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504 lines
19 KiB
C++
504 lines
19 KiB
C++
//
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// ScanTarget.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 05/11/2018.
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// Copyright © 2018 Thomas Harte. All rights reserved.
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//
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#include "ScanTarget.hpp"
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#include "OpenGL.hpp"
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#include "Primitives/Rectangle.hpp"
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#include <cassert>
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#include <cstring>
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#include <limits>
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using namespace Outputs::Display::OpenGL;
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#ifndef NDEBUG
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//#define LOG_LINES
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//#define LOG_SCANS
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#endif
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namespace {
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/// The texture unit from which to source input data.
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constexpr GLenum SourceDataTextureUnit = GL_TEXTURE0;
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/// The texture unit which contains raw line-by-line composite, S-Video or RGB data.
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constexpr GLenum UnprocessedLineBufferTextureUnit = GL_TEXTURE1;
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/// The texture unit that contains a pre-lowpass-filtered but fixed-resolution version of the chroma signal;
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/// this is used when processing composite video only, and for chroma information only. Luminance is calculated
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/// at the fidelity permitted by the output target, but my efforts to separate, demodulate and filter
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/// chrominance during output without either massively sampling or else incurring significant high-frequency
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/// noise that sampling reduces into a Moire, have proven to be unsuccessful for the time being.
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constexpr GLenum QAMChromaTextureUnit = GL_TEXTURE2;
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/// The texture unit that contains the current display.
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constexpr GLenum AccumulationTextureUnit = GL_TEXTURE3;
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constexpr GLint internalFormatForDepth(std::size_t depth) {
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switch(depth) {
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default: return GL_FALSE;
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case 1: return GL_R8UI;
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case 2: return GL_RG8UI;
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case 3: return GL_RGB8UI;
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case 4: return GL_RGBA8UI;
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}
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}
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constexpr GLenum formatForDepth(std::size_t depth) {
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switch(depth) {
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default: return GL_FALSE;
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case 1: return GL_RED_INTEGER;
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case 2: return GL_RG_INTEGER;
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case 3: return GL_RGB_INTEGER;
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case 4: return GL_RGBA_INTEGER;
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}
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}
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}
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template <typename T> void ScanTarget::allocate_buffer(const T &array, GLuint &buffer_name, GLuint &vertex_array_name) {
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const auto buffer_size = array.size() * sizeof(array[0]);
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test_gl(glGenBuffers, 1, &buffer_name);
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test_gl(glBindBuffer, GL_ARRAY_BUFFER, buffer_name);
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test_gl(glBufferData, GL_ARRAY_BUFFER, GLsizeiptr(buffer_size), NULL, GL_STREAM_DRAW);
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test_gl(glGenVertexArrays, 1, &vertex_array_name);
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test_gl(glBindVertexArray, vertex_array_name);
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test_gl(glBindBuffer, GL_ARRAY_BUFFER, buffer_name);
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}
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ScanTarget::ScanTarget(GLuint target_framebuffer, float output_gamma) :
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target_framebuffer_(target_framebuffer),
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output_gamma_(output_gamma),
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unprocessed_line_texture_(LineBufferWidth, LineBufferHeight, UnprocessedLineBufferTextureUnit, GL_NEAREST, false),
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full_display_rectangle_(-1.0f, -1.0f, 2.0f, 2.0f) {
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set_scan_buffer(scan_buffer_.data(), scan_buffer_.size());
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set_line_buffer(line_buffer_.data(), line_metadata_buffer_.data(), line_buffer_.size());
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// Allocate space for the scans and lines.
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allocate_buffer(scan_buffer_, scan_buffer_name_, scan_vertex_array_);
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allocate_buffer(line_buffer_, line_buffer_name_, line_vertex_array_);
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// TODO: if this is OpenGL 4.4 or newer, use glBufferStorage rather than glBufferData
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// and specify GL_MAP_PERSISTENT_BIT. Then map the buffer now, and let the client
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// write straight into it.
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test_gl(glGenTextures, 1, &write_area_texture_name_);
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test_gl(glBlendFunc, GL_SRC_ALPHA, GL_CONSTANT_COLOR);
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test_gl(glBlendColor, 0.4f, 0.4f, 0.4f, 1.0f);
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// Establish initial state for is_drawing_to_accumulation_buffer_.
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is_drawing_to_accumulation_buffer_.clear();
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}
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ScanTarget::~ScanTarget() {
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perform([=] {
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glDeleteBuffers(1, &scan_buffer_name_);
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glDeleteTextures(1, &write_area_texture_name_);
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glDeleteVertexArrays(1, &scan_vertex_array_);
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});
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}
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void ScanTarget::set_target_framebuffer(GLuint target_framebuffer) {
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perform([=] {
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target_framebuffer_ = target_framebuffer;
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});
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}
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void ScanTarget::setup_pipeline() {
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auto modals = BufferingScanTarget::modals();
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const auto data_type_size = Outputs::Display::size_for_data_type(modals.input_data_type);
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// Resize the texture only if required.
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const size_t required_size = WriteAreaWidth*WriteAreaHeight*data_type_size;
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if(required_size != write_area_data_size()) {
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write_area_texture_.resize(required_size);
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set_write_area(write_area_texture_.data());
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}
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// Prepare to bind line shaders.
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test_gl(glBindVertexArray, line_vertex_array_);
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test_gl(glBindBuffer, GL_ARRAY_BUFFER, line_buffer_name_);
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// Destroy or create a QAM buffer and shader, if appropriate.
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const bool needs_qam_buffer = (modals.display_type == DisplayType::CompositeColour || modals.display_type == DisplayType::SVideo);
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if(needs_qam_buffer) {
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if(!qam_chroma_texture_) {
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qam_chroma_texture_ = std::make_unique<TextureTarget>(LineBufferWidth, LineBufferHeight, QAMChromaTextureUnit, GL_NEAREST, false);
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}
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qam_separation_shader_ = qam_separation_shader();
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enable_vertex_attributes(ShaderType::QAMSeparation, *qam_separation_shader_);
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set_uniforms(ShaderType::QAMSeparation, *qam_separation_shader_);
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qam_separation_shader_->set_uniform("textureName", GLint(UnprocessedLineBufferTextureUnit - GL_TEXTURE0));
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} else {
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qam_chroma_texture_.reset();
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qam_separation_shader_.reset();
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}
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// Establish an output shader.
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output_shader_ = conversion_shader();
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enable_vertex_attributes(ShaderType::Conversion, *output_shader_);
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set_uniforms(ShaderType::Conversion, *output_shader_);
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output_shader_->set_uniform("origin", modals.visible_area.origin.x, modals.visible_area.origin.y);
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output_shader_->set_uniform("size", modals.visible_area.size.width, modals.visible_area.size.height);
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output_shader_->set_uniform("textureName", GLint(UnprocessedLineBufferTextureUnit - GL_TEXTURE0));
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output_shader_->set_uniform("qamTextureName", GLint(QAMChromaTextureUnit - GL_TEXTURE0));
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// Establish an input shader.
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input_shader_ = composition_shader();
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test_gl(glBindVertexArray, scan_vertex_array_);
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test_gl(glBindBuffer, GL_ARRAY_BUFFER, scan_buffer_name_);
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enable_vertex_attributes(ShaderType::Composition, *input_shader_);
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set_uniforms(ShaderType::Composition, *input_shader_);
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input_shader_->set_uniform("textureName", GLint(SourceDataTextureUnit - GL_TEXTURE0));
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}
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bool ScanTarget::is_soft_display_type() {
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const auto display_type = modals().display_type;
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return display_type == DisplayType::CompositeColour || display_type == DisplayType::CompositeMonochrome;
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}
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void ScanTarget::update(int, int output_height) {
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// If the GPU is still busy, don't wait; we'll catch it next time.
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if(fence_ != nullptr) {
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if(glClientWaitSync(fence_, GL_SYNC_FLUSH_COMMANDS_BIT, 0) == GL_TIMEOUT_EXPIRED) {
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display_metrics_.announce_draw_status(
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lines_submitted_,
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std::chrono::high_resolution_clock::now() - line_submission_begin_time_,
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false);
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return;
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}
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fence_ = nullptr;
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}
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// Update the display metrics.
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display_metrics_.announce_draw_status(
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lines_submitted_,
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std::chrono::high_resolution_clock::now() - line_submission_begin_time_,
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true);
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// Grab the new output list.
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perform([=] {
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OutputArea area = get_output_area();
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// Establish the pipeline if necessary.
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const auto new_modals = BufferingScanTarget::new_modals();
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const bool did_setup_pipeline = bool(new_modals);
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if(did_setup_pipeline) {
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setup_pipeline();
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}
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// Determine the start time of this submission group and the number of lines it will contain.
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line_submission_begin_time_ = std::chrono::high_resolution_clock::now();
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lines_submitted_ = (area.end.line - area.start.line + line_buffer_.size()) % line_buffer_.size();
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// Submit scans; only the new ones need to be communicated.
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size_t new_scans = (area.end.scan - area.start.scan + scan_buffer_.size()) % scan_buffer_.size();
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if(new_scans) {
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test_gl(glBindBuffer, GL_ARRAY_BUFFER, scan_buffer_name_);
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// Map only the required portion of the buffer.
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const size_t new_scans_size = new_scans * sizeof(Scan);
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uint8_t *const destination = static_cast<uint8_t *>(
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glMapBufferRange(GL_ARRAY_BUFFER, 0, GLsizeiptr(new_scans_size), GL_MAP_WRITE_BIT | GL_MAP_FLUSH_EXPLICIT_BIT)
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);
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test_gl_error();
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// Copy as a single chunk if possible; otherwise copy in two parts.
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if(area.start.scan < area.end.scan) {
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memcpy(destination, &scan_buffer_[size_t(area.start.scan)], new_scans_size);
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} else {
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const size_t first_portion_length = (scan_buffer_.size() - area.start.scan) * sizeof(Scan);
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memcpy(destination, &scan_buffer_[area.start.scan], first_portion_length);
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memcpy(&destination[first_portion_length], &scan_buffer_[0], new_scans_size - first_portion_length);
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}
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// Flush and unmap the buffer.
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test_gl(glFlushMappedBufferRange, GL_ARRAY_BUFFER, 0, GLsizeiptr(new_scans_size));
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test_gl(glUnmapBuffer, GL_ARRAY_BUFFER);
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}
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// Submit texture.
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if(area.start.write_area_x != area.end.write_area_x || area.start.write_area_y != area.end.write_area_y) {
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test_gl(glActiveTexture, SourceDataTextureUnit);
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test_gl(glBindTexture, GL_TEXTURE_2D, write_area_texture_name_);
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// Create storage for the texture if it doesn't yet exist; this was deferred until here
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// because the pixel format wasn't initially known.
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if(!texture_exists_) {
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test_gl(glTexParameteri, GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
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test_gl(glTexParameteri, GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
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test_gl(glTexParameteri, GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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test_gl(glTexParameteri, GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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test_gl(glTexImage2D,
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GL_TEXTURE_2D,
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0,
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internalFormatForDepth(write_area_data_size()),
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WriteAreaWidth,
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WriteAreaHeight,
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0,
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formatForDepth(write_area_data_size()),
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GL_UNSIGNED_BYTE,
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nullptr);
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texture_exists_ = true;
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}
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if(area.end.write_area_y >= area.start.write_area_y) {
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// Submit the direct region from the submit pointer to the read pointer.
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test_gl(glTexSubImage2D,
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GL_TEXTURE_2D, 0,
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0, area.start.write_area_y,
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WriteAreaWidth,
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1 + area.end.write_area_y - area.start.write_area_y,
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formatForDepth(write_area_data_size()),
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GL_UNSIGNED_BYTE,
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&write_area_texture_[size_t(area.start.write_area_y * WriteAreaWidth) * write_area_data_size()]);
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} else {
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// The circular buffer wrapped around; submit the data from the read pointer to the end of
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// the buffer and from the start of the buffer to the submit pointer.
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test_gl(glTexSubImage2D,
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GL_TEXTURE_2D, 0,
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0, area.start.write_area_y,
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WriteAreaWidth,
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WriteAreaHeight - area.start.write_area_y,
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formatForDepth(write_area_data_size()),
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GL_UNSIGNED_BYTE,
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&write_area_texture_[size_t(area.start.write_area_y * WriteAreaWidth) * write_area_data_size()]);
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test_gl(glTexSubImage2D,
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GL_TEXTURE_2D, 0,
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0, 0,
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WriteAreaWidth,
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1 + area.end.write_area_y,
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formatForDepth(write_area_data_size()),
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GL_UNSIGNED_BYTE,
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&write_area_texture_[0]);
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}
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}
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// Push new input to the unprocessed line buffer.
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if(new_scans) {
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unprocessed_line_texture_.bind_framebuffer();
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// Clear newly-touched lines; that is everything from (read+1) to submit.
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const auto first_line_to_clear = GLsizei((area.start.line+1)%line_buffer_.size());
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const auto final_line_to_clear = GLsizei(area.end.line);
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if(first_line_to_clear != final_line_to_clear) {
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test_gl(glEnable, GL_SCISSOR_TEST);
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// Determine the proper clear colour — this needs to be anything that describes black
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// in the input colour encoding at use.
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if(modals().input_data_type == InputDataType::Luminance8Phase8) {
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// Supply both a zero luminance and a colour-subcarrier-disengaging phase.
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test_gl(glClearColor, 0.0f, 1.0f, 0.0f, 0.0f);
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} else {
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test_gl(glClearColor, 0.0f, 0.0f, 0.0f, 0.0f);
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}
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if(first_line_to_clear < final_line_to_clear) {
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test_gl(glScissor, GLint(0), GLint(first_line_to_clear), unprocessed_line_texture_.get_width(), final_line_to_clear - first_line_to_clear);
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test_gl(glClear, GL_COLOR_BUFFER_BIT);
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} else {
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test_gl(glScissor, GLint(0), GLint(0), unprocessed_line_texture_.get_width(), final_line_to_clear);
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test_gl(glClear, GL_COLOR_BUFFER_BIT);
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test_gl(glScissor, GLint(0), GLint(first_line_to_clear), unprocessed_line_texture_.get_width(), unprocessed_line_texture_.get_height() - first_line_to_clear);
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test_gl(glClear, GL_COLOR_BUFFER_BIT);
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}
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test_gl(glDisable, GL_SCISSOR_TEST);
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}
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// Apply new spans. They definitely always go to the first buffer.
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test_gl(glBindVertexArray, scan_vertex_array_);
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input_shader_->bind();
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test_gl(glDrawArraysInstanced, GL_TRIANGLE_STRIP, 0, 4, GLsizei(new_scans));
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}
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// Logic for reducing resolution: start doing so if the metrics object reports that
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// it's a good idea. Go up to a quarter of the requested resolution, subject to
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// clamping at each stage. If the output resolution changes, or anything else about
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// the output pipeline, just start trying the highest size again.
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if(display_metrics_.should_lower_resolution() && is_soft_display_type()) {
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resolution_reduction_level_ = std::min(resolution_reduction_level_+1, 4);
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}
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if(output_height_ != output_height || did_setup_pipeline) {
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resolution_reduction_level_ = 1;
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output_height_ = output_height;
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}
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// Ensure the accumulation buffer is properly sized, allowing for the metrics object's
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// feelings about whether too high a resolution is being used.
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const int framebuffer_height = std::max(output_height / resolution_reduction_level_, std::min(540, output_height));
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const int proportional_width = (framebuffer_height * 4) / 3;
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const bool did_create_accumulation_texture = !accumulation_texture_ || ( (accumulation_texture_->get_width() != proportional_width || accumulation_texture_->get_height() != framebuffer_height));
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// Work with the accumulation_buffer_ potentially starts from here onwards; set its flag.
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while(is_drawing_to_accumulation_buffer_.test_and_set());
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if(did_create_accumulation_texture) {
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LOG("Changed output resolution to " << proportional_width << " by " << framebuffer_height);
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display_metrics_.announce_did_resize();
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std::unique_ptr<OpenGL::TextureTarget> new_framebuffer(
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new TextureTarget(
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GLsizei(proportional_width),
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GLsizei(framebuffer_height),
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AccumulationTextureUnit,
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GL_NEAREST,
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true));
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if(accumulation_texture_) {
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new_framebuffer->bind_framebuffer();
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test_gl(glClear, GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
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test_gl(glActiveTexture, AccumulationTextureUnit);
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accumulation_texture_->bind_texture();
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accumulation_texture_->draw(4.0f / 3.0f);
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test_gl(glClear, GL_STENCIL_BUFFER_BIT);
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new_framebuffer->bind_texture();
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}
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accumulation_texture_ = std::move(new_framebuffer);
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// In the absence of a way to resize a stencil buffer, just mark
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// what's currently present as invalid to avoid an improper clear
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// for this frame.
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stencil_is_valid_ = false;
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}
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if(did_setup_pipeline || did_create_accumulation_texture) {
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set_sampling_window(proportional_width, framebuffer_height, *output_shader_);
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}
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// Figure out how many new lines are ready.
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auto new_lines = (area.end.line - area.start.line + LineBufferHeight) % LineBufferHeight;
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if(new_lines) {
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// Prepare to output lines.
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test_gl(glBindVertexArray, line_vertex_array_);
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// Bind the accumulation framebuffer, unless there's going to be QAM work first.
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if(!qam_separation_shader_ || line_metadata_buffer_[area.start.line].is_first_in_frame) {
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accumulation_texture_->bind_framebuffer();
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output_shader_->bind();
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// Enable blending and stenciling.
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test_gl(glEnable, GL_BLEND);
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test_gl(glEnable, GL_STENCIL_TEST);
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}
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// Set the proper stencil function regardless.
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test_gl(glStencilFunc, GL_EQUAL, 0, GLuint(~0));
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test_gl(glStencilOp, GL_KEEP, GL_KEEP, GL_INCR);
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// Prepare to upload data that will consitute lines.
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test_gl(glBindBuffer, GL_ARRAY_BUFFER, line_buffer_name_);
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// Divide spans by which frame they're in.
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auto start_line = area.start.line;
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while(new_lines) {
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uint16_t end_line = (start_line + 1) % LineBufferHeight;
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// Find the limit of spans to draw in this cycle.
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size_t lines = 1;
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while(end_line != area.end.line && !line_metadata_buffer_[end_line].is_first_in_frame) {
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end_line = (end_line + 1) % LineBufferHeight;
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++lines;
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}
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// If this is start-of-frame, clear any untouched pixels and flush the stencil buffer
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if(line_metadata_buffer_[start_line].is_first_in_frame) {
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if(stencil_is_valid_ && line_metadata_buffer_[start_line].previous_frame_was_complete) {
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full_display_rectangle_.draw(0.0f, 0.0f, 0.0f);
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}
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stencil_is_valid_ = true;
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test_gl(glClear, GL_STENCIL_BUFFER_BIT);
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|
|
|
// Rebind the program for span output.
|
|
test_gl(glBindVertexArray, line_vertex_array_);
|
|
if(!qam_separation_shader_) {
|
|
output_shader_->bind();
|
|
}
|
|
}
|
|
|
|
// Upload.
|
|
const auto buffer_size = lines * sizeof(Line);
|
|
if(!end_line || end_line > start_line) {
|
|
test_gl(glBufferSubData, GL_ARRAY_BUFFER, 0, GLsizeiptr(buffer_size), &line_buffer_[start_line]);
|
|
} else {
|
|
uint8_t *destination = static_cast<uint8_t *>(
|
|
glMapBufferRange(GL_ARRAY_BUFFER, 0, GLsizeiptr(buffer_size), GL_MAP_WRITE_BIT | GL_MAP_FLUSH_EXPLICIT_BIT)
|
|
);
|
|
assert(destination);
|
|
test_gl_error();
|
|
|
|
const size_t buffer_length = line_buffer_.size() * sizeof(Line);
|
|
const size_t start_position = start_line * sizeof(Line);
|
|
memcpy(&destination[0], &line_buffer_[start_line], buffer_length - start_position);
|
|
memcpy(&destination[buffer_length - start_position], &line_buffer_[0], end_line * sizeof(Line));
|
|
|
|
test_gl(glFlushMappedBufferRange, GL_ARRAY_BUFFER, 0, GLsizeiptr(buffer_size));
|
|
test_gl(glUnmapBuffer, GL_ARRAY_BUFFER);
|
|
}
|
|
|
|
// Produce colour information, if required.
|
|
if(qam_separation_shader_) {
|
|
qam_separation_shader_->bind();
|
|
qam_chroma_texture_->bind_framebuffer();
|
|
test_gl(glClear, GL_COLOR_BUFFER_BIT); // TODO: this is here as a hint that the old framebuffer doesn't need reloading;
|
|
// test whether that's a valid optimisation on desktop OpenGL.
|
|
|
|
test_gl(glDisable, GL_BLEND);
|
|
test_gl(glDisable, GL_STENCIL_TEST);
|
|
test_gl(glDrawArraysInstanced, GL_TRIANGLE_STRIP, 0, 4, GLsizei(lines));
|
|
|
|
accumulation_texture_->bind_framebuffer();
|
|
output_shader_->bind();
|
|
test_gl(glEnable, GL_BLEND);
|
|
test_gl(glEnable, GL_STENCIL_TEST);
|
|
}
|
|
|
|
// Render to the output.
|
|
test_gl(glDrawArraysInstanced, GL_TRIANGLE_STRIP, 0, 4, GLsizei(lines));
|
|
|
|
start_line = end_line;
|
|
new_lines -= lines;
|
|
}
|
|
|
|
// Disable blending and the stencil test again.
|
|
test_gl(glDisable, GL_STENCIL_TEST);
|
|
test_gl(glDisable, GL_BLEND);
|
|
}
|
|
|
|
// That's it for operations affecting the accumulation buffer.
|
|
is_drawing_to_accumulation_buffer_.clear();
|
|
|
|
// Grab a fence sync object to avoid busy waiting upon the next extry into this
|
|
// function, and reset the is_updating_ flag.
|
|
fence_ = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
|
|
complete_output_area(area);
|
|
});
|
|
}
|
|
|
|
void ScanTarget::draw(int output_width, int output_height) {
|
|
while(is_drawing_to_accumulation_buffer_.test_and_set(std::memory_order_acquire));
|
|
|
|
if(accumulation_texture_) {
|
|
// Copy the accumulation texture to the target.
|
|
test_gl(glBindFramebuffer, GL_FRAMEBUFFER, target_framebuffer_);
|
|
test_gl(glViewport, 0, 0, (GLsizei)output_width, (GLsizei)output_height);
|
|
|
|
test_gl(glClearColor, 0.0f, 0.0f, 0.0f, 0.0f);
|
|
test_gl(glClear, GL_COLOR_BUFFER_BIT);
|
|
accumulation_texture_->bind_texture();
|
|
accumulation_texture_->draw(float(output_width) / float(output_height), 4.0f / 255.0f);
|
|
}
|
|
|
|
is_drawing_to_accumulation_buffer_.clear(std::memory_order_release);
|
|
}
|