plot_3D_histogram.m

function plot_3D_histogram(raw_emg_data, subject_id, condition_id, participant_ids)
    % Generates a 3D histogram comparing EMG signal amplitude distributions
    % for Activity 1, Condition 1 across multiple participants.
    
    num_bins = 50; % Number of bins for histogram
    num_muscles = 8; % Number of muscle channels
    muscle_labels = {'BB', 'PD', 'AD', 'MD', 'TL', 'WF', 'WE', 'BR'};

    % Define colors for each muscle
    muscle_colors = lines(num_muscles);

    % Identify valid participants (only those with data)
    valid_indices = find(~cellfun(@isempty, raw_emg_data));
    valid_participants = participant_ids(valid_indices); % Extract actual labels
    num_valid_participants = length(valid_indices);
    
    % Ensure we have data to plot
    if num_valid_participants == 0
        warning('No valid EMG data found for any participants.');
        return;
    end

    % Initialize figure
    figure;
    hold on;

    % Loop through valid participants and plot histograms for each muscle
    for p_idx = 1:num_valid_participants
        p = valid_indices(p_idx);
        emg_data = raw_emg_data{p};

        for m = 1:num_muscles
            muscle_data = emg_data(:, m); % Extract muscle data

            % Compute histogram
            [counts, edges] = histcounts(muscle_data, num_bins, 'Normalization', 'probability');
            bin_centers = edges(1:end-1) + diff(edges) / 2; % Compute bin centers

            % Offset Y-axis to align participant IDs
            y_shift = p_idx;  

            % Plot 3D histogram using `plot3()`
            plot3(bin_centers, ones(size(bin_centers)) * y_shift, counts, ...
                'Color', muscle_colors(m, :), 'LineWidth', 2);
        end
    end

    hold off;
    xlabel('EMG Signal Amplitude');
    ylabel('Participants');
    zlabel('Probability Density');
    title(sprintf('3D Histogram: Activity 1 - Condition %s Across Participants', condition_id), 'FontSize', 14);
    
    % Set correct participant labels
    yticks(1:num_valid_participants);
    yticklabels(valid_participants); 
    
    grid on;
    legend(muscle_labels, 'Location', 'northeastoutside');
    view(-30, 30); % Adjust viewing angle
end