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draw.c, DrawLayer(): impl. proper linescroll, fixes issue #56

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dinkc64 2020-03-13 19:26:09 -04:00
parent d0eab7dae8
commit ce32676eb8
1 changed files with 2 additions and 2 deletions
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4
pico/draw.c
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@ -411,6 +411,7 @@ static void DrawLayer(int plane_sh, int *hcache, int cellskip, int maxcells,
{ {
struct PicoVideo *pvid=&Pico.video; struct PicoVideo *pvid=&Pico.video;
const char shift[4]={5,6,5,7}; // 32,64 or 128 sized tilemaps (2 is invalid) const char shift[4]={5,6,5,7}; // 32,64 or 128 sized tilemaps (2 is invalid)
const unsigned char h_masks[4] = { 0x00, 0x07, 0xf8, 0xff };
struct TileStrip ts; struct TileStrip ts;
int width, height, ymask; int width, height, ymask;
int vscroll, htab; int vscroll, htab;
@ -437,8 +438,7 @@ static void DrawLayer(int plane_sh, int *hcache, int cellskip, int maxcells,
else ts.nametab=(pvid->reg[2]&0x38)<< 9; // A else ts.nametab=(pvid->reg[2]&0x38)<< 9; // A
htab=pvid->reg[13]<<9; // Horizontal scroll table address htab=pvid->reg[13]<<9; // Horizontal scroll table address
if ( pvid->reg[11]&2) htab+=est->DrawScanline<<1; // Offset by line htab+=(est->DrawScanline&h_masks[pvid->reg[11]&3])<<1; // Point to line (masked)
if ((pvid->reg[11]&1)==0) htab&=~0xf; // Offset by tile
htab+=plane_sh&1; // A or B htab+=plane_sh&1; // A or B
// Get horizontal scroll value, will be masked later // Get horizontal scroll value, will be masked later