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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
commit | 6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch) | |
tree | a68f146d7fa01f0134297619fbe7e33db084e0aa /testing/web-platform/tests/webaudio/resources/panner-formulas.js | |
parent | Initial commit. (diff) | |
download | thunderbird-upstream.tar.xz thunderbird-upstream.zip |
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'testing/web-platform/tests/webaudio/resources/panner-formulas.js')
-rw-r--r-- | testing/web-platform/tests/webaudio/resources/panner-formulas.js | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/testing/web-platform/tests/webaudio/resources/panner-formulas.js b/testing/web-platform/tests/webaudio/resources/panner-formulas.js new file mode 100644 index 0000000000..ae6f516668 --- /dev/null +++ b/testing/web-platform/tests/webaudio/resources/panner-formulas.js @@ -0,0 +1,190 @@ +// For the record, these distance formulas were taken from the OpenAL +// spec +// (http://connect.creativelabs.com/openal/Documentation/OpenAL%201.1%20Specification.pdf), +// not the code. The Web Audio spec follows the OpenAL formulas. + +function linearDistance(panner, x, y, z) { + let distance = Math.sqrt(x * x + y * y + z * z); + let dref = Math.min(panner.refDistance, panner.maxDistance); + let dmax = Math.max(panner.refDistance, panner.maxDistance); + distance = Math.max(Math.min(distance, dmax), dref); + let rolloff = Math.max(Math.min(panner.rolloffFactor, 1), 0); + if (dref === dmax) + return 1 - rolloff; + + let gain = (1 - rolloff * (distance - dref) / (dmax - dref)); + + return gain; +} + +function inverseDistance(panner, x, y, z) { + let distance = Math.sqrt(x * x + y * y + z * z); + distance = Math.max(distance, panner.refDistance); + let rolloff = panner.rolloffFactor; + let gain = panner.refDistance / + (panner.refDistance + + rolloff * (Math.max(distance, panner.refDistance) - panner.refDistance)); + + return gain; +} + +function exponentialDistance(panner, x, y, z) { + let distance = Math.sqrt(x * x + y * y + z * z); + distance = Math.max(distance, panner.refDistance); + let rolloff = panner.rolloffFactor; + let gain = Math.pow(distance / panner.refDistance, -rolloff); + + return gain; +} + +// Simple implementations of 3D vectors implemented as a 3-element array. + +// x - y +function vec3Sub(x, y) { + let z = new Float32Array(3); + z[0] = x[0] - y[0]; + z[1] = x[1] - y[1]; + z[2] = x[2] - y[2]; + + return z; +} + +// x/|x| +function vec3Normalize(x) { + let mag = Math.hypot(...x); + return x.map(function(c) { + return c / mag; + }); +} + +// x == 0? +function vec3IsZero(x) { + return x[0] === 0 && x[1] === 0 && x[2] === 0; +} + +// Vector cross product +function vec3Cross(u, v) { + let cross = new Float32Array(3); + cross[0] = u[1] * v[2] - u[2] * v[1]; + cross[1] = u[2] * v[0] - u[0] * v[2]; + cross[2] = u[0] * v[1] - u[1] * v[0]; + return cross; +} + +// Dot product +function vec3Dot(x, y) { + return x[0] * y[0] + x[1] * y[1] + x[2] * y[2]; +} + +// a*x, for scalar a +function vec3Scale(a, x) { + return x.map(function(c) { + return a * c; + }); +} + +function calculateAzimuth(source, listener, listenerForward, listenerUp) { + let sourceListener = vec3Sub(source, listener); + + if (vec3IsZero(sourceListener)) + return 0; + + sourceListener = vec3Normalize(sourceListener); + + let listenerRight = vec3Normalize(vec3Cross(listenerForward, listenerUp)); + let listenerForwardNorm = vec3Normalize(listenerForward); + + let up = vec3Cross(listenerRight, listenerForwardNorm); + let upProjection = vec3Dot(sourceListener, up); + + let projectedSource = + vec3Normalize(vec3Sub(sourceListener, vec3Scale(upProjection, up))); + + let azimuth = + 180 / Math.PI * Math.acos(vec3Dot(projectedSource, listenerRight)); + + // Source in front or behind the listener + let frontBack = vec3Dot(projectedSource, listenerForwardNorm); + if (frontBack < 0) + azimuth = 360 - azimuth; + + // Make azimuth relative to "front" and not "right" listener vector. + if (azimuth >= 0 && azimuth <= 270) + azimuth = 90 - azimuth; + else + azimuth = 450 - azimuth; + + // We don't need elevation, so we're skipping that computation. + return azimuth; +} + +// Map our position angle to the azimuth angle (in degrees). +// +// An angle of 0 corresponds to an azimuth of 90 deg; pi, to -90 deg. +function angleToAzimuth(angle) { + return 90 - angle * 180 / Math.PI; +} + +// The gain caused by the EQUALPOWER panning model +function equalPowerGain(azimuth, numberOfChannels) { + let halfPi = Math.PI / 2; + + if (azimuth < -90) + azimuth = -180 - azimuth; + else + azimuth = 180 - azimuth; + + if (numberOfChannels == 1) { + let panPosition = (azimuth + 90) / 180; + + let gainL = Math.cos(halfPi * panPosition); + let gainR = Math.sin(halfPi * panPosition); + + return {left: gainL, right: gainR}; + } else { + if (azimuth <= 0) { + let panPosition = (azimuth + 90) / 90; + + let gainL = Math.cos(halfPi * panPosition); + let gainR = Math.sin(halfPi * panPosition); + + return {left: gainL, right: gainR}; + } else { + let panPosition = azimuth / 90; + + let gainL = Math.cos(halfPi * panPosition); + let gainR = Math.sin(halfPi * panPosition); + + return {left: gainL, right: gainR}; + } + } +} + +function applyPanner(azimuth, srcL, srcR, numberOfChannels) { + let length = srcL.length; + let outL = new Float32Array(length); + let outR = new Float32Array(length); + + if (numberOfChannels == 1) { + for (let k = 0; k < length; ++k) { + let gains = equalPowerGain(azimuth[k], numberOfChannels); + + outL[k] = srcL[k] * gains.left; + outR[k] = srcR[k] * gains.right; + } + } else { + for (let k = 0; k < length; ++k) { + let gains = equalPowerGain(azimuth[k], numberOfChannels); + + if (azimuth[k] <= 0) { + outL[k] = srcL[k] + srcR[k] * gains.left; + outR[k] = srcR[k] * gains.right; + } else { + outL[k] = srcL[k] * gains.left; + outR[k] = srcR[k] + srcL[k] * gains.right; + } + } + } + + return {left: outL, right: outR}; +} |