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Eliminated use of zero-alpha runs to clear new lines in the intermediate buffer in favour of a scissored glClear. It's just an easier way to scale the current approach to three intermediate buffers.

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This commit is contained in:
Thomas Harte 2016-04-20 20:44:25 -04:00
parent e2da77fb8b
commit 8232ed765e
3 changed files with 56 additions and 21 deletions
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10
Outputs/CRT/CRT.cpp
View File

@ -106,7 +106,6 @@ Flywheel::SyncEvent CRT::get_next_horizontal_sync_event(bool hsync_is_requested,
#define source_output_position_y(v) (*(uint16_t *)&next_run[SourceVertexSize*v + SourceVertexOffsetOfOutputPosition + 2])
#define source_phase(v) next_run[SourceVertexSize*v + SourceVertexOffsetOfPhaseAmplitudeAndAlpha + 0]
#define source_amplitude(v) next_run[SourceVertexSize*v + SourceVertexOffsetOfPhaseAmplitudeAndAlpha + 1]
#define source_alpha(v) next_run[SourceVertexSize*v + SourceVertexOffsetOfPhaseAmplitudeAndAlpha + 2]
#define source_phase_time(v) (*(uint16_t *)&next_run[SourceVertexSize*v + SourceVertexOffsetOfPhaseTime])
void CRT::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)
@ -165,7 +164,6 @@ void CRT::advance_cycles(unsigned int number_of_cycles, unsigned int source_divi
source_phase(0) = source_phase(1) = _colour_burst_phase;
source_amplitude(0) = source_amplitude(1) = _colour_burst_amplitude;
source_phase_time(0) = source_phase_time(1) = _colour_burst_time;
source_alpha(0) = source_alpha(1) = 255;
}
}
@ -244,14 +242,6 @@ void CRT::advance_cycles(unsigned int number_of_cycles, unsigned int source_divi
if(next_run_length == time_until_horizontal_sync_event && next_horizontal_sync_event == Flywheel::SyncEvent::StartRetrace)
{
_openGL_output_builder->increment_composite_output_y();
// store a run to clear the new line
next_run = _openGL_output_builder->get_next_source_run();
source_output_position_x(0) = 0;
source_output_position_x(1) = IntermediateBufferWidth;
source_output_position_y(0) = source_output_position_y(1) = _openGL_output_builder->get_composite_output_y();
source_alpha(0) = source_alpha(1) = 0;
_openGL_output_builder->complete_source_run();
}
}

61
Outputs/CRT/Internals/CRTOpenGL.cpp
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@ -206,12 +206,59 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
// decide how much to draw
if(_drawn_source_buffer_data_pointer != _source_buffer_data_pointer)
{
// determine how many lines are newly reclaimed; they'll need to be cleared
uint16_t clearing_zones[4];
int number_of_clearing_zones = 0;
if(_composite_src_output_y != _cleared_composite_output_y)
{
uint16_t lines_to_clear = _composite_src_output_y - _cleared_composite_output_y;
if(lines_to_clear > IntermediateBufferHeight)
{
number_of_clearing_zones = 1;
clearing_zones[0] = 0;
clearing_zones[1] = IntermediateBufferHeight;
}
else
{
clearing_zones[0] = (_cleared_composite_output_y+1)%IntermediateBufferHeight;
if(clearing_zones[0]+lines_to_clear < IntermediateBufferHeight)
{
clearing_zones[1] = lines_to_clear;
number_of_clearing_zones = 1;
}
else
{
clearing_zones[1] = IntermediateBufferHeight - clearing_zones[0];
clearing_zones[2] = 0;
clearing_zones[3] = lines_to_clear - clearing_zones[1];
number_of_clearing_zones = 2;
}
}
_composite_src_output_y %= IntermediateBufferHeight;
_cleared_composite_output_y = _composite_src_output_y;
}
// all drawing will be from the source vertex array and without blending
glBindVertexArray(source_vertex_array);
glDisable(GL_BLEND);
// switch to the initial texture
compositeTexture->bind_framebuffer();
composite_input_shader_program->bind();
compositeTexture->bind_framebuffer();
glBindVertexArray(source_vertex_array);
glDisable(GL_BLEND);
// clear as desired
if(number_of_clearing_zones)
{
glEnable(GL_SCISSOR_TEST);
for(int c = 0; c < number_of_clearing_zones; c++)
{
glScissor(0, clearing_zones[c*2], IntermediateBufferWidth, clearing_zones[c*2 + 1]);
glClear(GL_COLOR_BUFFER_BIT);
}
glDisable(GL_SCISSOR_TEST);
}
size_t new_data_size = _source_buffer_data_pointer - _drawn_source_buffer_data_pointer;
size_t new_data_start = _drawn_source_buffer_data_pointer;
@ -231,6 +278,7 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
glDrawArrays(GL_LINES, 0, (GLsizei)((new_data_size - first_data_length) / SourceVertexSize));
}
// switch back to screen output
glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);
glViewport(0, 0, (GLsizei)output_width, (GLsizei)output_height);
}
@ -358,7 +406,6 @@ char *OpenGLOutputBuilder::get_input_vertex_shader()
"out vec2 inputPositionVarying;"
"out vec2 iInputPositionVarying;"
"out float phaseVarying;"
"out float alphaVarying;"
"void main(void)"
"{"
@ -367,7 +414,6 @@ char *OpenGLOutputBuilder::get_input_vertex_shader()
"inputPositionVarying = (inputPosition + vec2(0.0, 0.5)) / vec2(textureSize);"
"phaseVarying = (phaseCyclesPerTick * phaseTime + phaseAmplitudeAndAlpha.x) * 2.0 * 3.141592654;"
"alphaVarying = phaseAmplitudeAndAlpha.z;"
"vec2 eyePosition = 2.0*(outputPosition / outputTextureSize) - vec2(1.0) + vec2(0.5)/textureSize;"
"gl_Position = vec4(eyePosition, 0.0, 1.0);"
@ -390,7 +436,6 @@ char *OpenGLOutputBuilder::get_input_fragment_shader()
"in vec2 inputPositionVarying;"
"in vec2 iInputPositionVarying;"
"in float phaseVarying;"
"in float alphaVarying;"
"out vec4 fragColour;"
@ -400,7 +445,7 @@ char *OpenGLOutputBuilder::get_input_fragment_shader()
"void main(void)"
"{"
"fragColour = vec4(rgb_sample(texID, inputPositionVarying, iInputPositionVarying) * alphaVarying, 1.0);" // composite
"fragColour = vec4(rgb_sample(texID, inputPositionVarying, iInputPositionVarying), 1.0);"
"}"
, composite_shader);
return result;

6
Outputs/CRT/Internals/CRTOpenGL.hpp
View File

@ -60,7 +60,7 @@ class OpenGLOutputBuilder {
std::shared_ptr<std::mutex> _output_mutex;
// transient buffers indicating composite data not yet decoded
uint16_t _composite_src_output_y;
uint16_t _composite_src_output_y, _cleared_composite_output_y;
char *get_output_vertex_shader(const char *header);
char *get_rgb_output_vertex_shader();
@ -150,12 +150,12 @@ class OpenGLOutputBuilder {
inline uint16_t get_composite_output_y()
{
return _composite_src_output_y;
return _composite_src_output_y % IntermediateBufferHeight;
}
inline void increment_composite_output_y()
{
_composite_src_output_y = (_composite_src_output_y + 1) % IntermediateBufferHeight;
_composite_src_output_y++;
}
inline void increment_field()