tilt correction? (yes, ai wrote it, you hate me because of that? find a tilt filter yourself then that you can copy the code of)

filter/iir.c

@@ -13,4 +13,49 @@ inline float apply_preemphasis(ResistorCapacitor *filter, float sample) {
 	float out = (sample - filter->alpha * filter->prev_sample) * filter->gain;
 	filter->prev_sample = sample;
 	return out;
+}
+
+void tilt_init(TiltCorrectionFilter* filter, float correction_strength) {
+    // This filter is a first-order IIR low-shelf filter.
+    // The difference equation is: y[n] = b0*x[n] + b1*x[n-1] - a1*y[n-1]
+    // We simplify it to y[n] = x[n] - a1*y[n-1] which acts as a leaky integrator.
+    
+    // The "correction_strength" is our leaky factor. It is the pole of the filter.
+    // A value close to 1.0 places the pole very close to the unit circle,
+    // providing a large boost to low frequencies (and DC).
+    
+    if (correction_strength >= 1.0f) {
+        correction_strength = 0.99999f; // Prevent instability
+    }
+
+    filter->b0 = 1.0f;
+    filter->b1 = 0.0f;
+    filter->a1 = -correction_strength; // The feedback coefficient
+
+    // Reset filter state
+    filter->x_prev = 0.0f;
+    filter->y_prev = 0.0f;
+}
+
+float tilt(TiltCorrectionFilter* filter, float input_sample) {
+    // Apply the difference equation: y[n] = b0*x[n] + b1*x[n-1] - a1*y[n-1]
+    float output_sample = filter->b0 * input_sample + filter->b1 * filter->x_prev - filter->a1 * filter->y_prev;
+
+    // Important: Prevent output from running away due to DC offset accumulation
+    // This is a simple guard. If the filter becomes unstable or the output
+    // grows too large, it gets reset. For square waves, the absolute value of the
+    // output should not significantly exceed the absolute value of the input.
+    if (fabsf(output_sample) > 2.0f * fabsf(input_sample) && fabsf(input_sample) > 0.001f) {
+       // This condition indicates the filter state might be diverging. Resetting it.
+       // You may need to adjust the '2.0f' factor based on your signal.
+       filter->y_prev = 0; 
+       output_sample = input_sample;
+    }
+
+
+    // Update the state for the next iteration
+    filter->x_prev = input_sample;
+    filter->y_prev = output_sample;
+    
+    return output_sample;
 }