From 1db713fec1be7339fdb9898821eedc4ddf8a27a2 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sun, 15 Nov 2020 18:36:24 -0500
Subject: [PATCH] Attempts more meaningful super high-res pixel output.
With a timing hack as noted.
---
Machines/Apple/AppleIIgs/Video.cpp | 51 ++++++++++++++++++++++++------
Machines/Apple/AppleIIgs/Video.hpp | 4 +++
2 files changed, 46 insertions(+), 9 deletions(-)
diff --git a/Machines/Apple/AppleIIgs/Video.cpp b/Machines/Apple/AppleIIgs/Video.cpp
index 8cec46cfc..e1d06ec85 100644
--- a/Machines/Apple/AppleIIgs/Video.cpp
+++ b/Machines/Apple/AppleIIgs/Video.cpp
@@ -22,9 +22,9 @@ constexpr auto FinalColumn = CyclesPerLine / CyclesPerTick;
// Converts from Apple's RGB ordering to this emulator's.
#if TARGET_RT_BIG_ENDIAN
-#define PaletteConvulve(x) x
+#define PaletteConvulve(x) uint16_t(x)
#else
-#define PaletteConvulve(x) ((x&0xf00) >> 8) | ((x&0x0ff) << 8)
+#define PaletteConvulve(x) uint16_t(((x&0xf00) >> 8) | ((x&0x0ff) << 8))
#endif
// The 12-bit values used by the Apple IIgs to approximate Apple II colours,
@@ -178,6 +178,21 @@ void VideoBase::output_row(int row, int start, int end) {
if(start == start_of_pixels) {
// 640 is the absolute most number of pixels that might be generated
next_pixel_ = pixels_ = reinterpret_cast<uint16_t *>(crt_.begin_data(640, 2));
+
+ // YUCKY HACK. I do not know when the IIgs fetches its super high-res palette
+ // and control byte. Since I do not know, any guess is equally likely negatively
+ // to affect software. Therefore this hack is as good as any other guess:
+ // assume RAM has magical burst bandwidth, and fetch the whole set instantly.
+ // I could spread this stuff out to allow for real bandwidth, but it'd likely be
+ // no more accurate, while having less of an obvious I-HACKED-THIS red flag attached.
+ line_control_ = ram_[0x19d00 + row];
+ const int palette_base = (line_control_ & 15) * 16 + 0x19e00;
+ for(int c = 0; c < 16; c++) {
+ const int entry = ram_[palette_base + (c << 1)] | (ram_[palette_base + (c << 1) + 1] << 8);
+ palette_[c] = PaletteConvulve(entry);
+ }
+
+ // TODO: obey line_control_ & 0x40 interrupt control bit.
}
if(next_pixel_) {
@@ -289,7 +304,7 @@ bool VideoBase::get_composite_is_colour() {
// MARK: - Outputters.
uint16_t *VideoBase::output_text(uint16_t *target, int start, int end, int row) const {
- uint16_t row_address = get_row_address(row);
+ const uint16_t row_address = get_row_address(row);
for(int c = start; c < end; c++) {
const uint8_t source = ram_[row_address + c];
const int character = source & character_zones_[source >> 6].address_mask;
@@ -311,12 +326,30 @@ uint16_t *VideoBase::output_text(uint16_t *target, int start, int end, int row)
return target;
}
-uint16_t *VideoBase::output_super_high_res(uint16_t *target, int start, int end, int row [[maybe_unused]]) const {
- for(int c = start; c < end; c++) {
- // TODO!
- target[0] = 0x0000;
- target[1] = 0xffff;
- target += 2;
+uint16_t *VideoBase::output_super_high_res(uint16_t *target, int start, int end, int row) const {
+ // TODO: both the palette and the mode byte should have been fetched by now, and just be
+ // available. I haven't implemented that yet, so the below just tries to show _something_.
+ // The use of appleii_palette is complete nonsense, as is the assumption of two pixels per byte.
+
+ const int row_address = row * 160 + 0x12000;
+
+ // TODO: line_control_ & 0x20 should enable or disable colour fill mode.
+ if(line_control_ & 0x80) {
+ for(int c = start * 4; c < end * 4; c++) {
+ const uint8_t source = ram_[row_address + c];
+ target[0] = palette_[(source >> 6) & 0x3 + 0x8];
+ target[1] = palette_[(source >> 4) & 0x3 + 0xc];
+ target[2] = palette_[(source >> 2) & 0x3 + 0x0];
+ target[3] = palette_[(source >> 0) & 0x3 + 0x4];
+ target += 4;
+ }
+ } else {
+ for(int c = start * 4; c < end * 4; c++) {
+ const uint8_t source = ram_[row_address + c];
+ target[0] = palette_[(source >> 4) & 0xf];
+ target[1] = palette_[source & 0xf];
+ target += 2;
+ }
}
return target;
diff --git a/Machines/Apple/AppleIIgs/Video.hpp b/Machines/Apple/AppleIIgs/Video.hpp
index b2894f5bf..17820426f 100644
--- a/Machines/Apple/AppleIIgs/Video.hpp
+++ b/Machines/Apple/AppleIIgs/Video.hpp
@@ -80,6 +80,10 @@ class VideoBase: public Apple::II::VideoSwitches<Cycles> {
uint16_t *output_super_high_res(uint16_t *target, int start, int end, int row) const;
uint16_t *output_text(uint16_t *target, int start, int end, int row) const;
+
+ // Super high-res per-line state.
+ uint8_t line_control_;
+ uint16_t palette_[16];
};
class Video: public VideoBase {