| <!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> |
