move EngineFilter classes to their own folder

1 files changed, 34 insertions, 0 deletions

diff --git a/src/engine/filters/enginefilterbessel4.h b/src/engine/filters/enginefilterbessel4.h
new file mode 100644
index 0000000000..02fa3dd25e
--- /dev/null
+++ b/src/engine/filters/enginefilterbessel4.h
@@ -0,0 +1,34 @@
+#ifndef ENGINEFILTERBESSEL4_H
+#define ENGINEFILTERBESSEL4_H
+
+#include "engine/filters/enginefilteriir.h"
+
+class EngineFilterBessel4Low : public EngineFilterIIR<4, IIR_LP> {
+    Q_OBJECT
+  public:
+    EngineFilterBessel4Low(int sampleRate, double freqCorner1);
+    void setFrequencyCorners(int sampleRate, double freqCorner1);
+    // This function selects a corner frequency near the
+    // desiredCorner1Ratio freqCorner / sampleRate
+    // the produces an integer group delay at the passband
+    // Optimized for freqCorner / 20
+    int setFrequencyCornersForIntDelay(double desiredCorner1Ratio, int maxDelay);
+};
+
+class EngineFilterBessel4Band : public EngineFilterIIR<8, IIR_BP> {
+    Q_OBJECT
+  public:
+    EngineFilterBessel4Band(int sampleRate, double freqCorner1,
+            double freqCorner2);
+    void setFrequencyCorners(int sampleRate, double freqCorner1,
+            double freqCorner2);
+};
+
+class EngineFilterBessel4High : public EngineFilterIIR<4, IIR_HP> {
+    Q_OBJECT
+  public:
+    EngineFilterBessel4High(int sampleRate, double freqCorner1);
+    void setFrequencyCorners(int sampleRate, double freqCorner1);
+};
+
+#endif // ENGINEFILTERBESSEL4_H