From afe4e0d8be50abf23ac700356805e6d43a4d0712 Mon Sep 17 00:00:00 2001
From: Spencer Russell <spencer.f.russell@gmail.com>
Date: Mon, 23 Jun 2014 17:58:32 -0400
Subject: [PATCH] fixes imprecise SinOsc

---
 src/nodes.jl       | 13 +++++++++----
 test/test_nodes.jl |  9 +++++----
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/nodes.jl b/src/nodes.jl
index f83a1ba..95607a7 100644
--- a/src/nodes.jl
+++ b/src/nodes.jl
@@ -29,10 +29,15 @@ SinOsc() = SinOsc(440)
 export SinOsc
 
 function render(node::SinOscRenderer, device_input::AudioBuf, info::DeviceInfo)
-    phase = AudioSample[0:(info.buf_size-1)] * 2pi * node.freq / info.sample_rate
-    phase .+= node.phase
-    node.phase = phase[end] + 2pi * node.freq / info.sample_rate
-    return sin(phase)
+    outbuf = Array(AudioSample, info.buf_size)
+    phase = node.phase
+    dt = 1/info.sample_rate
+    for i in 1:info.buf_size
+        outbuf[i] = sin(2pi*node.freq*phase)
+        phase += dt
+    end
+    node.phase = phase
+    return outbuf
 end
 
 #### AudioMixer ####
diff --git a/test/test_nodes.jl b/test/test_nodes.jl
index 93442e0..64bddf9 100644
--- a/test/test_nodes.jl
+++ b/test/test_nodes.jl
@@ -56,13 +56,14 @@ render_output = render(mix, dev_input, test_info)
 
 info("Testing SinOSC...")
 freq = 440
-t = linspace(0,
-             (test_info.buf_size-1) / test_info.sample_rate,
-             test_info.buf_size)
+# note that this range includes the end, which is why there are sample_rate+1 samples
+t = linspace(0, 1, test_info.sample_rate+1)
 test_vect = convert(AudioBuf, sin(2pi * t * freq))
 osc = SinOsc(freq)
 render_output = render(osc, dev_input, test_info)
-@test_approx_eq(render_output, test_vect)
+@test render_output == test_vect[1:test_info.buf_size]
+render_output = render(osc, dev_input, test_info)
+@test render_output == test_vect[test_info.buf_size+1:2*test_info.buf_size]
 stop(osc)
 render_output = render(osc, dev_input, test_info)
 @test render_output == AudioSample[]