Enable & fix qgl autotests on 16-bpp systems

Introduce a fuzzy pixel and image compare which changes it's allowed
fuzz based on the system's color depth. If the compared images are
different, the autotests will also save the two images to the current
directory for comparison.

Reviewed-By: Samuel
(cherry picked from commit c92670dc8b2e5cf727c33943dde0755c17d0dac2)

1 files changed, 111 insertions, 49 deletions

diff --git a/tests/auto/qgl/tst_qgl.cpp b/tests/auto/qgl/tst_qgl.cpp
index c25c05c..adb494e 100644
--- a/tests/auto/qgl/tst_qgl.cpp
+++ b/tests/auto/qgl/tst_qgl.cpp
@@ -711,6 +711,79 @@ void tst_QGL::openGLVersionCheck()
 #endif //QT_BUILD_INTERNAL
 }
 
+static bool fuzzyComparePixels(const QRgb testPixel, const QRgb refPixel, const char* file, int line, int x = -1, int y = -1)
+{
+    static int maxFuzz = 1;
+    static bool maxFuzzSet = false;
+
+    // On 16 bpp systems, we need to allow for more fuzz:
+    if (!maxFuzzSet) {
+        maxFuzzSet = true;
+        if (appDefaultDepth() < 24)
+            maxFuzz = 32;
+    }
+
+    int redFuzz = qAbs(qRed(testPixel) - qRed(refPixel));
+    int greenFuzz = qAbs(qGreen(testPixel) - qGreen(refPixel));
+    int blueFuzz = qAbs(qBlue(testPixel) - qBlue(refPixel));
+    int alphaFuzz = qAbs(qAlpha(testPixel) - qAlpha(refPixel));
+
+    if (refPixel != 0 && testPixel == 0) {
+        QString msg;
+        if (x >= 0) {
+            msg = QString("Test pixel [%1, %2] is null (black) when it should be (%3,%4,%5,%6)")
+                            .arg(x).arg(y)
+                            .arg(qRed(refPixel)).arg(qGreen(refPixel)).arg(qBlue(refPixel)).arg(qAlpha(refPixel));
+        } else {
+            msg = QString("Test pixel is null (black) when it should be (%2,%3,%4,%5)")
+                            .arg(qRed(refPixel)).arg(qGreen(refPixel)).arg(qBlue(refPixel)).arg(qAlpha(refPixel));
+        }
+
+        QTest::qFail(msg.toLatin1(), file, line);
+        return false;
+    }
+
+    if (redFuzz > maxFuzz || greenFuzz > maxFuzz || blueFuzz > maxFuzz || alphaFuzz > maxFuzz) {
+        QString msg;
+
+        if (x >= 0)
+            msg = QString("Pixel [%1,%2]: ").arg(x).arg(y);
+        else
+            msg = QString("Pixel ");
+
+        msg += QString("Max fuzz (%1) exceeded: (%2,%3,%4,%5) vs (%6,%7,%8,%9)")
+                      .arg(maxFuzz)
+                      .arg(qRed(testPixel)).arg(qGreen(testPixel)).arg(qBlue(testPixel)).arg(qAlpha(testPixel))
+                      .arg(qRed(refPixel)).arg(qGreen(refPixel)).arg(qBlue(refPixel)).arg(qAlpha(refPixel));
+        QTest::qFail(msg.toLatin1(), file, line);
+        return false;
+    }
+    return true;
+}
+
+static void fuzzyCompareImages(const QImage &testImage, const QImage &referenceImage, const char* file, int line)
+{
+    QCOMPARE(testImage.width(), referenceImage.width());
+    QCOMPARE(testImage.height(), referenceImage.height());
+
+    for (int y = 0; y < testImage.height(); y++) {
+        for (int x = 0; x < testImage.width(); x++) {
+            if (!fuzzyComparePixels(testImage.pixel(x, y), referenceImage.pixel(x, y), file, line, x, y)) {
+                // Might as well save the images for easier debugging:
+                referenceImage.save("referenceImage.png");
+                testImage.save("testImage.png");
+                return;
+            }
+        }
+    }
+}
+
+#define QFUZZY_COMPARE_IMAGES(A,B) \
+            fuzzyCompareImages(A, B, __FILE__, __LINE__)
+
+#define QFUZZY_COMPARE_PIXELS(A,B) \
+            fuzzyComparePixels(A, B, __FILE__, __LINE__)
+
 class UnclippedWidget : public QWidget
 {
 public:
@@ -723,8 +796,6 @@ public:
 
 void tst_QGL::graphicsViewClipping()
 {
-    if (appDefaultDepth() < 24)
-        QSKIP("This test won't work for bit depths < 24", SkipAll);
     const int size = 64;
     UnclippedWidget *widget = new UnclippedWidget;
     widget->setFixedSize(size, size);
@@ -758,7 +829,7 @@ void tst_QGL::graphicsViewClipping()
     p.fillRect(QRect(0, 0, size, size), Qt::black);
     p.end();
 
-    QCOMPARE(image, expected);
+    QFUZZY_COMPARE_IMAGES(image, expected);
 }
 
 void tst_QGL::partialGLWidgetUpdates_data()
@@ -849,7 +920,7 @@ void tst_QGL::glPBufferRendering()
     p.fillRect(32, 32, 64, 64, Qt::blue);
     p.end();
 
-    QCOMPARE(fb, reference);
+    QFUZZY_COMPARE_IMAGES(fb, reference);
 }
 
 class GLWidget : public QGLWidget
@@ -877,9 +948,8 @@ public:
 
 void tst_QGL::glWidgetRendering()
 {
-    if (appDefaultDepth() < 24)
-        QSKIP("This test won't work for bit depths < 24", SkipAll);
     GLWidget w;
+    w.setGeometry(100, 100, 200, 200);
     w.show();
 
 #ifdef Q_WS_X11
@@ -894,7 +964,7 @@ void tst_QGL::glWidgetRendering()
     QImage reference(fb.size(), QImage::Format_RGB32);
     reference.fill(0xffff0000);
 
-    QCOMPARE(fb, reference);
+    QFUZZY_COMPARE_IMAGES(fb, reference);
 }
 
 // NOTE: This tests that CombinedDepthStencil attachment works by assuming the
@@ -949,14 +1019,14 @@ void tst_QGL::glFBORendering()
     // As we're doing more than trivial painting, we can't just compare to
     // an image rendered with raster. Instead, we sample at well-defined
     // test-points:
-    QCOMPARE(fb.pixel(39, 64), QColor(Qt::red).rgb());
-    QCOMPARE(fb.pixel(89, 64), QColor(Qt::red).rgb());
-    QCOMPARE(fb.pixel(64, 39), QColor(Qt::blue).rgb());
-    QCOMPARE(fb.pixel(64, 89), QColor(Qt::blue).rgb());
-
-    QCOMPARE(fb.pixel(167, 39), QColor(Qt::red).rgb());
-    QCOMPARE(fb.pixel(217, 39), QColor(Qt::red).rgb());
-    QCOMPARE(fb.pixel(192, 64), QColor(Qt::green).rgb());
+    QFUZZY_COMPARE_PIXELS(fb.pixel(39, 64), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb.pixel(89, 64), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb.pixel(64, 39), QColor(Qt::blue).rgb());
+    QFUZZY_COMPARE_PIXELS(fb.pixel(64, 89), QColor(Qt::blue).rgb());
+
+    QFUZZY_COMPARE_PIXELS(fb.pixel(167, 39), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb.pixel(217, 39), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb.pixel(192, 64), QColor(Qt::green).rgb());
 }
 
 
@@ -1047,29 +1117,29 @@ void tst_QGL::multipleFBOInterleavedRendering()
     // As we're doing more than trivial painting, we can't just compare to
     // an image rendered with raster. Instead, we sample at well-defined
     // test-points:
-    QCOMPARE(fb1.pixel(39, 64), QColor(Qt::red).rgb());
-    QCOMPARE(fb1.pixel(89, 64), QColor(Qt::red).rgb());
-    QCOMPARE(fb1.pixel(64, 39), QColor(Qt::blue).rgb());
-    QCOMPARE(fb1.pixel(64, 89), QColor(Qt::blue).rgb());
-    QCOMPARE(fb1.pixel(167, 39), QColor(Qt::red).rgb());
-    QCOMPARE(fb1.pixel(217, 39), QColor(Qt::red).rgb());
-    QCOMPARE(fb1.pixel(192, 64), QColor(Qt::green).rgb());
-
-    QCOMPARE(fb2.pixel(39, 64), QColor(Qt::green).rgb());
-    QCOMPARE(fb2.pixel(89, 64), QColor(Qt::green).rgb());
-    QCOMPARE(fb2.pixel(64, 39), QColor(Qt::red).rgb());
-    QCOMPARE(fb2.pixel(64, 89), QColor(Qt::red).rgb());
-    QCOMPARE(fb2.pixel(167, 39), QColor(Qt::green).rgb());
-    QCOMPARE(fb2.pixel(217, 39), QColor(Qt::green).rgb());
-    QCOMPARE(fb2.pixel(192, 64), QColor(Qt::blue).rgb());
-
-    QCOMPARE(fb3.pixel(39, 64), QColor(Qt::blue).rgb());
-    QCOMPARE(fb3.pixel(89, 64), QColor(Qt::blue).rgb());
-    QCOMPARE(fb3.pixel(64, 39), QColor(Qt::green).rgb());
-    QCOMPARE(fb3.pixel(64, 89), QColor(Qt::green).rgb());
-    QCOMPARE(fb3.pixel(167, 39), QColor(Qt::blue).rgb());
-    QCOMPARE(fb3.pixel(217, 39), QColor(Qt::blue).rgb());
-    QCOMPARE(fb3.pixel(192, 64), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb1.pixel(39, 64), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb1.pixel(89, 64), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb1.pixel(64, 39), QColor(Qt::blue).rgb());
+    QFUZZY_COMPARE_PIXELS(fb1.pixel(64, 89), QColor(Qt::blue).rgb());
+    QFUZZY_COMPARE_PIXELS(fb1.pixel(167, 39), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb1.pixel(217, 39), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb1.pixel(192, 64), QColor(Qt::green).rgb());
+
+    QFUZZY_COMPARE_PIXELS(fb2.pixel(39, 64), QColor(Qt::green).rgb());
+    QFUZZY_COMPARE_PIXELS(fb2.pixel(89, 64), QColor(Qt::green).rgb());
+    QFUZZY_COMPARE_PIXELS(fb2.pixel(64, 39), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb2.pixel(64, 89), QColor(Qt::red).rgb());
+    QFUZZY_COMPARE_PIXELS(fb2.pixel(167, 39), QColor(Qt::green).rgb());
+    QFUZZY_COMPARE_PIXELS(fb2.pixel(217, 39), QColor(Qt::green).rgb());
+    QFUZZY_COMPARE_PIXELS(fb2.pixel(192, 64), QColor(Qt::blue).rgb());
+
+    QFUZZY_COMPARE_PIXELS(fb3.pixel(39, 64), QColor(Qt::blue).rgb());
+    QFUZZY_COMPARE_PIXELS(fb3.pixel(89, 64), QColor(Qt::blue).rgb());
+    QFUZZY_COMPARE_PIXELS(fb3.pixel(64, 39), QColor(Qt::green).rgb());
+    QFUZZY_COMPARE_PIXELS(fb3.pixel(64, 89), QColor(Qt::green).rgb());
+    QFUZZY_COMPARE_PIXELS(fb3.pixel(167, 39), QColor(Qt::blue).rgb());
+    QFUZZY_COMPARE_PIXELS(fb3.pixel(217, 39), QColor(Qt::blue).rgb());
+    QFUZZY_COMPARE_PIXELS(fb3.pixel(192, 64), QColor(Qt::red).rgb());
 }
 
 class FBOUseInGLWidget : public QGLWidget
@@ -1102,8 +1172,6 @@ protected:
 
 void tst_QGL::glFBOUseInGLWidget()
 {
-    if (appDefaultDepth() < 24)
-        QSKIP("This test won't work for bit depths < 24", SkipAll);
     if (!QGLFramebufferObject::hasOpenGLFramebufferObjects())
         QSKIP("QGLFramebufferObject not supported on this platform", SkipSingle);
 
@@ -1122,17 +1190,15 @@ void tst_QGL::glFBOUseInGLWidget()
     QImage widgetFB = w.grabFrameBuffer(false);
     QImage widgetReference(widgetFB.size(), widgetFB.format());
     widgetReference.fill(0xff0000ff);
-    QCOMPARE(widgetFB, widgetReference);
+    QFUZZY_COMPARE_IMAGES(widgetFB, widgetReference);
 
     QImage fboReference(w.fboImage.size(), w.fboImage.format());
     fboReference.fill(0xffff0000);
-    QCOMPARE(w.fboImage, fboReference);
+    QFUZZY_COMPARE_IMAGES(w.fboImage, fboReference);
 }
 
 void tst_QGL::glWidgetReparent()
 {
-    if (appDefaultDepth() < 24)
-        QSKIP("This test won't work for bit depths < 24", SkipAll);
     // Try it as a top-level first:
     GLWidget *widget = new GLWidget;
     widget->setGeometry(0, 0, 200, 30);
@@ -1222,7 +1288,7 @@ void tst_QGL::glWidgetRenderPixmap()
     QImage reference(fb.size(), QImage::Format_RGB32);
     reference.fill(0xffff0000);
 
-    QCOMPARE(fb, reference);
+    QFUZZY_COMPARE_IMAGES(fb, reference);
 }
 
 class ColormapExtended : public QGLColormap
@@ -1495,8 +1561,6 @@ protected:
 
 void tst_QGL::replaceClipping()
 {
-    if (appDefaultDepth() < 24)
-        QSKIP("This test won't work for bit depths < 24", SkipAll);
     ReplaceClippingGLWidget glw;
     glw.resize(300, 300);
     glw.show();
@@ -1622,8 +1686,6 @@ protected:
 
 void tst_QGL::clipTest()
 {
-    if (appDefaultDepth() < 24)
-        QSKIP("This test won't work for bit depths < 24", SkipAll);
     ClipTestGLWidget glw;
     glw.resize(220, 220);
     glw.show();