Accelerometer Tolerance is now calibrated before Gyro Drift.

HilariousCow · slouken · commit 6bfc54508c55 · 2025-07-22T12:59:47.000-07:00
diff --git a/test/gamepadutils.c b/test/gamepadutils.c
@@ -1031,8 +1031,10 @@ struct GyroDisplay
     int estimated_sensor_rate_hz;          /*hz - our estimation of the actual polling rate by observing packets received*/
     float euler_displacement_angles[3];    /* pitch, yaw, roll */
     Quaternion gyro_quaternion;            /* Rotation since startup/reset, comprised of each gyro speed packet times sensor delta time. */
-    float drift_calibration_progress_frac; /* [0..1] */
+    EGyroCalibrationPhase current_calibration_phase;
+    float calibration_phase_progress_fraction; /* [0..1] */
     float accelerometer_noise_sq;          /* Distance between last noise and new noise. Used to indicate motion.*/
+    float accelerometer_noise_tolerance_sq; /* Maximum amount of noise detected during the Noise Profiling Phase */
 
     GamepadButton *reset_gyro_button;
     GamepadButton *calibrate_gyro_button;
@@ -1049,6 +1051,10 @@ GyroDisplay *CreateGyroDisplay(SDL_Renderer *renderer)
         ctx->gyro_quaternion = quat_identity;
         ctx->reported_sensor_rate_hz = 0;
         ctx->next_reported_sensor_time = 0;
+        ctx->current_calibration_phase = GYRO_CALIBRATION_PHASE_OFF;
+        ctx->calibration_phase_progress_fraction = 0.0f; /* [0..1] */
+        ctx->accelerometer_noise_sq = 0.0f;              
+        ctx->accelerometer_noise_tolerance_sq = ACCELEROMETER_NOISE_THRESHOLD; /* Will be overwritten but this avoids divide by zero. */
         ctx->reset_gyro_button = CreateGamepadButton(renderer, "Reset View");
         ctx->calibrate_gyro_button = CreateGamepadButton(renderer, "Recalibrate Drift");
     }
@@ -1362,17 +1368,7 @@ static void RenderGamepadElementHighlight(GamepadDisplay *ctx, int element, cons
     }
 }
 
-bool BHasCachedGyroDriftSolution(GyroDisplay *ctx)
-{
-    if (!ctx) {
-        return false;
-    }
-    return (ctx->gyro_drift_solution[0] != 0.0f ||
-            ctx->gyro_drift_solution[1] != 0.0f ||
-            ctx->gyro_drift_solution[2] != 0.0f);
-}
-
-void SetGamepadDisplayIMUValues(GyroDisplay *ctx, float *gyro_drift_solution, float *euler_displacement_angles, Quaternion *gyro_quaternion, int reported_senor_rate_hz, int estimated_sensor_rate_hz, float drift_calibration_progress_frac, float accelerometer_noise_sq)
+void SetGamepadDisplayIMUValues(GyroDisplay *ctx, float *gyro_drift_solution, float *euler_displacement_angles, Quaternion *gyro_quaternion, int reported_senor_rate_hz, int estimated_sensor_rate_hz, EGyroCalibrationPhase calibration_phase, float drift_calibration_progress_frac, float accelerometer_noise_sq, float accelerometer_noise_tolerance_sq)
 {
     if (!ctx) {
         return;
@@ -1391,8 +1387,10 @@ void SetGamepadDisplayIMUValues(GyroDisplay *ctx, float *gyro_drift_solution, fl
     SDL_memcpy(ctx->gyro_drift_solution, gyro_drift_solution, sizeof(ctx->gyro_drift_solution));
     SDL_memcpy(ctx->euler_displacement_angles, euler_displacement_angles, sizeof(ctx->euler_displacement_angles));
     ctx->gyro_quaternion = *gyro_quaternion;
-    ctx->drift_calibration_progress_frac = drift_calibration_progress_frac;
+    ctx->current_calibration_phase = calibration_phase;
+    ctx->calibration_phase_progress_fraction = drift_calibration_progress_frac;
     ctx->accelerometer_noise_sq = accelerometer_noise_sq;
+    ctx->accelerometer_noise_tolerance_sq = accelerometer_noise_tolerance_sq;
 }
 
 extern GamepadButton *GetGyroResetButton(GyroDisplay *ctx)
@@ -1713,7 +1711,7 @@ void RenderSensorTimingInfo(GyroDisplay *ctx, GamepadDisplay *gamepad_display)
     /* Sensor timing section */
     char text[128];
     const float new_line_height = gamepad_display->button_height + 2.0f;
-    const float text_offset_x = ctx->area.x + ctx->area.w / 4.0f + 40.0f;
+    const float text_offset_x = ctx->area.x + ctx->area.w / 4.0f + 35.0f;
     /* Anchor to bottom left of principle rect. */
     float text_y_pos = ctx->area.y + ctx->area.h - new_line_height * 2;
     /*
@@ -1759,7 +1757,7 @@ void RenderGyroDriftCalibrationButton(GyroDisplay *ctx, GamepadDisplay *gamepad_
     float log_y = ctx->area.y + BUTTON_PADDING;
     const float new_line_height = gamepad_display->button_height + 2.0f;
     GamepadButton *start_calibration_button = GetGyroCalibrateButton(ctx);
-    bool bHasCachedDriftSolution = BHasCachedGyroDriftSolution(ctx);
+
 
     /* Show the recalibration progress bar. */
     float recalibrate_button_width = GetGamepadButtonLabelWidth(start_calibration_button) + 2 * BUTTON_PADDING;
@@ -1769,24 +1767,46 @@ void RenderGyroDriftCalibrationButton(GyroDisplay *ctx, GamepadDisplay *gamepad_
     recalibrate_button_area.w = GetGamepadButtonLabelWidth(start_calibration_button) + 2.0f * BUTTON_PADDING;
     recalibrate_button_area.h = gamepad_display->button_height + BUTTON_PADDING * 2.0f;
 
-     if (!bHasCachedDriftSolution) {
-        SDL_snprintf(label_text, sizeof(label_text), "Progress: %3.0f%% ", ctx->drift_calibration_progress_frac * 100.0f);
-    } else {
-         SDL_strlcpy(label_text, "Calibrate Drift", sizeof(label_text));
+    /* Above button */
+    SDL_strlcpy(label_text, "Gyro Orientation:", sizeof(label_text));
+    SDLTest_DrawString(ctx->renderer, recalibrate_button_area.x, recalibrate_button_area.y - new_line_height, label_text);
+
+    /* Button label vs state */
+    if (ctx->current_calibration_phase == GYRO_CALIBRATION_PHASE_OFF) {
+        SDL_strlcpy(label_text, "Start Gyro Calibration", sizeof(label_text));
+    } else if (ctx->current_calibration_phase == GYRO_CALIBRATION_PHASE_NOISE_PROFILING) {
+        SDL_snprintf(label_text, sizeof(label_text), "Noise Progress: %3.0f%% ", ctx->calibration_phase_progress_fraction * 100.0f);
+    } else if (ctx->current_calibration_phase == GYRO_CALIBRATION_PHASE_DRIFT_PROFILING) {
+        SDL_snprintf(label_text, sizeof(label_text), "Drift Progress: %3.0f%% ", ctx->calibration_phase_progress_fraction * 100.0f);
+    } else if (ctx->current_calibration_phase == GYRO_CALIBRATION_PHASE_COMPLETE) {
+        SDL_strlcpy(label_text, "Recalibrate Gyro", sizeof(label_text));
     }
 
     SetGamepadButtonLabel(start_calibration_button, label_text);
     SetGamepadButtonArea(start_calibration_button, &recalibrate_button_area);
-    RenderGamepadButton(start_calibration_button);
+    RenderGamepadButton(start_calibration_button);  
 
-    /* Above button */
-    SDL_strlcpy(label_text, "Gyro Orientation:", sizeof(label_text));
-    SDLTest_DrawString(ctx->renderer, recalibrate_button_area.x, recalibrate_button_area.y - new_line_height, label_text);
-
-    if (!bHasCachedDriftSolution) {
+    const float flAbsoluteMaxAccelerationG = 0.125f;
+    bool bExtremeNoise = ctx->accelerometer_noise_sq > (flAbsoluteMaxAccelerationG * flAbsoluteMaxAccelerationG);
+    /* Explicit warning message if we detect too much movement */
+    if (ctx->current_calibration_phase == GYRO_CALIBRATION_PHASE_OFF) {
+        
+        if (bExtremeNoise)
+        {
+            SDL_strlcpy(label_text, "GamePad Must Be Still", sizeof(label_text));
+            SDLTest_DrawString(ctx->renderer, recalibrate_button_area.x, recalibrate_button_area.y + recalibrate_button_area.h + new_line_height, label_text);
+            SDL_strlcpy(label_text, "Place GamePad On Table", sizeof(label_text));
+            SDLTest_DrawString(ctx->renderer, recalibrate_button_area.x, recalibrate_button_area.y + recalibrate_button_area.h + new_line_height * 2, label_text);
+        }
+    }
 
-        float flNoiseFraction = SDL_clamp(SDL_sqrtf(ctx->accelerometer_noise_sq) / ACCELEROMETER_NOISE_THRESHOLD, 0.0f, 1.0f);
-        bool bTooMuchNoise = (flNoiseFraction == 1.0f);
+    if (ctx->current_calibration_phase == GYRO_CALIBRATION_PHASE_NOISE_PROFILING
+        || ctx->current_calibration_phase == GYRO_CALIBRATION_PHASE_DRIFT_PROFILING)
+    {
+        float flAbsoluteNoiseFraction = SDL_clamp(ctx->accelerometer_noise_sq / (flAbsoluteMaxAccelerationG * flAbsoluteMaxAccelerationG), 0.0f, 1.0f);
+        float flAbsoluteToleranceFraction = SDL_clamp(ctx->accelerometer_noise_tolerance_sq / (flAbsoluteMaxAccelerationG * flAbsoluteMaxAccelerationG), 0.0f, 1.0f);
+        float flRelativeNoiseFraction = SDL_clamp(ctx->accelerometer_noise_sq / ctx->accelerometer_noise_tolerance_sq, 0.0f, 1.0f);
+        bool bTooMuchNoise = (flAbsoluteNoiseFraction == 1.0f);
 
         float noise_bar_height = gamepad_display->button_height;
         SDL_FRect noise_bar_rect;
@@ -1795,21 +1815,35 @@ void RenderGyroDriftCalibrationButton(GyroDisplay *ctx, GamepadDisplay *gamepad_
         noise_bar_rect.w = recalibrate_button_area.w;
         noise_bar_rect.h = noise_bar_height;
 
+        //SDL_strlcpy(label_text, "Place GamePad On Table", sizeof(label_text));
+        SDL_snprintf(label_text, sizeof(label_text), "Noise Tolerance: %3.3fG ", SDL_sqrtf(ctx->accelerometer_noise_tolerance_sq) );
+        SDLTest_DrawString(ctx->renderer, recalibrate_button_area.x, recalibrate_button_area.y + recalibrate_button_area.h + new_line_height * 2, label_text);
+
         /* Adjust the noise bar rectangle based on the accelerometer noise value */
 
-        float noise_bar_fill_width = flNoiseFraction * noise_bar_rect.w; /* Scale the width based on the noise value */
+        float noise_bar_fill_width = flAbsoluteNoiseFraction * noise_bar_rect.w; /* Scale the width based on the noise value */
         SDL_FRect noise_bar_fill_rect;
         noise_bar_fill_rect.x = noise_bar_rect.x + (noise_bar_rect.w - noise_bar_fill_width) * 0.5f;
         noise_bar_fill_rect.y = noise_bar_rect.y;
         noise_bar_fill_rect.w = noise_bar_fill_width;
         noise_bar_fill_rect.h = noise_bar_height;
 
-        /* Set the color based on the noise value */
-        Uint8 red = (Uint8)(flNoiseFraction * 255.0f);
-        Uint8 green = (Uint8)((1.0f - flNoiseFraction) * 255.0f);
+        /* Set the color based on the noise value vs the tolerance */
+        Uint8 red = (Uint8)(flRelativeNoiseFraction * 255.0f);
+        Uint8 green = (Uint8)((1.0f - flRelativeNoiseFraction) * 255.0f);
         SDL_SetRenderDrawColor(ctx->renderer, red, green, 0, 255); /* red when high noise, green when low noise */
         SDL_RenderFillRect(ctx->renderer, &noise_bar_fill_rect);   /* draw the filled rectangle */
 
+        float tolerance_bar_fill_width = flAbsoluteToleranceFraction * noise_bar_rect.w; /* Scale the width based on the noise value */
+        SDL_FRect tolerance_bar_rect;
+        tolerance_bar_rect.x = noise_bar_rect.x + (noise_bar_rect.w - tolerance_bar_fill_width) * 0.5f;
+        tolerance_bar_rect.y = noise_bar_rect.y;
+        tolerance_bar_rect.w = tolerance_bar_fill_width;
+        tolerance_bar_rect.h = noise_bar_height;
+
+        SDL_SetRenderDrawColor(ctx->renderer, 128, 128, 0, 255); 
+        SDL_RenderRect(ctx->renderer, &tolerance_bar_rect);        /* draw the tolerance rectangle */
+
         SDL_SetRenderDrawColor(ctx->renderer, 100, 100, 100, 255); /* gray box */
         SDL_RenderRect(ctx->renderer, &noise_bar_rect);            /* draw the outline rectangle */
 
@@ -1828,7 +1862,7 @@ void RenderGyroDriftCalibrationButton(GyroDisplay *ctx, GamepadDisplay *gamepad_
         progress_bar_rect.h = BUTTON_PADDING * 0.5f;
 
         /* Adjust the drift bar rectangle based on the drift calibration progress fraction */
-        float drift_bar_fill_width = bTooMuchNoise ? 1.0f : ctx->drift_calibration_progress_frac * progress_bar_rect.w;
+        float drift_bar_fill_width = bTooMuchNoise ? 1.0f : ctx->calibration_phase_progress_fraction * progress_bar_rect.w;
         SDL_FRect progress_bar_fill;
         progress_bar_fill.x = progress_bar_rect.x;
         progress_bar_fill.y = progress_bar_rect.y;
@@ -1947,14 +1981,14 @@ void RenderGyroDisplay(GyroDisplay *ctx, GamepadDisplay *gamepadElements, SDL_Ga
     SDL_GetRenderDrawColor(ctx->renderer, &r, &g, &b, &a);
 
     RenderSensorTimingInfo(ctx, gamepadElements);
-
     RenderGyroDriftCalibrationButton(ctx, gamepadElements);
 
-    bool bHasCachedDriftSolution = BHasCachedGyroDriftSolution(ctx);
-    if (bHasCachedDriftSolution) {
+    /* Render Gyro calibration phases */
+    if (ctx->current_calibration_phase == GYRO_CALIBRATION_PHASE_COMPLETE) {
         float bottom = RenderEulerReadout(ctx, gamepadElements);
         RenderGyroGizmo(ctx, gamepad, bottom);
     }
+
     SDL_SetRenderDrawColor(ctx->renderer, r, g, b, a);
 }
 
diff --git a/test/gamepadutils.h b/test/gamepadutils.h
@@ -142,16 +142,26 @@ extern void RenderGamepadButton(GamepadButton *ctx);
 extern void DestroyGamepadButton(GamepadButton *ctx);
 
 /* Gyro element Display */
-/* If you want to calbirate against a known rotation (i.e. a turn table test) Increase ACCELEROMETER_NOISE_THRESHOLD to about 5, or drift correction will be constantly reset.*/
-#define ACCELEROMETER_NOISE_THRESHOLD 0.5f
+
+/* This is used as the initial noise tolernace threshold. It's set very close to zero to avoid divide by zero while we're evaluating the noise profile. Each controller may have a very different noise profile.*/
+#define ACCELEROMETER_NOISE_THRESHOLD 1e-6f
+
+/* Gyro Calibration Phases */
+typedef enum
+{
+    GYRO_CALIBRATION_PHASE_OFF,              /* Calibration has not yet been evaluated - signal to the user to put the controller on a flat surface before beginning the calibration process */
+    GYRO_CALIBRATION_PHASE_NOISE_PROFILING,  /* Find the max accelerometer noise for a fixed period */
+    GYRO_CALIBRATION_PHASE_DRIFT_PROFILING,  /* Find the drift while the accelerometer is below the accelerometer noise tolerance */
+    GYRO_CALIBRATION_PHASE_COMPLETE,         /* Calibration has finished */
+} EGyroCalibrationPhase;
+
 typedef struct Quaternion Quaternion;
 typedef struct GyroDisplay GyroDisplay;
 
 extern void InitCirclePoints3D();
 extern GyroDisplay *CreateGyroDisplay(SDL_Renderer *renderer);
 extern void SetGyroDisplayArea(GyroDisplay *ctx, const SDL_FRect *area);
-extern bool BHasCachedGyroDriftSolution(GyroDisplay *ctx);
-extern void SetGamepadDisplayIMUValues(GyroDisplay *ctx, float *gyro_drift_solution, float *euler_displacement_angles, Quaternion *gyro_quaternion, int reported_senor_rate_hz, int estimated_sensor_rate_hz, float drift_calibration_progress_frac, float accelerometer_noise_sq); 
+extern void SetGamepadDisplayIMUValues(GyroDisplay *ctx, float *gyro_drift_solution, float *euler_displacement_angles, Quaternion *gyro_quaternion, int reported_senor_rate_hz, int estimated_sensor_rate_hz, EGyroCalibrationPhase calibration_phase, float drift_calibration_progress_frac, float accelerometer_noise_sq, float accelerometer_noise_tolerance_sq);
 extern GamepadButton *GetGyroResetButton(GyroDisplay *ctx);
 extern GamepadButton *GetGyroCalibrateButton(GyroDisplay *ctx);
 extern void RenderGyroDisplay(GyroDisplay *ctx, GamepadDisplay *gamepadElements, SDL_Gamepad *gamepad);
diff --git a/test/testcontroller.c b/test/testcontroller.c
