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Merge pull request #609 from TomHarte/ReducedScanTargetContention

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Reduces draw/update contention.
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Thomas Harte 2019-03-07 19:31:35 -05:00 committed by GitHub
commit 13b6079826
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2 changed files with 21 additions and 12 deletions
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30
Outputs/OpenGL/ScanTarget.cpp
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@ -101,29 +101,31 @@ ScanTarget::ScanTarget(GLuint target_framebuffer, float output_gamma) :
test_gl(glBlendFunc, GL_SRC_ALPHA, GL_CONSTANT_COLOR); test_gl(glBlendFunc, GL_SRC_ALPHA, GL_CONSTANT_COLOR);
test_gl(glBlendColor, 0.4f, 0.4f, 0.4f, 1.0f); test_gl(glBlendColor, 0.4f, 0.4f, 0.4f, 1.0f);
is_drawing_.clear(); // Establish initial state for the two atomic flags.
is_updating_.clear();
is_drawing_to_accumulation_buffer_.clear();
} }
ScanTarget::~ScanTarget() { ScanTarget::~ScanTarget() {
while(is_drawing_.test_and_set()); while(is_updating_.test_and_set());
glDeleteBuffers(1, &scan_buffer_name_); glDeleteBuffers(1, &scan_buffer_name_);
glDeleteTextures(1, &write_area_texture_name_); glDeleteTextures(1, &write_area_texture_name_);
glDeleteVertexArrays(1, &scan_vertex_array_); glDeleteVertexArrays(1, &scan_vertex_array_);
} }
void ScanTarget::set_target_framebuffer(GLuint target_framebuffer) { void ScanTarget::set_target_framebuffer(GLuint target_framebuffer) {
while(is_drawing_.test_and_set()); while(is_updating_.test_and_set());
target_framebuffer_ = target_framebuffer; target_framebuffer_ = target_framebuffer;
is_drawing_.clear(); is_updating_.clear();
} }
void ScanTarget::set_modals(Modals modals) { void ScanTarget::set_modals(Modals modals) {
// Don't change the modals while drawing is ongoing; a previous set might be // Don't change the modals while drawing is ongoing; a previous set might be
// in the process of being established. // in the process of being established.
while(is_drawing_.test_and_set()); while(is_updating_.test_and_set());
modals_ = modals; modals_ = modals;
modals_are_dirty_ = true; modals_are_dirty_ = true;
is_drawing_.clear(); is_updating_.clear();
} }
Outputs::Display::ScanTarget::Scan *ScanTarget::begin_scan() { Outputs::Display::ScanTarget::Scan *ScanTarget::begin_scan() {
@ -410,7 +412,7 @@ void ScanTarget::update(int output_width, int output_height) {
// Spin until the is-drawing flag is reset; the wait sync above will deal // Spin until the is-drawing flag is reset; the wait sync above will deal
// with instances where waiting is inappropriate. // with instances where waiting is inappropriate.
while(is_drawing_.test_and_set()); while(is_updating_.test_and_set());
// Establish the pipeline if necessary. // Establish the pipeline if necessary.
const bool did_setup_pipeline = modals_are_dirty_; const bool did_setup_pipeline = modals_are_dirty_;
@ -568,6 +570,9 @@ void ScanTarget::update(int output_width, int output_height) {
const int framebuffer_height = std::max(output_height / resolution_reduction_level_, std::min(540, output_height)); const int framebuffer_height = std::max(output_height / resolution_reduction_level_, std::min(540, output_height));
const int proportional_width = (framebuffer_height * 4) / 3; const int proportional_width = (framebuffer_height * 4) / 3;
const bool did_create_accumulation_texture = !accumulation_texture_ || ( (accumulation_texture_->get_width() != proportional_width || accumulation_texture_->get_height() != framebuffer_height)); const bool did_create_accumulation_texture = !accumulation_texture_ || ( (accumulation_texture_->get_width() != proportional_width || accumulation_texture_->get_height() != framebuffer_height));
// Work with the accumulation_buffer_ potentially starts from here onwards; set its flag.
while(is_drawing_to_accumulation_buffer_.test_and_set());
if(did_create_accumulation_texture) { if(did_create_accumulation_texture) {
LOG("Changed output resolution to " << proportional_width << " by " << framebuffer_height); LOG("Changed output resolution to " << proportional_width << " by " << framebuffer_height);
display_metrics_.announce_did_resize(); display_metrics_.announce_did_resize();
@ -701,18 +706,21 @@ void ScanTarget::update(int output_width, int output_height) {
test_gl(glDisable, GL_BLEND); test_gl(glDisable, GL_BLEND);
} }
// That's it for operations affecting the accumulation buffer.
is_drawing_to_accumulation_buffer_.clear();
// All data now having been spooled to the GPU, update the read pointers to // All data now having been spooled to the GPU, update the read pointers to
// the submit pointer location. // the submit pointer location.
read_pointers_.store(submit_pointers); read_pointers_.store(submit_pointers);
// Grab a fence sync object to avoid busy waiting upon the next extry into this // Grab a fence sync object to avoid busy waiting upon the next extry into this
// function, and reset the is_drawing_ flag. // function, and reset the is_updating_ flag.
fence_ = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0); fence_ = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
is_drawing_.clear(); is_updating_.clear();
} }
void ScanTarget::draw(int output_width, int output_height) { void ScanTarget::draw(int output_width, int output_height) {
while(is_drawing_.test_and_set()); while(is_drawing_to_accumulation_buffer_.test_and_set());
if(accumulation_texture_) { if(accumulation_texture_) {
// Copy the accumulation texture to the target. // Copy the accumulation texture to the target.
@ -725,5 +733,5 @@ void ScanTarget::draw(int output_width, int output_height) {
accumulation_texture_->draw(float(output_width) / float(output_height), 4.0f / 255.0f); accumulation_texture_->draw(float(output_width) / float(output_height), 4.0f / 255.0f);
} }
is_drawing_.clear(); is_drawing_to_accumulation_buffer_.clear();
} }

3
Outputs/OpenGL/ScanTarget.hpp
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@ -209,7 +209,8 @@ class ScanTarget: public Outputs::Display::ScanTarget {
std::vector<std::string> bindings(ShaderType type) const; std::vector<std::string> bindings(ShaderType type) const;
GLsync fence_ = nullptr; GLsync fence_ = nullptr;
std::atomic_flag is_drawing_; std::atomic_flag is_updating_;
std::atomic_flag is_drawing_to_accumulation_buffer_;
std::unique_ptr<Shader> input_shader_; std::unique_ptr<Shader> input_shader_;
std::unique_ptr<Shader> output_shader_; std::unique_ptr<Shader> output_shader_;