| <!DOCTYPE html> |
| <!-- |
| Tests that multiple audio-rate signals (AudioNode outputs) can be connected to an AudioParam |
| and that these signals are summed, along with the AudioParams intrinsic value. |
| --> |
| <html> |
| <head> |
| <title> |
| audioparam-summingjunction.html |
| </title> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="/webaudio/resources/audit-util.js"></script> |
| <script src="/webaudio/resources/audit.js"></script> |
| <script src="/webaudio/resources/mix-testing.js"></script> |
| </head> |
| <body> |
| <script id="layout-test-code"> |
| let audit = Audit.createTaskRunner(); |
| |
| let sampleRate = 44100.0; |
| let lengthInSeconds = 1; |
| |
| let context = 0; |
| |
| // Buffers used by the two gain controlling sources. |
| let linearRampBuffer; |
| let toneBuffer; |
| let toneFrequency = 440; |
| |
| // Arbitrary non-zero value. |
| let baselineGain = 5; |
| |
| // Allow for a small round-off error. |
| let maxAllowedError = 1e-6; |
| |
| function checkResult(renderedBuffer, should) { |
| let renderedData = renderedBuffer.getChannelData(0); |
| |
| // Get buffer data from the two sources used to control gain. |
| let linearRampData = linearRampBuffer.getChannelData(0); |
| let toneData = toneBuffer.getChannelData(0); |
| |
| let n = renderedBuffer.length; |
| |
| should(n, 'Rendered signal length').beEqualTo(linearRampBuffer.length); |
| |
| // Check that the rendered result exactly matches the sum of the |
| // intrinsic gain plus the two sources used to control gain. This is |
| // because we're changing the gain of a signal having constant value 1. |
| let success = true; |
| for (let i = 0; i < n; ++i) { |
| let expectedValue = baselineGain + linearRampData[i] + toneData[i]; |
| let error = Math.abs(expectedValue - renderedData[i]); |
| |
| if (error > maxAllowedError) { |
| success = false; |
| break; |
| } |
| } |
| |
| should( |
| success, |
| 'Rendered signal matches sum of two audio-rate gain changing signals plus baseline gain') |
| .beTrue(); |
| } |
| |
| audit.define('test', function(task, should) { |
| let sampleFrameLength = sampleRate * lengthInSeconds; |
| |
| // Create offline audio context. |
| context = new OfflineAudioContext(1, sampleFrameLength, sampleRate); |
| |
| // Create buffer used by the source which will have its gain controlled. |
| let constantOneBuffer = |
| createConstantBuffer(context, sampleFrameLength, 1); |
| let constantSource = context.createBufferSource(); |
| constantSource.buffer = constantOneBuffer; |
| |
| // Create 1st buffer used to control gain (a linear ramp). |
| linearRampBuffer = createLinearRampBuffer(context, sampleFrameLength); |
| let gainSource1 = context.createBufferSource(); |
| gainSource1.buffer = linearRampBuffer; |
| |
| // Create 2st buffer used to control gain (a simple sine wave tone). |
| toneBuffer = |
| createToneBuffer(context, toneFrequency, lengthInSeconds, 1); |
| let gainSource2 = context.createBufferSource(); |
| gainSource2.buffer = toneBuffer; |
| |
| // Create a gain node controlling the gain of constantSource and make |
| // the connections. |
| let gainNode = context.createGain(); |
| |
| // Intrinsic baseline gain. |
| // This gain value should be summed with gainSource1 and gainSource2. |
| gainNode.gain.value = baselineGain; |
| |
| constantSource.connect(gainNode); |
| gainNode.connect(context.destination); |
| |
| // Connect two audio-rate signals to control the .gain AudioParam. |
| gainSource1.connect(gainNode.gain); |
| gainSource2.connect(gainNode.gain); |
| |
| // Start all sources at time 0. |
| constantSource.start(0); |
| gainSource1.start(0); |
| gainSource2.start(0); |
| |
| context.startRendering().then(buffer => { |
| checkResult(buffer, should); |
| task.done(); |
| }); |
| }); |
| |
| audit.run(); |
| </script> |
| </body> |
| </html> |
