add audio example

examples/sound-c/Makefile

@@ -0,0 +1,15 @@
+CFLAGS ?= -Wall -Wextra -std=c99
+
+ifeq ($(OS),Windows_NT)
+	LDFLAGS = -lgdi32
+else
+	UNAME_S := $(shell uname -s)
+	ifeq ($(UNAME_S),Darwin)
+		LDFLAGS = -framework Cocoa -framework AudioToolbox
+	else
+		LDFLAGS = -lX11
+	endif
+endif
+
+main: main.c ../../fenster.h
+	$(CC) main.c -I../.. -o $@ $(CFLAGS) $(LDFLAGS)

examples/sound-c/main.c

@@ -0,0 +1,74 @@
+#include "fenster.h"
+#include "fenster_audio.h"
+
+#define W 320
+#define H 240
+
+/* ============================================================
+ * A very minimal example of a Fenster app:
+ * - Opens a window
+ * - Starts a loop
+ * - Changes pixel colours based on some "shader" formula
+ * - Sleeps if needed to maintain a frame rate of 60 FPS
+ * - Closes a window
+ * ============================================================ */
+static int run() {
+  uint32_t buf[W * H];
+  struct fenster f = {
+      .title = "hello",
+      .width = W,
+      .height = H,
+      .buf = buf,
+  };
+	struct fenster_audio fa = {0};
+  fenster_open(&f);
+	fenster_audio_open(&fa);
+  uint32_t t, u = 0;
+	float audio[FENSTER_AUDIO_BUFSZ];
+  int64_t now = fenster_time();
+  while (fenster_loop(&f) == 0) {
+    t++;
+		int n = fenster_audio_available(&fa);
+		if (n > 0) {
+			for (int i = 0; i < n; i++) {
+				u++;
+				/*audio[i] = (rand() & 0xff)/256.f;*/
+				int x = u * 80/441;
+				audio[i] = ((((x >> 10) & 42) * x)&0xff)/256.f;
+			}
+			fenster_audio_write(&fa, audio, n);
+		}
+		if (f.keys[27]) break;
+
+    for (int i = 0; i < 320; i++) {
+      for (int j = 0; j < 240; j++) {
+        /* White noise: */
+        /* fenster_pixel(&f, i, j) = (rand() << 16) ^ (rand() << 8) ^ rand(); */
+
+        /* Colourful and moving: */
+        /* fenster_pixel(&f, i, j) = i * j * t; */
+
+        /* Munching squares: */
+        fenster_pixel(&f, i, j) = i ^ j ^ t;
+      }
+    }
+    int64_t time = fenster_time();
+    if (time - now < 1000 / 60) {
+			fenster_sleep(time - now);
+    }
+    now = time;
+  }
+	fenster_audio_close(&fa);
+  fenster_close(&f);
+  return 0;
+}
+
+#if defined(_WIN32)
+int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR pCmdLine,
+                   int nCmdShow) {
+  (void)hInstance, (void)hPrevInstance, (void)pCmdLine, (void)nCmdShow;
+  return run();
+}
+#else
+int main() { return run(); }
+#endif