mirror of
https://github.com/TomHarte/CLK.git
synced 2024-12-27 01:31:42 +00:00
272 lines
11 KiB
C++
272 lines
11 KiB
C++
//
|
|
// CRT.hpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 19/07/2015.
|
|
// Copyright © 2015 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#ifndef CRT_hpp
|
|
#define CRT_hpp
|
|
|
|
#include <stdint.h>
|
|
|
|
#include "CRTTypes.hpp"
|
|
#include "Internals/Flywheel.hpp"
|
|
#include "Internals/CRTOpenGL.hpp"
|
|
|
|
namespace Outputs {
|
|
namespace CRT {
|
|
|
|
class CRT;
|
|
|
|
class Delegate {
|
|
public:
|
|
virtual void crt_did_end_batch_of_frames(CRT *crt, unsigned int number_of_frames, unsigned int number_of_unexpected_vertical_syncs) = 0;
|
|
};
|
|
|
|
class CRT {
|
|
private:
|
|
CRT(unsigned int common_output_divisor);
|
|
|
|
// the incoming clock lengths will be multiplied by something to give at least 1000
|
|
// sample points per line
|
|
unsigned int _time_multiplier;
|
|
const unsigned int _common_output_divisor;
|
|
|
|
// fundamental creator-specified properties
|
|
unsigned int _cycles_per_line;
|
|
unsigned int _height_of_display;
|
|
|
|
// the two flywheels regulating scanning
|
|
std::unique_ptr<Flywheel> _horizontal_flywheel, _vertical_flywheel;
|
|
uint16_t _vertical_flywheel_output_divider;
|
|
|
|
// elements of sync separation
|
|
bool _is_receiving_sync; // true if the CRT is currently receiving sync (i.e. this is for edge triggering of horizontal sync)
|
|
int _sync_capacitor_charge_level; // this charges up during times of sync and depletes otherwise; needs to hit a required threshold to trigger a vertical sync
|
|
int _sync_capacitor_charge_threshold; // this charges up during times of sync and depletes otherwise; needs to hit a required threshold to trigger a vertical sync
|
|
unsigned int _sync_period;
|
|
|
|
// each call to output_* generates a scan. A two-slot queue for scans allows edge extensions.
|
|
struct Scan {
|
|
enum Type {
|
|
Sync, Level, Data, Blank, ColourBurst
|
|
} type;
|
|
unsigned int number_of_cycles;
|
|
union {
|
|
struct {
|
|
unsigned int source_divider;
|
|
uint16_t tex_x, tex_y;
|
|
};
|
|
struct {
|
|
uint8_t phase, amplitude;
|
|
};
|
|
};
|
|
};
|
|
void output_scan(const Scan *scan);
|
|
|
|
uint8_t _colour_burst_phase, _colour_burst_amplitude;
|
|
uint16_t _colour_burst_time;
|
|
bool _is_writing_composite_run;
|
|
|
|
// the outer entry point for dispatching output_sync, output_blank, output_level and output_data
|
|
void advance_cycles(unsigned int number_of_cycles, unsigned int source_divider, bool hsync_requested, bool vsync_requested, const bool vsync_charging, const Scan::Type type, uint16_t tex_x, uint16_t tex_y);
|
|
|
|
// the inner entry point that determines whether and when the next sync event will occur within
|
|
// the current output window
|
|
Flywheel::SyncEvent get_next_vertical_sync_event(bool vsync_is_requested, unsigned int cycles_to_run_for, unsigned int *cycles_advanced);
|
|
Flywheel::SyncEvent get_next_horizontal_sync_event(bool hsync_is_requested, unsigned int cycles_to_run_for, unsigned int *cycles_advanced);
|
|
|
|
// OpenGL state, kept behind an opaque pointer to avoid inclusion of the GL headers here.
|
|
std::unique_ptr<OpenGLOutputBuilder> _openGL_output_builder;
|
|
|
|
// temporary storage used during the construction of output runs
|
|
struct {
|
|
uint16_t x1, y, tex_y;
|
|
} _output_run;
|
|
|
|
// The delegate
|
|
Delegate *_delegate;
|
|
unsigned int _frames_since_last_delegate_call;
|
|
|
|
public:
|
|
/*! Constructs the CRT with a specified clock rate, height and colour subcarrier frequency.
|
|
The requested number of buffers, each with the requested number of bytes per pixel,
|
|
is created for the machine to write raw pixel data to.
|
|
|
|
@param cycles_per_line The clock rate at which this CRT will be driven, specified as the number
|
|
of cycles expected to take up one whole scanline of the display.
|
|
|
|
@param common_output_divisor The greatest a priori common divisor of all cycle counts that will be
|
|
supplied to @c output_sync, @c output_data, etc; supply 1 if no greater divisor is known. For many
|
|
machines output will run at a fixed multiple of the clock rate; knowing this divisor can improve
|
|
internal precision.
|
|
|
|
@param height_of_display The number of lines that nominally form one field of the display, rounded
|
|
up to the next whole integer.
|
|
|
|
@param colour_cycle_numerator Specifies the numerator for the per-line frequency of the colour subcarrier.
|
|
|
|
@param colour_cycle_denominator Specifies the denominator for the per-line frequency of the colour subcarrier.
|
|
The colour subcarrier is taken to have colour_cycle_numerator/colour_cycle_denominator cycles per line.
|
|
|
|
@param buffer_depth The depth per pixel of source data buffers to create for this machine. Machines
|
|
may provide per-clock-cycle data in the depth that they consider convenient, supplying a sampling
|
|
function to convert between their data format and either a composite or RGB signal, allowing that
|
|
work to be offloaded onto the GPU and allowing the output signal to be sampled at a rate appropriate
|
|
to the display size.
|
|
|
|
@see @c set_rgb_sampling_function , @c set_composite_sampling_function
|
|
*/
|
|
CRT(unsigned int cycles_per_line, unsigned int common_output_divisor, unsigned int height_of_display, ColourSpace colour_space, unsigned int colour_cycle_numerator, unsigned int colour_cycle_denominator, unsigned int buffer_depth);
|
|
|
|
/*! Constructs the CRT with the specified clock rate, with the display height and colour
|
|
subcarrier frequency dictated by a standard display type and with the requested number of
|
|
buffers, each with the requested number of bytes per pixel.
|
|
|
|
Exactly identical to calling the designated constructor with colour subcarrier information
|
|
looked up by display type.
|
|
*/
|
|
CRT(unsigned int cycles_per_line, unsigned int common_output_divisor, DisplayType displayType, unsigned int buffer_depth);
|
|
|
|
/*! Resets the CRT with new timing information. The CRT then continues as though the new timing had
|
|
been provided at construction. */
|
|
void set_new_timing(unsigned int cycles_per_line, unsigned int height_of_display, ColourSpace colour_space, unsigned int colour_cycle_numerator, unsigned int colour_cycle_denominator);
|
|
|
|
/*! Resets the CRT with new timing information derived from a new display type. The CRT then continues
|
|
as though the new timing had been provided at construction. */
|
|
void set_new_display_type(unsigned int cycles_per_line, DisplayType displayType);
|
|
|
|
/*! Output at the sync level.
|
|
|
|
@param number_of_cycles The amount of time to putput sync for.
|
|
*/
|
|
void output_sync(unsigned int number_of_cycles);
|
|
|
|
/*! Output at the blanking level.
|
|
|
|
@param number_of_cycles The amount of time to putput the blanking level for.
|
|
*/
|
|
void output_blank(unsigned int number_of_cycles);
|
|
|
|
/*! Outputs the first written to the most-recently created run of data repeatedly for a prolonged period.
|
|
|
|
@param number_of_cycles The number of cycles to repeat the output for.
|
|
*/
|
|
void output_level(unsigned int number_of_cycles);
|
|
|
|
/*! Declares that the caller has created a run of data via @c allocate_write_area and @c get_write_target_for_buffer
|
|
that is at least @c number_of_cycles long, and that the first @c number_of_cycles/source_divider should be spread
|
|
over that amount of time.
|
|
|
|
@param number_of_cycles The amount of data to output.
|
|
|
|
@param source_divider A divider for source data; if the divider is 1 then one source pixel is output every cycle,
|
|
if it is 2 then one source pixel covers two cycles; if it is n then one source pixel covers n cycles.
|
|
|
|
@see @c allocate_write_area , @c get_write_target_for_buffer
|
|
*/
|
|
void output_data(unsigned int number_of_cycles, unsigned int source_divider);
|
|
|
|
/*! Outputs a colour burst.
|
|
|
|
@param number_of_cycles The length of the colour burst.
|
|
|
|
@param phase The initial phase of the colour burst in a measuring system with 256 units
|
|
per circle, e.g. 0 = 0 degrees, 128 = 180 degrees, 256 = 360 degree.
|
|
|
|
@param amplitude The amplitude of the colour burst in 1/256ths of the amplitude of the
|
|
positive portion of the wave.
|
|
*/
|
|
void output_colour_burst(unsigned int number_of_cycles, uint8_t phase, uint8_t amplitude);
|
|
|
|
/*! Attempts to allocate the given number of output samples for writing.
|
|
|
|
The beginning of the most recently allocated area is used as the start
|
|
of data written by a call to @c output_data; it is acceptable to write and to
|
|
output less data than the amount requested but that may be less efficient.
|
|
|
|
Allocation should fail only if emulation is running significantly below real speed.
|
|
|
|
@param required_length The number of samples to allocate.
|
|
@returns A pointer to the allocated area if room is available; @c nullptr otherwise.
|
|
*/
|
|
inline uint8_t *allocate_write_area(size_t required_length)
|
|
{
|
|
return _openGL_output_builder->allocate_write_area(required_length);
|
|
}
|
|
|
|
/*! Causes appropriate OpenGL or OpenGL ES calls to be issued in order to draw the current CRT state.
|
|
The caller is responsible for ensuring that a valid OpenGL context exists for the duration of this call.
|
|
*/
|
|
inline void draw_frame(unsigned int output_width, unsigned int output_height, bool only_if_dirty)
|
|
{
|
|
_openGL_output_builder->draw_frame(output_width, output_height, only_if_dirty);
|
|
}
|
|
|
|
/*! Tells the CRT that the next call to draw_frame will occur on a different OpenGL context than
|
|
the previous.
|
|
|
|
@param should_delete_resources If @c true then all resources — textures, vertex arrays, etc —
|
|
currently held by the CRT will be deleted now via calls to glDeleteTexture and equivalent. If
|
|
@c false then the references are simply marked as invalid.
|
|
*/
|
|
inline void set_openGL_context_will_change(bool should_delete_resources)
|
|
{
|
|
_openGL_output_builder->set_openGL_context_will_change(should_delete_resources);
|
|
}
|
|
|
|
/*! Sets a function that will map from whatever data the machine provided to a composite signal.
|
|
|
|
@param shader A GLSL fragment including a function with the signature
|
|
`float composite_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase, float amplitude)`
|
|
that evaluates to the composite signal level as a function of a source buffer, sampling location, colour
|
|
carrier phase and amplitude.
|
|
*/
|
|
inline void set_composite_sampling_function(const char *shader)
|
|
{
|
|
_openGL_output_builder->set_composite_sampling_function(shader);
|
|
}
|
|
|
|
/*! Sets a function that will map from whatever data the machine provided to an RGB signal.
|
|
|
|
If the output mode is composite then a default mapping from RGB to the display's composite
|
|
format will be applied.
|
|
|
|
@param shader A GLSL fragent including a function with the signature
|
|
`vec3 rgb_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate)` that evaluates to an RGB colour
|
|
as a function of:
|
|
|
|
* `usampler2D sampler` representing the source buffer;
|
|
* `vec2 coordinate` representing the source buffer location to sample from in the range [0, 1); and
|
|
* `vec2 icoordinate` representing the source buffer location to sample from as a pixel count, for easier multiple-pixels-per-byte unpacking.
|
|
*/
|
|
inline void set_rgb_sampling_function(const char *shader)
|
|
{
|
|
_openGL_output_builder->set_rgb_sampling_function(shader);
|
|
}
|
|
|
|
inline void set_output_device(OutputDevice output_device)
|
|
{
|
|
_openGL_output_builder->set_output_device(output_device);
|
|
}
|
|
|
|
inline void set_visible_area(Rect visible_area)
|
|
{
|
|
_openGL_output_builder->set_visible_area(visible_area);
|
|
}
|
|
|
|
Rect get_rect_for_area(int first_line_after_sync, int number_of_lines, int first_cycle_after_sync, int number_of_cycles, float aspect_ratio);
|
|
|
|
inline void set_delegate(Delegate *delegate)
|
|
{
|
|
_delegate = delegate;
|
|
}
|
|
};
|
|
|
|
}
|
|
}
|
|
|
|
#endif /* CRT_cpp */
|