backend: Add linux as platform for tests (#7375)

- Also fixed a leak in `test_FeedbackLoops`

filament/backend/CMakeLists.txt

@@ -397,8 +397,8 @@ install(DIRECTORY ${PUBLIC_HDR_DIR}/backend DESTINATION include)
 # ==================================================================================================
 option(INSTALL_BACKEND_TEST "Install the backend test library so it can be consumed on iOS" OFF)
 
-if (APPLE)
-    add_library(backend_test STATIC
+if (APPLE OR LINUX)
+    set(BACKEND_TEST_SRC
         test/BackendTest.cpp
         test/ShaderGenerator.cpp
         test/TrianglePrimitive.cpp
@@ -410,19 +410,26 @@ if (APPLE)
         test/test_BufferUpdates.cpp
         test/test_MRT.cpp
         test/test_LoadImage.cpp
-        test/test_RenderExternalImage.cpp
         test/test_StencilBuffer.cpp
         test/test_Scissor.cpp
         test/test_MipLevels.cpp
-        )
-
-    target_link_libraries(backend_test PRIVATE
+    )
+    set(BACKEND_TEST_LIBS
         backend
         getopt
         gtest
+        imageio
         filamat
         SPIRV
         spirv-cross-glsl)
+endif()
+
+if (APPLE)
+    # TODO: we should expand this test to Linux and other platforms.
+    list(APPEND BACKEND_TEST_SRC
+         test/test_RenderExternalImage.cpp)
+    add_library(backend_test STATIC ${BACKEND_TEST_SRC})
+    target_link_libraries(backend_test PRIVATE ${BACKEND_TEST_LIBS})
 
     set(BACKEND_TEST_DEPS
             OGLCompiler
@@ -436,12 +443,11 @@ if (APPLE)
             glslang
             spirv-cross-core
             spirv-cross-glsl
-            spirv-cross-msl
-            )
+            spirv-cross-msl)
 
     if (NOT IOS)
         target_link_libraries(backend_test PRIVATE image imageio)
-        list(APPEND BACKEND_TEST_DEPS image imageio)
+        list(APPEND BACKEND_TEST_DEPS image)
     endif()
 
     set(BACKEND_TEST_COMBINED_OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/libbackendtest_combined.a")
@@ -455,15 +461,21 @@ if (APPLE)
     endif()
 
     set_target_properties(backend_test PROPERTIES FOLDER Tests)
+
+    if (APPLE AND NOT IOS)
+       add_executable(backend_test_mac test/mac_runner.mm)
+       target_link_libraries(backend_test_mac PRIVATE "-framework Metal -framework AppKit -framework QuartzCore")
+       # Because each test case is a separate file, the -force_load flag is necessary to prevent the
+       # linker from removing "unused" symbols.
+       target_link_libraries(backend_test_mac PRIVATE -force_load backend_test)
+       set_target_properties(backend_test_mac PROPERTIES FOLDER Tests)
+    endif()
 endif()
 
-if (APPLE AND NOT IOS)
-    add_executable(backend_test_mac test/mac_runner.mm)
-    target_link_libraries(backend_test_mac PRIVATE "-framework Metal -framework AppKit -framework QuartzCore")
-    # Because each test case is a separate file, the -force_load flag is necessary to prevent the
-    # linker from removing "unused" symbols.
-    target_link_libraries(backend_test_mac PRIVATE -force_load backend_test)
-    set_target_properties(backend_test_mac PROPERTIES FOLDER Tests)
+if (LINUX)
+    add_executable(backend_test_linux test/linux_runner.cpp ${BACKEND_TEST_SRC})
+    target_link_libraries(backend_test_linux PRIVATE ${BACKEND_TEST_LIBS})
+    set_target_properties(backend_test_linux PROPERTIES FOLDER Tests)
 endif()
 
 # ==================================================================================================

filament/backend/test/BackendTest.cpp

@@ -93,6 +93,9 @@ void BackendTest::flushAndWait() {
 
 Handle<HwSwapChain> BackendTest::createSwapChain() {
     const NativeView& view = getNativeView();
+    if (!view.ptr) {
+        return getDriverApi().createSwapChainHeadless(view.width, view.height, 0);
+    }
     return getDriverApi().createSwapChain(view.ptr, 0);
 }
 
@@ -212,4 +215,3 @@ int runTests() {
 }
 
 } // namespace test
-

filament/backend/test/PlatformRunner.h

@@ -22,6 +22,9 @@
 
 namespace test {
 
+constexpr uint32_t const WINDOW_WIDTH = 512;
+constexpr uint32_t const WINDOW_HEIGHT = 512;
+
 // To avoid a dependency on filabridge, the Backend enum is replicated here.
 enum class Backend : uint8_t {
     OPENGL = 1,

filament/backend/test/linux_runner.cpp

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include "BackendTest.h"
+#include "PlatformRunner.h"
+
+#include <array>
+#include <iostream>
+
+namespace test {
+
+test::NativeView getNativeView() {
+    return {
+            .ptr = nullptr,
+            .width = WINDOW_WIDTH,
+            .height = WINDOW_HEIGHT,
+    };
+}
+
+}// namespace test
+
+namespace {
+
+std::array<test::Backend, 2> const VALID_BACKENDS{
+        test::Backend::OPENGL,
+        test::Backend::VULKAN,
+};
+
+}// namespace
+
+int main(int argc, char* argv[]) {
+    auto backend = test::parseArgumentsForBackend(argc, argv);
+
+    if (!std::any_of(VALID_BACKENDS.begin(), VALID_BACKENDS.end(),
+                [backend](test::Backend validBackend) { return backend == validBackend; })) {
+        std::cerr << "Specified an invalid backend. Only GL and Vulkan are available" << std::endl;
+        return 1;
+    }
+
+    test::initTests(backend, false, argc, argv);
+    return test::runTests();
+}

filament/backend/test/mac_runner.mm

@@ -58,7 +58,7 @@ - (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
 }
 
 - (NSView*)createView {
-    NSRect frame = NSMakeRect(0, 0, 512, 512);
+    NSRect frame = NSMakeRect(0, 0, test::WINDOW_WIDTH, test::WINDOW_HEIGHT);
     NSWindow* window  = [[NSWindow alloc] initWithContentRect:frame
                                                      styleMask:NSWindowStyleMaskBorderless
                                                        backing:NSBackingStoreBuffered

filament/backend/test/test_FeedbackLoops.cpp

@@ -112,6 +112,7 @@ static void dumpScreenshot(DriverApi& dapi, Handle<HwRenderTarget> rt) {
         std::ofstream pngstrm("feedback.png", std::ios::binary | std::ios::trunc);
         ImageEncoder::encode(pngstrm, ImageEncoder::Format::PNG, image, "", "feedback.png");
         #endif
+        free(buffer);
     };
     PixelBufferDescriptor pb(buffer, size, PixelDataFormat::RGBA, PixelDataType::UBYTE, cb);
     dapi.readPixels(rt, 0, 0, kTexWidth, kTexHeight, std::move(pb));