Fix invalidation of GL_FRAMEBUFFER invalidating READ FBO

Per spec, GL_FRAMEBUFFER means GL_DRAW_FRAMEBUFFER for
glInvalidateFramebuffer.

Bug: chromium:1267424
Change-Id: I8c9ab61ecdbd4ccee4262dc8559b2feb02b4837c
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3266176
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>

src/libANGLE/Context.cpp

@@ -4144,8 +4144,14 @@ ANGLE_INLINE angle::Result Context::prepareForDispatch()
 
 angle::Result Context::prepareForInvalidate(GLenum target)
 {
-    // Only sync the FBO that's being invalidated
-    ANGLE_TRY(mState.syncDirtyObject(this, target));
+    // Only sync the FBO that's being invalidated.  Per the GLES3 spec, GL_FRAMEBUFFER is equivalent
+    // to GL_DRAW_FRAMEBUFFER for the purposes of invalidation.
+    GLenum effectiveTarget = target;
+    if (effectiveTarget == GL_FRAMEBUFFER)
+    {
+        effectiveTarget = GL_DRAW_FRAMEBUFFER;
+    }
+    ANGLE_TRY(mState.syncDirtyObject(this, effectiveTarget));
     return syncDirtyBits(mInvalidateDirtyBits, Command::Invalidate);
 }
 
@@ -4790,13 +4796,9 @@ void Context::readBuffer(GLenum mode)
 
 void Context::discardFramebuffer(GLenum target, GLsizei numAttachments, const GLenum *attachments)
 {
-    Framebuffer *framebuffer = mState.getTargetFramebuffer(target);
-    ASSERT(framebuffer);
-
     // The specification isn't clear what should be done when the framebuffer isn't complete.
-    // We leave it up to the framebuffer implementation to decide what to do.
-    ANGLE_CONTEXT_TRY(prepareForInvalidate(target));
-    ANGLE_CONTEXT_TRY(framebuffer->discard(this, numAttachments, attachments));
+    // We threat it the same way as GLES3 glInvalidateFramebuffer.
+    invalidateFramebuffer(target, numAttachments, attachments);
 }
 
 void Context::invalidateFramebuffer(GLenum target,

src/tests/gl_tests/FramebufferTest.cpp

@@ -744,6 +744,42 @@ TEST_P(FramebufferTest_ES3, AttachmentWith3DLayers)
     EXPECT_GL_NO_ERROR();
 }
 
+// Check that invalid layer is detected in framebuffer completeness check.
+TEST_P(FramebufferTest_ES3, 3DAttachmentInvalidLayer)
+{
+    GLTexture tex;
+    glBindTexture(GL_TEXTURE_3D, tex);
+    glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA8, 4, 4, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+
+    GLFramebuffer framebuffer;
+    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
+    glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 2);
+    EXPECT_GLENUM_EQ(GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT,
+                     glCheckFramebufferStatus(GL_FRAMEBUFFER));
+
+    glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 1);
+    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
+    EXPECT_GL_NO_ERROR();
+}
+
+// Check that invalid layer is detected in framebuffer completeness check.
+TEST_P(FramebufferTest_ES3, 2DArrayInvalidLayer)
+{
+    GLTexture tex;
+    glBindTexture(GL_TEXTURE_2D_ARRAY, tex);
+    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, 4, 4, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+
+    GLFramebuffer framebuffer;
+    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
+    glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 2);
+    EXPECT_GLENUM_EQ(GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT,
+                     glCheckFramebufferStatus(GL_FRAMEBUFFER));
+
+    glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 1);
+    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
+    EXPECT_GL_NO_ERROR();
+}
+
 // Test that clearing the stencil buffer when the framebuffer only has a color attachment does not
 // crash.
 TEST_P(FramebufferTest_ES3, ClearNonexistentStencil)

src/tests/gl_tests/StateChangeTest.cpp

@@ -7208,6 +7208,27 @@ TEST_P(SimpleStateChangeTestES3, ClearColorInvalidateDepthClearColor)
     glClear(GL_COLOR_BUFFER_BIT);
     ASSERT_GL_NO_ERROR();
 }
+
+// Regression test for a bug where glInvalidateFramebuffer(GL_FRAMEBUFFER, ...) was invalidating
+// both the draw and read framebuffers.
+TEST_P(SimpleStateChangeTestES3, InvalidateFramebufferShouldntInvalidateReadFramebuffer)
+{
+    // Create an invalid read framebuffer.
+    GLFramebuffer fbo;
+    glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
+
+    GLTexture tex;
+    glBindTexture(GL_TEXTURE_2D_ARRAY, tex);
+    glTexStorage3D(GL_TEXTURE_2D_ARRAY, 1, GL_R8, 1, 1, 1);
+    glFramebufferTextureLayer(GL_READ_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, tex, 0, 5);
+
+    // Invalidate using GL_FRAMEBUFFER.  If GL_READ_FRAMEBUFFER was used, validation would fail due
+    // to the framebuffer not being complete.  A bug here was attempting to invalidate the read
+    // framebuffer given GL_FRAMEBUFFER anyway.
+    constexpr std::array<GLenum, 2> kAttachments = {GL_DEPTH, GL_STENCIL};
+    glInvalidateFramebuffer(GL_FRAMEBUFFER, 2, kAttachments.data());
+    EXPECT_GL_NO_ERROR();
+}
 }  // anonymous namespace
 
 ANGLE_INSTANTIATE_TEST_ES2(StateChangeTest);