From 20cab08f8f480deea45af737b4d4a942b00b123a Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sat, 23 Jan 2016 17:44:34 -0500
Subject: [PATCH] Added a two-slot buffer of scans and a comon dispatch
mechanism.
---
Outputs/CRT.cpp | 75 +++++++++++++++++++++++++++++++------------------
Outputs/CRT.hpp | 19 ++++++++++++-
2 files changed, 66 insertions(+), 28 deletions(-)
diff --git a/Outputs/CRT.cpp b/Outputs/CRT.cpp
index 307be6caa..9e5b73204 100644
--- a/Outputs/CRT.cpp
+++ b/Outputs/CRT.cpp
@@ -64,7 +64,16 @@ void CRT::set_new_timing(unsigned int cycles_per_line, unsigned int height_of_di
}
}
-CRT::CRT(unsigned int cycles_per_line, unsigned int height_of_display, unsigned int number_of_buffers, ...)
+CRT::CRT(unsigned int cycles_per_line, unsigned int height_of_display, unsigned int number_of_buffers, ...) :
+ _next_scan(0),
+ _frames_with_delegate(0),
+ _frame_read_pointer(0),
+ _horizontal_counter(0),
+ _sync_capacitor_charge_level(0),
+ _is_receiving_sync(false),
+ _is_in_hsync(false),
+ _is_in_vsync(false),
+ _rasterPosition({.x = 0, .y = 0})
{
set_new_timing(cycles_per_line, height_of_display);
@@ -79,24 +88,10 @@ CRT::CRT(unsigned int cycles_per_line, unsigned int height_of_display, unsigned
_frame_builders[frame] = new CRTFrameBuilder(bufferWidth, bufferHeight, number_of_buffers, va);
va_end(va);
}
- _frames_with_delegate = 0;
- _frame_read_pointer = 0;
_current_frame_builder = _frame_builders[0];
- // reset raster position
- _rasterPosition.x = _rasterPosition.y = 0;
-
// reset flywheel sync
_expected_next_hsync = _cycles_per_line;
- _horizontal_counter = 0;
-
- // reset the vertical charge capacitor
- _sync_capacitor_charge_level = 0;
-
- // start off not in horizontal sync, not receiving a sync signal
- _is_receiving_sync = false;
- _is_in_hsync = false;
- _is_in_vsync = false;
}
CRT::~CRT()
@@ -349,35 +344,61 @@ void CRT::set_delegate(Delegate *delegate)
#pragma mark - stream feeding methods
+void CRT::output_scan(Scan *scan)
+{
+ bool this_is_sync = (scan->type == Type::Sync);
+ bool hsync_requested = !_is_receiving_sync && this_is_sync;
+ bool vsync_requested = _is_receiving_sync;
+ _is_receiving_sync = this_is_sync;
+
+ advance_cycles(scan->number_of_cycles, scan->source_divider, hsync_requested, vsync_requested, this_is_sync, scan->type);
+
+ _next_scan ^= 1;
+}
+
/*
These all merely channel into advance_cycles, supplying appropriate arguments
*/
void CRT::output_sync(unsigned int number_of_cycles)
{
- bool _hsync_requested = !_is_receiving_sync; // ensure this really is edge triggered; someone calling output_sync twice in succession shouldn't trigger it twice
- _is_receiving_sync = true;
- advance_cycles(number_of_cycles, 1, _hsync_requested, false, true, Type::Sync);
+ _scans[_next_scan].type = Type::Sync;
+ _scans[_next_scan].number_of_cycles = number_of_cycles;
+ output_scan(&_scans[_next_scan]);
}
void CRT::output_blank(unsigned int number_of_cycles)
{
- bool _vsync_requested = _is_receiving_sync;
- _is_receiving_sync = false;
- advance_cycles(number_of_cycles, 1, false, _vsync_requested, false, Type::Blank);
+ _scans[_next_scan].type = Type::Blank;
+ _scans[_next_scan].number_of_cycles = number_of_cycles;
+ output_scan(&_scans[_next_scan]);
}
void CRT::output_level(unsigned int number_of_cycles)
{
- bool _vsync_requested = _is_receiving_sync;
- _is_receiving_sync = false;
- advance_cycles(number_of_cycles, 1, false, _vsync_requested, false, Type::Level);
+ _scans[_next_scan].type = Type::Level;
+ _scans[_next_scan].number_of_cycles = number_of_cycles;
+ _scans[_next_scan].tex_x = _current_frame_builder ? _current_frame_builder->_write_x_position : 0;
+ _scans[_next_scan].tex_y = _current_frame_builder ? _current_frame_builder->_write_y_position : 0;
+ output_scan(&_scans[_next_scan]);
+}
+
+void CRT::output_colour_burst(unsigned int number_of_cycles, uint8_t phase, uint8_t magnitude)
+{
+ _scans[_next_scan].type = Type::ColourBurst;
+ _scans[_next_scan].number_of_cycles = number_of_cycles;
+ _scans[_next_scan].phase = phase;
+ _scans[_next_scan].magnitude = magnitude;
+ output_scan(&_scans[_next_scan]);
}
void CRT::output_data(unsigned int number_of_cycles, unsigned int source_divider)
{
- bool _vsync_requested = _is_receiving_sync;
- _is_receiving_sync = false;
- advance_cycles(number_of_cycles, source_divider, false, _vsync_requested, false, Type::Data);
+ _scans[_next_scan].type = Type::Data;
+ _scans[_next_scan].number_of_cycles = number_of_cycles;
+ _scans[_next_scan].tex_x = _current_frame_builder ? _current_frame_builder->_write_x_position : 0;
+ _scans[_next_scan].tex_y = _current_frame_builder ? _current_frame_builder->_write_y_position : 0;
+ _scans[_next_scan].source_divider = source_divider;
+ output_scan(&_scans[_next_scan]);
}
#pragma mark - Buffer supply
diff --git a/Outputs/CRT.hpp b/Outputs/CRT.hpp
index af87c4f29..865e9dda7 100644
--- a/Outputs/CRT.hpp
+++ b/Outputs/CRT.hpp
@@ -144,7 +144,7 @@ class CRT {
// the outer entry point for dispatching output_sync, output_blank, output_level and output_data
enum Type {
- Sync, Level, Data, Blank
+ Sync, Level, Data, Blank, ColourBurst
} type;
void advance_cycles(unsigned int number_of_cycles, unsigned int source_divider, bool hsync_requested, bool vsync_requested, bool vsync_charging, Type type);
@@ -157,6 +157,23 @@ class CRT {
};
SyncEvent get_next_vertical_sync_event(bool vsync_is_requested, unsigned int cycles_to_run_for, unsigned int *cycles_advanced);
SyncEvent get_next_horizontal_sync_event(bool hsync_is_requested, unsigned int cycles_to_run_for, unsigned int *cycles_advanced);
+
+ // each call to output_* generates a scan. A two-slot queue for scans allows edge extensions.
+ struct Scan {
+ Type type;
+ unsigned int number_of_cycles;
+ union {
+ struct {
+ unsigned int source_divider;
+ uint16_t tex_x, tex_y;
+ };
+ struct {
+ uint8_t phase, magnitude;
+ };
+ };
+ } _scans[2];
+ int _next_scan;
+ void output_scan(Scan *scan);
};
}