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Merge pull request #15 from TomHarte/2600PAL

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Adds an implementation of the PAL-region colour phase shift formula
This commit is contained in:
Thomas Harte 2016-05-13 09:00:25 -04:00
commit f487062c62
5 changed files with 60 additions and 15 deletions
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32
Machines/Atari2600/Atari2600.cpp
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@ -30,18 +30,37 @@ Machine::Machine() :
void Machine::setup_output(float aspect_ratio)
{
_crt = new Outputs::CRT::CRT(228, 1, 263, Outputs::CRT::ColourSpace::YIQ, 228, 1, 1);
// this is the NTSC phase offset function; see below for PAL
_crt->set_composite_sampling_function(
"float composite_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase, float amplitude)\n"
"float composite_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase, float amplitude)"
"{"
"uint c = texture(texID, coordinate).r;"
"uint y = (c >> 1) & 7u;"
"uint y = c & 14u;"
"uint iPhase = (c >> 4);"
"float phaseOffset = 6.283185308 * float(iPhase + 13u) / 16.0;"
"return (float(y) / 7.0) * (1.0 - amplitude) + step(1, iPhase) * amplitude * cos(phase + phaseOffset);"
"float phaseOffset = 6.283185308 * float(iPhase + 13u) / 14.0;"
"return (float(y) / 14.0) * (1.0 - amplitude) + step(1, iPhase) * amplitude * cos(phase + phaseOffset);"
"}");
_crt->set_output_device(Outputs::CRT::Television);
}
void Machine::switch_region()
{
// the PAL function
_crt->set_composite_sampling_function(
"float composite_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase, float amplitude)"
"{"
"uint c = texture(texID, coordinate).r;"
"uint y = c & 14u;"
"uint iPhase = (c >> 4);"
"float phaseOffset = (0.5 + 2.0 * (float(iPhase&1u) - 0.5) * (float((iPhase >> 1) + (iPhase&1u)) / 14.0));"
"return (float(y) / 14.0) * (1.0 - amplitude) + step(4, (iPhase + 2u) & 15u) * amplitude * cos(phase + 6.283185308 * phaseOffset);"
"}");
_crt->set_new_timing(228, 312, Outputs::CRT::ColourSpace::YUV, 228, 1);
}
void Machine::close_output()
{
delete _crt;
@ -54,11 +73,6 @@ Machine::~Machine()
close_output();
}
void Machine::switch_region()
{
_crt->set_new_timing(228, 312, Outputs::CRT::ColourSpace::YUV, 228, 1);
}
void Machine::get_output_pixel(uint8_t *pixel, int offset)
{
// get the playfield pixel and hence a proposed colour

10
Outputs/CRT/CRT.cpp
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@ -38,8 +38,8 @@ void CRT::set_new_timing(unsigned int cycles_per_line, unsigned int height_of_di
_sync_capacitor_charge_threshold = (int)(syncCapacityLineChargeThreshold * _cycles_per_line);
// create the two flywheels
_horizontal_flywheel = std::unique_ptr<Flywheel>(new Flywheel(_cycles_per_line, (millisecondsHorizontalRetraceTime * _cycles_per_line) >> 6));
_vertical_flywheel = std::unique_ptr<Flywheel>(new Flywheel(_cycles_per_line * height_of_display, scanlinesVerticalRetraceTime * _cycles_per_line));
_horizontal_flywheel = std::unique_ptr<Flywheel>(new Flywheel(_cycles_per_line, (millisecondsHorizontalRetraceTime * _cycles_per_line) >> 6, _cycles_per_line >> 6));
_vertical_flywheel = std::unique_ptr<Flywheel>(new Flywheel(_cycles_per_line * height_of_display, scanlinesVerticalRetraceTime * _cycles_per_line, (_cycles_per_line * height_of_display) >> 3));
// figure out the divisor necessary to get the horizontal flywheel into a 16-bit range
unsigned int real_clock_scan_period = (_cycles_per_line * height_of_display) / (_time_multiplier * _common_output_divisor);
@ -216,9 +216,13 @@ void CRT::advance_cycles(unsigned int number_of_cycles, unsigned int source_divi
if(_delegate)
{
_frames_since_last_delegate_call++;
if(_frames_since_last_delegate_call == 100)
if(_frames_since_last_delegate_call == 20)
{
// Yuck: to deal with the permitted ability of the delegate to make CRT changes that require the lock to be
// asserted during the delegate call, temporarily release the lock. TODO: find a less blunt instrument.
_openGL_output_builder->unlock_output();
_delegate->crt_did_end_batch_of_frames(this, _frames_since_last_delegate_call, _vertical_flywheel->get_and_reset_number_of_surprises());
_openGL_output_builder->lock_output();
_frames_since_last_delegate_call = 0;
}
}

24
Outputs/CRT/Internals/CRTOpenGL.cpp
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@ -325,24 +325,48 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
glViewport(0, 0, (GLsizei)output_width, (GLsizei)output_height);
glClear(GL_COLOR_BUFFER_BIT);
glActiveTexture(pixel_accumulation_texture_unit);
framebuffer->bind_texture();
framebuffer->draw((float)output_width / (float)output_height);
_fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
_output_mutex->unlock();
}
void OpenGLOutputBuilder::reset_all_OpenGL_state()
{
composite_input_shader_program = nullptr;
composite_separation_filter_program = nullptr;
composite_y_filter_shader_program = nullptr;
composite_chrominance_filter_shader_program = nullptr;
rgb_input_shader_program = nullptr;
rgb_filter_shader_program = nullptr;
output_shader_program = nullptr;
framebuffer = nullptr;
_last_output_width = _last_output_height = 0;
}
void OpenGLOutputBuilder::set_openGL_context_will_change(bool should_delete_resources)
{
_output_mutex->lock();
reset_all_OpenGL_state();
_output_mutex->unlock();
}
void OpenGLOutputBuilder::set_composite_sampling_function(const char *shader)
{
_output_mutex->lock();
_composite_shader = strdup(shader);
reset_all_OpenGL_state();
_output_mutex->unlock();
}
void OpenGLOutputBuilder::set_rgb_sampling_function(const char *shader)
{
_output_mutex->lock();
_rgb_shader = strdup(shader);
reset_all_OpenGL_state();
_output_mutex->unlock();
}
#pragma mark - Program compilation

3
Outputs/CRT/Internals/CRTOpenGL.hpp
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@ -85,6 +85,9 @@ class OpenGLOutputBuilder {
void set_timing_uniforms();
void set_colour_space_uniforms();
void establish_OpenGL_state();
void reset_all_OpenGL_state();
public:
OpenGLOutputBuilder(unsigned int buffer_depth);
~OpenGLOutputBuilder();

6
Outputs/CRT/Internals/Flywheel.hpp
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@ -27,13 +27,13 @@ struct Flywheel
Constructs an instance of @c Flywheel.
@param standard_period The expected amount of time between one synchronisation and the next.
@param retrace_time The amount of time it takes to complete a retrace.
@param sync_error_window The permitted deviation of sync timings from the norm.
*/
Flywheel(unsigned int standard_period, unsigned int retrace_time) :
Flywheel(unsigned int standard_period, unsigned int retrace_time, unsigned int sync_error_window) :
_standard_period(standard_period),
_retrace_time(retrace_time),
_sync_error_window(standard_period >> 7),
_sync_error_window(sync_error_window),
_counter(0),
_expected_next_sync(standard_period),
_counter_before_retrace(standard_period - retrace_time),