QSGDistanceFieldUtil: Remove a layer of indirection

These mysterious setters appear to be unused (and always were, as far
as I can see). How useful they are is not entirely clear (as opposed to
a patch to the source for instance, and as it's private API anyway, you'd be
touching internals to use this. Additionally, removing the indirection makes
the code a bit cleaner and more self-contained in my opinion.

This removal leaves the value of QSGDistanceFieldGlyphCacheManager in
some question to me, given that it's basically a glorified wrapper
around QHash.

Change-Id: I6d18eb40d8cd00ebe389b4ed53448f3401962ae6
Reviewed-by: Gunnar Sletta <gunnar@crimson.no>
Reviewed-by: Yoann Lopes <yoann.lopes@qt.io>

1 files changed, 30 insertions, 11 deletions

diff --git a/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp b/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp
index fc66f2f2cc..153f0a45c5 100644
--- a/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp
+++ b/src/quick/scenegraph/qsgdistancefieldglyphnode_p.cpp
@@ -58,7 +58,7 @@ public:
 protected:
     void initialize() override;
 
-    void updateAlphaRange(ThresholdFunc thresholdFunc, AntialiasingSpreadFunc spreadFunc);
+    void updateAlphaRange();
     void updateColor(const QVector4D &c);
     void updateTextureScale(const QVector2D &ts);
 
@@ -98,7 +98,31 @@ QSGDistanceFieldTextMaterialShader::QSGDistanceFieldTextMaterialShader()
     setShaderSourceFile(QOpenGLShader::Fragment, QStringLiteral(":/qt-project.org/scenegraph/shaders/distancefieldtext.frag"));
 }
 
-void QSGDistanceFieldTextMaterialShader::updateAlphaRange(ThresholdFunc thresholdFunc, AntialiasingSpreadFunc spreadFunc)
+static float qt_sg_envFloat(const char *name, float defaultValue)
+{
+    if (Q_LIKELY(!qEnvironmentVariableIsSet(name)))
+        return defaultValue;
+    bool ok = false;
+    const float value = qgetenv(name).toFloat(&ok);
+    return ok ? value : defaultValue;
+}
+
+static float thresholdFunc(float glyphScale)
+{
+    static const float base = qt_sg_envFloat("QT_DF_BASE", 0.5f);
+    static const float baseDev = qt_sg_envFloat("QT_DF_BASEDEVIATION", 0.065f);
+    static const float devScaleMin = qt_sg_envFloat("QT_DF_SCALEFORMAXDEV", 0.15f);
+    static const float devScaleMax = qt_sg_envFloat("QT_DF_SCALEFORNODEV", 0.3f);
+    return base - ((qBound(devScaleMin, glyphScale, devScaleMax) - devScaleMin) / (devScaleMax - devScaleMin) * -baseDev + baseDev);
+}
+
+static float spreadFunc(float glyphScale)
+{
+    static const float range = qt_sg_envFloat("QT_DF_RANGE", 0.06f);
+    return range / glyphScale;
+}
+
+void QSGDistanceFieldTextMaterialShader::updateAlphaRange()
 {
     float combinedScale = m_fontScale * m_matrixScale;
     float base = thresholdFunc(combinedScale);
@@ -169,8 +193,7 @@ void QSGDistanceFieldTextMaterialShader::updateState(const RenderState &state, Q
         updateRange = true;
     }
     if (updateRange) {
-        updateAlphaRange(material->glyphCache()->manager()->thresholdFunc(),
-                         material->glyphCache()->manager()->antialiasingSpreadFunc());
+        updateAlphaRange();
     }
 
     Q_ASSERT(material->glyphCache());
@@ -334,7 +357,7 @@ public:
 protected:
     void initialize() override;
 
-    void updateOutlineAlphaRange(ThresholdFunc thresholdFunc, AntialiasingSpreadFunc spreadFunc, int dfRadius);
+    void updateOutlineAlphaRange(int dfRadius);
 
     int m_outlineAlphaMax0_id;
     int m_outlineAlphaMax1_id;
@@ -355,9 +378,7 @@ void DistanceFieldOutlineTextMaterialShader::initialize()
     m_outlineAlphaMax1_id = program()->uniformLocation("outlineAlphaMax1");
 }
 
-void DistanceFieldOutlineTextMaterialShader::updateOutlineAlphaRange(ThresholdFunc thresholdFunc,
-                                                                     AntialiasingSpreadFunc spreadFunc,
-                                                                     int dfRadius)
+void DistanceFieldOutlineTextMaterialShader::updateOutlineAlphaRange(int dfRadius)
 {
     float combinedScale = m_fontScale * m_matrixScale;
     float base = thresholdFunc(combinedScale);
@@ -381,9 +402,7 @@ void DistanceFieldOutlineTextMaterialShader::updateState(const RenderState &stat
     if (oldMaterial == 0
             || material->fontScale() != oldMaterial->fontScale()
             || state.isMatrixDirty())
-        updateOutlineAlphaRange(material->glyphCache()->manager()->thresholdFunc(),
-                                material->glyphCache()->manager()->antialiasingSpreadFunc(),
-                                material->glyphCache()->distanceFieldRadius());
+        updateOutlineAlphaRange(material->glyphCache()->distanceFieldRadius());
 }