Rearranged files

src/utility/buffer.cpp

@@ -0,0 +1,86 @@
+#include "buffer.hpp"
+
+/*
+A Buffer consists of three parts:
+an incoming vector, a rollingbuffer, and an output vector.
+
+Note that the RollingBuffer class does most of the work:
+its `get` and `put` methods move the values in our
+input and output vectors.
+*/
+
+Buffer::Buffer(
+	const char *pipe_file,
+	size_t buffer_size,
+	size_t output_size
+):
+	buffer_size(buffer_size),
+	output_size(output_size),
+	pipe_file(pipe_file)
+{
+
+	sample_con_rate = 5;
+	sample_con_rate_up_ctr = 0;
+	sample_con_rate_dn_ctr = 0;
+
+	incoming.resize(buffer_size);
+	rolling_buffer.resize(buffer_size);
+
+	output.resize(output_size);
+}
+
+
+void Buffer::update() {
+	// TODO:
+	// Disable and enable FIFO here to get rid of
+	// the difference between audio and visualization.
+
+	int fd = open(pipe_file, O_RDONLY);
+
+	ssize_t bytes_read = read(
+		fd,
+		incoming.data(),
+		sizeof(int16_t) * incoming.size()
+	);
+
+	const auto begin = incoming.begin();
+	const auto end = incoming.begin() + bytes_read/sizeof(int16_t);
+
+	// Autoscale here
+
+	rolling_buffer.put(begin, end);
+
+	// 44100 samples per second / fps = samples per frame
+	// 60 fps
+	// *2 if stereo
+	size_t requested_samples = (44100 / 60) * pow(1.1, sample_con_rate);
+
+	size_t new_samples = rolling_buffer.get(
+		requested_samples,
+		output
+	);
+
+	if (new_samples == 0) {
+		printf("no new samples\n");
+		return;
+	}
+
+	// A crude way to adjust the amount of samples consumed from the buffer
+	// depending on how fast the rendering is.
+	if (rolling_buffer.size() > 0) {
+		if (++sample_con_rate_up_ctr > 8) {
+			sample_con_rate_up_ctr = 0;
+			++sample_con_rate;
+		}
+	} else if (sample_con_rate > 0) {
+		if (++sample_con_rate_dn_ctr > 4) {
+			sample_con_rate_dn_ctr = 0;
+			--sample_con_rate;
+		}
+		sample_con_rate_up_ctr = 0;
+	}
+
+	if (fd >= 0) {
+		close(fd);
+	}
+}