GL: Reset the texture base level before uploads on Mac.

BUILD.gn

@@ -691,6 +691,10 @@ angle_source_set("libANGLE") {
     sources += libangle_null_sources
   }
 
+  if (is_mac) {
+    sources += libangle_mac_sources
+  }
+
   if (is_debug) {
     defines += [ "ANGLE_GENERATE_SHADER_DEBUG_INFO" ]
   }

include/platform/FeaturesGL.h

@@ -298,6 +298,14 @@ struct FeaturesGL : FeatureSetBase
     Feature clampArrayAccess = {"clamp_array_access", FeatureCategory::OpenGLWorkarounds,
                                 "Clamp uniform array access to avoid reading invalid memory.",
                                 &members, "http://anglebug.com/2978"};
+
+    // Reset glTexImage2D base level to workaround pixel comparison failure above Mac OS 10.12.4 on
+    // Intel Mac.
+    Feature resetTexImage2DBaseLevel = {"reset_teximage2d_base_level",
+                                        FeatureCategory::OpenGLWorkarounds,
+                                        "Reset texture base level before calling glTexImage2D to "
+                                        "work around pixel comparison failure.",
+                                        &members, "https://crbug.com/705865"};
 };
 
 inline FeaturesGL::FeaturesGL()  = default;

src/libANGLE/renderer/driver_utils.cpp

@@ -157,4 +157,38 @@ int GetAndroidSDKVersion()
 #endif
 }
 
+OSVersion::OSVersion() {}
+OSVersion::OSVersion(int major, int minor, int patch)
+    : majorVersion(major), minorVersion(minor), patchVersion(patch)
+{}
+
+bool operator==(const OSVersion &a, const OSVersion &b)
+{
+    return std::tie(a.majorVersion, a.minorVersion, a.patchVersion) ==
+           std::tie(b.majorVersion, b.minorVersion, b.patchVersion);
+}
+bool operator!=(const OSVersion &a, const OSVersion &b)
+{
+    return std::tie(a.majorVersion, a.minorVersion, a.patchVersion) !=
+           std::tie(b.majorVersion, b.minorVersion, b.patchVersion);
+}
+bool operator<(const OSVersion &a, const OSVersion &b)
+{
+    return std::tie(a.majorVersion, a.minorVersion, a.patchVersion) <
+           std::tie(b.majorVersion, b.minorVersion, b.patchVersion);
+}
+bool operator>=(const OSVersion &a, const OSVersion &b)
+{
+    return std::tie(a.majorVersion, a.minorVersion, a.patchVersion) >=
+           std::tie(b.majorVersion, b.minorVersion, b.patchVersion);
+}
+
+#if !defined(ANGLE_PLATFORM_APPLE)
+OSVersion GetMacOSVersion()
+{
+    // Return a default version
+    return OSVersion(0, 0, 0);
+}
+#endif
+
 }  // namespace rx

src/libANGLE/renderer/driver_utils.h

@@ -129,6 +129,22 @@ inline bool IsApple()
 #endif
 }
 
+struct OSVersion
+{
+    OSVersion();
+    OSVersion(int major, int minor, int patch);
+
+    int majorVersion = 0;
+    int minorVersion = 0;
+    int patchVersion = 0;
+};
+bool operator==(const OSVersion &a, const OSVersion &b);
+bool operator!=(const OSVersion &a, const OSVersion &b);
+bool operator<(const OSVersion &a, const OSVersion &b);
+bool operator>=(const OSVersion &a, const OSVersion &b);
+
+OSVersion GetMacOSVersion();
+
 inline bool IsAndroid()
 {
 #if defined(ANGLE_PLATFORM_ANDROID)

src/libANGLE/renderer/driver_utils_mac.mm

+//
+// Copyright (c) The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+
+// driver_utils_mac.mm : provides mac-specific information about current driver.
+
+#include "libANGLE/renderer/driver_utils.h"
+
+#import <Foundation/Foundation.h>
+
+namespace rx
+{
+
+OSVersion GetMacOSVersion()
+{
+    OSVersion result;
+
+    NSOperatingSystemVersion version = [[NSProcessInfo processInfo] operatingSystemVersion];
+    result.majorVersion              = version.majorVersion;
+    result.minorVersion              = version.minorVersion;
+    result.patchVersion              = version.patchVersion;
+
+    return result;
+}
+
+}

src/libANGLE/renderer/gl/TextureGL.cpp

@@ -224,6 +224,12 @@ void TextureGL::setImageHelper(const gl::Context *context,
 
     stateManager->bindTexture(getType(), mTextureID);
 
+    if (features.resetTexImage2DBaseLevel.enabled)
+    {
+        // setBaseLevel doesn't ever generate errors.
+        (void)setBaseLevel(context, 0);
+    }
+
     if (nativegl::UseTexImage2D(getType()))
     {
         ASSERT(size.depth == 1);

src/libANGLE/renderer/gl/renderergl_utils.cpp

@@ -1514,6 +1514,9 @@ void InitializeFeatures(const FunctionsGL *functions, angle::FeaturesGL *feature
     // The WebGL conformance/uniforms/out-of-bounds-uniform-array-access test has been seen to fail
     // on AMD and Android devices.
     features->clampArrayAccess.enabled = IsAndroid() || IsAMD(vendor);
+
+    features->resetTexImage2DBaseLevel.enabled =
+        IsApple() && IsIntel(vendor) && GetMacOSVersion() >= OSVersion(10, 12, 4);
 }
 
 void InitializeFrontendFeatures(const FunctionsGL *functions, angle::FrontendFeatures *features)

src/libGLESv2.gni

@@ -802,6 +802,8 @@ libangle_gl_cgl_sources = [
   "src/libANGLE/renderer/gl/cgl/WindowSurfaceCGL.h",
 ]
 
+libangle_mac_sources = [ "src/libANGLE/renderer/driver_utils_mac.mm" ]
+
 libangle_vulkan_sources = [
   "src/libANGLE/renderer/vulkan/BufferVk.cpp",
   "src/libANGLE/renderer/vulkan/BufferVk.h",