Skip to content

Commit

Permalink
ppu: improve source code clarity
Browse files Browse the repository at this point in the history
  • Loading branch information
@asiekierka
asiekierka committed May 20, 2021
1 parent faf851b commit e88fc5a
Show file tree
Hide file tree
Showing 3 changed files with 30 additions and 28 deletions.
6 changes: 3 additions & 3 deletions arm9/source/emulator.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,7 @@ quit(void)
int
init(void)
{
if(!initppu(&ppu, 32, 24))
if(!initppu(&ppu))
return error("PPU", "Init failure");
fifoSendValue32(UXNDS_FIFO_CHANNEL, UXNDS_FIFO_CMD_SET_RATE | SAMPLE_FREQUENCY);
fifoSendValue32(UXNDS_FIFO_CHANNEL, UXNDS_FIFO_CMD_SET_ADDR | ((u32) (&apu_samples)));
Expand Down Expand Up @@ -393,8 +393,8 @@ main(int argc, char **argv)
portuxn(&u, 0xf, "---", nil_talk);

/* Write screen size to dev/screen */
mempoke16(devscreen->dat, 2, ppu.hor * 8);
mempoke16(devscreen->dat, 4, ppu.ver * 8);
mempoke16(devscreen->dat, 2, PPU_PIXELS_WIDTH);
mempoke16(devscreen->dat, 4, PPU_PIXELS_HEIGHT);

start(&u);
quit();
Expand Down
44 changes: 21 additions & 23 deletions arm9/source/ppu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,8 +33,11 @@ static Uint8 font[][8] = {
{0x00, 0x7c, 0x82, 0x80, 0xf0, 0x80, 0x82, 0x7c},
{0x00, 0x7c, 0x82, 0x80, 0xf0, 0x80, 0x80, 0x80}};

#define PPU_TILES_WIDTH 32
#define PPU_TILES_HEIGHT 24

DTCM_BSS
static Uint32 tile_dirty[24];
static Uint32 tile_dirty[PPU_TILES_HEIGHT];

DTCM_DATA
static Uint32 lut_expand_8_32[256] = {
Expand Down Expand Up @@ -67,9 +70,9 @@ ITCM_ARM_CODE
void
putpixel(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 color)
{
if(x >= 32 * 8 || y >= 24 * 8)
if(x >= PPU_TILES_WIDTH * 8 || y >= PPU_TILES_HEIGHT * 8)
return;
Uint32 pos = ((y & 7) + (((x >> 3) + (y >> 3) * 32) * 8));
Uint32 pos = ((y & 7) + (((x >> 3) + (y >> 3) * PPU_TILES_WIDTH) * 8));
Uint32 shift = (x & 7) << 2;
layer[pos] = (layer[pos] & (~(0xF << shift))) | (color << shift);
tile_dirty[y >> 3] |= 1 << (x >> 3);
Expand All @@ -80,25 +83,25 @@ void
puticn(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)
{
Uint8 sprline;
Uint8 xrightedge = x < (31 * 8);
Uint8 xrightedge = x < ((PPU_TILES_WIDTH - 1) * 8);
Uint16 v;
Uint32 dirtyflag = (1 << (x >> 3)) | (1 << ((x + 7) >> 3));

Uint32 layerpos = ((y & 7) + (((x >> 3) + (y >> 3) * 32) * 8));
Uint32 layerpos = ((y & 7) + (((x >> 3) + (y >> 3) * PPU_TILES_WIDTH) * 8));
Uint32 *layerptr = &layer[layerpos];
Uint32 shift = (x & 7) << 2;
Uint32 *lut_expand = flipx ? lut_expand_8_32 : lut_expand_8_32_flipx;

if (flipy) flipy = 7;

if(x >= 32 * 8 || y >= 24 * 8)
if(x >= PPU_TILES_WIDTH * 8 || y >= PPU_TILES_HEIGHT * 8)
return;

if (color != 0x05 && color != 0x0a && color != 0x0f) {
u64 mask = ~((u64)0xFFFFFFFF << shift);

for (v = 0; v < 8; v++, layerptr++) {
if ((y + v) >= (24 * 8)) break;
if ((y + v) >= (PPU_TILES_HEIGHT * 8)) break;

sprline = sprite[v ^ flipy];
u64 data = (u64)(lut_expand[sprline] * (color & 3)) << shift;
Expand All @@ -107,11 +110,11 @@ puticn(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Ui
layerptr[0] = (layerptr[0] & mask) | data;
if (xrightedge) layerptr[8] = (layerptr[8] & (mask >> 32)) | (data >> 32);

if (((y + v) & 7) == 7) layerptr += 248;
if (((y + v) & 7) == 7) layerptr += (PPU_TILES_WIDTH - 1) * 8;
}
} else {
for (v = 0; v < 8; v++, layerptr++) {
if ((y + v) >= (24 * 8)) break;
if ((y + v) >= (PPU_TILES_HEIGHT * 8)) break;

sprline = sprite[v ^ flipy];
u64 mask = ~((u64)(lut_expand[sprline] * 0xF) << shift);
Expand All @@ -120,7 +123,7 @@ puticn(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Ui
layerptr[0] = (layerptr[0] & mask) | data;
if (xrightedge) layerptr[8] = (layerptr[8] & (mask >> 32)) | (data >> 32);

if (((y + v) & 7) == 7) layerptr += 248;
if (((y + v) & 7) == 7) layerptr += (PPU_TILES_WIDTH - 1) * 8;
}
}

Expand All @@ -133,25 +136,25 @@ void
putchr(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)
{
Uint8 sprline1, sprline2;
Uint8 xrightedge = x < (31 * 8);
Uint8 xrightedge = x < ((PPU_TILES_WIDTH - 1) * 8);
Uint16 v;
Uint32 dirtyflag = (1 << (x >> 3)) | (1 << ((x + 7) >> 3));

Uint32 layerpos = ((y & 7) + (((x >> 3) + (y >> 3) * 32) * 8));
Uint32 layerpos = ((y & 7) + (((x >> 3) + (y >> 3) * PPU_TILES_WIDTH) * 8));
Uint32 *layerptr = &layer[layerpos];
Uint32 shift = (x & 7) << 2;
Uint32 *lut_expand = flipx ? lut_expand_8_32 : lut_expand_8_32_flipx;

if (flipy) flipy = 7;

if(x >= 32 * 8 || y >= 24 * 8)
if(x >= PPU_TILES_WIDTH * 8 || y >= PPU_TILES_HEIGHT * 8)
return;

u64 mask = ~((u64)0xFFFFFFFF << shift);
u32 colconst = (color >> 2) * 0x11111111;

for (v = 0; v < 8; v++, layerptr++) {
if ((y + v) >= (24 * 8)) break;
if ((y + v) >= (PPU_TILES_HEIGHT * 8)) break;

sprline1 = sprite[v ^ flipy];
sprline2 = sprite[(v ^ flipy) | 8];
Expand All @@ -165,7 +168,7 @@ putchr(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Ui
layerptr[0] = (layerptr[0] & mask) | data;
if (xrightedge) layerptr[8] = (layerptr[8] & (mask >> 32)) | (data >> 32);

if (((y + v) & 7) == 7) layerptr += 248;
if (((y + v) & 7) == 7) layerptr += (PPU_TILES_WIDTH - 1) * 8;
}

tile_dirty[y >> 3] |= dirtyflag;
Expand Down Expand Up @@ -244,30 +247,25 @@ copyppu(Ppu *p)
}

int
initppu(Ppu *p, Uint8 hor, Uint8 ver)
initppu(Ppu *p)
{
int i;
u16 *map_ptr;

p->hor = hor;
p->ver = ver;
p->width = (8 * p->hor);
p->height = (8 * p->ver);

videoSetMode(DISPLAY_BG0_ACTIVE | DISPLAY_BG1_ACTIVE | MODE_0_2D);
vramSetBankA(VRAM_A_MAIN_BG);

// clear tile data
p->bg = (Uint32*) BG_TILE_RAM(4);
p->fg = (Uint32*) BG_TILE_RAM(6);
for (i = 0; i < 8; i += 2) {
dmaFillWords(0, BG_TILE_RAM(i), 768 * 32);
dmaFillWords(0, BG_TILE_RAM(i), (PPU_TILES_WIDTH * PPU_TILES_HEIGHT) * 32);
}
memset(tile_dirty, 0, sizeof(tile_dirty));

// init bg data
map_ptr = BG_GFX + (24576 >> 1);
for (i = 0; i < 768; i++) {
for (i = 0; i < (PPU_TILES_WIDTH * PPU_TILES_HEIGHT); i++) {
*(map_ptr++) = i;
}

Expand Down
8 changes: 6 additions & 2 deletions arm9/source/ppu.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,16 +14,20 @@ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE.
*/

#define PPU_TILES_WIDTH 32
#define PPU_TILES_HEIGHT 24
#define PPU_PIXELS_WIDTH (PPU_TILES_WIDTH * 8)
#define PPU_PIXELS_HEIGHT (PPU_TILES_HEIGHT * 8)

typedef unsigned char Uint8;
typedef unsigned short Uint16;
typedef unsigned int Uint32;

typedef struct Ppu {
Uint32 *bg, *fg;
Uint16 hor, ver, width, height;
} Ppu;

int initppu(Ppu *p, Uint8 hor, Uint8 ver);
int initppu(Ppu *p);
void putcolors(Ppu *p, Uint8 *addr);
void putpixel(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 color);
void puticn(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy);
Expand Down

0 comments on commit e88fc5a

Please sign in to comment.