A start on movie rewind.

movie.c

@@ -87,6 +87,14 @@ struct bsv_movie
 {
    FILE *file;
    uint8_t *state;
+
+   uint16_t *frame_state; // A ring buffer keeping track of many key presses were requested per frame.
+   size_t frame_mask;
+   uint16_t current_frame_count;
+   size_t frame_ptr;
+
+   bool playback;
+   unsigned min_file_pos;
 };
 
 #define BSV_MAGIC 0x42535631
@@ -127,6 +135,7 @@ static inline uint16_t swap_if_big16(uint16_t val)
 
 static bool init_playback(bsv_movie_t *handle, const char *path)
 {
+   handle->playback = true;
    handle->file = fopen(path, "rb");
    if (!handle->file)
    {
@@ -158,6 +167,8 @@ static bool init_playback(bsv_movie_t *handle, const char *path)
    if (!handle->state)
       return false;
 
+   handle->min_file_pos = sizeof(header) + state_size;
+
    if (fread(handle->state, 1, state_size, handle->file) != state_size)
    {
       SSNES_ERR("Couldn't read state from movie.\n");
@@ -196,6 +207,8 @@ static bool init_record(bsv_movie_t *handle, const char *path)
    if (!handle->state)
       return false;
 
+   handle->min_file_pos = sizeof(header) + state_size;
+
    psnes_serialize(handle->state, state_size);
    fwrite(handle->state, 1, state_size, handle->file);
    return true;
@@ -208,6 +221,7 @@ void bsv_movie_free(bsv_movie_t *handle)
       if (handle->file)
          fclose(handle->file);
       free(handle->state);
+      free(handle->frame_state);
       free(handle);
    }
 }
@@ -218,12 +232,14 @@ bool bsv_movie_get_input(bsv_movie_t *handle, int16_t *input)
       return false;
 
    *input = swap_if_big16(*input);
+   handle->current_frame_count++;
    return true;
 }
 
 void bsv_movie_set_input(bsv_movie_t *handle, int16_t input)
 {
    fwrite(&input, sizeof(int16_t), 1, handle->file);
+   handle->current_frame_count++;
 }
 
 bsv_movie_t *bsv_movie_init(const char *path, enum ssnes_movie_type type)
@@ -240,9 +256,38 @@ bsv_movie_t *bsv_movie_init(const char *path, enum ssnes_movie_type type)
    else if (!init_record(handle, path))
       goto error;
 
+   if (!(handle->frame_state = malloc((1 << 20) * sizeof(uint16_t)))) // Just pick something really large :D
+      goto error; 
+   handle->frame_mask = (1 << 20) - 1;
+
    return handle;
 
 error:
    bsv_movie_free(handle);
    return NULL;
 }
+
+void bsv_movie_set_frame_end(bsv_movie_t *handle)
+{
+   handle->frame_state[handle->frame_ptr] = handle->current_frame_count;
+   handle->current_frame_count = 0;
+   handle->frame_ptr = (handle->frame_ptr + 1) & handle->frame_mask;
+}
+
+void bsv_movie_frame_rewind(bsv_movie_t *handle)
+{
+   if (ftell(handle->file) <= (long)handle->min_file_pos)
+   {
+      if (!handle->playback)
+      {
+         fseek(handle->file, 4 * sizeof(uint32_t), SEEK_SET);
+         psnes_serialize(handle->state, handle->min_file_pos - 4 * sizeof(uint32_t));
+         fwrite(handle->state, 1, handle->min_file_pos - 4 * sizeof(uint32_t), handle->file);
+      }
+   }
+   else
+   {
+      handle->frame_ptr = (handle->frame_ptr - 1) & handle->frame_mask;
+      fseek(handle->file, -((long)handle->frame_state[handle->frame_ptr] * sizeof(int16_t)), SEEK_CUR);
+   }
+}

movie.h

@@ -37,12 +37,13 @@ bool bsv_movie_get_input(bsv_movie_t *handle, int16_t *input);
 // Recording
 void bsv_movie_set_input(bsv_movie_t *handle, int16_t input);
 
+// Used for rewinding while playback/record.
+void bsv_movie_set_frame_end(bsv_movie_t *handle);
+void bsv_movie_frame_rewind(bsv_movie_t *handle);
+
 void bsv_movie_free(bsv_movie_t *handle);
 
 uint32_t crc32_calculate(const uint8_t *data, unsigned length);
 
-
-
-
 #endif
 

ssnes.c

@@ -241,7 +241,7 @@ static void input_poll(void)
 
 static int16_t input_state(bool port, unsigned device, unsigned index, unsigned id)
 {
-   if (g_extern.bsv_movie && g_extern.bsv_movie_playback)
+   if (g_extern.bsv_movie && g_extern.bsv_movie_playback && !g_extern.frame_is_reverse)
    {
       int16_t ret;
       if (bsv_movie_get_input(g_extern.bsv_movie, &ret))
@@ -258,7 +258,7 @@ static int16_t input_state(bool port, unsigned device, unsigned index, unsigned
       binds[i] = g_settings.input.binds[i];
 
    int16_t res = driver.input->input_state(driver.input_data, binds, port, device, index, id);
-   if (g_extern.bsv_movie && !g_extern.bsv_movie_playback)
+   if (g_extern.bsv_movie && !g_extern.bsv_movie_playback && !g_extern.frame_is_reverse)
       bsv_movie_set_input(g_extern.bsv_movie, res);
 
    return res;
@@ -1042,6 +1042,9 @@ static void check_rewind(void)
 
    if (driver.input->key_pressed(driver.input_data, SSNES_REWIND))
    {
+      if (g_extern.bsv_movie)
+         bsv_movie_frame_rewind(g_extern.bsv_movie);
+
       msg_queue_clear(g_extern.msg_queue);
       void *buf;
       if (state_manager_pop(g_extern.state_manager, &buf))
@@ -1174,8 +1177,8 @@ static void do_state_checks(void)
       {
          check_stateslots();
          check_savestates();
-         check_rewind();
       }
+      check_rewind();
 
       if (!g_extern.bsv_movie_playback)
          check_movie_record();
@@ -1207,14 +1210,15 @@ int main(int argc, char *argv[])
    init_movie();
 
    if (!g_extern.bsv_movie)
-   {
       load_save_files();
-      init_rewind();
-   }
+
 
    init_netplay();
    init_drivers();
 
+   if (!g_extern.netplay)
+      init_rewind();
+
    psnes_set_video_refresh(g_extern.netplay ? video_frame_net : video_frame);
    psnes_set_audio_sample(g_extern.netplay ? audio_sample_net : audio_sample);
    psnes_set_input_poll(g_extern.netplay ? input_poll_net : input_poll);
@@ -1250,6 +1254,8 @@ int main(int argc, char *argv[])
 
          psnes_run();
 
+         if (g_extern.bsv_movie)
+            bsv_movie_set_frame_end(g_extern.bsv_movie);
          if (g_extern.netplay)
             netplay_post_frame(g_extern.netplay);
 
@@ -1280,10 +1286,10 @@ int main(int argc, char *argv[])
 #endif
 
    if (!g_extern.bsv_movie_playback && !g_extern.netplay_is_client)
-   {
-      deinit_rewind();
       save_files();
-   }
+
+   if (!g_extern.netplay)
+      deinit_rewind();
 
    deinit_movie();
    deinit_msg_queue();