Avoid direct function template and alias types

It's somewhat ambiguous what they mean. Sometimes acting as a pointer, other
times having weird behavior. Pointer-to-function types are explicitly defined
as such, whereas uses of these tend to be as references (never null and not
changeable).

alc/effects/modulator.cpp

@@ -42,29 +42,22 @@ namespace {
 #define WAVEFORM_FRACONE   (1<<WAVEFORM_FRACBITS)
 #define WAVEFORM_FRACMASK  (WAVEFORM_FRACONE-1)
 
-inline ALfloat Sin(ALuint index)
+inline float Sin(ALuint index)
 {
-    return std::sin(static_cast<ALfloat>(index) *
-        (al::MathDefs<float>::Tau() / ALfloat{WAVEFORM_FRACONE}));
+    constexpr float scale{al::MathDefs<float>::Tau() / WAVEFORM_FRACONE};
+    return std::sin(static_cast<float>(index) * scale);
 }
 
-inline ALfloat Saw(ALuint index)
-{
-    return static_cast<ALfloat>(index)*(2.0f/WAVEFORM_FRACONE) - 1.0f;
-}
+inline float Saw(ALuint index)
+{ return static_cast<float>(index)*(2.0f/WAVEFORM_FRACONE) - 1.0f; }
 
-inline ALfloat Square(ALuint index)
-{
-    return static_cast<ALfloat>(((index>>(WAVEFORM_FRACBITS-2))&2) - 1);
-}
+inline float Square(ALuint index)
+{ return static_cast<float>(((index>>(WAVEFORM_FRACBITS-2))&2) - 1); }
 
-inline ALfloat One(ALuint)
-{
-    return 1.0f;
-}
+inline float One(ALuint) { return 1.0f; }
 
-template<ALfloat func(ALuint)>
-void Modulate(ALfloat *RESTRICT dst, ALuint index, const ALuint step, size_t todo)
+template<float (&func)(ALuint)>
+void Modulate(float *RESTRICT dst, ALuint index, const ALuint step, size_t todo)
 {
     for(size_t i{0u};i < todo;i++)
     {
@@ -76,7 +69,7 @@ void Modulate(ALfloat *RESTRICT dst, ALuint index, const ALuint step, size_t tod
 
 
 struct ModulatorState final : public EffectState {
-    void (*mGetSamples)(ALfloat*RESTRICT, ALuint, const ALuint, size_t){};
+    void (*mGetSamples)(float*RESTRICT, ALuint, const ALuint, size_t){};
 
     ALuint mIndex{0};
     ALuint mStep{1};

alc/effects/vmorpher.cpp

@@ -44,29 +44,22 @@ namespace {
 #define WAVEFORM_FRACONE   (1<<WAVEFORM_FRACBITS)
 #define WAVEFORM_FRACMASK  (WAVEFORM_FRACONE-1)
 
-inline ALfloat Sin(ALuint index)
+inline float Sin(ALuint index)
 {
-    constexpr ALfloat scale{al::MathDefs<float>::Tau() / ALfloat{WAVEFORM_FRACONE}};
-    return std::sin(static_cast<ALfloat>(index) * scale)*0.5f + 0.5f;
+    constexpr float scale{al::MathDefs<float>::Tau() / WAVEFORM_FRACONE};
+    return std::sin(static_cast<float>(index) * scale)*0.5f + 0.5f;
 }
 
-inline ALfloat Saw(ALuint index)
-{
-    return static_cast<ALfloat>(index) / ALfloat{WAVEFORM_FRACONE};
-}
+inline float Saw(ALuint index)
+{ return static_cast<float>(index) / float{WAVEFORM_FRACONE}; }
 
-inline ALfloat Triangle(ALuint index)
-{
-    return std::fabs(static_cast<ALfloat>(index)*(2.0f/WAVEFORM_FRACONE) - 1.0f);
-}
+inline float Triangle(ALuint index)
+{ return std::fabs(static_cast<float>(index)*(2.0f/WAVEFORM_FRACONE) - 1.0f); }
 
-inline ALfloat Half(ALuint)
-{
-    return 0.5f;
-}
+inline float Half(ALuint) { return 0.5f; }
 
-template<ALfloat func(ALuint)>
-void Oscillate(ALfloat *RESTRICT dst, ALuint index, const ALuint step, size_t todo)
+template<float (&func)(ALuint)>
+void Oscillate(float *RESTRICT dst, ALuint index, const ALuint step, size_t todo)
 {
     for(size_t i{0u};i < todo;i++)
     {
@@ -133,7 +126,7 @@ struct VmorpherState final : public EffectState {
         ALfloat TargetGains[MAX_OUTPUT_CHANNELS]{};
     } mChans[MAX_AMBI_CHANNELS];
 
-    void (*mGetSamples)(ALfloat* RESTRICT, ALuint, const ALuint, size_t){};
+    void (*mGetSamples)(float*RESTRICT, ALuint, const ALuint, size_t){};
 
     ALuint mIndex{0};
     ALuint mStep{1};

alc/mixer/mixer_c.cpp

@@ -62,8 +62,8 @@ inline float do_fastbsinc(const InterpState &istate, const float *RESTRICT vals,
     return r;
 }
 
-using SamplerT = float(const InterpState&, const float*RESTRICT, const ALuint);
-template<SamplerT &Sampler>
+using SamplerT = float(&)(const InterpState&, const float*RESTRICT, const ALuint);
+template<SamplerT Sampler>
 const float *DoResample(const InterpState *state, const float *RESTRICT src, ALuint frac,
     ALuint increment, const al::span<float> dst)
 {