6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2026-04-25 11:17:26 +00:00
Code Issues Projects Releases Wiki Activity

Adds latching of scroll values.

Browse Source
This commit is contained in:
Thomas Harte
2018-10-10 21:28:18 -04:00
parent f00f6c8c23
commit 2e379b0834
2 changed files with 22 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Components/9918/Implementation/9918Base.hpp
+15 -4
View File
@@ -199,13 +199,15 @@ class Base {
uint32_t colour_ram[32];
bool cram_is_selected = false;
// Temporary buffers for a line of Master System graphics.
// Temporary buffers for a line of Master System graphics,
// and latched scrolling offsets.
struct {
size_t offset;
uint8_t flags;
} names[32];
uint8_t tile_graphics[32][4];
size_t next_column = 0;
uint8_t latched_vertical_scroll = 0;
uint8_t latched_horizontal_scroll = 0;
} master_system_;
// Holds results of sprite data fetches that occur on this
@@ -654,12 +656,21 @@ class Base {
slot(location+14): \
slot(location+15): fetch_tile(column+3)
// Latch scrolling position at slot 33 for now; unless or until
// a more accurate number becomes apparent.
if(start < 33 && end >= 33) {
if(!row_) {
master_system_.latched_vertical_scroll = master_system_.vertical_scroll;
}
master_system_.latched_horizontal_scroll = master_system_.horizontal_scroll;
}
// Determine the coarse horizontal scrolling offset; this isn't applied on the first two lines if the programmer has requested it.
const int horizontal_offset = (row_ >= 16 || !master_system_.horizontal_scroll_lock) ? (master_system_.horizontal_scroll >> 3) : 0;
const int horizontal_offset = (row_ >= 16 || !master_system_.horizontal_scroll_lock) ? (master_system_.latched_horizontal_scroll >> 3) : 0;
// Determine row info for the screen both (i) if vertical scrolling is applied; and (ii) if it isn't.
// The programmer can opt out of applying vertical scrolling to the right-hand portion of the display.
const int scrolled_row = (row_ + master_system_.vertical_scroll) % 224;
const int scrolled_row = (row_ + master_system_.latched_vertical_scroll) % 224;
struct RowInfo {
size_t pattern_address_base;
size_t sub_row[2];