Add audio_graph.c example

ncc/examples/audio_graph.c

@@ -0,0 +1,107 @@
+#include <uvm/syscalls.h>
+#include <uvm/window.h>
+#include <uvm/math.h>
+#include <uvm/graphics.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#define FRAME_WIDTH 600
+#define FRAME_HEIGHT 200
+#define SAMPLE_RATE 44100
+#define DISP_SAMPLES 176400 // SAMPLE_RATE * 4
+
+// RGBA pixels
+u32 frame_buffer[FRAME_HEIGHT][FRAME_WIDTH];
+
+// Buffer for incoming samples
+i16 buffer[1024];
+
+// Buffer for display
+i16 disp_samples[DISP_SAMPLES];
+
+// Current recording position
+size_t rec_pos = 0;
+
+void update()
+{
+    // Clear the frame buffer, set all pixels to black
+    memset32(frame_buffer, 0, sizeof(frame_buffer) / sizeof(u32));
+
+    int prev_y = FRAME_HEIGHT / 2;
+
+    for (size_t x = 1; x < FRAME_WIDTH; ++x)
+    {
+        size_t sample_idx = x * DISP_SAMPLES / FRAME_WIDTH;
+
+        // Bring sample into the [-1, 1] range
+        float sample = (float)disp_samples[sample_idx] / (INT16_MAX + 1);
+
+        // Bring the sample into the [0, 1] range
+        sample = (sample + 1.0f) / 2;
+
+        int y = (int)(sample * (FRAME_HEIGHT - 1));
+
+        draw_line(
+            (u32*)&frame_buffer,
+            FRAME_WIDTH,
+            FRAME_HEIGHT,
+            x - 1,
+            prev_y,
+            x,
+            y,
+            COLOR_RED,
+        );
+
+        prev_y = y;
+    }
+
+    // Draw vertical line at recording position
+    u32 rec_x = rec_pos * FRAME_WIDTH / DISP_SAMPLES;
+    draw_line(
+        (u32*)&frame_buffer,
+        FRAME_WIDTH,
+        FRAME_HEIGHT,
+        rec_x,
+        0,
+        rec_x,
+        FRAME_HEIGHT - 1,
+        COLOR_WHITE,
+    );
+
+    window_draw_frame(0, frame_buffer);
+}
+
+void audio_cb(u16 num_channels, u32 num_samples)
+{
+    assert(num_channels == 1);
+    assert(num_samples <= 1024);
+
+    audio_read_samples(&buffer, num_samples);
+
+    size_t end_pos = MIN(rec_pos + num_samples, sizeof(disp_samples) / sizeof(i16));
+    size_t num_copy = end_pos - rec_pos;
+
+    memcpy(&disp_samples[rec_pos], &buffer, num_copy * sizeof(i16));
+
+    rec_pos = (rec_pos + num_copy) % DISP_SAMPLES;
+
+    if (num_copy < num_samples)
+    {
+        size_t buf_pos = num_copy;
+        size_t num_copy = num_samples - buf_pos;
+
+        memcpy(&disp_samples, &buffer[buf_pos], num_copy * sizeof(i16));
+        rec_pos = num_copy;
+    }
+
+    //printf("%d\n", rec_pos);
+}
+
+void main()
+{
+    window_create(FRAME_WIDTH, FRAME_HEIGHT, "Audio Input Graph", 0);
+    audio_open_input(SAMPLE_RATE, 1, AUDIO_FORMAT_I16, audio_cb);
+
+    anim_event_loop(30, update);
+}

ncc/examples/ball.c

@@ -1,5 +1,4 @@
 #include <uvm/syscalls.h>
-#include <uvm/utils.h>
 #include <uvm/window.h>
 #include <stdlib.h>
 #include <stdint.h>