mirror of
https://github.com/TomHarte/CLK.git
synced 2024-10-16 11:23:51 +00:00
Merge pull request #409 from TomHarte/BitShader
Switches ZX80/81 video bit unpacking to the GPU.
This commit is contained in:
commit
28947bb3c4
@ -10,15 +10,29 @@
|
|||||||
|
|
||||||
using namespace ZX8081;
|
using namespace ZX8081;
|
||||||
|
|
||||||
|
namespace {
|
||||||
|
|
||||||
|
/*!
|
||||||
|
The number of bytes of PCM data to allocate at once; if/when more are required,
|
||||||
|
the class will simply allocate another batch.
|
||||||
|
*/
|
||||||
|
const std::size_t StandardAllocationSize = 40;
|
||||||
|
|
||||||
|
/// The amount of time a byte takes to output.
|
||||||
|
const std::size_t HalfCyclesPerByte = 8;
|
||||||
|
|
||||||
|
}
|
||||||
|
|
||||||
Video::Video() :
|
Video::Video() :
|
||||||
crt_(new Outputs::CRT::CRT(207 * 2, 1, Outputs::CRT::DisplayType::PAL50, 1)) {
|
crt_(new Outputs::CRT::CRT(207 * 2, 1, Outputs::CRT::DisplayType::PAL50, 1)) {
|
||||||
|
|
||||||
// Set a composite sampling function that assumes 8bpp input grayscale.
|
// Set a composite sampling function that assumes 1bpp input.
|
||||||
// TODO: lessen this to 1bpp.
|
|
||||||
crt_->set_composite_sampling_function(
|
crt_->set_composite_sampling_function(
|
||||||
"float composite_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate, float phase, float amplitude)"
|
"float composite_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate, float phase, float amplitude)"
|
||||||
"{"
|
"{"
|
||||||
"return float(texture(texID, coordinate).r) / 255.0;"
|
"uint texValue = texture(sampler, coordinate).r;"
|
||||||
|
"texValue <<= int(icoordinate.x * 8) & 7;"
|
||||||
|
"return float(texValue & 128u);"
|
||||||
"}");
|
"}");
|
||||||
|
|
||||||
// Show only the centre 80% of the TV frame.
|
// Show only the centre 80% of the TV frame.
|
||||||
@ -45,10 +59,10 @@ void Video::flush(bool next_sync) {
|
|||||||
if(line_data_) {
|
if(line_data_) {
|
||||||
// If there is output data queued, output it either if it's being interrupted by
|
// If there is output data queued, output it either if it's being interrupted by
|
||||||
// sync, or if we're past its end anyway. Otherwise let it be.
|
// sync, or if we're past its end anyway. Otherwise let it be.
|
||||||
unsigned int data_length = static_cast<unsigned int>(line_data_pointer_ - line_data_);
|
unsigned int data_length = static_cast<unsigned int>(line_data_pointer_ - line_data_) * HalfCyclesPerByte;
|
||||||
if(data_length < cycles_since_update_ || next_sync) {
|
if(data_length < cycles_since_update_ || next_sync) {
|
||||||
unsigned int output_length = std::min(data_length, cycles_since_update_);
|
unsigned int output_length = std::min(data_length, cycles_since_update_);
|
||||||
crt_->output_data(output_length, 1);
|
crt_->output_data(output_length, HalfCyclesPerByte);
|
||||||
line_data_pointer_ = line_data_ = nullptr;
|
line_data_pointer_ = line_data_ = nullptr;
|
||||||
cycles_since_update_ -= output_length;
|
cycles_since_update_ -= output_length;
|
||||||
} else return;
|
} else return;
|
||||||
@ -79,25 +93,21 @@ void Video::output_byte(uint8_t byte) {
|
|||||||
|
|
||||||
// Grab a buffer if one isn't already available.
|
// Grab a buffer if one isn't already available.
|
||||||
if(!line_data_) {
|
if(!line_data_) {
|
||||||
line_data_pointer_ = line_data_ = crt_->allocate_write_area(320);
|
line_data_pointer_ = line_data_ = crt_->allocate_write_area(StandardAllocationSize);
|
||||||
}
|
}
|
||||||
|
|
||||||
// If a buffer was obtained, serialise the new pixels.
|
// If a buffer was obtained, serialise the new pixels.
|
||||||
if(line_data_) {
|
if(line_data_) {
|
||||||
// If the buffer is full, output it now and obtain a new one
|
// If the buffer is full, output it now and obtain a new one
|
||||||
if(line_data_pointer_ - line_data_ == 320) {
|
if(line_data_pointer_ - line_data_ == StandardAllocationSize) {
|
||||||
crt_->output_data(320, 1);
|
crt_->output_data(StandardAllocationSize, HalfCyclesPerByte);
|
||||||
cycles_since_update_ -= 320;
|
cycles_since_update_ -= StandardAllocationSize * HalfCyclesPerByte;
|
||||||
line_data_pointer_ = line_data_ = crt_->allocate_write_area(320);
|
line_data_pointer_ = line_data_ = crt_->allocate_write_area(StandardAllocationSize);
|
||||||
if(!line_data_) return;
|
if(!line_data_) return;
|
||||||
}
|
}
|
||||||
|
|
||||||
uint8_t mask = 0x80;
|
line_data_pointer_[0] = byte;
|
||||||
for(int c = 0; c < 8; c++) {
|
line_data_pointer_ ++;
|
||||||
line_data_pointer_[c] = (byte & mask) ? 0xff : 0x00;
|
|
||||||
mask >>= 1;
|
|
||||||
}
|
|
||||||
line_data_pointer_ += 8;
|
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
Loading…
Reference in New Issue
Block a user