test: fix VK backend FeedbackLoops test

filament/backend/test/BackendTest.cpp

@@ -18,11 +18,16 @@
 
 #include <private/backend/PlatformFactory.h>
 
+#if defined(FILAMENT_DRIVER_SUPPORTS_VULKAN)
+#include <backend/platforms/VulkanPlatform.h>
+#endif
+
 #include "BackendTest.h"
 
 #include <utils/Hash.h>
 
 #include <fstream>
+#include <string>
 
 #include "ShaderGenerator.h"
 #include "TrianglePrimitive.h"
@@ -33,6 +38,25 @@ static constexpr size_t CONFIG_COMMAND_BUFFERS_SIZE     = 3 * CONFIG_MIN_COMMAND
 using namespace filament;
 using namespace filament::backend;
 
+#if defined(FILAMENT_DRIVER_SUPPORTS_VULKAN)
+namespace filament {
+class InternalVulkanPlatform : public VulkanPlatform {
+public:
+    InternalVulkanPlatform() {
+        mCustomization = {
+            .gpu = { .index = 0 },
+        };
+    }
+
+    virtual VulkanPlatform::Customization getCustomization() const noexcept override {
+        return mCustomization;
+    }
+private:
+    VulkanPlatform::Customization mCustomization;
+};
+}
+#endif
+
 #ifndef IOS
 #include <imageio/ImageEncoder.h>
 #include <image/ColorTransform.h>
@@ -40,6 +64,11 @@ using namespace filament::backend;
 using namespace image;
 #endif
 
+namespace {
+std::string const SHADER_VULKAN_TAG = "// select(vulkan) ";
+std::string const SHADER_METAL_TAG = "// select(metal) ";
+}
+
 namespace test {
 
 Backend BackendTest::sBackend = Backend::NOOP;
@@ -67,7 +96,14 @@ BackendTest::~BackendTest() {
 
 void BackendTest::initializeDriver() {
     auto backend = static_cast<filament::backend::Backend>(sBackend);
-    Platform* platform = PlatformFactory::create(&backend);
+
+    Platform* platform = nullptr;
+    if (backend == filament::backend::Backend::VULKAN) {
+        platform = new InternalVulkanPlatform();
+    } else {
+        platform = PlatformFactory::create(&backend);        
+    }
+
     assert_invariant(static_cast<uint8_t>(backend) == static_cast<uint8_t>(sBackend));
     Platform::DriverConfig const driverConfig;
     driver = platform->createDriver(nullptr, driverConfig);
@@ -193,6 +229,32 @@ void BackendTest::readPixelsAndAssertHash(const char* testName, size_t width, si
     getDriverApi().readPixels(rt, 0, 0, width, height, std::move(pbd));
 }
 
+std::string BackendTest::transformShaderText(std::string const& shader) const {
+    std::string replacement;
+    switch (sBackend) {
+        case test::Backend::VULKAN:
+            replacement = SHADER_VULKAN_TAG;
+            break;
+        case test::Backend::METAL:
+            replacement = SHADER_METAL_TAG;
+            break;
+        default:
+            break;
+    }
+    if (replacement.size() == 0) {
+        return shader;
+    }
+    std::string replaced = shader;
+    while (true) {
+        size_t pos = replaced.find(replacement);
+        if (pos == std::string::npos) {
+            break;
+        }
+        replaced.replace(pos, replacement.length(), "");
+    }
+    return replaced;
+}
+
 class Environment : public ::testing::Environment {
 public:
     virtual void SetUp() override {

filament/backend/test/BackendTest.h

@@ -66,6 +66,8 @@ protected:
     filament::backend::DriverApi& getDriverApi() { return *commandStream; }
     filament::backend::Driver& getDriver() { return *driver; }
 
+    std::string transformShaderText(std::string const& shader) const;
+
 private:
 
     filament::backend::Driver* driver = nullptr;

filament/backend/test/test_FeedbackLoops.cpp

@@ -33,6 +33,8 @@
 using namespace image;
 #endif
 
+#define DUMP_INTERMEDIATE_SCREENSHOTS 1
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // Shaders
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -42,6 +44,7 @@ layout(location = 0) in vec4 mesh_position;
 void main() {
     // Hack: move and scale triangle so that it covers entire viewport.
     gl_Position = vec4((mesh_position.xy + 0.5) * 5.0, 0.0, 1.0);
+    // select(vulkan) gl_Position.y = - gl_Position.y;
 })";
 
 static std::string fullscreenFs = R"(#version 450 core
@@ -50,7 +53,7 @@ layout(location = 0) out vec4 fragColor;
 
 // Filament's Vulkan backend requires a descriptor set index of 1 for all samplers.
 // This parameter is ignored for other backends.
-layout(location = 0, set = 1) uniform sampler2D test_tex;
+layout(binding = 0, set = 1) uniform sampler2D test_tex;
 
 uniform Params {
     highp float fbWidth;
@@ -60,7 +63,18 @@ uniform Params {
 } params;
 void main() {
     vec2 fbsize = vec2(params.fbWidth, params.fbHeight);
-    vec2 uv = (gl_FragCoord.xy + 0.5) / fbsize;
+    float offset = 0;
+    // select(vulkan) offset = -offset;
+    vec2 uv = (gl_FragCoord.xy + offset) / fbsize;
+    // select(vulkan) uv.y = 1.0 - uv.y;
+    vec4 oo = vec4(0, 0, 0, 0);
+    if (uv.x > .5) {
+        oo += vec4(0.5, 0.0, 0.0, 1.0);
+    }
+    if (uv.y > .5) {
+        oo += vec4(0.0, 0.5, 0.0, 1.0);
+    }
+//    fragColor = oo;
     fragColor = textureLod(test_tex, uv, params.sourceLevel);
 })";
 
@@ -99,23 +113,58 @@ static void uploadUniforms(DriverApi& dapi, Handle<HwBufferObject> ubh, Material
     dapi.updateBufferObject(ubh, std::move(bd), 0);
 }
 
-static void dumpScreenshot(DriverApi& dapi, Handle<HwRenderTarget> rt) {
-    const size_t size = kTexWidth * kTexHeight * 4;
+static void readScreenshot(DriverApi& dapi, Handle<HwRenderTarget> renderTargets[kNumLevels],
+        uint32_t target, std::function<void(void*)> output) {
+    Handle<HwRenderTarget> rt = renderTargets[target];
+    size_t const readWidth = kTexWidth >> target;
+    size_t const readHeight = kTexHeight >> target;
+    size_t const size = readWidth * readHeight * 4;
     void* buffer = calloc(1, size);
-    auto cb = [](void* buffer, size_t size, void* user) {
-        int w = kTexWidth, h = kTexHeight;
-        const uint32_t* texels = (uint32_t*) buffer;
-        sPixelHashResult = utils::hash::murmur3(texels, size / 4, 0);
-        #ifndef IOS
-        LinearImage image(w, h, 4);
-        image = toLinearWithAlpha<uint8_t>(w, h, w * 4, (uint8_t*) buffer);
-        std::ofstream pngstrm("feedback.png", std::ios::binary | std::ios::trunc);
-        ImageEncoder::encode(pngstrm, ImageEncoder::Format::PNG, image, "", "feedback.png");
-        #endif
-        free(buffer);
+    struct ReadPixelUserData {
+        std::function<void(void*)> onRead;
     };
-    PixelBufferDescriptor pb(buffer, size, PixelDataFormat::RGBA, PixelDataType::UBYTE, cb);
-    dapi.readPixels(rt, 0, 0, kTexWidth, kTexHeight, std::move(pb));
+    ReadPixelUserData* userdata = new ReadPixelUserData { output };
+    auto cb = [](void* buffer, size_t size, void* user) {
+        ReadPixelUserData* data = (ReadPixelUserData*) user;
+        data->onRead(buffer);
+        free(buffer);
+        delete data;
+    };
+    PixelBufferDescriptor pb(buffer, size, PixelDataFormat::RGBA, PixelDataType::UBYTE, cb,
+            userdata);
+    dapi.readPixels(rt, 0, 0, readWidth, readHeight, std::move(pb));
+}
+
+static void dumpScreenshot(DriverApi& dapi, Handle<HwRenderTarget> renderTargets[kNumLevels],
+        uint32_t target, uint32_t numFrame, bool downscale, test::Backend backend,
+        std::string fname="") {
+    Handle<HwRenderTarget> rt = renderTargets[target];
+    size_t const readWidth = kTexWidth >> target;
+    size_t const readHeight = kTexHeight >> target;
+    size_t const size = readWidth * readHeight * 4;
+    if (fname.empty()) {
+        std::string backendStr = "gl";
+        if (backend == test::Backend::METAL) {
+            backendStr = "mtl";
+        } else if (backend == test::Backend::VULKAN) {
+            backendStr = "vk";
+        }
+        std::string const down = downscale ? "down" : "up";
+        fname = "feedback_" + backendStr + "_" + std::to_string(numFrame) + "_" + down + "_" +
+                std::to_string(target) + ".png";
+    }
+    utils::slog.e <<"writing: " << fname << utils::io::endl;
+    readScreenshot(dapi, renderTargets, target,
+            [w = readWidth, h = readHeight, size, fname](void* buffer) {
+                uint32_t const* texels = (uint32_t*) buffer;
+                sPixelHashResult = utils::hash::murmur3(texels, size / 4, 0);
+#ifndef IOS
+                LinearImage image(w, h, 4);
+                image = toLinearWithAlpha<uint8_t>(w, h, w * 4, (uint8_t*) buffer);
+                std::ofstream pngstrm(fname.c_str(), std::ios::binary | std::ios::trunc);
+                ImageEncoder::encode(pngstrm, ImageEncoder::Format::PNG, image, "", fname.c_str());
+#endif
+            });
 }
 
 // TODO: This test needs work to get Metal and OpenGL to agree on results.
@@ -131,6 +180,8 @@ TEST_F(BackendTest, FeedbackLoops) {
         auto swapChain = createSwapChain();
         api.makeCurrent(swapChain, swapChain);
 
+        bool const backendIsVulkan = sBackend == test::Backend::VULKAN;
+
         // Create a program.
         ProgramHandle program;
         {
@@ -139,10 +190,12 @@ TEST_F(BackendTest, FeedbackLoops) {
                     .stageFlags(backend::ShaderStageFlags::ALL_SHADER_STAGE_FLAGS)
                     .add( {{"tex", SamplerType::SAMPLER_2D, SamplerFormat::FLOAT, Precision::HIGH }} )
                     .build();
-            ShaderGenerator shaderGen(fullscreenVs, fullscreenFs, sBackend, sIsMobilePlatform, &sib);
+            ShaderGenerator shaderGen(transformShaderText(fullscreenVs),
+                    transformShaderText(fullscreenFs), sBackend, sIsMobilePlatform, &sib);
             Program prog = shaderGen.getProgram(api);
-            Program::Sampler psamplers[] = { utils::CString("test_tex"), 0 };
-            prog.setSamplerGroup(0, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, psamplers, sizeof(psamplers) / sizeof(psamplers[0]));
+            Program::Sampler psamplers[] = {utils::CString("test_tex"), 0};
+            prog.setSamplerGroup(0, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, psamplers,
+                    sizeof(psamplers) / sizeof(psamplers[0]));
             prog.uniformBlockBindings({{"params", 1}});
             program = api.createProgram(std::move(prog));
         }
@@ -167,10 +220,25 @@ TEST_F(BackendTest, FeedbackLoops) {
         const size_t size = kTexHeight * kTexWidth * 4;
         uint8_t* buffer = (uint8_t*) malloc(size);
         for (int r = 0, i = 0; r < kTexHeight; r++) {
+            int const adjustedR = backendIsVulkan ? r : kTexHeight - r - 1;
             for (int c = 0; c < kTexWidth; c++, i += 4) {
+                auto hval = 0x1f * c / (kTexWidth - 1);
+                if (hval > 0x05) {
+                    hval = 0x1f;
+                } else {
+                    hval = 0x00;
+                }
+                auto vval = 0x1f * adjustedR / (kTexHeight - 1);
+                if (vval > 0x05) {
+                    vval = 0x1f;
+                } else {
+                    vval = 0x00;
+                }
                 buffer[i + 0] = 0x10;
-                buffer[i + 1] = 0x1f * r / (kTexHeight - 1);
+                buffer[i + 1] = 0x1f * adjustedR / (kTexHeight - 1);
+//                buffer[i + 1] = vval;
                 buffer[i + 2] = 0x1f * c / (kTexWidth - 1);
+//                buffer[i + 2] = hval;
                 buffer[i + 3] = 0xf0;
             }
          }
@@ -179,7 +247,6 @@ TEST_F(BackendTest, FeedbackLoops) {
         api.update3DImage(texture, 0, 0, 0, 0, kTexWidth, kTexHeight, 1, std::move(pb));
 
         for (int frame = 0; frame < kNumFrames; frame++) {
-
             // Prep for rendering.
             RenderPassParams params = {};
             params.flags.clear = TargetBufferFlags::NONE;
@@ -191,8 +258,9 @@ TEST_F(BackendTest, FeedbackLoops) {
             state.program = program;
             SamplerGroup samplers(1);
             SamplerParams sparams = {};
-            sparams.filterMag = SamplerMagFilter::LINEAR;
-            sparams.filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST;
+            sparams.filterMag = SamplerMagFilter::NEAREST;
+//            sparams.filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST;
+            sparams.filterMin = SamplerMinFilter::NEAREST;
             samplers.setSampler(0, { texture, sparams });
             auto sgroup =
                     api.createSamplerGroup(samplers.getSize(), utils::FixedSizeString<32>("Test"));
@@ -207,19 +275,24 @@ TEST_F(BackendTest, FeedbackLoops) {
             // Downsample passes
             params.flags.discardStart = TargetBufferFlags::ALL;
             state.rasterState.disableBlending();
-            for (int targetLevel = 1; targetLevel < kNumLevels; targetLevel++) {
-                const uint32_t sourceLevel = targetLevel - 1;
-                params.viewport.width = kTexWidth >> targetLevel;
-                params.viewport.height = kTexHeight >> targetLevel;
-                getDriverApi().setMinMaxLevels(texture, sourceLevel, sourceLevel);
-                uploadUniforms(getDriverApi(), ubuffer, {
-                    .fbWidth = float(params.viewport.width),
-                    .fbHeight = float(params.viewport.height),
-                    .sourceLevel = float(sourceLevel),
-                });
-                api.beginRenderPass(renderTargets[targetLevel], params);
-                api.draw(state, triangle.getRenderPrimitive(), 1);
-                api.endRenderPass();
+            for (int targetLevel = 0; targetLevel < kNumLevels; targetLevel++) {
+                if (targetLevel > 0) {
+                    const uint32_t sourceLevel = targetLevel - 1;
+                    params.viewport.width = kTexWidth >> targetLevel;
+                    params.viewport.height = kTexHeight >> targetLevel;
+                    getDriverApi().setMinMaxLevels(texture, sourceLevel, sourceLevel);
+                    uploadUniforms(getDriverApi(), ubuffer, {
+                        .fbWidth = float(params.viewport.width),
+                        .fbHeight = float(params.viewport.height),
+                        .sourceLevel = float(sourceLevel),
+                    });
+                    api.beginRenderPass(renderTargets[targetLevel], params);
+                    api.draw(state, triangle.getRenderPrimitive(), 1);
+                    api.endRenderPass();
+                }
+                #if DUMP_INTERMEDIATE_SCREENSHOTS
+                dumpScreenshot(api, renderTargets, targetLevel, frame, true, sBackend);
+                #endif
             }
 
             // Upsample passes
@@ -239,16 +312,22 @@ TEST_F(BackendTest, FeedbackLoops) {
                 api.beginRenderPass(renderTargets[targetLevel], params);
                 api.draw(state, triangle.getRenderPrimitive(), 1);
                 api.endRenderPass();
+
+                #if DUMP_INTERMEDIATE_SCREENSHOTS
+                dumpScreenshot(api, renderTargets, targetLevel, frame, false, sBackend);
+                #endif
             }
 
             getDriverApi().setMinMaxLevels(texture, 0, 0x7f);
+            getDriverApi().destroySamplerGroup(sgroup);
+            getDriverApi().destroyBufferObject(ubuffer);
 
             // Read back the render target corresponding to the base level.
             //
             // NOTE: Calling glReadPixels on any miplevel other than the base level
             // seems to be un-reliable on some GPU's.
             if (frame == kNumFrames - 1) {
-                dumpScreenshot(api, renderTargets[0]);
+                dumpScreenshot(api, renderTargets, 0, frame, false, sBackend, "Feedback.png");
             }
 
             api.flush();