Effects_Buffer.h

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// Multi-channel effects buffer with panning, echo and reverb
 
// Game_Music_Emu https://bitbucket.org/mpyne/game-music-emu/
#ifndef EFFECTS_BUFFER_H
#define EFFECTS_BUFFER_H
 
#include "Multi_Buffer.h"
 
#include <vector>
 
// Effects_Buffer uses several buffers and outputs stereo sample pairs.
class Effects_Buffer : public Multi_Buffer {
public:
        // nVoices indicates the number of voices for which buffers will be allocated
        // to make Effects_Buffer work as "mix everything to one", nVoices will be 1
        // If center_only is true, only center buffers are created and
        // less memory is used.
        Effects_Buffer( int nVoices = 1, bool center_only = false );
        
        // Channel  Effect    Center Pan
        // ---------------------------------
        //    0,5    reverb       pan_1
        //    1,6    reverb       pan_2
        //    2,7    echo         -
        //    3      echo         -
        //    4      echo         -
        
        // Channel configuration
        struct config_t {
                double pan_1;           // -1.0 = left, 0.0 = center, 1.0 = right
                double pan_2;
                double echo_delay;      // msec
                double echo_level;      // 0.0 to 1.0
                double reverb_delay;    // msec
                double delay_variance;  // difference between left/right delays (msec)
                double reverb_level;    // 0.0 to 1.0
                bool effects_enabled;   // if false, use optimized simple mixer
                config_t();
        };
        
        // Set configuration of buffer
        virtual void config( const config_t& );
        void set_depth( double );
        
public:
        ~Effects_Buffer();
        blargg_err_t set_sample_rate( long samples_per_sec, int msec = blip_default_length );
        void clock_rate( long );
        void bass_freq( int );
        void clear();
        channel_t channel( int, int );
        void end_frame( blip_time_t );
        long read_samples( blip_sample_t*, long );
        long samples_avail() const;
private:
        typedef long fixed_t;
        int max_voices;
        enum { max_buf_count = 7 };
        std::vector<Blip_Buffer> bufs;
        enum { chan_types_count = 3 };
        std::vector<channel_t> chan_types;
        config_t config_;
        long stereo_remain;
        long effect_remain;
        int buf_count;
        bool effects_enabled;
        
        std::vector<std::vector<blip_sample_t> > reverb_buf;
        std::vector<std::vector<blip_sample_t> > echo_buf;
        std::vector<int> reverb_pos;
        std::vector<int> echo_pos;
        
        struct {
                fixed_t pan_1_levels [2];
                fixed_t pan_2_levels [2];
                int echo_delay_l;
                int echo_delay_r;
                fixed_t echo_level;
                int reverb_delay_l;
                int reverb_delay_r;
                fixed_t reverb_level;
        } chans;
        
        void mix_mono( blip_sample_t*, blargg_long );
        void mix_stereo( blip_sample_t*, blargg_long );
        void mix_enhanced( blip_sample_t*, blargg_long );
        void mix_mono_enhanced( blip_sample_t*, blargg_long );
};
 
#endif