Add GL_ANGLE_get_serialized_context_string.

extensions/ANGLE_get_serialized_context_string.txt

+Name
+
+    ANGLE_get_serialized_context_string
+
+Name Strings
+
+    GL_ANGLE_get_serialized_context_string
+
+Contributors
+
+    Jamie Madill, Google
+
+Contact
+
+    Jamie Madill, Google (jmadill 'at' google.com)
+
+Status
+
+    Implemented in ANGLE.
+
+Version
+
+    Last Modified Date: April 2, 2021
+    Revision: #1
+
+Number
+
+    TBD
+
+Dependencies
+
+    OpenGL ES 2.0 is required.
+
+Overview
+
+    Adds a query for a serialized string representation of a context.
+    Useful for testing to easily compare two states.
+
+New Tokens
+
+    Accepted by the <name> parameter of glGetString:
+
+        SERIALIZED_CONTEXT_STRING_ANGLE   0x96B0
+
+Additions to Chapter 6 of the OpenGL ES 2.0 Specification (Querying GL State)
+
+    Update Section 6.1.5 "String Queries" to accept the new enum specified
+    above. The SERIALIZED_CONTEXT_STRING_ANGLE string is an implementation-
+    dependent representation of the current context state. Two contexts
+    with the same internal state are guaranteed to have the same value. Note
+    that the reverse is not true - two contexts with different states are
+    may also have the same serialized string.
+
+New State
+
+    None.
+
+Issues
+
+    1) Should two contexts with different states return different strings?
+
+    RESOLVED: We don't provide a guarantee that every state is serialized
+      into the string. This loose wording lets the extension provide
+      some additional extra validation without being overly strict and
+      making the implementation difficult. It also allow a no-op
+      implementation to satisfy the extension requirements.
+
+Revision History
+
+    2021/04/02  jmadill  Initial revision.
+

include/GLES2/gl2ext_angle.h

@@ -570,6 +570,11 @@ GL_APICALL void GL_APIENTRY glImportSemaphoreZirconHandleANGLE(GLuint memory,
 #define GL_PURGED_CONTEXT_RESET_NV 0x92BB
 #endif /* GL_NV_robustness_video_memory */
 
+#ifndef GL_ANGLE_get_serialized_context_string
+#define GL_ANGLE_get_serialized_context_string
+#define GL_SERIALIZED_CONTEXT_STRING_ANGLE 0x96B0
+#endif /* GL_ANGLE_get_serialized_context_string */
+
 // clang-format on
 
 #endif  // INCLUDE_GLES2_GL2EXT_ANGLE_H_

scripts/code_generation_hashes/GL_EGL_WGL_loader.json

@@ -12,7 +12,7 @@
   "scripts/gl_angle_ext.xml":
     "08f74b35d908b7c02b45fdf45572c434",
   "scripts/registry_xml.py":
-    "7e9b9e8b735dadb417b2d10434f56a41",
+    "2d623a8b4a8a49213e8d0c0a0c8c4dd8",
   "scripts/wgl.xml":
     "c36001431919e1c435f1215a85f7e1db",
   "src/libEGL/egl_loader_autogen.cpp":

scripts/code_generation_hashes/GL_EGL_entry_points.json

@@ -16,7 +16,7 @@
   "scripts/gl_angle_ext.xml":
     "08f74b35d908b7c02b45fdf45572c434",
   "scripts/registry_xml.py":
-    "7e9b9e8b735dadb417b2d10434f56a41",
+    "2d623a8b4a8a49213e8d0c0a0c8c4dd8",
   "scripts/wgl.xml":
     "c36001431919e1c435f1215a85f7e1db",
   "src/common/entry_points_enum_autogen.cpp":
@@ -42,7 +42,7 @@
   "src/libANGLE/Context_gles_3_2_autogen.h":
     "48567dca16fd881dfe6d61fee0e3106f",
   "src/libANGLE/Context_gles_ext_autogen.h":
-    "d6b07fcd1713e3eddf6156e9cf477ec9",
+    "865ac7b504d009956f9de60fd00f7bb3",
   "src/libANGLE/capture/capture_gles_1_0_autogen.cpp":
     "7ec7ef8f779b809a45d74b97502c419b",
   "src/libANGLE/capture/capture_gles_1_0_autogen.h":

scripts/code_generation_hashes/GLenum_value_to_string_map.json

@@ -6,7 +6,7 @@
   "scripts/gl_angle_ext.xml":
     "08f74b35d908b7c02b45fdf45572c434",
   "scripts/registry_xml.py":
-    "7e9b9e8b735dadb417b2d10434f56a41",
+    "2d623a8b4a8a49213e8d0c0a0c8c4dd8",
   "src/libANGLE/capture/gl_enum_utils_autogen.cpp":
     "9517df43e12c9d27cdf40a0db05bc85b",
   "src/libANGLE/capture/gl_enum_utils_autogen.h":

scripts/code_generation_hashes/proc_table.json

@@ -12,7 +12,7 @@
   "scripts/gl_angle_ext.xml":
     "08f74b35d908b7c02b45fdf45572c434",
   "scripts/registry_xml.py":
-    "7e9b9e8b735dadb417b2d10434f56a41",
+    "2d623a8b4a8a49213e8d0c0a0c8c4dd8",
   "scripts/wgl.xml":
     "c36001431919e1c435f1215a85f7e1db",
   "src/libGL/proc_table_wgl_autogen.cpp":

scripts/registry_xml.py

@@ -36,6 +36,7 @@ angle_extensions = [
     "GL_CHROMIUM_lose_context",
     "GL_ANGLE_copy_texture_3d",
     "GL_ANGLE_get_image",
+    "GL_ANGLE_get_serialized_context_string",
     "GL_ANGLE_get_tex_level_parameter",
     "GL_ANGLE_program_binary",
     "GL_ANGLE_request_extension",

src/libANGLE/Caps.cpp

@@ -1056,6 +1056,7 @@ const ExtensionInfoMap &GetExtensionInfoMap()
         map["GL_OES_shader_io_blocks"] = enableableExtension(&Extensions::shaderIoBlocksOES);
         map["GL_EXT_shader_io_blocks"] = enableableExtension(&Extensions::shaderIoBlocksEXT);
         map["GL_EXT_clip_cull_distance"] = enableableExtension(&Extensions::clipCullDistanceEXT);
+        map["GL_ANGLE_get_serialized_context_string"] = enableableExtension(&Extensions::getSerializedContextStringANGLE);
         // GLES1 extensions
         map["GL_OES_point_size_array"] = enableableExtension(&Extensions::pointSizeArrayOES);
         map["GL_OES_texture_cube_map"] = enableableExtension(&Extensions::textureCubeMapOES);

src/libANGLE/Caps.h

@@ -718,6 +718,9 @@ struct Extensions
 
     // GL_EXT_clip_cull_distance
     bool clipCullDistanceEXT = false;
+
+    // GL_ANGLE_get_serialized_context_string
+    bool getSerializedContextStringANGLE = false;
 };
 
 // Pointer to a boolean memeber of the Extensions struct

src/libANGLE/Context.cpp

@@ -40,6 +40,7 @@
 #include "libANGLE/TransformFeedback.h"
 #include "libANGLE/VertexArray.h"
 #include "libANGLE/capture/FrameCapture.h"
+#include "libANGLE/capture/frame_capture_utils.h"
 #include "libANGLE/formatutils.h"
 #include "libANGLE/queryconversions.h"
 #include "libANGLE/queryutils.h"
@@ -3215,6 +3216,17 @@ const GLubyte *Context::getString(GLenum name) const
         case GL_REQUESTABLE_EXTENSIONS_ANGLE:
             return reinterpret_cast<const GLubyte *>(mRequestableExtensionString);
 
+        case GL_SERIALIZED_CONTEXT_STRING_ANGLE:
+            if (angle::SerializeContextToString(this, &mCachedSerializedStateString) ==
+                angle::Result::Continue)
+            {
+                return reinterpret_cast<const GLubyte *>(mCachedSerializedStateString.c_str());
+            }
+            else
+            {
+                return nullptr;
+            }
+
         default:
             UNREACHABLE();
             return nullptr;
@@ -3535,6 +3547,9 @@ Extensions Context::generateSupportedExtensions() const
     // GL_ANGLE_get_tex_level_parameter is implemented in the frontend
     supportedExtensions.getTexLevelParameterANGLE = true;
 
+    // Always enabled. Will return a default string if capture is not enabled.
+    supportedExtensions.getSerializedContextStringANGLE = true;
+
     return supportedExtensions;
 }
 

src/libANGLE/Context.h

@@ -782,6 +782,9 @@ class Context final : public egl::LabeledObject, angle::NonCopyable, public angl
     // Note: we use a raw pointer here so we can exclude frame capture sources from the build.
     std::unique_ptr<angle::FrameCapture> mFrameCapture;
 
+    // Cache representation of the serialized context string.
+    mutable std::string mCachedSerializedStateString;
+
     mutable size_t mRefCount;
 
     OverlayType mOverlay;

src/libANGLE/Context_gles_ext_autogen.h

@@ -276,6 +276,7 @@
     void getTexImage(TextureTarget targetPacked, GLint level, GLenum format, GLenum type,          \
                      void *pixels);                                                                \
     void getRenderbufferImage(GLenum target, GLenum format, GLenum type, void *pixels);            \
+    /* GL_ANGLE_get_serialized_context_string */                                                   \
     /* GL_ANGLE_get_tex_level_parameter */                                                         \
     /* GL_ANGLE_program_binary */                                                                  \
     /* GL_ANGLE_request_extension */                                                               \

src/libANGLE/validationES2.cpp

@@ -3903,6 +3903,14 @@ bool ValidateGetString(const Context *context, GLenum name)
             }
             break;
 
+        case GL_SERIALIZED_CONTEXT_STRING_ANGLE:
+            if (!context->getExtensions().getSerializedContextStringANGLE)
+            {
+                context->validationError(GL_INVALID_ENUM, kInvalidName);
+                return false;
+            }
+            break;
+
         default:
             context->validationError(GL_INVALID_ENUM, kInvalidName);
             return false;