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Made an attempt to introduce the proper eventful loop for player output. With debugging yet to occur.

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This commit is contained in:
Thomas Harte 2017-02-11 21:01:58 -05:00
parent aeff59addc
commit b8abeced6d
1 changed files with 68 additions and 27 deletions
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95
Machines/Atari2600/TIA.cpp
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@ -276,7 +276,7 @@ void TIA::set_player_number_and_size(int player, uint8_t value)
break;
case 6:
player_[player].size = 0;
player_[player].copy_flags = 7;
player_[player].copy_flags = 6;
break;
case 7:
player_[player].size = 2;
@ -582,12 +582,12 @@ void TIA::draw_player(Player &player, CollisionType collision_identity, const in
int &motion = motion_[position_identity];
bool &is_moving = is_moving_[position_identity];
// movement is applied prior to the drawing area (as well as within)
// movement works across the entire screen, so do work that falls outside of the pixel area
int first_pixel = first_pixel_cycle + (horizontal_blank_extend_ ? 8 : 0);
int movement_time = (start + 3) & ~3;
if(is_moving)
{
// round up to the next H@1 cycle
int movement_time = (start + 3) & ~3;
while(movement_time < end && movement_time < first_pixel)
{
int movement = (movement_time - horizontal_move_start_time_) >> 2;
@ -602,36 +602,77 @@ void TIA::draw_player(Player &player, CollisionType collision_identity, const in
position %= 160;
}
// don't do any drawing if this window ends too early
// don't continue to do any drawing if this window ends too early
if(end < first_pixel) return;
if(start < first_pixel) start = first_pixel;
// while(start < end)
// {
int length = end - start;
// quick hack!
// if(is_moving)
// {
// position += (motion ^ 8);
// is_moving_[position_identity] = false;
// position %= 160;
// }
// check for initial trigger; player.position is guaranteed to be less than 160 so this is easy
if(player.graphic && position + length >= 160)
// perform a miniature event loop on (i) triggering draws; (ii) drawing; and (iii) motion
if(is_moving || player.graphic)
{
while(start < end)
{
int trigger_position = 160 - position + 5 + start - first_pixel_cycle;
int next_event_time = end;
int terminus = std::min(160, trigger_position+8);
while(trigger_position < terminus)
// is the next event a movement tick?
if(is_moving && movement_time + 4 < next_event_time)
{
collision_buffer_[trigger_position] |= (uint8_t)collision_identity;
trigger_position++;
next_event_time = movement_time + 4;
}
// is the next event a graphics draw?
int next_copy = 160;
if(player.graphic)
{
if(position < 16 && player.copy_flags&1)
{
next_copy = 16;
} else if(position < 32 && player.copy_flags&2)
{
next_copy = 32;
} else if(position < 64 && player.copy_flags&4)
{
next_copy = 64;
}
int time_until_copy = next_copy - position;
if(start+time_until_copy < next_event_time) next_event_time = start+time_until_copy;
}
// the next interesting event is after next_event_time cycles, so progress
position = (position + next_event_time) % 160;
start = next_event_time;
// if the event is a motion tick, apply
if(is_moving && start == movement_time + 4)
{
int movement_step = (movement_time - horizontal_move_start_time_) >> 2;
if(movement_step == (motion ^ 8))
{
is_moving = false;
}
else
{
position ++;
movement_time += 4;
}
}
// if it's a draw trigger, draw (TODO: use the actual graphic)
if(position == (next_copy % 160))
{
int cursor = start + 5 - first_pixel_cycle;
int terminus = std::min(160, cursor+8);
while(cursor < terminus)
{
collision_buffer_[cursor] |= (uint8_t)collision_identity;
cursor++;
}
}
}
// }
// update position counter
position = (position + end - start) % 160;
}
else
{
// just advance the timer all in one jump
position = (position + start - end) % 160;
}
}