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Add cursor within 4bpp pixel area.

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This commit is contained in:
Thomas Harte 2024-04-05 22:43:10 -04:00
parent b821645644
commit cfaea7a90c
1 changed files with 59 additions and 3 deletions
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62
Machines/Acorn/Archimedes/Video.hpp
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@ -56,7 +56,7 @@ struct Video {
case 0x40: border_colour_ = colour(value); break;
case 0x44: case 0x48: case 0x4c:
cursor_colours_[(target - 0x44) >> 2] = colour(value);
cursor_colours_[(target - 0x40) >> 2] = colour(value);
break;
case 0x80: horizontal_timing_.period = timing_value(value); break;
@ -65,7 +65,10 @@ struct Video {
case 0x8c: horizontal_timing_.display_start = timing_value(value); break;
case 0x90: horizontal_timing_.display_end = timing_value(value); break;
case 0x94: horizontal_timing_.border_end = timing_value(value); break;
case 0x98: horizontal_timing_.cursor_start = timing_value(value); break;
case 0x98:
horizontal_timing_.cursor_start = (value >> 13) & 0x7ff;
cursor_shift_ = (value >> 11) & 3;
break;
case 0x9c:
logger.error().append("TODO: Video horizontal interlace: %d", (value >> 14) & 0x3ff);
break;
@ -130,6 +133,31 @@ struct Video {
entered_sync_ = true;
interrupt_observer_.update_interrupts();
}
// Determine which next 8 bytes will be the cursor image for this line.
// Pragmatically, updating cursor_address_ once per line avoids probable
// errors in getting it to appear appropriately over both pixels and border.
if(vertical_state_.cursor_active) {
uint8_t *cursor_pixel = cursor_image_.data();
for(int byte = 0; byte < 8; byte ++) {
cursor_pixel[0] = (ram_[cursor_address_] >> 0) & 3;
cursor_pixel[1] = (ram_[cursor_address_] >> 2) & 3;
cursor_pixel[2] = (ram_[cursor_address_] >> 4) & 3;
cursor_pixel[3] = (ram_[cursor_address_] >> 6) & 3;
cursor_pixel += 4;
++cursor_address_;
}
}
cursor_pixel_ = 32;
}
// Update cursor pixel counter if applicable; this might mean triggering it
// and it might just mean advancing it if it has already been triggered.
if(vertical_state_.cursor_active) {
const auto pixel_position = horizontal_state_.position << 1;
if(pixel_position <= horizontal_timing_.cursor_start && (pixel_position + 2) > horizontal_timing_.cursor_start) {
cursor_pixel_ = int(horizontal_timing_.cursor_start) - int(pixel_position);
}
}
// Grab some more pixels if appropriate.
@ -189,6 +217,26 @@ struct Video {
pixels_[0] = colours_[next & 0xf];
pixels_[1] = colours_[next >> 4];
// Overlay cursor if applicable.
// TODO: have all BPP modes output only two pixels at a time, and pull this out of the loop.
// TODO: pull this so far out that the cursor can display over the border, too.
if(cursor_pixel_ < 32) {
if(cursor_pixel_ >= 0) {
const auto colour = cursor_image_[static_cast<size_t>(cursor_pixel_)];
if(colour) {
pixels_[0] = cursor_colours_[colour];
}
}
if(cursor_pixel_ < 31) {
const auto colour = cursor_image_[static_cast<size_t>(cursor_pixel_ + 1)];
if(colour) {
pixels_[1] = cursor_colours_[colour];
}
}
cursor_pixel_ += 2;
}
pixels_ += 2;
} break;
@ -322,6 +370,7 @@ private:
uint32_t cursor_start = 0;
uint32_t cursor_end = 0;
};
uint32_t cursor_shift_ = 0;
Timing horizontal_timing_, vertical_timing_;
// Current video state.
@ -341,12 +390,16 @@ private:
display_ended = !timing.display_end;
border_started = !timing.border_start;
border_ended = !timing.border_end;
cursor_active = !timing.cursor_start;
} else {
sync_active &= position != timing.sync_width;
display_started |= position == timing.display_start;
display_ended |= position == timing.display_end;
border_started |= position == timing.border_start;
border_ended |= position == timing.border_end;
cursor_active |= position == timing.cursor_start;
cursor_active &= position != timing.cursor_end;
}
}
@ -381,12 +434,15 @@ private:
// Ephemeral address state.
uint32_t address_ = 0;
uint32_t cursor_address_ = 0;
int cursor_pixel_ = 0;
std::array<uint8_t, 32> cursor_image_;
// Colour palette, converted to internal format.
uint16_t border_colour_;
std::array<uint16_t, 16> colours_{};
std::array<uint16_t, 3> cursor_colours_{};
std::array<uint16_t, 4> cursor_colours_{};
// An interrupt flag; more closely related to the interface by which
// my implementation of the IOC picks up an interrupt request than