Added MathConstants::halfPi to improve readability

examples/audio plugin host/Source/GraphEditorPanel.cpp

@@ -509,7 +509,7 @@ struct GraphEditorPanel::ConnectorComponent   : public Component,
                            arrowL, 0.0f);
 
         arrow.applyTransform (AffineTransform()
-                                .rotated (MathConstants<float>::pi * 0.5f - (float) atan2 (p2.x - p1.x, p2.y - p1.y))
+                                .rotated (MathConstants<float>::halfPi - (float) atan2 (p2.x - p1.x, p2.y - p1.y))
                                 .translated ((p1 + p2) * 0.5f));
 
         linePath.addPath (arrow);

extras/Projucer/Source/Utility/UI/jucer_ProjucerLookAndFeel.cpp

@@ -461,7 +461,7 @@ Path ProjucerLookAndFeel::getArrowPath (Rectangle<float> arrowZone, const int di
     if (filled)
         path.closeSubPath();
 
-    path.applyTransform (AffineTransform::rotation (direction * (MathConstants<float>::pi / 2.0f),
+    path.applyTransform (AffineTransform::rotation (direction * MathConstants<float>::halfPi,
                                                     arrowZone.getCentreX(), arrowZone.getCentreY()));
 
     return path;

modules/juce_core/maths/juce_MathsFunctions.h

@@ -326,7 +326,6 @@ inline int64 abs64 (const int64 n) noexcept
 #endif
 
 //==============================================================================
-
 #if JUCE_HAS_CONSTEXPR
 
 /** Commonly used mathematical constants */
@@ -339,6 +338,9 @@ struct MathConstants
     /** A predefined value for 2 * Pi */
     static constexpr FloatType twoPi = static_cast<FloatType> (2 * 3.141592653589793238L);
 
+    /** A predefined value for Pi / 2 */
+    static constexpr FloatType halfPi = static_cast<FloatType> (3.141592653589793238L / 2);
+
     /** A predfined value for Euler's number */
     static constexpr FloatType euler = static_cast<FloatType> (2.71828182845904523536L);
 };
@@ -355,6 +357,9 @@ struct MathConstants
     /** A predefined value for 2 * Pi */
     static const FloatType twoPi;
 
+    /** A predefined value for Pi / 2 */
+    static const FloatType halfPi;
+
     /** A predfined value for Euler's number */
     static const FloatType euler;
 };
@@ -365,6 +370,9 @@ const FloatType MathConstants<FloatType>::pi = static_cast<FloatType> (3.1415926
 template <typename FloatType>
 const FloatType MathConstants<FloatType>::twoPi = static_cast<FloatType> (2 * 3.141592653589793238L);
 
+template <typename FloatType>
+const FloatType MathConstants<FloatType>::halfPi = static_cast<FloatType> (3.141592653589793238L / 2);
+
 template <typename FloatType>
 const FloatType MathConstants<FloatType>::euler = static_cast<FloatType> (2.71828182845904523536L);
 

modules/juce_dsp/filter_design/juce_FilterDesign.cpp

@@ -407,6 +407,7 @@ Array<IIR::Coefficients<FloatType>>
 
     auto omegap = std::tan (MathConstants<double>::pi * fp);
     auto omegas = std::tan (MathConstants<double>::pi * fs);
+    constexpr auto halfPi = MathConstants<double>::halfPi;
 
     auto k = omegap / omegas;
     auto k1 = epsp / epss;
@@ -446,35 +447,35 @@ Array<IIR::Coefficients<FloatType>>
         for (int i = 1; i <= L; ++i)
         {
             auto ui = (2 * i - 1.0) / (double) N;
-            pa.add (omegap * std::pow (epsp, -1.0 / (double) N) * j * exp (ui * 0.5 * MathConstants<double>::pi * j));
+            pa.add (omegap * std::pow (epsp, -1.0 / (double) N) * j * exp (ui * halfPi * j));
         }
     }
     else if (type == 1)
     {
-        auto v0 = std::asinh (1.0 / epsp) / (0.5 * N * MathConstants<double>::pi);
+        auto v0 = std::asinh (1.0 / epsp) / (N * halfPi);
 
         if (r == 1)
-            pa.add (-omegap * std::sinh (v0 * 0.5 * MathConstants<double>::pi));
+            pa.add (-omegap * std::sinh (v0 * halfPi));
 
         for (int i = 1; i <= L; ++i)
         {
             auto ui = (2 * i - 1.0) / (double) N;
-            pa.add (omegap * j * std::cos ((ui - j * v0) * 0.5 * MathConstants<double>::pi));
+            pa.add (omegap * j * std::cos ((ui - j * v0) * halfPi));
         }
     }
     else if (type == 2)
     {
-        auto v0 = std::asinh (epss) / (N * 0.5 * MathConstants<double>::pi);
+        auto v0 = std::asinh (epss) / (N * halfPi);
 
         if (r == 1)
-            pa.add(-1.0 / (k / omegap * std::sinh (v0 * 0.5 * MathConstants<double>::pi)));
+            pa.add(-1.0 / (k / omegap * std::sinh (v0 * halfPi)));
 
         for (int i = 1; i <= L; ++i)
         {
             auto ui = (2 * i - 1.0) / (double) N;
 
-            pa.add (1.0 / (k / omegap * j * std::cos ((ui - j * v0) * 0.5 * MathConstants<double>::pi)));
-            za.add (1.0 / (k / omegap * j * std::cos (ui * 0.5 * MathConstants<double>::pi)));
+            pa.add (1.0 / (k / omegap * j * std::cos ((ui - j * v0) * halfPi)));
+            za.add (1.0 / (k / omegap * j * std::cos (ui * halfPi)));
         }
     }
     else
@@ -591,7 +592,7 @@ typename FilterDesign<FloatType>::IIRPolyphaseAllpassStructure
         while (std::abs (delta) > 1e-100)
         {
             delta = std::pow (-1, m) * std::pow (q, m * m)
-                     * std::cos (2 * m * MathConstants<double>::pi * i / (double) n);
+                     * std::cos (m * MathConstants<double>::twoPi * i / (double) n);
             den += delta;
             ++m;
         }

modules/juce_dsp/maths/juce_SpecialFunctions.cpp

@@ -53,7 +53,7 @@ void SpecialFunctions::ellipticIntegralK (double k, double& K, double& Kp) noexc
 {
     constexpr int M = 4;
 
-    K = MathConstants<double>::pi * 0.5;
+    K = MathConstants<double>::halfPi;
     auto lastK = k;
 
     for (int i = 0; i < M; ++i)
@@ -62,7 +62,7 @@ void SpecialFunctions::ellipticIntegralK (double k, double& K, double& Kp) noexc
         K *= 1 + lastK;
     }
 
-    Kp = MathConstants<double>::pi * 0.5;
+    Kp = MathConstants<double>::halfPi;
     auto last = std::sqrt (1 - k * k);
 
     for (int i = 0; i < M; ++i)
@@ -86,7 +86,8 @@ Complex<double> SpecialFunctions::cde (Complex<double> u, double k) noexcept
         *++kei = next;
     }
 
-    std::complex<double> last = std::cos (0.5 * u * MathConstants<double>::pi);
+    // NB: the spurious cast to double here is a workaround for a very odd link-time failure
+    std::complex<double> last = std::cos (u * (double) MathConstants<double>::halfPi);
 
     for (int i = M - 1; i >= 0; --i)
         last = (1.0 + ke[i + 1]) / (1.0 / last + ke[i + 1] * last);
@@ -108,7 +109,8 @@ Complex<double> SpecialFunctions::sne (Complex<double> u, double k) noexcept
         *++kei = next;
     }
 
-    std::complex<double> last = std::sin (0.5 * u * MathConstants<double>::pi);
+    // NB: the spurious cast to double here is a workaround for a very odd link-time failure
+    std::complex<double> last = std::sin (u * (double) MathConstants<double>::halfPi);
 
     for (int i = M - 1; i >= 0; --i)
         last = (1.0 + ke[i + 1]) / (1.0 / last + ke[i + 1] * last);

modules/juce_dsp/processors/juce_LadderFilter.cpp

@@ -155,7 +155,7 @@ void LadderFilter<Type>::setSampleRate (Type newValue) noexcept
     jassert (newValue > Type (0));
     cutoffFreqScaler = Type (-2.0 * juce::MathConstants<double>::pi) / newValue;
 
-    static constexpr Type smootherRampTimeSec (0.05);
+    static constexpr Type smootherRampTimeSec = Type (0.05);
     cutoffTransformSmoother.reset (newValue, smootherRampTimeSec);
     scaledResonanceSmoother.reset (newValue, smootherRampTimeSec);
 

modules/juce_graphics/geometry/juce_Path.cpp

@@ -784,7 +784,7 @@ void Path::addBubble (Rectangle<float> bodyArea,
     }
 
     lineTo (bodyArea.getRight() - cornerSizeW, bodyArea.getY());
-    addArc (bodyArea.getRight() - cornerSizeW2, bodyArea.getY(), cornerSizeW2, cornerSizeH2, 0, MathConstants<float>::pi * 0.5f);
+    addArc (bodyArea.getRight() - cornerSizeW2, bodyArea.getY(), cornerSizeW2, cornerSizeH2, 0, MathConstants<float>::halfPi);
 
     if (Rectangle<float> (bodyArea.getRight(), targetLimit.getY(),
                           maximumArea.getRight() - bodyArea.getRight(), targetLimit.getHeight()).contains (arrowTip))
@@ -795,7 +795,7 @@ void Path::addBubble (Rectangle<float> bodyArea,
     }
 
     lineTo (bodyArea.getRight(), bodyArea.getBottom() - cornerSizeH);
-    addArc (bodyArea.getRight() - cornerSizeW2, bodyArea.getBottom() - cornerSizeH2, cornerSizeW2, cornerSizeH2, MathConstants<float>::pi * 0.5f, MathConstants<float>::pi);
+    addArc (bodyArea.getRight() - cornerSizeW2, bodyArea.getBottom() - cornerSizeH2, cornerSizeW2, cornerSizeH2, MathConstants<float>::halfPi, MathConstants<float>::pi);
 
     if (Rectangle<float> (targetLimit.getX(), bodyArea.getBottom(),
                           targetLimit.getWidth(), maximumArea.getBottom() - bodyArea.getBottom()).contains (arrowTip))

modules/juce_gui_basics/drawables/juce_SVGParser.cpp

@@ -1669,7 +1669,7 @@ private:
         if (uy < 0)
             startAngle = -startAngle;
 
-        startAngle += MathConstants<double>::pi * 0.5;
+        startAngle += MathConstants<double>::halfPi;
 
         deltaAngle = acos (jlimit (-1.0, 1.0, ((ux * vx) + (uy * vy))
                                                 / (length * juce_hypot (vx, vy))));

modules/juce_gui_basics/lookandfeel/juce_LookAndFeel_V2.cpp

@@ -2024,10 +2024,10 @@ void LookAndFeel_V2::drawGroupComponentOutline (Graphics& g, int width, int heig
     p.startNewSubPath (x + textX + textW, y);
     p.lineTo (x + w - cs, y);
 
-    p.addArc (x + w - cs2, y, cs2, cs2, 0, MathConstants<float>::pi * 0.5f);
+    p.addArc (x + w - cs2, y, cs2, cs2, 0, MathConstants<float>::halfPi);
     p.lineTo (x + w, y + h - cs);
 
-    p.addArc (x + w - cs2, y + h - cs2, cs2, cs2, MathConstants<float>::pi * 0.5f, MathConstants<float>::pi);
+    p.addArc (x + w - cs2, y + h - cs2, cs2, cs2, MathConstants<float>::halfPi, MathConstants<float>::pi);
     p.lineTo (x + cs, y + h);
 
     p.addArc (x, y + h - cs2, cs2, cs2, MathConstants<float>::pi, MathConstants<float>::pi * 1.5f);
@@ -2948,7 +2948,7 @@ void LookAndFeel_V2::drawGlassPointer (Graphics& g,
     p.lineTo (x, y + diameter * 0.6f);
     p.closeSubPath();
 
-    p.applyTransform (AffineTransform::rotation (direction * (MathConstants<float>::pi * 0.5f), x + diameter * 0.5f, y + diameter * 0.5f));
+    p.applyTransform (AffineTransform::rotation (direction * MathConstants<float>::halfPi, x + diameter * 0.5f, y + diameter * 0.5f));
 
     {
         ColourGradient cg (Colours::white.overlaidWith (colour.withMultipliedAlpha (0.3f)), 0, y,

modules/juce_gui_basics/lookandfeel/juce_LookAndFeel_V4.cpp

@@ -1071,8 +1071,8 @@ void LookAndFeel_V4::drawRotarySlider (Graphics& g, int x, int y, int width, int
     }
 
     auto thumbWidth = lineW * 2.0f;
-    Point<float> thumbPoint (bounds.getCentreX() + arcRadius * std::cos (toAngle - MathConstants<float>::pi * 0.5f),
-                             bounds.getCentreY() + arcRadius * std::sin (toAngle - MathConstants<float>::pi * 0.5f));
+    Point<float> thumbPoint (bounds.getCentreX() + arcRadius * std::cos (toAngle - MathConstants<float>::halfPi),
+                             bounds.getCentreY() + arcRadius * std::sin (toAngle - MathConstants<float>::halfPi));
 
     g.setColour (slider.findColour (Slider::thumbColourId));
     g.fillEllipse (Rectangle<float> (thumbWidth, thumbWidth).withCentre (thumbPoint));
@@ -1089,8 +1089,8 @@ void LookAndFeel_V4::drawPointer (Graphics& g, const float x, const float y, con
     p.lineTo (x, y + diameter * 0.6f);
     p.closeSubPath();
 
-    p.applyTransform (AffineTransform::rotation (direction * (MathConstants<float>::pi * 0.5f), x + diameter * 0.5f, y + diameter * 0.5f));
-
+    p.applyTransform (AffineTransform::rotation (direction * MathConstants<float>::halfPi,
+                                                 x + diameter * 0.5f, y + diameter * 0.5f));
     g.setColour (colour);
     g.fillPath (p);
 }