRVhUX3RleHR1 cmVfcmcgR0xfRVhUX3RleHR1cmVfc3RvcmFnZSBHTF9BUFBMRV9mcmFtZWJ1ZmZlcl9tdWx0aXNh bXBsZSBHTF9BUFBMRV9zeW5jIEdMX0FQUExFX3RleHR1cmVfbWF4X2xldmVsIEdMX0FQUExFX3Rl eHR1cmVfcGFja2VkX2Zsb2F0IjsKKyAgICB9CisjZW5kaWYKICAgICByZXR1cm4gU3RyaW5nKHJl aW50ZXJwcmV0X2Nhc3Q8Y29uc3QgY2hhcio+KDo6Z2xHZXRTdHJpbmcoR0xfRVhURU5TSU9OUykp KTsKIH0KIAo=