Add regression test cases for IIR filter (#1429)

test/CMakeLists.txt

@@ -43,3 +43,64 @@ if ( LIBSNDFILE_HASVORBIS )
     ADD_FLUID_TEST(test_sf3_sfont_loading)
     ADD_FLUID_SF_DUMP_TEST(VintageDreamsWaves-v2.sf3)
 endif ( LIBSNDFILE_HASVORBIS )
+
+
+# Prepare the manual test suite down here
+if(NOT DEFINED GENERAL_USER_GS2)
+    add_custom_target(check_manual
+        COMMAND ${CMAKE_COMMAND} -E cmake_echo_color --red "In order to run the manual test suite, you need to set variable GENERAL_USER_GS2 to the path of the soundfont.")
+else()
+
+    set(IIR_FILTER_RENDER_DIR "${CMAKE_CURRENT_BINARY_DIR}/manual/iir_filter")
+
+    if(LIBSNDFILE_SUPPORT)
+      set(FEXT "wav")
+    else()
+      set(FEXT "raw")
+    endif()
+
+    # Add an empty pseudo target
+    add_custom_target(check_manual)
+
+    add_custom_target(create_iir_dir
+        COMMAND ${CMAKE_COMMAND} -E make_directory ${IIR_FILTER_RENDER_DIR})
+
+    add_custom_target(render1415
+        COMMAND fluidsynth -R 0 -C 0 -g 1 -F ${IIR_FILTER_RENDER_DIR}/1415_the-nervous-filter.${FEXT} "The Nervous Filter trimmed.mid" ${GENERAL_USER_GS2}
+        COMMENT "Rendering testfile of issue 1415"
+        DEPENDS fluidsynth create_iir_dir
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/manual/iir_filter/1415_the-nervous-filter/
+        VERBATIM
+    )
+
+    add_custom_target(render1417
+        COMMAND fluidsynth -R 0 -C 0 -g 1 -F ${IIR_FILTER_RENDER_DIR}/1417_filter-envelope-noise.${FEXT} filter-envelope-noise.mid ${GENERAL_USER_GS2}
+        COMMENT "Rendering testfile of issue 1417"
+        DEPENDS fluidsynth create_iir_dir
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/manual/iir_filter/1417_filter-envelope-noise/
+        VERBATIM
+    )
+
+    add_custom_target(render1424
+        COMMAND fluidsynth -R 0 -C 0 -g 1 -F ${IIR_FILTER_RENDER_DIR}/1424_clicks-on-ModEnv-FilterFc-change.${FEXT} 1424.mid echo_drops.sf2
+        COMMENT "Rendering testfile of issue 1424"
+        DEPENDS fluidsynth create_iir_dir
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/manual/iir_filter/1424_clicks-on-ModEnv-FilterFc-change/
+        VERBATIM
+    )
+
+    add_custom_target(render1427
+        COMMAND fluidsynth -R 0 -C 0 -g 5 -F ${IIR_FILTER_RENDER_DIR}/1427_high-Q-note-cutoff.${FEXT} high_Q_note_cutoff_test.mid high_Q_note_cutoff_test.sf2
+        COMMENT "Rendering testfile of issue 1427"
+        DEPENDS fluidsynth create_iir_dir
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/manual/iir_filter/1427_high-Q-note-cutoff/
+        VERBATIM
+    )
+
+    # Add a dependency so that rendering targets depends on check_manual
+    add_dependencies(check_manual render1415)
+    add_dependencies(check_manual render1417)
+    add_dependencies(check_manual render1424)
+    add_dependencies(check_manual render1427)
+
+endif()

test/manual/iir_filter/1415_the-nervous-filter/.gitattributes

@@ -0,0 +1,4 @@
+*.ogg filter=lfs diff=lfs merge=lfs -text
+*.flac filter=lfs diff=lfs merge=lfs -text
+*.wav filter=lfs diff=lfs merge=lfs -text
+*.sf2 filter=lfs diff=lfs merge=lfs -text

test/manual/iir_filter/1417_filter-envelope-noise/.gitattributes

@@ -0,0 +1,5 @@
+filter-envelope-noise-1345[[:space:]]reverted.flac filter=lfs diff=lfs merge=lfs -text
+filter-envelope-noise-FluidSynth[[:space:]]2.4.flac filter=lfs diff=lfs merge=lfs -text
+filter-envelope-noise.mid filter=lfs diff=lfs merge=lfs -text
+*.flac filter=lfs diff=lfs merge=lfs -text
+*.sf2 filter=lfs diff=lfs merge=lfs -text

test/manual/iir_filter/1424_clicks-on-ModEnv-FilterFc-change/.gitattributes

@@ -0,0 +1 @@
+echo_drops.sf2 filter=lfs diff=lfs merge=lfs -text

test/manual/iir_filter/1427_high-Q-note-cutoff/.gitattributes

@@ -0,0 +1,3 @@
+high_Q_note_cutoff_test.sf2 filter=lfs diff=lfs merge=lfs -text
+fluidsynth_iir-tests.flac filter=lfs diff=lfs merge=lfs -text
+high_Q_note_cutoff_test.mid filter=lfs diff=lfs merge=lfs -text

test/manual/iir_filter/interactive_biquad_lowpass.m

@@ -0,0 +1,86 @@
+#
+# This Matlab script implements an interactive Bode plot of fluidsynth's IIR filter.
+# To run it, just call interactive_biquad_lowpass() and a window will open up, allowing
+# you to adjust the cutoff frequency and Q.
+# Note that Q is in linear range here!
+#
+function interactive_biquad_lowpass()
+    % Initial values
+    f_c = 1000;  % Initial cutoff frequency in Hz
+    Q = 0.707;   % Initial quality factor
+    f_s = 48000; % Sampling frequency in Hz
+
+    % Create the figure
+    hFig = figure('Name', 'Interactive Biquad Lowpass Filter', 'NumberTitle', 'off');
+
+    % Create axes for the magnitude and phase plots
+    hAxesMag = subplot(2, 1, 1, 'Parent', hFig);
+    hAxesPhase = subplot(2, 1, 2, 'Parent', hFig);
+
+    % Plot the initial response
+    plot_response(hAxesMag, hAxesPhase, f_c, Q, f_s);
+
+    % Create slider for cutoff frequency
+    uicontrol('Style', 'text', 'Position', [20 20 150 20], 'String', 'Cutoff Frequency (Hz)');
+    hSliderFc = uicontrol('Style', 'slider', 'Min', 100, 'Max', 20000, 'Value', f_c, ...
+                          'Position', [20 40 300 20]);
+    hTextFc = uicontrol('Style', 'text', 'Position', [330 40 50 20], 'String', num2str(f_c));
+
+    % Create slider for quality factor
+    uicontrol('Style', 'text', 'Position', [20 80 150 20], 'String', 'Quality Factor (Q)');
+    hSliderQ = uicontrol('Style', 'slider', 'Min', 0.1, 'Max', 100, 'Value', Q, ...
+                         'Position', [20 100 300 20]);
+    hTextQ = uicontrol('Style', 'text', 'Position', [330 100 50 20], 'String', num2str(Q));
+
+    % Add listeners for both sliders
+    addlistener(hSliderFc, 'Value', 'PreSet', @(src, event) update_plot(hAxesMag, hAxesPhase, hSliderFc, hSliderQ, f_s, hTextFc, hTextQ));
+    addlistener(hSliderQ, 'Value', 'PreSet', @(src, event) update_plot(hAxesMag, hAxesPhase, hSliderFc, hSliderQ, f_s, hTextFc, hTextQ));
+end
+
+function update_plot(hAxesMag, hAxesPhase, hSliderFc, hSliderQ, f_s, hTextFc, hTextQ)
+    % Get the current values from the sliders
+    f_c = get(hSliderFc, 'Value');
+    Q = get(hSliderQ, 'Value');
+
+    % Update the text displays
+    set(hTextFc, 'String', num2str(f_c, '%.1f'));  % Display cutoff frequency
+    set(hTextQ, 'String', num2str(Q, '%.2f'));      % Display quality factor
+
+    % Update the plot with the new values
+    plot_response(hAxesMag, hAxesPhase, f_c, Q, f_s);
+end
+
+function plot_response(hAxesMag, hAxesPhase, f_c, Q, f_s)
+    % Design the biquad lowpass filter
+    w0 = 2 * pi * f_c / f_s;
+    alpha = sin(w0) / (2 * Q);
+
+    b0 = (1 - cos(w0)) / 2;
+    b1 = 1 - cos(w0);
+    b2 = (1 - cos(w0)) / 2;
+    a0 = 1 + alpha;
+    a1 = -2 * cos(w0);
+    a2 = 1 - alpha;
+
+    % Normalize coefficients
+    b = [b0 / a0, b1 / a0, b2 / a0];
+    a = [1, a1 / a0, a2 / a0];
+
+    % Compute the frequency response
+    [h, w] = freqz(b, a, 1024, f_s);
+
+    % Clear the axes and plot the new response
+    cla(hAxesMag);
+    plot(hAxesMag, w, 20*log10(abs(h)));
+    title(hAxesMag, 'Magnitude Response');
+    xlabel(hAxesMag, 'Frequency (Hz)');
+    ylabel(hAxesMag, 'Magnitude (dB)');
+    grid(hAxesMag, 'on');
+
+    cla(hAxesPhase);
+    plot(hAxesPhase, w, angle(h) * (180/pi));
+    title(hAxesPhase, 'Phase Response');
+    xlabel(hAxesPhase, 'Frequency (Hz)');
+    ylabel(hAxesPhase, 'Phase (degrees)');
+    grid(hAxesPhase, 'on');
+end