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Makes first attempt at a stable display area. Not entirely successful.

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This commit is contained in:
Thomas Harte 2018-04-15 18:00:40 -04:00
parent 61659faeaa
commit abe47b6ed8
2 changed files with 72 additions and 3 deletions
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71
Machines/AppleII/Video.cpp
View File

@ -22,16 +22,81 @@ Video::Video() :
"return float(texValue & 128u);"
"}");
// Show only the centre 80% of the TV frame.
// Show only the centre 75% of the TV frame.
crt_->set_video_signal(Outputs::CRT::VideoSignal::Composite);
crt_->set_visible_area(Outputs::CRT::Rect(0.1f, 0.1f, 0.8f, 0.8f));
crt_->set_visible_area(Outputs::CRT::Rect(0.115f, 0.115f, 0.77f, 0.77f));
}
Outputs::CRT::CRT *Video::get_crt() {
return crt_.get();
}
void Video::run_for(const Cycles) {
void Video::run_for(const Cycles cycles) {
/*
Addressing scheme used throughout is that column 0 is the first column with pixels in it;
row 0 is the first row with pixels in it.
A frame is oriented around 65 cycles across, 262 lines down.
*/
const int first_sync_line = 220; // A complete guess. Information needed.
const int first_sync_column = 49; // Also a guess.
int int_cycles = cycles.as_int();
while(int_cycles) {
const int cycles_this_line = std::min(65 - column_, int_cycles);
if(row_ >= first_sync_line && row_ < first_sync_line + 3) {
crt_->output_sync(static_cast<unsigned int>(cycles_this_line) * 7);
} else {
const int ending_column = column_ + cycles_this_line;
if(column_ < 40) {
if(row_ < 192) {
if(!column_) {
pixel_pointer_ = crt_->allocate_write_area(40);
}
// TODO: actually store pixels.
if(ending_column >= 40) {
for(int c = 0; c < 40; ++c) {
pixel_pointer_[c] = 0xaa;
}
crt_->output_data(280, 7);
}
} else {
if(ending_column >= 40) {
crt_->output_blank(280);
}
}
}
const int first_blank_start = std::max(40, column_);
const int first_blank_end = std::min(first_sync_column, ending_column);
if(first_blank_end > first_blank_start) {
crt_->output_blank(static_cast<unsigned int>(first_blank_end - first_blank_start) * 7);
}
// TODO: colour burst.
const int sync_start = std::max(first_sync_column, column_);
const int sync_end = std::min(first_sync_column + 4, ending_column);
if(sync_end > sync_start) {
crt_->output_sync(static_cast<unsigned int>(sync_end - sync_start) * 7);
}
const int second_blank_start = std::max(first_sync_column + 4, column_);
if(ending_column > second_blank_start) {
crt_->output_blank(static_cast<unsigned int>(ending_column - second_blank_start) * 7);
}
}
int_cycles -= cycles_this_line;
column_ = (column_ + cycles_this_line) % 65;
if(!column_) {
row_ = (row_ + 1) % 262;
}
}
}
void Video::set_graphics_mode() {

4
Machines/AppleII/Video.hpp
View File

@ -38,6 +38,10 @@ class Video {
private:
std::unique_ptr<Outputs::CRT::CRT> crt_;
int video_page_ = 0;
int row_ = 0, column_ = 0;
uint8_t *pixel_pointer_ = nullptr;
};
}