| <!DOCTYPE html> |
| <html> |
| <head> |
| <title> |
| Test linearRampToValue Updates the Param Value |
| </title> |
| <script src="../../imported/w3c/web-platform-tests/resources/testharness.js"></script> |
| <script src="../../resources/testharnessreport.js"></script> |
| <script src="../resources/audit-util.js"></script> |
| <script src="../resources/audit.js"></script> |
| </head> |
| <body> |
| <script id="layout-test-code"> |
| let renderQuantumSize = 128; |
| // Should be a power of two to get rid of rounding errors when converting |
| // between time and frame. |
| let sampleRate = 8192; |
| let renderDuration = 1; |
| // End time of the linear ramp automation |
| let rampEndTime = renderDuration / 2; |
| |
| let audit = Audit.createTaskRunner(); |
| |
| // Test that linearRampToValue properly sets the AudioParam .value |
| // attribute when the linearRamp automation is running. |
| audit.define('propagate', (task, should) => { |
| let context = |
| new OfflineAudioContext(1, renderDuration * sampleRate, sampleRate); |
| |
| // Create a constant source. |
| let source = context.createBufferSource(); |
| source.buffer = createConstantBuffer(context, 1, 1); |
| source.loop = true; |
| |
| // The gain node to be automated for testing. |
| let gain = context.createGain(); |
| |
| gain.gain.setValueAtTime(0, 0); |
| gain.gain.linearRampToValueAtTime(1, rampEndTime); |
| |
| // Connect up the graph |
| source.connect(gain); |
| gain.connect(context.destination); |
| |
| let success = true; |
| |
| // The number of rendering quanta that will be processed in the context. |
| // At the beginning of each rendering quantum (except the first), we |
| // will check that gain.gain.value has the expected value. |
| let renderLoops = |
| Math.floor(renderDuration * sampleRate / renderQuantumSize); |
| |
| for (let k = 1; k < renderLoops; ++k) { |
| let time = k * renderQuantumSize / sampleRate; |
| context.suspend(time) |
| .then(function() { |
| let expected = 1; |
| |
| if (context.currentTime <= rampEndTime) { |
| // The expected value of the gain is the last computed value |
| // from the previous rendering quantum because suspend() stops |
| // at the beginning of a rendering quantum, so we haven't |
| // computed the new value yet. |
| expected = |
| (context.currentTime - 1 / sampleRate) / rampEndTime; |
| } |
| |
| let frame = context.currentTime * sampleRate - 1; |
| success = |
| should(gain.gain.value, 'gain.gain.value at frame ' + frame) |
| .beEqualTo(expected); |
| }) |
| .then(context.resume.bind(context)); |
| } |
| |
| // Rock and roll! |
| source.start(); |
| context.startRendering() |
| .then(function(result) { |
| should(success, 'linearRampToValue') |
| .message( |
| 'properly set the AudioParam value', |
| 'did not properly set the AudioParam value'); |
| }) |
| .then(() => task.done()); |
| }); |
| |
| audit.run(); |
| </script> |
| </body> |
| </html> |
