Fix CI tests and extract math utilities for testability

.github/workflows/main.yml

@@ -173,7 +173,11 @@ jobs:
     - name: Configure CMake
       run: |
         mkdir -p build && cd build
-        cmake -G Ninja -DCMAKE_BUILD_TYPE=${{ matrix.config.build_type }} ..
+        cmake -G Ninja \
+          -DCMAKE_BUILD_TYPE=${{ matrix.config.build_type }} \
+          -DBUILD_TESTING=ON \
+          -DENABLE_COVERAGE=ON \
+          ..
 
     - name: Build project
       run: |

CMakeLists.txt

@@ -75,6 +75,7 @@ set(MATRIX_SOURCES
 
 set(MATRIX_HEADERS
   src/main.h
+  src/math_utils.h
   src/tracyprofiler.h
   src/stb_image.h
   ${kissfft_SOURCE_DIR}/kiss_fft.h

src/main.cpp

@@ -6,6 +6,7 @@
  */
 
 #include "main.h"
+#include "math_utils.h"
 
 #include <regex>
 
@@ -19,7 +20,6 @@
 
 #include <algorithm>
 #include <chrono>
-#include <cmath>
 #include <memory>
 
 #define SMOOTHING_TIME_CONSTANT (0.5f) // default 0.8
@@ -673,35 +673,6 @@ GLuint CVisualizationMatrix::CreateTexture(const std::string& file, GLint intern
   return texture;
 }
 
-float CVisualizationMatrix::BlackmanWindow(float in, size_t i, size_t length)
-{
-  constexpr double alpha = 0.16;
-  constexpr double a0 = 0.5 * (1.0 - alpha);
-  constexpr double a1 = 0.5;
-  constexpr double a2 = 0.5 * alpha;
-
-  const float x = static_cast<float>(i) / static_cast<float>(length);
-  return in * static_cast<float>(a0 - a1 * std::cos(2.0 * M_PI * x) + a2 * std::cos(4.0 * M_PI * x));
-}
-
-void CVisualizationMatrix::SmoothingOverTime(std::vector<float>& outputBuffer, const std::vector<float>& lastOutputBuffer, 
-                                           kiss_fft_cpx* inputBuffer, size_t length, float smoothingTimeConstant, unsigned int fftSize)
-{
-  for (size_t i = 0; i < length; i++)
-  {
-    const kiss_fft_cpx c = inputBuffer[i];
-    const float magnitude = std::sqrt(c.r * c.r + c.i * c.i) / static_cast<float>(fftSize);
-    outputBuffer[i] = smoothingTimeConstant * lastOutputBuffer[i] + (1.0f - smoothingTimeConstant) * magnitude;
-  }
-}
-
-float CVisualizationMatrix::LinearToDecibels(float linear)
-{
-  if (!linear)
-    return -1000.0f;
-  return 20.0f * std::log10(linear);
-}
-
 int CVisualizationMatrix::DetermineBitsPrecision()
 {
   m_state.fbwidth = 32;

src/main.h

@@ -14,6 +14,7 @@
 #include <glm/gtc/type_ptr.hpp>
 
 #include <kissfft/kiss_fft.h>
+#include "math_utils.h"
 
 #include <vector>
 #include <string>
@@ -56,18 +57,9 @@ class ATTRIBUTE_HIDDEN CVisualizationMatrix
   GLuint CreateTexture(GLint format, unsigned int w, unsigned int h, const GLvoid* data);
   GLuint CreateTexture(const GLvoid* data, GLint format, unsigned int w, unsigned int h, GLint internalFormat, GLint scaling, GLint repeat);
   GLuint CreateTexture(const std::string& file, GLint internalFormat, GLint scaling, GLint repeat);
-  float BlackmanWindow(float in, size_t i, size_t length);
-  void SmoothingOverTime(std::vector<float>& outputBuffer, const std::vector<float>& lastOutputBuffer, 
-                         kiss_fft_cpx* inputBuffer, size_t length, float smoothingTimeConstant, unsigned int fftSize);
-  float LinearToDecibels(float linear);
   int DetermineBitsPrecision();
   bool UpdateAlbumart();
   void GatherDefines();
-
-  // FFT configuration
-  static constexpr size_t AUDIO_BUFFER = 1024;
-  static constexpr size_t NUM_BANDS = AUDIO_BUFFER / 2;
-
   // Audio processing
   kiss_fft_cfg m_kissCfg;
   std::vector<GLubyte> m_audioData;

src/math_utils.h

@@ -0,0 +1,62 @@
+/*
+ *  Copyright (C) 2005-2021 Team Kodi <https://kodi.tv>
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSE.md for more information.
+ */
+
+#pragma once
+
+#include <cmath>
+#include <vector>
+
+// FFT configuration constants
+static constexpr size_t AUDIO_BUFFER = 1024;
+static constexpr size_t NUM_BANDS = AUDIO_BUFFER / 2;
+
+struct kiss_fft_cpx
+{
+  float r;
+  float i;
+};
+
+/**
+ * Apply Blackman window function to a sample.
+ * The Blackman window reduces spectral leakage in FFT analysis.
+ */
+inline float BlackmanWindow(float in, size_t i, size_t length)
+{
+  constexpr double alpha = 0.16;
+  constexpr double a0 = 0.5 * (1.0 - alpha);
+  constexpr double a1 = 0.5;
+  constexpr double a2 = 0.5 * alpha;
+
+  const float x = static_cast<float>(i) / static_cast<float>(length);
+  return in * static_cast<float>(a0 - a1 * std::cos(2.0 * M_PI * x) + a2 * std::cos(4.0 * M_PI * x));
+}
+
+/**
+ * Convert linear amplitude to decibels.
+ * Returns -1000 dB for zero input (effectively negative infinity).
+ */
+inline float LinearToDecibels(float linear)
+{
+  if (!linear)
+    return -1000.0f;
+  return 20.0f * std::log10(linear);
+}
+
+/**
+ * Apply exponential smoothing to magnitude values over time.
+ * This smooths the FFT output to reduce flickering in the visualization.
+ */
+inline void SmoothingOverTime(std::vector<float>& outputBuffer, const std::vector<float>& lastOutputBuffer,
+                              kiss_fft_cpx* inputBuffer, size_t length, float smoothingTimeConstant, unsigned int fftSize)
+{
+  for (size_t i = 0; i < length; i++)
+  {
+    const kiss_fft_cpx c = inputBuffer[i];
+    const float magnitude = std::sqrt(c.r * c.r + c.i * c.i) / static_cast<float>(fftSize);
+    outputBuffer[i] = smoothingTimeConstant * lastOutputBuffer[i] + (1.0f - smoothingTimeConstant) * magnitude;
+  }
+}

tests/test_visualization_matrix.cpp

@@ -9,50 +9,8 @@
 #include <cmath>
 #include <vector>
 
-// Include the functions to test from main.cpp
-// We need to extract the pure functions that don't depend on OpenGL/Kodi
-
-// --- Copied from main.cpp for testing ---
-
-#define AUDIO_BUFFER (1024)
-#define NUM_BANDS (AUDIO_BUFFER / 2)
-
-struct kiss_fft_cpx
-{
-  float r;
-  float i;
-};
-
-// BlackmanWindow function (copied from main.cpp)
-float BlackmanWindow(float in, size_t i, size_t length)
-{
-  double alpha = 0.16;
-  double a0 = 0.5 * (1.0 - alpha);
-  double a1 = 0.5;
-  double a2 = 0.5 * alpha;
-
-  float x = (float)i / (float)length;
-  return in * (a0 - a1 * cos(2.0 * M_PI * x) + a2 * cos(4.0 * M_PI * x));
-}
-
-// LinearToDecibels function (copied from main.cpp)
-float LinearToDecibels(float linear)
-{
-  if (!linear)
-    return -1000;
-  return 20 * log10f(linear);
-}
-
-// SmoothingOverTime function (copied from main.cpp)
-void SmoothingOverTime(float* outputBuffer, float* lastOutputBuffer, kiss_fft_cpx* inputBuffer, size_t length, float smoothingTimeConstant, unsigned int fftSize)
-{
-  for (size_t i = 0; i < length; i++)
-  {
-    kiss_fft_cpx c = inputBuffer[i];
-    float magnitude = sqrt(c.r * c.r + c.i * c.i) / (float)fftSize;
-    outputBuffer[i] = smoothingTimeConstant * lastOutputBuffer[i] + (1.0 - smoothingTimeConstant) * magnitude;
-  }
-}
+// Include the actual math utilities
+#include "../src/math_utils.h"
 
 // --- Tests ---
 
@@ -152,7 +110,7 @@ TEST_F(VisualizationMatrixTest, SmoothingOverTime_ZeroInput)
     inputBuffer[i].i = 0.0f;
   }
 
-  SmoothingOverTime(outputBuffer.data(), lastOutputBuffer.data(), inputBuffer.data(), NUM_BANDS, 0.5f, AUDIO_BUFFER);
+  SmoothingOverTime(outputBuffer, lastOutputBuffer, inputBuffer.data(), NUM_BANDS, 0.5f, AUDIO_BUFFER);
 
   for (size_t i = 0; i < NUM_BANDS; i++)
   {
@@ -174,7 +132,7 @@ TEST_F(VisualizationMatrixTest, SmoothingOverTime_NonZeroInput)
     inputBuffer[i].i = 0.0f;
   }
 
-  SmoothingOverTime(outputBuffer.data(), lastOutputBuffer.data(), inputBuffer.data(), NUM_BANDS, 0.0f, AUDIO_BUFFER);
+  SmoothingOverTime(outputBuffer, lastOutputBuffer, inputBuffer.data(), NUM_BANDS, 0.0f, AUDIO_BUFFER);
 
   for (size_t i = 0; i < NUM_BANDS; i++)
   {
@@ -198,7 +156,7 @@ TEST_F(VisualizationMatrixTest, SmoothingOverTime_FullSmoothing)
   }
 
   // With smoothingTimeConstant = 1.0, output should be: 1.0 * lastOutputBuffer[i] + 0 * magnitude = lastOutputBuffer[i]
-  SmoothingOverTime(outputBuffer.data(), lastOutputBuffer.data(), inputBuffer.data(), NUM_BANDS, 1.0f, AUDIO_BUFFER);
+  SmoothingOverTime(outputBuffer, lastOutputBuffer, inputBuffer.data(), NUM_BANDS, 1.0f, AUDIO_BUFFER);
 
   for (size_t i = 0; i < NUM_BANDS; i++)
   {