No-op glGenerateMipmap on zero-sized textures

src/libANGLE/Texture.cpp

@@ -1657,6 +1657,16 @@ angle::Result Texture::generateMipmap(Context *context)
         return angle::Result::Continue;
     }
 
+    // If any dimension is zero, this is a no-op:
+    //
+    // > Otherwise, if level_base is not defined, or if any dimension is zero, all mipmap levels are
+    // > left unchanged. This is not an error.
+    const ImageDesc &baseImageInfo = mState.getImageDesc(mState.getBaseImageTarget(), baseLevel);
+    if (baseImageInfo.size.empty())
+    {
+        return angle::Result::Continue;
+    }
+
     ANGLE_TRY(syncState(context, Command::GenerateMipmap));
 
     // Clear the base image(s) immediately if needed
@@ -1681,7 +1691,6 @@ angle::Result Texture::generateMipmap(Context *context)
 
     // Propagate the format and size of the base mip to the smaller ones. Cube maps are guaranteed
     // to have faces of the same size and format so any faces can be picked.
-    const ImageDesc &baseImageInfo = mState.getImageDesc(mState.getBaseImageTarget(), baseLevel);
     mState.setImageDescChain(baseLevel, maxLevel, baseImageInfo.size, baseImageInfo.format,
                              InitState::Initialized);
 

src/libANGLE/renderer/vulkan/TextureVk.cpp

@@ -1609,10 +1609,7 @@ angle::Result TextureVk::redefineLevel(const gl::Context *context,
     // is still valid and we shouldn't redefine it to use the new format.  In that case,
     // ensureImageAllocated will only use the format to update the staging buffer's alignment to
     // support both the previous and the new formats.
-    if (!size.empty())
-    {
-        ANGLE_TRY(ensureImageAllocated(contextVk, format));
-    }
+    ANGLE_TRY(ensureImageAllocated(contextVk, format));
 
     return angle::Result::Continue;
 }

src/tests/gl_tests/MipmapTest.cpp

@@ -2086,6 +2086,26 @@ TEST_P(MipmapTestES3, Generate3DMipmapRespecification)
     ASSERT_GL_NO_ERROR();
 }
 
+// Test the calling glGenerateMipmap on a texture with a zero dimension doesn't crash.
+TEST_P(MipmapTestES3, GenerateMipmapZeroSize)
+{
+    GLTexture texture;
+    glBindTexture(GL_TEXTURE_2D, texture);
+
+    // Create a texture with at least one dimension that's zero.
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 2, 0, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+
+    // Attempt to generate mipmap.  This shouldn't crash.
+    glGenerateMipmap(GL_TEXTURE_2D);
+    EXPECT_GL_NO_ERROR();
+
+    // Try the same with a 3D texture where depth is 0.
+    GLTexture texture2;
+    glBindTexture(GL_TEXTURE_3D, texture2);
+    glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA8, 2, 2, 0, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+    glGenerateMipmap(GL_TEXTURE_3D);
+}
+
 // Use this to select which configurations (e.g. which renderer, which GLES major version) these
 // tests should be run against.
 ANGLE_INSTANTIATE_TEST_ES2_AND_ES3(MipmapTest);