add alsa output to STCode

wip/tv_encoder.c

@@ -0,0 +1,48 @@
+// This will encode a black and white TV signal using a luminance value, how does it work?
+/*
+    It encodes the luminance into negative values, so totally white pixel should output -1, a black one should be 0
+    
+    Every new line it sends a 0.5, every frame it is a 1.0
+*/
+
+#include "../lib/fm_modulator.h"
+
+unsigned int rgb_to_luminance(unsigned int r, unsigned int g, unsigned int b) {
+    return (unsigned int)(0.299 * r + 0.587 * g + 0.114 * b);
+}
+
+typedef struct {
+    int line;
+    int pixel;
+    int lines;
+    int pixels;
+} TVEncoder;
+
+void init_tv_modulator(TVEncoder* tv, int lines, int pixels) {
+    tv->pixels = pixels;
+    tv->lines = lines;
+    tv->line = 0;
+    tv->pixel = 0;
+}
+
+float tv_encode(TVEncoder* tv, float luminance) {
+    float normalized_luminance = luminance / 255.0f;  // Normalize luminance to [0, 1]
+
+    if (tv->line < tv->lines) {
+        if (tv->pixel < tv->pixels) {
+            // Process pixel within the current line
+            tv->pixel++;
+            return -normalized_luminance;
+        } else {
+            // End of line: reset pixel counter and move to the next line
+            tv->pixel = 0;
+            tv->line++;
+            return 0.5f;
+        }
+    } else {
+        // End of frame: reset frame counters
+        tv->line = 0;
+        tv->pixel = 0;
+        return 1.0f;
+    }
+}