diff options
Diffstat (limited to 'Alc/effects/reverb.c')
| -rw-r--r-- | Alc/effects/reverb.c | 55 |
1 files changed, 33 insertions, 22 deletions
diff --git a/Alc/effects/reverb.c b/Alc/effects/reverb.c index 864163be..9fba183a 100644 --- a/Alc/effects/reverb.c +++ b/Alc/effects/reverb.c @@ -82,14 +82,21 @@ static const aluMatrixf A2B = {{ static const ALfloat FadeStep = 1.0f / FADE_SAMPLES; /* The all-pass and delay lines have a variable length dependent on the - * effect's density parameter. The resulting density multiplier is: + * effect's density parameter, which helps alter the perceived environment + * size. The size-to-density conversion is a cubed scale: * - * multiplier = 1 + (density * LINE_MULTIPLIER) + * density = min(1.0, pow(size, 3.0) / DENSITY_SCALE); * - * Thus the line multiplier below will result in a maximum density multiplier - * of 10. + * The line lengths scale linearly with room size, so the inverse density + * conversion is needed, taking the cube root of the re-scaled density to + * calculate the line length multiplier: + * + * length_mult = max(5.0, cbrtf(density*DENSITY_SCALE)); + * + * The density scale below will result in a max line multiplier of 50, for an + * effective size range of 5m to 50m. */ -static const ALfloat LINE_MULTIPLIER = 9.0f; +static const ALfloat DENSITY_SCALE = 125000.0f; /* All delay line lengths are specified in seconds. * @@ -133,12 +140,11 @@ static const ALfloat LINE_MULTIPLIER = 9.0f; * T_i = R_i - r_0 * = (2^(i / (2 N - 1)) - 1) r_d * - * Assuming an average of 5m (up to 50m with the density multiplier), we get - * the following taps: + * Assuming an average of 1m, we get the following taps: */ static const ALfloat EARLY_TAP_LENGTHS[NUM_LINES] = { - 0.000000e+0f, 1.010676e-3f, 2.126553e-3f, 3.358580e-3f + 0.0000000e+0f, 2.0213520e-4f, 4.2531060e-4f, 6.7171600e-4f }; /* The early all-pass filter lengths are based on the early tap lengths: @@ -149,7 +155,7 @@ static const ALfloat EARLY_TAP_LENGTHS[NUM_LINES] = */ static const ALfloat EARLY_ALLPASS_LENGTHS[NUM_LINES] = { - 4.854840e-4f, 5.360178e-4f, 5.918117e-4f, 6.534130e-4f + 9.7096800e-5f, 1.0720356e-4f, 1.1836234e-4f, 1.3068260e-4f }; /* The early delay lines are used to transform the primary reflections into @@ -172,11 +178,11 @@ static const ALfloat EARLY_ALLPASS_LENGTHS[NUM_LINES] = * = 2 (r_a - T_(N-i-1) - r_0) * = 2 r_a (1 - (2 / 3) 2^((N - i - 1) / (2 N - 1))) * - * Using an average dimension of 5m, we get: + * Using an average dimension of 1m, we get: */ static const ALfloat EARLY_LINE_LENGTHS[NUM_LINES] = { - 2.992520e-3f, 5.456575e-3f, 7.688329e-3f, 9.709681e-3f + 5.9850400e-4f, 1.0913150e-3f, 1.5376658e-3f, 1.9419362e-3f }; /* The late all-pass filter lengths are based on the late line lengths: @@ -185,7 +191,7 @@ static const ALfloat EARLY_LINE_LENGTHS[NUM_LINES] = */ static const ALfloat LATE_ALLPASS_LENGTHS[NUM_LINES] = { - 8.091400e-4f, 1.019453e-3f, 1.407968e-3f, 1.618280e-3f + 1.6182800e-4f, 2.0389060e-4f, 2.8159360e-4f, 3.2365600e-4f }; /* The late lines are used to approximate the decaying cycle of recursive @@ -201,19 +207,19 @@ static const ALfloat LATE_ALLPASS_LENGTHS[NUM_LINES] = * L_i = 2 r_a - L_(i-N/2) * = 2 r_a - 2^((i - N / 2) / (N - 1)) r_d * - * For our 5m average room, we get: + * For our 1m average room, we get: */ static const ALfloat LATE_LINE_LENGTHS[NUM_LINES] = { - 9.709681e-3f, 1.223343e-2f, 1.689561e-2f, 1.941936e-2f + 1.9419362e-3f, 2.4466860e-3f, 3.3791220e-3f, 3.8838720e-3f }; /* This coefficient is used to define the delay scale from the sinus, according * to the modulation depth property. This value must be below the shortest late - * line length (0.0097), otherwise with certain parameters (high mod time, low - * density) the downswing can sample before the input. + * line length, otherwise with certain parameters (high mod time, low density) + * the downswing can sample before the input. */ -static const ALfloat MODULATION_DEPTH_COEFF = 0.0032f; +static const ALfloat MODULATION_DEPTH_COEFF = 0.001f; typedef struct DelayLineI { @@ -464,6 +470,11 @@ static ALvoid ALreverbState_Destruct(ALreverbState *State) * Device Update * **************************************/ +static inline ALfloat CalcDelayLengthMult(ALfloat density) +{ + return maxf(5.0f, cbrtf(density*DENSITY_SCALE)); +} + /* Given the allocated sample buffer, this function updates each delay line * offset. */ @@ -514,7 +525,7 @@ static ALboolean AllocLines(const ALuint frequency, ALreverbState *State) /* Multiplier for the maximum density value, i.e. density=1, which is * actually the least density... */ - multiplier = 1.0f + AL_EAXREVERB_MAX_DENSITY*LINE_MULTIPLIER; + multiplier = CalcDelayLengthMult(AL_EAXREVERB_MAX_DENSITY); /* The main delay length includes the maximum early reflection delay, the * largest early tap width, the maximum late reverb delay, and the @@ -588,7 +599,7 @@ static ALboolean ALreverbState_deviceUpdate(ALreverbState *State, ALCdevice *Dev if(!AllocLines(frequency, State)) return AL_FALSE; - multiplier = 1.0f + AL_EAXREVERB_MAX_DENSITY*LINE_MULTIPLIER; + multiplier = CalcDelayLengthMult(AL_EAXREVERB_MAX_DENSITY); /* The late feed taps are set a fixed position past the latest delay tap. */ State->LateFeedTap = fastf2i((AL_EAXREVERB_MAX_REFLECTIONS_DELAY + @@ -993,7 +1004,7 @@ static ALvoid UpdateDelayLine(const ALfloat earlyDelay, const ALfloat lateDelay, ALfloat multiplier, length; ALuint i; - multiplier = 1.0f + density*LINE_MULTIPLIER; + multiplier = CalcDelayLengthMult(density); /* Early reflection taps are decorrelated by means of an average room * reflection approximation described above the definition of the taps. @@ -1024,7 +1035,7 @@ static ALvoid UpdateEarlyLines(const ALfloat density, const ALfloat decayTime, c ALfloat multiplier, length; ALsizei i; - multiplier = 1.0f + density*LINE_MULTIPLIER; + multiplier = CalcDelayLengthMult(density); for(i = 0;i < NUM_LINES;i++) { @@ -1059,7 +1070,7 @@ static ALvoid UpdateLateLines(const ALfloat density, const ALfloat diffusion, co * The average length of the delay lines is used to calculate the * attenuation coefficient. */ - multiplier = 1.0f + density*LINE_MULTIPLIER; + multiplier = CalcDelayLengthMult(density); length = (LATE_LINE_LENGTHS[0] + LATE_LINE_LENGTHS[1] + LATE_LINE_LENGTHS[2] + LATE_LINE_LENGTHS[3]) / 4.0f * multiplier; /* Include the echo transformation (see below). */ |