Apply effective base and max level on GL backend

This works around GL drivers that neglect to clamp the base level or
max level of immutable textures.

BUG=angleproject:596
BUG=610800
TEST=angle_end2end_tests

Change-Id: Ie4e04aaa9253f2befd73bccefa7759486b3ef487
Reviewed-on: https://chromium-review.googlesource.com/344590
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>

src/libANGLE/Texture.cpp

@@ -80,6 +80,7 @@ GLuint TextureState::getEffectiveBaseLevel() const
 {
     if (immutableFormat)
     {
+        // GLES 3.0.4 section 3.8.10
         return std::min(baseLevel, immutableLevels - 1);
     }
     // Some classes use the effective base level to index arrays with level data. By clamping the
@@ -89,6 +90,18 @@ GLuint TextureState::getEffectiveBaseLevel() const
     return std::min(baseLevel, static_cast<GLuint>(gl::IMPLEMENTATION_MAX_TEXTURE_LEVELS));
 }
 
+GLuint TextureState::getEffectiveMaxLevel() const
+{
+    if (immutableFormat)
+    {
+        // GLES 3.0.4 section 3.8.10
+        GLuint clampedMaxLevel = std::max(maxLevel, getEffectiveBaseLevel());
+        clampedMaxLevel        = std::min(clampedMaxLevel, immutableLevels - 1);
+        return clampedMaxLevel;
+    }
+    return maxLevel;
+}
+
 Texture::Texture(rx::GLImplFactory *factory, GLuint id, GLenum target)
     : egl::ImageSibling(id),
       mState(target),

src/libANGLE/Texture.h

@@ -49,6 +49,7 @@ struct TextureState final : public angle::NonCopyable
 
     bool swizzleRequired() const;
     GLuint getEffectiveBaseLevel() const;
+    GLuint getEffectiveMaxLevel() const;
 
     // TODO(jmadill): Make the data members here private.
 

src/libANGLE/renderer/gl/TextureGL.cpp

@@ -726,12 +726,25 @@ void TextureGL::syncState(size_t textureUnit) const
         }
     };
 
-    // clang-format off
-
     // Sync texture state
-    SyncTextureStateMember(mFunctions, applyTextureFunc, mState, mAppliedTextureState, mState.target, GL_TEXTURE_BASE_LEVEL, &gl::TextureState::baseLevel);
-    SyncTextureStateMember(mFunctions, applyTextureFunc, mState, mAppliedTextureState, mState.target, GL_TEXTURE_MAX_LEVEL, &gl::TextureState::maxLevel);
+    // Apply the effective base level and max level instead of the base level and max level set from
+    // the API. This can help with buggy drivers.
+    if (mAppliedTextureState.getEffectiveBaseLevel() != mState.getEffectiveBaseLevel())
+    {
+        applyTextureFunc();
+        mFunctions->texParameteri(mState.target, GL_TEXTURE_BASE_LEVEL,
+                                  mState.getEffectiveBaseLevel());
+    }
+    mAppliedTextureState.baseLevel = mState.baseLevel;
+    if (mAppliedTextureState.getEffectiveMaxLevel() != mState.getEffectiveMaxLevel())
+    {
+        applyTextureFunc();
+        mFunctions->texParameteri(mState.target, GL_TEXTURE_MAX_LEVEL,
+                                  mState.getEffectiveMaxLevel());
+    }
+    mAppliedTextureState.maxLevel = mState.maxLevel;
 
+    // clang-format off
     const LevelInfoGL &levelInfo = mLevelInfo[mState.getEffectiveBaseLevel()];
     SyncTextureStateSwizzle(mFunctions, applyTextureFunc, levelInfo, mState, mAppliedTextureState, mState.target, GL_TEXTURE_SWIZZLE_R, &gl::TextureState::swizzleRed);
     SyncTextureStateSwizzle(mFunctions, applyTextureFunc, levelInfo, mState, mAppliedTextureState, mState.target, GL_TEXTURE_SWIZZLE_G, &gl::TextureState::swizzleGreen);

src/tests/gl_tests/TextureTest.cpp

@@ -2126,26 +2126,6 @@ TEST_P(Texture2DTestES3, TextureBaseLevelGreaterThanMaxLevel)
 // GLES 3.0.4 section 3.8.10 subsection Mipmapping
 TEST_P(Texture2DTestES3, ImmutableTextureBaseLevelOutOfRange)
 {
-    if (IsOSX())
-    {
-        // Observed incorrect rendering on OSX.
-        std::cout << "Test skipped on OSX." << std::endl;
-        return;
-    }
-    if (IsAMD() && isOpenGL())
-    {
-        // Observed incorrect rendering on AMD OpenGL.
-        std::cout << "Test skipped on AMD OpenGL." << std::endl;
-        return;
-    }
-
-    if (IsLinux() && IsIntel() && isOpenGL())
-    {
-        // The Mesa Intel driver doesn't clamp the base level
-        std::cout << "Test skipped on Intel Linux OpenGL." << std::endl;
-        return;
-    }
-
     glActiveTexture(GL_TEXTURE0);
     glBindTexture(GL_TEXTURE_2D, mTexture2D);