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Reverses bit order of graphics stream; apparently the ROM is backwards.

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This commit is contained in:
Thomas Harte 2018-04-19 20:39:38 -04:00
parent b4a2d1395c
commit ba43b3e6b8
1 changed files with 24 additions and 12 deletions
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36
Machines/AppleII/Video.cpp
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@ -28,8 +28,8 @@ VideoBase::VideoBase() :
"float composite_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate, float phase, float amplitude)"
"{"
"uint texValue = texture(sampler, coordinate).r;"
"texValue <<= int(icoordinate.x) % 7;"
"return float(texValue & 64u);"
"texValue >>= int(icoordinate.x) % 7;"
"return float(texValue & 1u);"
"}");
crt_->set_integer_coordinate_multiplier(7.0f);
@ -57,32 +57,33 @@ void VideoBase::setup_tables() {
((c & 0x40) ? 0x6000 : 0x0000);
uint8_t *const table_entry = reinterpret_cast<uint8_t *>(&scaled_byte[c]);
table_entry[0] = static_cast<uint8_t>(value >> 8);
table_entry[1] = static_cast<uint8_t>(value & 0xff);
table_entry[0] = static_cast<uint8_t>(value & 0xff);
table_entry[1] = static_cast<uint8_t>(value >> 8);
}
for(int c = 128; c < 256; ++c) {
uint8_t *const source_table_entry = reinterpret_cast<uint8_t *>(&scaled_byte[c & 0x7f]);
uint8_t *const destination_table_entry = reinterpret_cast<uint8_t *>(&scaled_byte[c]);
destination_table_entry[0] = static_cast<uint8_t>(source_table_entry[0] >> 1);
destination_table_entry[1] = static_cast<uint8_t>((source_table_entry[1] >> 1) | ((source_table_entry[0]&1) << 6));
destination_table_entry[0] = static_cast<uint8_t>(source_table_entry[0] << 1);
destination_table_entry[1] = static_cast<uint8_t>((source_table_entry[1] << 1) | (source_table_entry[0] >> 6));
}
for(int c = 0; c < 16; ++c) {
// Produce the whole 28-bit pattern that would cover two bytes.
// Produce the whole 28-bit pattern that would cover two columns.
const int reversed_c = ((c&0x1) ? 0x8 : 0x0) | ((c&0x2) ? 0x4 : 0x0) | ((c&0x4) ? 0x2 : 0x0) | ((c&0x8) ? 0x1 : 0x0);
int pattern = 0;
for(int l = 0; l < 7; ++l) {
pattern <<= 4;
pattern |= c;
pattern |= reversed_c;
}
// Pack that 28-bit pattern into the appropriate look-up tables.
uint8_t *const left_entry = reinterpret_cast<uint8_t *>(&low_resolution_patterns[0][c]);
uint8_t *const right_entry = reinterpret_cast<uint8_t *>(&low_resolution_patterns[1][c]);
left_entry[0] = static_cast<uint8_t>(pattern >> 21);
left_entry[1] = static_cast<uint8_t>(pattern >> 14);
right_entry[0] = static_cast<uint8_t>(pattern >> 7);
right_entry[1] = static_cast<uint8_t>(pattern);
left_entry[0] = static_cast<uint8_t>(pattern);;
left_entry[1] = static_cast<uint8_t>(pattern >> 7);
right_entry[0] = static_cast<uint8_t>(pattern >> 14);
right_entry[1] = static_cast<uint8_t>(pattern >> 21);
}
printf("");
@ -114,4 +115,15 @@ void VideoBase::set_high_resolution() {
void VideoBase::set_character_rom(const std::vector<uint8_t> &character_rom) {
character_rom_ = character_rom;
for(auto &byte : character_rom_) {
byte =
((byte & 0x40) ? 0x01 : 0x00) |
((byte & 0x20) ? 0x02 : 0x00) |
((byte & 0x10) ? 0x04 : 0x00) |
((byte & 0x08) ? 0x08 : 0x00) |
((byte & 0x04) ? 0x10 : 0x00) |
((byte & 0x02) ? 0x20 : 0x00) |
((byte & 0x01) ? 0x40 : 0x00) |
(byte & 0x80);
}
}