Initial community commit

Src/external_dependencies/openmpt-trunk/soundlib/Mixer.h

@@ -0,0 +1,63 @@
+/*
+ * Mixer.h
+ * -------
+ * Purpose: Basic mixer constants
+ * Notes  : (currently none)
+ * Authors: OpenMPT Devs
+ * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
+ */
+
+
+#pragma once
+
+#include "openmpt/all/BuildSettings.hpp"
+
+#include "openmpt/soundbase/MixSample.hpp"
+
+OPENMPT_NAMESPACE_BEGIN
+
+#define MPT_INTMIXER
+
+#ifdef MPT_INTMIXER
+using mixsample_t = MixSampleIntTraits::sample_type;
+enum { MIXING_FILTER_PRECISION = MixSampleIntTraits::filter_precision_bits };  // Fixed point resonant filter bits
+#else
+using mixsample_t = MixSampleFloat;
+#endif
+enum { MIXING_ATTENUATION = MixSampleIntTraits::mix_headroom_bits };
+enum { MIXING_FRACTIONAL_BITS = MixSampleIntTraits::mix_fractional_bits };
+
+inline constexpr float MIXING_SCALEF = MixSampleIntTraits::mix_scale<float>;
+
+#ifdef MPT_INTMIXER
+static_assert(sizeof(mixsample_t) == 4);
+static_assert(MIXING_FILTER_PRECISION == 24);
+static_assert(MIXING_ATTENUATION == 4);
+static_assert(MIXING_FRACTIONAL_BITS == 27);
+static_assert(MixSampleIntTraits::mix_clip_max == int32(0x7FFFFFF));
+static_assert(MixSampleIntTraits::mix_clip_min == (0 - int32(0x7FFFFFF)));
+static_assert(MIXING_SCALEF == 134217728.0f);
+#else
+static_assert(sizeof(mixsample_t) == 4);
+#endif
+
+#define MIXBUFFERSIZE 512
+#define NUMMIXINPUTBUFFERS 4
+
+#define VOLUMERAMPPRECISION 12	// Fractional bits in volume ramp variables
+
+// The absolute maximum number of sampling points any interpolation algorithm is going to look at in any direction from the current sampling point
+// Currently, the maximum is 4 sampling points forwards and 3 sampling points backwards (Polyphase / FIR algorithms).
+// Hence, this value must be at least 4.
+inline constexpr uint8 InterpolationMaxLookahead = 4;
+// While we could directly use the previous value in various places such as the interpolation wrap-around handling at loop points,
+// choosing a higher value (e.g. 16) will reduce CPU usage when using many extremely short (length < 16) samples.
+inline constexpr uint8 InterpolationLookaheadBufferSize = 16;
+
+static_assert(InterpolationLookaheadBufferSize >= InterpolationMaxLookahead);
+
+// Maximum size of a sampling point of a sample, in bytes.
+// The biggest sampling point size is currently 16-bit stereo = 2 * 2 bytes.
+inline constexpr uint8 MaxSamplingPointSize = 4;
+
+OPENMPT_NAMESPACE_END