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Adds submission of scans to the GPU.

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This commit is contained in:
Thomas Harte 2018-11-08 22:21:11 -05:00
parent 4fe5c7c24e
commit 20faf4e477
1 changed files with 41 additions and 10 deletions
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51
Outputs/OpenGL/ScanTarget.cpp
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@ -24,15 +24,20 @@ constexpr int WriteAreaHeight = 2048;
}
ScanTarget::ScanTarget() {
// Allocate space for the spans.
// Allocate space for the scans.
glGenBuffers(1, &scan_buffer_name_);
glBindBuffer(GL_ARRAY_BUFFER, scan_buffer_name_);
const auto buffer_size = scan_buffer_.size() * sizeof(Scan);
glBufferData(GL_ARRAY_BUFFER, GLsizeiptr(buffer_size), NULL, GL_STREAM_DRAW);
// TODO: if this is OpenGL 4.4 or newer, use glBufferStorage rather than glBufferData
// and specify GL_MAP_PERSISTENT_BIT. Then map the buffer now, and let the client
// write straight into it.
}
ScanTarget::~ScanTarget() {
// Release span space.
// Release scan space.
glDeleteBuffers(1, &scan_buffer_name_);
}
@ -115,8 +120,8 @@ uint8_t *ScanTarget::allocate_write_area(size_t required_length, size_t required
void ScanTarget::reduce_previous_allocation_to(size_t actual_length) {
if(allocation_has_failed_) return;
// The span was allocated in the knowledge that there's sufficient distance
// left on the current line, so there's no need to worry about carry.
// The write area was allocated in the knowledge that there's sufficient
// distance left on the current line, so there's no need to worry about carry.
write_pointers_.write_area += actual_length + 1;
}
@ -137,17 +142,43 @@ void ScanTarget::draw() {
const auto submit_pointers = submit_pointers_.load();
const auto read_pointers = read_pointers_.load();
// Submit spans.
// Submit scans.
if(submit_pointers.scan_buffer != read_pointers.scan_buffer) {
// uint8_t *destination = static_cast<uint8_t *>(glMapBufferRange(GL_ARRAY_BUFFER, 0, (GLsizeiptr)length, GL_MAP_WRITE_BIT | GL_MAP_UNSYNCHRONIZED_BIT | GL_MAP_FLUSH_EXPLICIT_BIT));
// if(!glGetError() && destination) {
// }
const auto buffer_size = scan_buffer_.size() * sizeof(Scan);
uint8_t *destination = static_cast<uint8_t *>(
glMapBufferRange(GL_ARRAY_BUFFER, 0, GLsizeiptr(buffer_size), GL_MAP_WRITE_BIT | GL_MAP_FLUSH_EXPLICIT_BIT)
);
// TODO: submit all scans from scan_buffer_pointers_.read_pointer to scan_buffer_pointers_.submit_pointer.
// read_pointers_.scan_buffer = submit_pointers.scan_buffer;
if(submit_pointers.scan_buffer > read_pointers.scan_buffer) {
// Submit the direct region from the submit pointer to the read pointer.
const size_t offset = read_pointers.scan_buffer * sizeof(Scan);
const size_t length = (submit_pointers.scan_buffer - read_pointers.scan_buffer) * sizeof(Scan);
memcpy(&destination[offset], &scan_buffer_[read_pointers.scan_buffer], length);
glFlushMappedBufferRange(GL_ARRAY_BUFFER, GLintptr(offset), GLsizeiptr(length));
} else {
// The circular buffer wrapped around; submit the data from the read pointer to the end of
// the buffer and from the start of the buffer to the submit pointer.
const size_t offset = read_pointers.scan_buffer * sizeof(Scan);
const size_t end_length = (scan_buffer_.size() - read_pointers.scan_buffer) * sizeof(Scan);
const size_t start_length = submit_pointers.scan_buffer * sizeof(Scan);
memcpy(&destination[offset], &scan_buffer_[read_pointers.scan_buffer], end_length);
memcpy(&destination[0], &scan_buffer_[0], start_length);
glFlushMappedBufferRange(GL_ARRAY_BUFFER, GLintptr(offset), GLsizeiptr(end_length));
glFlushMappedBufferRange(GL_ARRAY_BUFFER, 0, GLsizeiptr(start_length));
}
glUnmapBuffer(GL_ARRAY_BUFFER);
}
// TODO: submit texture.
// TODO: clear composite buffer (if needed).
// TODO: drawing (!)
// All data now having been spooled to the GPU, update the read pointers to
// the submit pointer location.
read_pointers_.store(submit_pointers);