<!DOCTYPE html>
<title>Test setTargetAtTime after an event in the same processing block</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
promise_test(function() {
const bufferSize = 179;
const valueStartOffset = 42;
const targetStartOffset = 53;
const sampleRate = 48000;
const scheduledValue = -0.5;
var context = new OfflineAudioContext(1, bufferSize, sampleRate);
var gain = context.createGain();
gain.gain.setValueAtTime(scheduledValue, valueStartOffset/sampleRate);
gain.gain.setTargetAtTime(scheduledValue, targetStartOffset/sampleRate,
128/sampleRate);
gain.connect(context.destination);
// Apply unit DC signal to gain node.
var source = context.createBufferSource();
source.buffer =
function() {
var buffer = context.createBuffer(1, 1, context.sampleRate);
buffer.getChannelData(0)[0] = 1.0;
return buffer;
}();
source.loop = true;
source.start();
source.connect(gain);
return context.startRendering().
then(function(buffer) {
assert_equals(buffer.length, bufferSize, "output buffer length");
var output = buffer.getChannelData(0);
var i = 0;
for (; i < valueStartOffset; ++i) {
// "Its default value is 1."
assert_equals(output[i], 1.0, "default gain at sample " + i);
}
for (; i < buffer.length; ++i) {
// "If the next event (having time T1) after this SetValue event is
// not of type LinearRampToValue or ExponentialRampToValue, then, for
// T0≤t<T1: v(t)=V".
// "Start exponentially approaching the target value at the given time
// with a rate having the given time constant."
// The target is the same value, and so the SetValue value continues.
assert_equals(output[i], scheduledValue,
"scheduled value at sample " + i);
}
});
}, "setTargetAtTime() after setValueAtTime()");
promise_test(async function() {
const bufferSize = 129;
const sampleRate = 16384;
const startSample1 = 125;
const target1 = Math.fround(-1./Math.expm1(-1.));
// Intentionally testing the second curve before and after the
// rendering quantum boundary.
const startSample2 = startSample1 + 1;
const target2 = 0.;
const timeConstant = 1./sampleRate;
const tolerance = Math.pow(2, -24); // Allow single precision math.
const context = new OfflineAudioContext(1, bufferSize, sampleRate);
const source = new ConstantSourceNode(context, {offset: 0.});
source.start();
source.offset.setTargetAtTime(target1, startSample1/sampleRate,
timeConstant);
source.offset.setTargetAtTime(target2, startSample2/sampleRate,
timeConstant);
source.connect(context.destination);
const buffer = await context.startRendering();
assert_equals(buffer.length, bufferSize, "output buffer length");
const output = buffer.getChannelData(0);
for (let i = 0; i <= startSample1; ++i) {
assert_equals(output[i], 0., "initial offset at sample " + i);
}
assert_approx_equals(
output[startSample2],
Math.fround(target1 * -Math.expm1(-(startSample2 - startSample1))),
tolerance,
"scheduled value at startSample2");
assert_approx_equals(
output[startSample2 + 1],
Math.fround(output[startSample2] * Math.exp(-1.)),
tolerance,
"scheduled value at startSample2 + 1");
assert_approx_equals(
output[startSample2 + 2],
Math.fround(output[startSample2] * Math.exp(-2.)),
tolerance,
"scheduled value at startSample2 + 2");
}, "setTargetAtTime() after setTargetAtTime()");
</script>
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