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d97a073d1b
They all just as the CRT, as all are currently based on the CRT. Which doesn't currently know the total clock rate it would need to in order properly to scale the answer to the question. Further thought coming.
318 lines
11 KiB
C++
318 lines
11 KiB
C++
//
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// TIA.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 28/01/2017.
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// Copyright 2017 Thomas Harte. All rights reserved.
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//
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#ifndef TIA_hpp
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#define TIA_hpp
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#include <algorithm>
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#include <array>
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#include <cstdint>
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#include <functional>
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#include "../../../Outputs/CRT/CRT.hpp"
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#include "../../../ClockReceiver/ClockReceiver.hpp"
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namespace Atari2600 {
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class TIA {
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public:
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TIA();
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enum class OutputMode {
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NTSC, PAL
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};
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/*!
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Advances the TIA by @c cycles. Any queued setters take effect in the first cycle performed.
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*/
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void run_for(const Cycles cycles);
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void set_output_mode(OutputMode output_mode);
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void set_sync(bool sync);
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void set_blank(bool blank);
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void reset_horizontal_counter(); // Reset is delayed by four cycles.
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/*!
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@returns the number of cycles between (current TIA time) + from_offset to the current or
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next horizontal blanking period. Returns numbers in the range [0, 227].
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*/
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int get_cycles_until_horizontal_blank(const Cycles from_offset);
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void set_background_colour(uint8_t colour);
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void set_playfield(uint16_t offset, uint8_t value);
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void set_playfield_control_and_ball_size(uint8_t value);
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void set_playfield_ball_colour(uint8_t colour);
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void set_player_number_and_size(int player, uint8_t value);
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void set_player_graphic(int player, uint8_t value);
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void set_player_reflected(int player, bool reflected);
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void set_player_delay(int player, bool delay);
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void set_player_position(int player);
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void set_player_motion(int player, uint8_t motion);
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void set_player_missile_colour(int player, uint8_t colour);
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void set_missile_enable(int missile, bool enabled);
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void set_missile_position(int missile);
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void set_missile_position_to_player(int missile, bool lock);
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void set_missile_motion(int missile, uint8_t motion);
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void set_ball_enable(bool enabled);
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void set_ball_delay(bool delay);
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void set_ball_position();
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void set_ball_motion(uint8_t motion);
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void move();
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void clear_motion();
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uint8_t get_collision_flags(int offset);
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void clear_collision_flags();
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void set_crt_delegate(Outputs::CRT::Delegate *);
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void set_scan_target(Outputs::Display::ScanTarget *);
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Outputs::Display::ScanStatus get_scan_status() const;
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private:
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Outputs::CRT::CRT crt_;
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// the master counter; counts from 0 to 228 with all visible pixels being in the final 160
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int horizontal_counter_ = 0;
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// contains flags to indicate whether sync or blank are currently active
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int output_mode_ = 0;
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// keeps track of the target pixel buffer for this line and when it was acquired, and a corresponding collision buffer
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alignas(alignof(uint32_t)) uint8_t collision_buffer_[160];
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enum class CollisionType : uint8_t {
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Playfield = (1 << 0),
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Ball = (1 << 1),
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Player0 = (1 << 2),
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Player1 = (1 << 3),
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Missile0 = (1 << 4),
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Missile1 = (1 << 5)
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};
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int collision_flags_ = 0;
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int collision_flags_by_buffer_vaules_[64];
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// colour mapping tables
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enum class ColourMode {
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Standard = 0,
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ScoreLeft,
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ScoreRight,
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OnTop
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};
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uint8_t colour_mask_by_mode_collision_flags_[4][64]; // maps from [ColourMode][CollisionMark] to colour_palette_ entry
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enum class ColourIndex {
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Background = 0,
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PlayfieldBall,
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PlayerMissile0,
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PlayerMissile1
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};
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struct Colour {
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uint16_t luminance_phase;
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uint8_t original;
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};
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std::array<Colour, 4> colour_palette_;
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void set_colour_palette_entry(size_t index, uint8_t colour);
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OutputMode tv_standard_;
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// playfield state
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int background_half_mask_ = 0;
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enum class PlayfieldPriority {
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Standard,
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Score,
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OnTop
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} playfield_priority_;
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uint32_t background_[2] = {0, 0};
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// contains two 20-bit bitfields representing the background state;
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// at index 0 is the left-hand side of the playfield with bit 0 being
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// the first bit to display, bit 1 the second, etc. Index 1 contains
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// a mirror image of index 0. If the playfield is being displayed in
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// mirroring mode, background_[0] will be output on the left and
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// background_[1] on the right; otherwise background_[0] will be
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// output twice.
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// objects
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template<class T> struct Object {
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// the two programmer-set values
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int position = 0;
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int motion = 0;
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// motion_step_ is the current motion counter value; motion_time_ is the next time it will fire
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int motion_step = 0;
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int motion_time = 0;
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// indicates whether this object is currently undergoing motion
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bool is_moving = false;
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};
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// player state
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struct Player: public Object<Player> {
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int adder = 4;
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int copy_flags = 0; // a bit field, corresponding to the first few values of NUSIZ
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uint8_t graphic[2] = {0, 0}; // the player graphic; 1 = new, 0 = current
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int reverse_mask = false; // 7 for a reflected player, 0 for normal
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int graphic_index = 0;
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int pixel_position = 32, pixel_counter = 0;
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int latched_pixel4_time = -1;
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const bool enqueues = true;
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inline void skip_pixels(const int count, int from_horizontal_counter) {
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int old_pixel_counter = pixel_counter;
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pixel_position = std::min(32, pixel_position + count * adder);
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pixel_counter += count;
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if(!copy_index_ && old_pixel_counter < 4 && pixel_counter >= 4) {
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latched_pixel4_time = from_horizontal_counter + 4 - old_pixel_counter;
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}
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}
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inline void reset_pixels(int copy) {
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pixel_position = pixel_counter = 0;
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copy_index_ = copy;
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}
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inline void output_pixels(uint8_t *const target, const int count, const uint8_t collision_identity, int from_horizontal_counter) {
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output_pixels(target, count, collision_identity, pixel_position, adder, reverse_mask);
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skip_pixels(count, from_horizontal_counter);
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}
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void dequeue_pixels(uint8_t *const target, const uint8_t collision_identity, const int time_now) {
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while(queue_read_pointer_ != queue_write_pointer_) {
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uint8_t *const start_ptr = &target[queue_[queue_read_pointer_].start];
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if(queue_[queue_read_pointer_].end > time_now) {
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const int length = time_now - queue_[queue_read_pointer_].start;
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output_pixels(start_ptr, length, collision_identity, queue_[queue_read_pointer_].pixel_position, queue_[queue_read_pointer_].adder, queue_[queue_read_pointer_].reverse_mask);
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queue_[queue_read_pointer_].pixel_position += length * queue_[queue_read_pointer_].adder;
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queue_[queue_read_pointer_].start = time_now;
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return;
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} else {
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output_pixels(start_ptr, queue_[queue_read_pointer_].end - queue_[queue_read_pointer_].start, collision_identity, queue_[queue_read_pointer_].pixel_position, queue_[queue_read_pointer_].adder, queue_[queue_read_pointer_].reverse_mask);
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}
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queue_read_pointer_ = (queue_read_pointer_ + 1)&3;
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}
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}
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void enqueue_pixels(const int start, const int end, int from_horizontal_counter) {
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queue_[queue_write_pointer_].start = start;
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queue_[queue_write_pointer_].end = end;
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queue_[queue_write_pointer_].pixel_position = pixel_position;
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queue_[queue_write_pointer_].adder = adder;
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queue_[queue_write_pointer_].reverse_mask = reverse_mask;
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queue_write_pointer_ = (queue_write_pointer_ + 1)&3;
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skip_pixels(end - start, from_horizontal_counter);
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}
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private:
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int copy_index_ = 0;
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struct QueuedPixels {
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int start = 0, end = 0;
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int pixel_position = 0;
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int adder = 0;
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int reverse_mask = false;
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} queue_[4];
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int queue_read_pointer_ = 0, queue_write_pointer_ = 0;
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inline void output_pixels(uint8_t *const target, const int count, const uint8_t collision_identity, int output_pixel_position, int output_adder, int output_reverse_mask) {
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if(output_pixel_position == 32 || !graphic[graphic_index]) return;
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int output_cursor = 0;
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while(output_pixel_position < 32 && output_cursor < count) {
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int shift = (output_pixel_position >> 2) ^ output_reverse_mask;
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target[output_cursor] |= ((graphic[graphic_index] >> shift)&1) * collision_identity;
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output_cursor++;
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output_pixel_position += output_adder;
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}
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}
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} player_[2];
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// common actor for things that appear as a horizontal run of pixels
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struct HorizontalRun: public Object<HorizontalRun> {
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int pixel_position = 0;
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int size = 1;
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const bool enqueues = false;
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inline void skip_pixels(const int count, int from_horizontal_counter) {
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pixel_position = std::max(0, pixel_position - count);
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}
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inline void reset_pixels(int copy) {
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pixel_position = size;
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}
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inline void output_pixels(uint8_t *const target, const int count, const uint8_t collision_identity, int from_horizontal_counter) {
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int output_cursor = 0;
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while(pixel_position && output_cursor < count)
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{
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target[output_cursor] |= collision_identity;
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output_cursor++;
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pixel_position--;
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}
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}
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void dequeue_pixels(uint8_t *const target, const uint8_t collision_identity, const int time_now) {}
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void enqueue_pixels(const int start, const int end, int from_horizontal_counter) {}
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};
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// missile state
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struct Missile: public HorizontalRun {
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bool enabled = false;
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bool locked_to_player = false;
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int copy_flags = 0;
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inline void output_pixels(uint8_t *const target, const int count, const uint8_t collision_identity, int from_horizontal_counter) {
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if(!pixel_position) return;
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if(enabled && !locked_to_player) {
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HorizontalRun::output_pixels(target, count, collision_identity, from_horizontal_counter);
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} else {
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skip_pixels(count, from_horizontal_counter);
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}
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}
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} missile_[2];
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// ball state
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struct Ball: public HorizontalRun {
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bool enabled[2] = {false, false};
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int enabled_index = 0;
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const int copy_flags = 0;
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inline void output_pixels(uint8_t *const target, const int count, const uint8_t collision_identity, int from_horizontal_counter) {
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if(!pixel_position) return;
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if(enabled[enabled_index]) {
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HorizontalRun::output_pixels(target, count, collision_identity, from_horizontal_counter);
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} else {
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skip_pixels(count, from_horizontal_counter);
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}
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}
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} ball_;
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// motion
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bool horizontal_blank_extend_ = false;
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template<class T> void perform_border_motion(T &object, int start, int end);
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template<class T> void perform_motion_step(T &object);
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// drawing methods and state
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void draw_missile(Missile &, Player &, const uint8_t collision_identity, int start, int end);
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template<class T> void draw_object(T &, const uint8_t collision_identity, int start, int end);
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template<class T> void draw_object_visible(T &, const uint8_t collision_identity, int start, int end, int time_now);
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inline void draw_playfield(int start, int end);
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inline void output_for_cycles(int number_of_cycles);
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inline void output_line();
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int pixels_start_location_ = 0;
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uint16_t *pixel_target_ = nullptr;
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inline void output_pixels(int start, int end);
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};
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}
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#endif /* TIA_hpp */
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