backend-test: centralize read pixel logic

filament/backend/test/BackendTest.cpp

@@ -20,6 +20,7 @@
 
 #include "BackendTest.h"
 
+#include <utils/Log.h>
 #include <utils/Hash.h>
 
 #include <fstream>
@@ -149,50 +150,59 @@ void BackendTest::renderTriangle(Handle<HwRenderTarget> renderTarget,
 }
 
 void BackendTest::readPixelsAndAssertHash(const char* testName, size_t width, size_t height,
-        Handle<HwRenderTarget> rt, uint32_t expectedHash, bool exportScreenshot) {
-    void* buffer = calloc(1, width * height * 4);
+        Handle<HwRenderTarget> rt, uint32_t const expectedHash, bool const exportScreenshot) {
+    auto img = getRenderTargetRGB(rt, width, height);
+    uint32_t hash = computeImageHash(img);
 
-    struct Capture {
-        uint32_t expectedHash;
-        char* name;
-        bool exportScreenshot;
-        size_t width, height;
-    };
-    auto* c = new Capture();
-    c->expectedHash = expectedHash;
-    c->name = strdup(testName);
-    c->exportScreenshot = exportScreenshot;
-    c->width = width;
-    c->height = height;
-
-    PixelBufferDescriptor pbd(buffer, width * height * 4, PixelDataFormat::RGBA, PixelDataType::UBYTE,
-            1, 0, 0, width, [](void* buffer, size_t size, void* user) {
-                auto* c = (Capture*)user;
-
-                // Export a screenshot, if requested.
-                if (c->exportScreenshot) {
-#ifndef IOS
-                    LinearImage image(c->width, c->height, 4);
-                    image = toLinearWithAlpha<uint8_t>(c->width, c->height, c->width * 4,
-                            (uint8_t*) buffer);
-                    const std::string png = std::string(c->name) + ".png";
-                    std::ofstream outputStream(png.c_str(), std::ios::binary | std::ios::trunc);
-                    ImageEncoder::encode(outputStream, ImageEncoder::Format::PNG, image, "",
-                            png);
-#endif
-                }
-
-                // Hash the contents of the buffer and check that they match.
-                uint32_t hash = utils::hash::murmur3((const uint32_t*) buffer, size / 4, 0);
-                ASSERT_EQ(hash, c->expectedHash) << c->name << " failed: hashes do not match." << std::endl;
-
-                free(buffer);
-                free(c->name);
-                free(c);
-            }, (void*)c);
-    getDriverApi().readPixels(rt, 0, 0, width, height, std::move(pbd));
+    if (exportScreenshot) {
+        writeImage(img, width, height, utils::CString(testName));
+    }
+    ASSERT_EQ(hash, expectedHash) << testName << " failed: hashes do not match." << std::endl;
 }
 
+void BackendTest::writeImage(utils::FixedCapacityVector<uint8_t> img, size_t w, size_t h,
+        utils::CString const& fname) {
+    constexpr size_t MAX_FNAME_LEN = 50;
+    constexpr size_t FNAME_EXT_LEN = 4;
+    constexpr size_t TOTAL_LEN = MAX_FNAME_LEN + FNAME_EXT_LEN + 1;
+    char buf[TOTAL_LEN];
+
+    ASSERT_PRECONDITION(fname.size() <= MAX_FNAME_LEN, "File name %s is too long", fname.c_str());
+
+    snprintf(buf, TOTAL_LEN, "%s.png", fname.c_str());
+
+#ifndef IOS
+    LinearImage image(w, h, 4);
+    image = toLinearWithAlpha<uint8_t>(w, h, w * 4, img.data());
+    std::ofstream pngstrm(buf, std::ios::binary | std::ios::trunc);
+    ImageEncoder::encode(pngstrm, ImageEncoder::Format::PNG, image, "", buf);
+#endif
+}
+
+utils::FixedCapacityVector<uint8_t> BackendTest::getRenderTarget(
+        Handle<HwRenderTarget> rt, size_t width, size_t height, PixelDataFormat format,
+        PixelDataType dataType) {
+    auto& api = getDriverApi();
+    size_t const size = width * height * 4;
+    utils::FixedCapacityVector<uint8_t> result(size);
+    PixelBufferDescriptor pb(result.data(), size, format, dataType);
+    api.readPixels(rt, 0, 0, width, height, std::move(pb));
+    flushAndWait();
+
+    return result;
+}
+
+uint32_t BackendTest::computeImageHash(utils::FixedCapacityVector<uint8_t> const& img) {
+    return utils::hash::murmur3((uint32_t*) img.data(), img.size() / 4, 0);
+}
+
+utils::FixedCapacityVector<uint8_t> BackendTest::getRenderTargetRGB(
+        Handle<HwRenderTarget> rt, size_t width, size_t height) {
+    return getRenderTarget(rt, width, height, PixelDataFormat::RGBA,
+            PixelDataType::UBYTE);
+}
+
+
 class Environment : public ::testing::Environment {
 public:
     virtual void SetUp() override {

filament/backend/test/BackendTest.h

@@ -67,6 +67,17 @@ protected:
     filament::backend::Driver& getDriver() { return *driver; }
 
 private:
+    void writeImage(utils::FixedCapacityVector<uint8_t> img, size_t w, size_t h,
+            utils::CString const& fname);
+    utils::FixedCapacityVector<uint8_t> getRenderTarget(
+            filament::backend::Handle<filament::backend::HwRenderTarget> rt, size_t width,
+            size_t height, filament::backend::PixelDataFormat format,
+            filament::backend::PixelDataType dataType);
+    uint32_t computeImageHash(utils::FixedCapacityVector<uint8_t> const& img);
+
+    utils::FixedCapacityVector<uint8_t> getRenderTargetRGB(
+            filament::backend::Handle<filament::backend::HwRenderTarget> rt, size_t width,
+            size_t height);
 
     filament::backend::Driver* driver = nullptr;
     filament::backend::CommandBufferQueue commandBufferQueue;

filament/backend/test/test_Blit.cpp

@@ -60,36 +60,6 @@ struct MaterialParams {
     float4 scale;
 };
 
-struct ScreenshotParams {
-    int width;
-    int height;
-    const char* filename;
-    uint32_t pixelHashResult;
-};
-
-#ifdef IOS
-static void dumpScreenshot(DriverApi& dapi, Handle<HwRenderTarget> rt, ScreenshotParams* params) {}
-#else
-static void dumpScreenshot(DriverApi& dapi, Handle<HwRenderTarget> rt, ScreenshotParams* params) {
-    using namespace image;
-    const size_t size = params->width * params->height * 4;
-    void* buffer = calloc(1, size);
-    auto cb = [](void* buffer, size_t size, void* user) {
-        ScreenshotParams* params = (ScreenshotParams*) user;
-        int w = params->width, h = params->height;
-        const uint32_t* texels = (uint32_t*) buffer;
-        params->pixelHashResult = utils::hash::murmur3(texels, size / 4, 0);
-        LinearImage image(w, h, 4);
-        image = toLinearWithAlpha<uint8_t>(w, h, w * 4, (uint8_t*) buffer);
-        std::ofstream pngstrm(params->filename, std::ios::binary | std::ios::trunc);
-        ImageEncoder::encode(pngstrm, ImageEncoder::Format::PNG, image, "", params->filename);
-    };
-    PixelBufferDescriptor pb(buffer, size, PixelDataFormat::RGBA, PixelDataType::UBYTE, cb,
-            (void*) params);
-    dapi.readPixels(rt, 0, 0, params->width, params->height, std::move(pb));
-}
-#endif
-
 static void uploadUniforms(DriverApi& dapi, Handle<HwBufferObject> ubh, MaterialParams params) {
     MaterialParams* tmp = new MaterialParams(params);
     auto cb = [](void* buffer, size_t size, void* user) {
@@ -243,21 +213,12 @@ TEST_F(BackendTest, ColorMagnify) {
     api.endFrame(0);
 
     // Grab a screenshot.
-    ScreenshotParams params { kDstTexWidth, kDstTexHeight, "ColorMagnify.png" };
     api.beginFrame(0, 0, 0);
-    dumpScreenshot(api, dstRenderTargets[0], &params);
-    api.commit(swapChain);
+    constexpr uint32_t expected = 0x410bdd31;
+    readPixelsAndAssertHash("ColorMagnify", kDstTexWidth, kDstTexHeight, dstRenderTargets[0],
+            expected, true);
     api.endFrame(0);
-
-    // Wait for the ReadPixels result to come back.
-    api.finish();
-    executeCommands();
-    getDriver().purge();
-
-    // Check if the image matches perfectly to our golden run.
-    const uint32_t expected = 0x410bdd31;
-    printf("Computed hash is 0x%8.8x, Expected 0x%8.8x\n", params.pixelHashResult, expected);
-    EXPECT_TRUE(params.pixelHashResult == expected);
+    flushAndWait();
 
     // Cleanup.
     api.destroyTexture(srcTexture);
@@ -315,17 +276,15 @@ TEST_F(BackendTest, ColorMinify) {
             SamplerMagFilter::LINEAR);
 
     // Grab a screenshot.
-    ScreenshotParams params { kDstTexWidth, kDstTexHeight, "ColorMinify.png" };
-    dumpScreenshot(api, dstRenderTargets[0], &params);
+    api.beginFrame(0, 0, 0);
+    constexpr uint32_t expected = 0xf3d9c53f;
+    readPixelsAndAssertHash("ColorMinify", kDstTexWidth, kDstTexHeight, dstRenderTargets[0],
+            expected, true);
 
-    // Wait for the ReadPixels result to come back.
+    api.commit(swapChain);
+    api.endFrame(0);
     flushAndWait();
 
-    // Check if the image matches perfectly to our golden run.
-    const uint32_t expected = 0xf3d9c53f;
-    printf("Computed hash is 0x%8.8x, Expected 0x%8.8x\n", params.pixelHashResult, expected);
-    EXPECT_TRUE(params.pixelHashResult == expected);
-
     // Cleanup.
     api.destroyTexture(srcTexture);
     api.destroyTexture(dstTexture);
@@ -416,17 +375,13 @@ TEST_F(BackendTest, ColorResolve) {
             SamplerMagFilter::NEAREST);
 
     // Grab a screenshot.
-    ScreenshotParams sparams{ kDstTexWidth, kDstTexHeight, "ColorResolve.png" };
-    dumpScreenshot(api, dstRenderTarget, &sparams);
-
-    // Wait for the ReadPixels result to come back.
+    api.beginFrame(0, 0, 0);
+    constexpr uint32_t expected = 0xebfac2ef;
+    readPixelsAndAssertHash("ColorResolve", kDstTexWidth, kDstTexHeight, dstRenderTarget,
+            expected, true);
+    api.endFrame(0);
     flushAndWait();
 
-    // Check if the image matches perfectly to our golden run.
-    const uint32_t expected = 0xebfac2ef;
-    printf("Computed hash is 0x%8.8x, Expected 0x%8.8x\n", sparams.pixelHashResult, expected);
-    EXPECT_TRUE(sparams.pixelHashResult == expected);
-
     // Cleanup.
     api.destroyBufferObject(ubuffer);
     api.destroyProgram(program);
@@ -489,21 +444,12 @@ TEST_F(BackendTest, Blit2DTextureArray) {
     api.endFrame(0);
 
     // Grab a screenshot.
-    ScreenshotParams params { kDstTexWidth, kDstTexHeight, "Blit2DTextureArray.png" };
     api.beginFrame(0, 0, 0);
-    dumpScreenshot(api, dstRenderTarget, &params);
-    api.commit(swapChain);
+    constexpr uint32_t expected = 0x8de7d55b;
+    readPixelsAndAssertHash("Blit2DTextureArray", kDstTexWidth, kDstTexHeight, dstRenderTarget,
+            expected, true);
     api.endFrame(0);
-
-    // Wait for the ReadPixels result to come back.
-    api.finish();
-    executeCommands();
-    getDriver().purge();
-
-    // Check if the image matches perfectly to our golden run.
-    const uint32_t expected = 0x8de7d55b;
-    printf("Computed hash is 0x%8.8x, Expected 0x%8.8x\n", params.pixelHashResult, expected);
-    EXPECT_TRUE(params.pixelHashResult == expected);
+    flushAndWait();
 
     // Cleanup.
     api.destroyTexture(srcTexture);
@@ -578,28 +524,17 @@ TEST_F(BackendTest, BlitRegion) {
     api.commit(swapChain);
     api.endFrame(0);
 
-    // Grab a screenshot.
-    ScreenshotParams params { kDstTexWidth, kDstTexHeight, "BlitRegion.png" };
-    api.beginFrame(0, 0, 0);
-    dumpScreenshot(api, dstRenderTarget, &params);
-    api.commit(swapChain);
-    api.endFrame(0);
-
-    // Wait for the ReadPixels result to come back.
-    api.finish();
-    executeCommands();
-    getDriver().purge();
-
     // Check if the image matches perfectly to our golden run.
-    //
     // TODO: for some reason, this test has very, very slight (as in one pixel) differences between
     // OpenGL and Metal. So disable golden checking for now.
     // Use the compare tool from ImageMagick to see visual differences:
     // compare -verbose -metric mae BlitRegion_Metal.png BlitRegion_OpenGL.png difference.png
-    //
-    // const uint32_t expected = 0x74fa34ed;
-    // printf("Computed hash is 0x%8.8x, Expected 0x%8.8x\n", params.pixelHashResult, expected);
-    // EXPECT_TRUE(params.pixelHashResult == expected);
+    // api.beginFrame(0, 0, 0);
+    // constexpr uint32_t expected = 0x74fa34ed;
+    // readPixelsAndAssertHash("BlitRegion", kDstTexWidth, kDstTexHeight, dstRenderTarget,
+    //         expected, true);
+    // api.endFrame(0);
+    // flushAndWait();
 
     // Cleanup.
     api.destroyTexture(srcTexture);
@@ -655,23 +590,22 @@ TEST_F(BackendTest, BlitRegionToSwapChain) {
         .height = kDstTexHeight - 10,
     };
 
-    api.beginFrame(0, 0, 0);
-
     api.blitDEPRECATED(TargetBufferFlags::COLOR0, dstRenderTarget,
             dstRect, srcRenderTargets[srcLevel],
             srcRect, SamplerMagFilter::LINEAR);
 
-    ScreenshotParams params { kDstTexWidth, kDstTexHeight, "BlitRegionToSwapChain.png" };
-    dumpScreenshot(api, dstRenderTarget, &params);
-
+    // Push through an empty frame to allow the texture to upload and the blit to execute.
+    api.beginFrame(0, 0, 0);
     api.commit(swapChain);
-
     api.endFrame(0);
 
-    // Wait for the ReadPixels result to come back.
-    api.finish();
-    executeCommands();
-    getDriver().purge();
+    // Grab a screenshot.
+    api.beginFrame(0, 0, 0);
+    constexpr uint32_t expected = 0xebfac2ef;
+    readPixelsAndAssertHash("BlitRegionToSwapChain", kDstTexWidth, kDstTexHeight, dstRenderTarget,
+            expected, true);
+    api.endFrame(0);
+    flushAndWait();
 
     // Cleanup.
     api.destroyTexture(srcTexture);

filament/backend/test/test_FeedbackLoops.cpp

@@ -16,6 +16,7 @@
 
 #include "BackendTest.h"
 
+#include "BackendTestUtils.h"
 #include "ShaderGenerator.h"
 #include "TrianglePrimitive.h"
 
@@ -64,8 +65,6 @@ void main() {
     fragColor = textureLod(test_tex, uv, params.sourceLevel);
 })";
 
-static uint32_t sPixelHashResult = 0;
-
 // Selecting a NPOT texture size seems to exacerbate the bug seen with Intel GPU's.
 // Note that Filament uses a higher precision format (R11F_G11F_B10F) but this does not seem
 // necessary to trigger the bug.
@@ -99,30 +98,13 @@ 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;
-    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);
-    };
-    PixelBufferDescriptor pb(buffer, size, PixelDataFormat::RGBA, PixelDataType::UBYTE, cb);
-    dapi.readPixels(rt, 0, 0, kTexWidth, kTexHeight, std::move(pb));
-}
-
 // TODO: This test needs work to get Metal and OpenGL to agree on results.
 // The problems are caused by both uploading and rendering into the same texture, since the OpenGL
 // backend's readPixels does not work correctly with textures that have image data uploaded.
 TEST_F(BackendTest, FeedbackLoops) {
     auto& api = getDriverApi();
+    auto& driver = getDriver();
+    uint32_t pixelHashResult = 0;
 
     // The test is executed within this block scope to force destructors to run before
     // executeCommands().
@@ -147,7 +129,7 @@ TEST_F(BackendTest, FeedbackLoops) {
             program = api.createProgram(std::move(prog));
         }
 
-        TrianglePrimitive const triangle(getDriverApi());
+        TrianglePrimitive const triangle(api);
 
         // Create a texture.
         auto usage = TextureUsage::COLOR_ATTACHMENT | TextureUsage::SAMPLEABLE;
@@ -211,8 +193,8 @@ TEST_F(BackendTest, FeedbackLoops) {
                 const uint32_t sourceLevel = targetLevel - 1;
                 params.viewport.width = kTexWidth >> targetLevel;
                 params.viewport.height = kTexHeight >> targetLevel;
-                getDriverApi().setMinMaxLevels(texture, sourceLevel, sourceLevel);
-                uploadUniforms(getDriverApi(), ubuffer, {
+                api.setMinMaxLevels(texture, sourceLevel, sourceLevel);
+                uploadUniforms(api, ubuffer, {
                     .fbWidth = float(params.viewport.width),
                     .fbHeight = float(params.viewport.height),
                     .sourceLevel = float(sourceLevel),
@@ -230,8 +212,8 @@ TEST_F(BackendTest, FeedbackLoops) {
                 const uint32_t sourceLevel = targetLevel + 1;
                 params.viewport.width = kTexWidth >> targetLevel;
                 params.viewport.height = kTexHeight >> targetLevel;
-                getDriverApi().setMinMaxLevels(texture, sourceLevel, sourceLevel);
-                uploadUniforms(getDriverApi(), ubuffer, {
+                api.setMinMaxLevels(texture, sourceLevel, sourceLevel);
+                uploadUniforms(api, ubuffer, {
                     .fbWidth = float(params.viewport.width),
                     .fbHeight = float(params.viewport.height),
                     .sourceLevel = float(sourceLevel),
@@ -241,14 +223,16 @@ TEST_F(BackendTest, FeedbackLoops) {
                 api.endRenderPass();
             }
 
-            getDriverApi().setMinMaxLevels(texture, 0, 0x7f);
+            api.setMinMaxLevels(texture, 0, 0x7f);
 
             // 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]);
+                constexpr uint32_t expected = 0x70695aa1;
+                readPixelsAndAssertHash("feedback", kTexWidth, kTexHeight, renderTargets[0],
+                        expected, true);
             }
 
             api.flush();
@@ -256,7 +240,7 @@ TEST_F(BackendTest, FeedbackLoops) {
             api.endFrame(0);
             api.finish();
             executeCommands();
-            getDriver().purge();
+            driver.purge();
         }
 
         api.destroyProgram(program);
@@ -264,10 +248,6 @@ TEST_F(BackendTest, FeedbackLoops) {
         api.destroyTexture(texture);
         for (auto rt : renderTargets)  api.destroyRenderTarget(rt);
     }
-
-    const uint32_t expected = 0x70695aa1;
-    printf("Computed hash is 0x%8.8x, Expected 0x%8.8x\n", sPixelHashResult, expected);
-    EXPECT_TRUE(sPixelHashResult == expected);
 }
 
 } // namespace test