Generate errors when read buffers are missing in BlitFramebuffer.

src/libANGLE/validationES.cpp

@@ -1987,10 +1987,9 @@ bool ValidateBlitFramebufferParameters(ValidationContext *context,
     if (mask & GL_COLOR_BUFFER_BIT)
     {
         const gl::FramebufferAttachment *readColorBuffer = readFramebuffer->getReadColorbuffer();
-        const gl::FramebufferAttachment *drawColorBuffer = drawFramebuffer->getFirstColorbuffer();
         const Extensions &extensions                     = context->getExtensions();
 
-        if (readColorBuffer && drawColorBuffer)
+        if (readColorBuffer)
         {
             const Format &readFormat = readColorBuffer->getFormat();
 
@@ -2070,6 +2069,17 @@ bool ValidateBlitFramebufferParameters(ValidationContext *context,
                 return false;
             }
         }
+        // WebGL 2.0 BlitFramebuffer when blitting from a missing attachment
+        // In OpenGL ES it is undefined what happens when an operation tries to blit from a missing
+        // attachment and WebGL defines it to be an error. We do the check unconditionally as the
+        // situation is an application error that would lead to a crash in ANGLE.
+        else if (drawFramebuffer->hasEnabledDrawBuffer())
+        {
+            context->handleError(Error(
+                GL_INVALID_OPERATION,
+                "Attempt to read from a missing color attachment of a complete framebuffer."));
+            return false;
+        }
     }
 
     GLenum masks[]       = {GL_DEPTH_BUFFER_BIT, GL_STENCIL_BUFFER_BIT};
@@ -2097,6 +2107,14 @@ bool ValidateBlitFramebufferParameters(ValidationContext *context,
                     return false;
                 }
             }
+            // WebGL 2.0 BlitFramebuffer when blitting from a missing attachment
+            else if (drawBuffer)
+            {
+                context->handleError(Error(GL_INVALID_OPERATION,
+                                           "Attempt to read from a missing depth/stencil "
+                                           "attachment of a complete framebuffer."));
+                return false;
+            }
         }
     }
 
@@ -2974,7 +2992,7 @@ bool ValidateCopyTexImageParametersBase(ValidationContext *context,
 
     // WebGL 1.0 [Section 6.26] Reading From a Missing Attachment
     // In OpenGL ES it is undefined what happens when an operation tries to read from a missing
-    // attachment and WebGL defines it to be an error. We do the check unconditionnaly as the
+    // attachment and WebGL defines it to be an error. We do the check unconditionally as the
     // situation is an application error that would lead to a crash in ANGLE.
     if (readFramebuffer->getReadColorbuffer() == nullptr)
     {

src/tests/gl_tests/BlitFramebufferANGLETest.cpp

@@ -678,29 +678,26 @@ TEST_P(BlitFramebufferANGLETest, BlitWithMissingAttachments)
     glClearColor(1.0, 1.0, 1.0, 1.0);
     glClear(GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
 
-    // depth blit request should be silently ignored, because the read FBO has no depth attachment
-    glBlitFramebufferANGLE(0, 0, getWindowWidth(), getWindowHeight(), 0, 0, getWindowWidth(), getWindowHeight(),
-                           GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT, GL_NEAREST); 
+    // generate INVALID_OPERATION if the read FBO has no depth attachment
+    glBlitFramebufferANGLE(0, 0, getWindowWidth(), getWindowHeight(), 0, 0, getWindowWidth(),
+                           getWindowHeight(), GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT,
+                           GL_NEAREST);
 
-    EXPECT_GL_NO_ERROR();
+    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
 
-    glBindFramebuffer(GL_FRAMEBUFFER, mOriginalFBO);
+    // generate INVALID_OPERATION if the read FBO has no stencil attachment
+    glBlitFramebufferANGLE(0, 0, getWindowWidth(), getWindowHeight(), 0, 0, getWindowWidth(),
+                           getWindowHeight(), GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT,
+                           GL_NEAREST);
 
-    EXPECT_PIXEL_EQ(    getWindowWidth() / 4,     getWindowHeight() / 4, 255,   0,   0, 255);
-    EXPECT_PIXEL_EQ(3 * getWindowWidth() / 4,     getWindowHeight() / 4,   0, 255,   0, 255);
-    EXPECT_PIXEL_EQ(3 * getWindowWidth() / 4, 3 * getWindowHeight() / 4, 255,   0,   0, 255);
-    EXPECT_PIXEL_EQ(    getWindowWidth() / 4, 3 * getWindowHeight() / 4,   0, 255,   0, 255);
+    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
 
-    // unlike in the depth blit tests, this *should* draw a blue quad, because depth info
-    // has not been copied
-    glEnable(GL_DEPTH_TEST);
-    drawQuad(mBlueProgram, "position", 0.8f);
-    glDisable(GL_DEPTH_TEST);
+    // generate INVALID_OPERATION if we read from a missing color attachment
+    glReadBuffer(GL_COLOR_ATTACHMENT1);
+    glBlitFramebufferANGLE(0, 0, getWindowWidth(), getWindowHeight(), 0, 0, getWindowWidth(),
+                           getWindowHeight(), GL_COLOR_BUFFER_BIT, GL_NEAREST);
 
-    EXPECT_PIXEL_EQ(    getWindowWidth() / 4,     getWindowHeight() / 4,   0,   0, 255, 255);
-    EXPECT_PIXEL_EQ(3 * getWindowWidth() / 4,     getWindowHeight() / 4,   0,   0, 255, 255);
-    EXPECT_PIXEL_EQ(3 * getWindowWidth() / 4, 3 * getWindowHeight() / 4,   0,   0, 255, 255);
-    EXPECT_PIXEL_EQ(    getWindowWidth() / 4, 3 * getWindowHeight() / 4,   0,   0, 255, 255);
+    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
 }
 
 TEST_P(BlitFramebufferANGLETest, BlitStencil)
@@ -1067,4 +1064,4 @@ ANGLE_INSTANTIATE_TEST(BlitFramebufferANGLETest,
                        ES2_D3D11(EGL_EXPERIMENTAL_PRESENT_PATH_COPY_ANGLE),
                        ES2_D3D11(EGL_EXPERIMENTAL_PRESENT_PATH_FAST_ANGLE));
 
-ANGLE_INSTANTIATE_TEST(BlitFramebufferTest, ES3_D3D11());
+ANGLE_INSTANTIATE_TEST(BlitFramebufferTest, ES3_D3D11());
\ No newline at end of file