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<!DOCTYPE html>
<title>Test setValueAtTime with startTime in the past</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
function do_test(t, context) {
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();
// Use a ramp of slope 1/sample to measure time.
// The end value is the extent of exact precision in single precision float.
const rampEnd = Math.pow(2, 24);
const rampEndSeconds = rampEnd / context.sampleRate;
var test = context.createGain();
test.gain.setValueAtTime(0.0, 0.0);
test.gain.linearRampToValueAtTime(rampEnd, rampEndSeconds);
// With a different starting point on the same line, the result should be
// the same. |currentTime| may include double precision floating point
// rounding errors, so round to nearest integer sample to ignore these.
var scheduledSample = Math.round(context.currentTime * context.sampleRate);
assert_equals(scheduledSample % 128, 0,
"currentTime advances in blocks of 128 samples");
var reference = context.createGain();
reference.gain.setValueAtTime(scheduledSample, context.currentTime);
reference.gain.linearRampToValueAtTime(rampEnd, rampEndSeconds);
source.connect(test);
source.connect(reference);
var merger = context.createChannelMerger();
test.connect(merger, 0, 0);
reference.connect(merger, 0, 1);
var processor = context.createScriptProcessor(0, 2, 0);
merger.connect(processor);
processor.onaudioprocess =
t.step_func_done((e) => {
source.stop();
processor.onaudioprocess = null;
var testValue = e.inputBuffer.getChannelData(0)[0];
var referenceValue = e.inputBuffer.getChannelData(1)[0];
assert_equals(testValue, referenceValue,
"ramp value matches expected");
assert_greater_than_equal(testValue, scheduledSample,
"time does not retreat");
assert_equals(testValue % 128, 0,
"ScriptProcessor blocks align on 128-sample blocks");
});
}
async_test(function(t) {
var context = new AudioContext;
(function waitForTimeAdvance() {
if (context.currentTime == 0) {
t.step_timeout(waitForTimeAdvance, 0);
} else {
do_test(t, context);
}
})();
});
</script>
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