ref: c08fcb7d885380bec787f8aa7848bcc13afbc464
dir: /snes/ppu.c/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>
#include <assert.h>
#include "ppu.h"
#include "../types.h"
static const uint8 kSpriteSizes[8][2] = {
{8, 16}, {8, 32}, {8, 64}, {16, 32},
{16, 64}, {32, 64}, {16, 32}, {16, 32}
};
static void ppu_handlePixel(Ppu* ppu, int x, int y);
static int ppu_getPixel(Ppu* ppu, int x, int y, bool sub, int* r, int* g, int* b);
static int ppu_getPixelForBgLayer(Ppu *ppu, int x, int y, int layer, bool priority);
static void ppu_calculateMode7Starts(Ppu* ppu, int y);
static int ppu_getPixelForMode7(Ppu* ppu, int x, int layer, bool priority);
static bool ppu_getWindowState(Ppu* ppu, int layer, int x);
static bool ppu_evaluateSprites(Ppu* ppu, int line);
static void PpuDrawWholeLine(Ppu *ppu, uint y);
#define IS_SCREEN_ENABLED(ppu, sub, layer) (ppu->screenEnabled[sub] & (1 << layer))
#define IS_SCREEN_WINDOWED(ppu, sub, layer) (ppu->screenWindowed[sub] & (1 << layer))
#define IS_MOSAIC_ENABLED(ppu, layer) ((ppu->mosaicEnabled & (1 << layer)))
#define GET_WINDOW_FLAGS(ppu, layer) (ppu->windowsel >> (layer * 4))
enum {
kWindow1Inversed = 1,
kWindow1Enabled = 2,
kWindow2Inversed = 4,
kWindow2Enabled = 8,
};
Ppu* ppu_init() {
Ppu* ppu = (Ppu * )malloc(sizeof(Ppu));
ppu->extraLeftRight = kPpuExtraLeftRight;
return ppu;
}
void ppu_free(Ppu* ppu) {
free(ppu);
}
void ppu_reset(Ppu* ppu) {
memset(ppu->vram, 0, sizeof(ppu->vram));
ppu->lastBrightnessMult = 0xff;
ppu->lastMosaicModulo = 0xff;
ppu->extraLeftCur = 0;
ppu->extraRightCur = 0;
ppu->extraBottomCur = 0;
ppu->vramPointer = 0;
ppu->vramIncrementOnHigh = false;
ppu->vramIncrement = 1;
memset(ppu->cgram, 0, sizeof(ppu->cgram));
ppu->cgramPointer = 0;
ppu->cgramSecondWrite = false;
ppu->cgramBuffer = 0;
memset(ppu->oam, 0, sizeof(ppu->oam));
ppu->oamAdr = 0;
ppu->oamSecondWrite = false;
ppu->oamBuffer = 0;
ppu->objTileAdr1 = 0x4000;
ppu->objTileAdr2 = 0x5000;
ppu->objSize = 0;
memset(&ppu->objBuffer, 0, sizeof(ppu->objBuffer));
for(int i = 0; i < 4; i++) {
ppu->bgLayer[i].hScroll = 0;
ppu->bgLayer[i].vScroll = 0;
ppu->bgLayer[i].tilemapWider = false;
ppu->bgLayer[i].tilemapHigher = false;
ppu->bgLayer[i].tilemapAdr = 0;
ppu->bgLayer[i].tileAdr = 0;
}
ppu->scrollPrev = 0;
ppu->scrollPrev2 = 0;
ppu->mosaicSize = 1;
ppu->screenEnabled[0] = ppu->screenEnabled[1] = 0;
ppu->screenWindowed[0] = ppu->screenWindowed[1] = 0;
memset(ppu->m7matrix, 0, sizeof(ppu->m7matrix));
ppu->m7prev = 0;
ppu->m7largeField = true;
ppu->m7charFill = false;
ppu->m7xFlip = false;
ppu->m7yFlip = false;
ppu->m7extBg_always_zero = false;
ppu->m7startX = 0;
ppu->m7startY = 0;
ppu->windowsel = 0;
ppu->window1left = 0;
ppu->window1right = 0;
ppu->window2left = 0;
ppu->window2right = 0;
ppu->clipMode = 0;
ppu->preventMathMode = 0;
ppu->addSubscreen = false;
ppu->subtractColor = false;
ppu->halfColor = false;
ppu->mathEnabled = 0;
ppu->fixedColorR = 0;
ppu->fixedColorG = 0;
ppu->fixedColorB = 0;
ppu->forcedBlank = true;
ppu->brightness = 0;
ppu->mode = 0;
}
void ppu_saveload(Ppu *ppu, SaveLoadFunc *func, void *ctx) {
uint8 tmp[556] = { 0 };
func(ctx, &ppu->vram, 0x8000 * 2);
func(ctx, tmp, 10);
func(ctx, &ppu->cgram, 512);
func(ctx, tmp, 556);
func(ctx, tmp, 520);
for (int i = 0; i < 4; i++) {
func(ctx, tmp, 4);
func(ctx, &ppu->bgLayer[i].tilemapWider, 4);
func(ctx, tmp, 4);
}
func(ctx, tmp, 123);
}
int PpuGetCurrentRenderScale(Ppu *ppu, uint32_t render_flags) {
bool hq = ppu->mode == 7 && !ppu->forcedBlank &&
(render_flags & (kPpuRenderFlags_4x4Mode7 | kPpuRenderFlags_NewRenderer)) == (kPpuRenderFlags_4x4Mode7 | kPpuRenderFlags_NewRenderer);
return hq ? 4 : 1;
}
void PpuBeginDrawing(Ppu *ppu, uint8_t *pixels, size_t pitch, uint32_t render_flags) {
ppu->renderFlags = render_flags;
ppu->renderPitch = (uint)pitch;
ppu->renderBuffer = pixels;
// Cache the brightness computation
if (ppu->brightness != ppu->lastBrightnessMult) {
uint8_t ppu_brightness = ppu->brightness;
ppu->lastBrightnessMult = ppu_brightness;
for (int i = 0; i < 32; i++)
ppu->brightnessMultHalf[i * 2] = ppu->brightnessMultHalf[i * 2 + 1] = ppu->brightnessMult[i] =
((i << 3) | (i >> 2)) * ppu_brightness / 15;
// Store 31 extra entries to remove the need for clamping to 31.
memset(&ppu->brightnessMult[32], ppu->brightnessMult[31], 31);
}
if (PpuGetCurrentRenderScale(ppu, ppu->renderFlags) == 4) {
for (int i = 0; i < 256; i++) {
uint32 color = ppu->cgram[i];
ppu->colorMapRgb[i] = ppu->brightnessMult[color & 0x1f] << 16 | ppu->brightnessMult[(color >> 5) & 0x1f] << 8 | ppu->brightnessMult[(color >> 10) & 0x1f];
}
}
}
static inline void ClearBackdrop(PpuPixelPrioBufs *buf) {
for (size_t i = 0; i != countof(buf->data); i += 4)
*(uint64*)&buf->data[i] = 0x0500050005000500;
}
void ppu_runLine(Ppu *ppu, int line) {
if(line != 0) {
if (ppu->mosaicSize != ppu->lastMosaicModulo) {
int mod = ppu->mosaicSize;
ppu->lastMosaicModulo = mod;
for (int i = 0, j = 0; i < countof(ppu->mosaicModulo); i++) {
ppu->mosaicModulo[i] = i - j;
j = (j + 1 == mod ? 0 : j + 1);
}
}
// evaluate sprites
ClearBackdrop(&ppu->objBuffer);
ppu->lineHasSprites = !ppu->forcedBlank && ppu_evaluateSprites(ppu, line - 1);
// outside of visible range?
if (line >= 225 + ppu->extraBottomCur) {
uint8 *dst = &ppu->renderBuffer[(line - 1) * 2 * ppu->renderPitch];
size_t n = sizeof(uint32) * 2 * (256 + ppu->extraLeftRight * 2);
memset(dst, 0, n);
memset(dst + ppu->renderPitch, 0, n);
return;
}
if (ppu->renderFlags & kPpuRenderFlags_NewRenderer) {
PpuDrawWholeLine(ppu, line);
} else {
if (ppu->mode == 7)
ppu_calculateMode7Starts(ppu, line);
for (int x = 0; x < 256; x++)
ppu_handlePixel(ppu, x, line);
uint8 *dst = ppu->renderBuffer + ((line - 1) * ppu->renderPitch);
if (ppu->extraLeftRight != 0) {
memset(dst, 0, sizeof(uint32) * ppu->extraLeftRight);
memset(dst + sizeof(uint32) * (256 + ppu->extraLeftRight), 0, sizeof(uint32) * ppu->extraLeftRight);
}
}
}
}
typedef struct PpuWindows {
int16 edges[6];
uint8 nr;
uint8 bits;
} PpuWindows;
static void PpuWindows_Clear(PpuWindows *win, Ppu *ppu, uint layer) {
win->edges[0] = -(layer != 2 ? ppu->extraLeftCur : 0);
win->edges[1] = 256 + (layer != 2 ? ppu->extraRightCur : 0);
win->nr = 1;
win->bits = 0;
}
static void PpuWindows_Calc(PpuWindows *win, Ppu *ppu, uint layer) {
// Evaluate which spans to render based on the window settings.
// There are at most 5 windows.
// Algorithm from Snes9x
uint32 winflags = GET_WINDOW_FLAGS(ppu, layer);
uint nr = 1;
int window_right = 256 + (layer != 2 ? ppu->extraRightCur : 0);
win->edges[0] = - (layer != 2 ? ppu->extraLeftCur : 0);
win->edges[1] = window_right;
uint i, j;
int t;
bool w1_ena = (winflags & kWindow1Enabled) && ppu->window1left <= ppu->window1right;
if (w1_ena) {
if (ppu->window1left > win->edges[0]) {
win->edges[nr] = ppu->window1left;
win->edges[++nr] = window_right;
}
if (ppu->window1right + 1 < window_right) {
win->edges[nr] = ppu->window1right + 1;
win->edges[++nr] = window_right;
}
}
bool w2_ena = (winflags & kWindow2Enabled) && ppu->window2left <= ppu->window2right;
if (w2_ena) {
for (i = 0; i <= nr && (t = ppu->window2left) != win->edges[i]; i++) {
if (t < win->edges[i]) {
for (j = nr++; j >= i; j--)
win->edges[j + 1] = win->edges[j];
win->edges[i] = t;
break;
}
}
for (; i <= nr && (t = ppu->window2right + 1) != win->edges[i]; i++) {
if (t < win->edges[i]) {
for (j = nr++; j >= i; j--)
win->edges[j + 1] = win->edges[j];
win->edges[i] = t;
break;
}
}
}
win->nr = nr;
// get a bitmap of how regions map to windows
uint8 w1_bits = 0, w2_bits = 0;
if (w1_ena) {
for (i = 0; win->edges[i] != ppu->window1left; i++);
for (j = i; win->edges[j] != ppu->window1right + 1; j++);
w1_bits = ((1 << (j - i)) - 1) << i;
}
if ((winflags & (kWindow1Enabled | kWindow1Inversed)) == (kWindow1Enabled | kWindow1Inversed))
w1_bits = ~w1_bits;
if (w2_ena) {
for (i = 0; win->edges[i] != ppu->window2left; i++);
for (j = i; win->edges[j] != ppu->window2right + 1; j++);
w2_bits = ((1 << (j - i)) - 1) << i;
}
if ((winflags & (kWindow2Enabled | kWindow2Inversed)) == (kWindow2Enabled | kWindow2Inversed))
w2_bits = ~w2_bits;
win->bits = w1_bits | w2_bits;
}
// Draw a whole line of a 4bpp background layer into bgBuffers
static void PpuDrawBackground_4bpp(Ppu *ppu, uint y, bool sub, uint layer, PpuZbufType zhi, PpuZbufType zlo) {
#define DO_PIXEL(i) do { \
pixel = (bits >> i) & 1 | (bits >> (7 + i)) & 2 | (bits >> (14 + i)) & 4 | (bits >> (21 + i)) & 8; \
if ((bits & (0x01010101 << i)) && z > dstz[i]) dstz[i] = z + pixel; } while (0)
#define DO_PIXEL_HFLIP(i) do { \
pixel = (bits >> (7 - i)) & 1 | (bits >> (14 - i)) & 2 | (bits >> (21 - i)) & 4 | (bits >> (28 - i)) & 8; \
if ((bits & (0x80808080 >> i)) && z > dstz[i]) dstz[i] = z + pixel; } while (0)
#define READ_BITS(ta, tile) (addr = &ppu->vram[((ta) + (tile) * 16) & 0x7fff], addr[0] | addr[8] << 16)
enum { kPaletteShift = 6 };
if (!IS_SCREEN_ENABLED(ppu, sub, layer))
return; // layer is completely hidden
PpuWindows win;
IS_SCREEN_WINDOWED(ppu, sub, layer) ? PpuWindows_Calc(&win, ppu, layer) : PpuWindows_Clear(&win, ppu, layer);
BgLayer *bglayer = &ppu->bgLayer[layer];
y += bglayer->vScroll;
int sc_offs = bglayer->tilemapAdr + (((y >> 3) & 0x1f) << 5);
if ((y & 0x100) && bglayer->tilemapHigher)
sc_offs += bglayer->tilemapWider ? 0x800 : 0x400;
const uint16 *tps[2] = {
&ppu->vram[sc_offs & 0x7fff],
&ppu->vram[sc_offs + (bglayer->tilemapWider ? 0x400 : 0) & 0x7fff]
};
int tileadr = ppu->bgLayer[layer].tileAdr, pixel;
int tileadr1 = tileadr + 7 - (y & 0x7), tileadr0 = tileadr + (y & 0x7);
const uint16 *addr;
for (size_t windex = 0; windex < win.nr; windex++) {
if (win.bits & (1 << windex))
continue; // layer is disabled for this window part
uint x = win.edges[windex] + bglayer->hScroll;
uint w = win.edges[windex + 1] - win.edges[windex];
PpuZbufType *dstz = ppu->bgBuffers[sub].data + win.edges[windex] + kPpuExtraLeftRight;
const uint16 *tp = tps[x >> 8 & 1] + ((x >> 3) & 0x1f);
const uint16 *tp_last = tps[x >> 8 & 1] + 31;
const uint16 *tp_next = tps[(x >> 8 & 1) ^ 1];
#define NEXT_TP() if (tp != tp_last) tp += 1; else tp = tp_next, tp_next = tp_last - 31, tp_last = tp + 31;
// Handle clipped pixels on left side
if (x & 7) {
int curw = IntMin(8 - (x & 7), w);
w -= curw;
uint32 tile = *tp;
NEXT_TP();
int ta = (tile & 0x8000) ? tileadr1 : tileadr0;
PpuZbufType z = (tile & 0x2000) ? zhi : zlo;
uint32 bits = READ_BITS(ta, tile & 0x3ff);
if (bits) {
z += ((tile & 0x1c00) >> kPaletteShift);
if (tile & 0x4000) {
bits >>= (x & 7), x += curw;
do DO_PIXEL(0); while (bits >>= 1, dstz++, --curw);
} else {
bits <<= (x & 7), x += curw;
do DO_PIXEL_HFLIP(0); while (bits <<= 1, dstz++, --curw);
}
} else {
dstz += curw;
}
}
// Handle full tiles in the middle
while (w >= 8) {
uint32 tile = *tp;
NEXT_TP();
int ta = (tile & 0x8000) ? tileadr1 : tileadr0;
PpuZbufType z = (tile & 0x2000) ? zhi : zlo;
uint32 bits = READ_BITS(ta, tile & 0x3ff);
if (bits) {
z += ((tile & 0x1c00) >> kPaletteShift);
if (tile & 0x4000) {
DO_PIXEL(0); DO_PIXEL(1); DO_PIXEL(2); DO_PIXEL(3);
DO_PIXEL(4); DO_PIXEL(5); DO_PIXEL(6); DO_PIXEL(7);
} else {
DO_PIXEL_HFLIP(0); DO_PIXEL_HFLIP(1); DO_PIXEL_HFLIP(2); DO_PIXEL_HFLIP(3);
DO_PIXEL_HFLIP(4); DO_PIXEL_HFLIP(5); DO_PIXEL_HFLIP(6); DO_PIXEL_HFLIP(7);
}
}
dstz += 8, w -= 8;
}
// Handle remaining clipped part
if (w) {
uint32 tile = *tp;
int ta = (tile & 0x8000) ? tileadr1 : tileadr0;
PpuZbufType z = (tile & 0x2000) ? zhi : zlo;
uint32 bits = READ_BITS(ta, tile & 0x3ff);
if (bits) {
z += ((tile & 0x1c00) >> kPaletteShift);
if (tile & 0x4000) {
do DO_PIXEL(0); while (bits >>= 1, dstz++, --w);
} else {
do DO_PIXEL_HFLIP(0); while (bits <<= 1, dstz++, --w);
}
}
}
}
#undef READ_BITS
#undef DO_PIXEL
#undef DO_PIXEL_HFLIP
}
// Draw a whole line of a 2bpp background layer into bgBuffers
static void PpuDrawBackground_2bpp(Ppu *ppu, uint y, bool sub, uint layer, PpuZbufType zhi, PpuZbufType zlo) {
#define DO_PIXEL(i) do { \
pixel = (bits >> i) & 1 | (bits >> (7 + i)) & 2; \
if (pixel && z > dstz[i]) dstz[i] = z + pixel; } while (0)
#define DO_PIXEL_HFLIP(i) do { \
pixel = (bits >> (7 - i)) & 1 | (bits >> (14 - i)) & 2; \
if (pixel && z > dstz[i]) dstz[i] = z + pixel; } while (0)
#define READ_BITS(ta, tile) (addr = &ppu->vram[(ta) + (tile) * 8 & 0x7fff], addr[0])
enum { kPaletteShift = 8 };
if (!IS_SCREEN_ENABLED(ppu, sub, layer))
return; // layer is completely hidden
PpuWindows win;
IS_SCREEN_WINDOWED(ppu, sub, layer) ? PpuWindows_Calc(&win, ppu, layer) : PpuWindows_Clear(&win, ppu, layer);
BgLayer *bglayer = &ppu->bgLayer[layer];
y += bglayer->vScroll;
int sc_offs = bglayer->tilemapAdr + (((y >> 3) & 0x1f) << 5);
if ((y & 0x100) && bglayer->tilemapHigher)
sc_offs += bglayer->tilemapWider ? 0x800 : 0x400;
const uint16 *tps[2] = {
&ppu->vram[sc_offs & 0x7fff],
&ppu->vram[sc_offs + (bglayer->tilemapWider ? 0x400 : 0) & 0x7fff]
};
int tileadr = ppu->bgLayer[layer].tileAdr, pixel;
int tileadr1 = tileadr + 7 - (y & 0x7), tileadr0 = tileadr + (y & 0x7);
const uint16 *addr;
for (size_t windex = 0; windex < win.nr; windex++) {
if (win.bits & (1 << windex))
continue; // layer is disabled for this window part
uint x = win.edges[windex] + bglayer->hScroll;
uint w = win.edges[windex + 1] - win.edges[windex];
PpuZbufType *dstz = ppu->bgBuffers[sub].data + win.edges[windex] + kPpuExtraLeftRight;
const uint16 *tp = tps[x >> 8 & 1] + ((x >> 3) & 0x1f);
const uint16 *tp_last = tps[x >> 8 & 1] + 31;
const uint16 *tp_next = tps[(x >> 8 & 1) ^ 1];
#define NEXT_TP() if (tp != tp_last) tp += 1; else tp = tp_next, tp_next = tp_last - 31, tp_last = tp + 31;
// Handle clipped pixels on left side
if (x & 7) {
int curw = IntMin(8 - (x & 7), w);
w -= curw;
uint32 tile = *tp;
NEXT_TP();
int ta = (tile & 0x8000) ? tileadr1 : tileadr0;
PpuZbufType z = (tile & 0x2000) ? zhi : zlo;
uint32 bits = READ_BITS(ta, tile & 0x3ff);
if (bits) {
z += ((tile & 0x1c00) >> kPaletteShift);
if (tile & 0x4000) {
bits >>= (x & 7), x += curw;
do DO_PIXEL(0); while (bits >>= 1, dstz++, --curw);
} else {
bits <<= (x & 7), x += curw;
do DO_PIXEL_HFLIP(0); while (bits <<= 1, dstz++, --curw);
}
} else {
dstz += curw;
}
}
// Handle full tiles in the middle
while (w >= 8) {
uint32 tile = *tp;
NEXT_TP();
int ta = (tile & 0x8000) ? tileadr1 : tileadr0;
PpuZbufType z = (tile & 0x2000) ? zhi : zlo;
uint32 bits = READ_BITS(ta, tile & 0x3ff);
if (bits) {
z += ((tile & 0x1c00) >> kPaletteShift);
if (tile & 0x4000) {
DO_PIXEL(0); DO_PIXEL(1); DO_PIXEL(2); DO_PIXEL(3);
DO_PIXEL(4); DO_PIXEL(5); DO_PIXEL(6); DO_PIXEL(7);
} else {
DO_PIXEL_HFLIP(0); DO_PIXEL_HFLIP(1); DO_PIXEL_HFLIP(2); DO_PIXEL_HFLIP(3);
DO_PIXEL_HFLIP(4); DO_PIXEL_HFLIP(5); DO_PIXEL_HFLIP(6); DO_PIXEL_HFLIP(7);
}
}
dstz += 8, w -= 8;
}
// Handle remaining clipped part
if (w) {
uint32 tile = *tp;
int ta = (tile & 0x8000) ? tileadr1 : tileadr0;
PpuZbufType z = (tile & 0x2000) ? zhi : zlo;
uint32 bits = READ_BITS(ta, tile & 0x3ff);
if (bits) {
z += ((tile & 0x1c00) >> kPaletteShift);
if (tile & 0x4000) {
do DO_PIXEL(0); while (bits >>= 1, dstz++, --w);
} else {
do DO_PIXEL_HFLIP(0); while (bits <<= 1, dstz++, --w);
}
}
}
}
#undef NEXT_TP
#undef READ_BITS
#undef DO_PIXEL
#undef DO_PIXEL_HFLIP
}
// Draw a whole line of a 4bpp background layer into bgBuffers, with mosaic applied
static void PpuDrawBackground_4bpp_mosaic(Ppu *ppu, uint y, bool sub, uint layer, PpuZbufType zhi, PpuZbufType zlo) {
#define GET_PIXEL() pixel = (bits) & 1 | (bits >> 7) & 2 | (bits >> 14) & 4 | (bits >> 21) & 8
#define GET_PIXEL_HFLIP() pixel = (bits >> 7) & 1 | (bits >> 14) & 2 | (bits >> 21) & 4 | (bits >> 28) & 8
#define READ_BITS(ta, tile) (addr = &ppu->vram[((ta) + (tile) * 16) & 0x7fff], addr[0] | addr[8] << 16)
enum { kPaletteShift = 6 };
if (!IS_SCREEN_ENABLED(ppu, sub, layer))
return; // layer is completely hidden
PpuWindows win;
IS_SCREEN_WINDOWED(ppu, sub, layer) ? PpuWindows_Calc(&win, ppu, layer) : PpuWindows_Clear(&win, ppu, layer);
BgLayer *bglayer = &ppu->bgLayer[layer];
y = ppu->mosaicModulo[y] + bglayer->vScroll;
int sc_offs = bglayer->tilemapAdr + (((y >> 3) & 0x1f) << 5);
if ((y & 0x100) && bglayer->tilemapHigher)
sc_offs += bglayer->tilemapWider ? 0x800 : 0x400;
const uint16 *tps[2] = {
&ppu->vram[sc_offs & 0x7fff],
&ppu->vram[sc_offs + (bglayer->tilemapWider ? 0x400 : 0) & 0x7fff]
};
int tileadr = ppu->bgLayer[layer].tileAdr, pixel;
int tileadr1 = tileadr + 7 - (y & 0x7), tileadr0 = tileadr + (y & 0x7);
const uint16 *addr;
for (size_t windex = 0; windex < win.nr; windex++) {
if (win.bits & (1 << windex))
continue; // layer is disabled for this window part
int sx = win.edges[windex];
PpuZbufType *dstz = ppu->bgBuffers[sub].data + sx + kPpuExtraLeftRight;
PpuZbufType *dstz_end = ppu->bgBuffers[sub].data + win.edges[windex + 1] + kPpuExtraLeftRight;
uint x = sx + bglayer->hScroll;
const uint16 *tp = tps[x >> 8 & 1] + ((x >> 3) & 0x1f);
const uint16 *tp_last = tps[x >> 8 & 1] + 31, *tp_next = tps[(x >> 8 & 1) ^ 1];
x &= 7;
int w = ppu->mosaicSize - (sx - ppu->mosaicModulo[sx]);
do {
w = IntMin(w, dstz_end - dstz);
uint32 tile = *tp;
int ta = (tile & 0x8000) ? tileadr1 : tileadr0;
PpuZbufType z = (tile & 0x2000) ? zhi : zlo;
uint32 bits = READ_BITS(ta, tile & 0x3ff);
if (tile & 0x4000) bits >>= x, GET_PIXEL(); else bits <<= x, GET_PIXEL_HFLIP();
if (pixel) {
pixel += (tile & 0x1c00) >> kPaletteShift;
int i = 0;
do {
if (z > dstz[i])
dstz[i] = pixel + z;
} while (++i != w);
}
dstz += w, x += w;
for (; x >= 8; x -= 8)
tp = (tp != tp_last) ? tp + 1 : tp_next;
w = ppu->mosaicSize;
} while (dstz_end - dstz != 0);
}
#undef READ_BITS
#undef GET_PIXEL
#undef GET_PIXEL_HFLIP
}
// Draw a whole line of a 2bpp background layer into bgBuffers, with mosaic applied
static void PpuDrawBackground_2bpp_mosaic(Ppu *ppu, int y, bool sub, uint layer, PpuZbufType zhi, PpuZbufType zlo) {
#define GET_PIXEL() pixel = (bits) & 1 | (bits >> 7) & 2
#define GET_PIXEL_HFLIP() pixel = (bits >> 7) & 1 | (bits >> 14) & 2
#define READ_BITS(ta, tile) (addr = &ppu->vram[((ta) + (tile) * 8) & 0x7fff], addr[0])
enum { kPaletteShift = 8 };
if (!IS_SCREEN_ENABLED(ppu, sub, layer))
return; // layer is completely hidden
PpuWindows win;
IS_SCREEN_WINDOWED(ppu, sub, layer) ? PpuWindows_Calc(&win, ppu, layer) : PpuWindows_Clear(&win, ppu, layer);
BgLayer *bglayer = &ppu->bgLayer[layer];
y = ppu->mosaicModulo[y] + bglayer->vScroll;
int sc_offs = bglayer->tilemapAdr + (((y >> 3) & 0x1f) << 5);
if ((y & 0x100) && bglayer->tilemapHigher)
sc_offs += bglayer->tilemapWider ? 0x800 : 0x400;
const uint16 *tps[2] = {
&ppu->vram[sc_offs & 0x7fff],
&ppu->vram[sc_offs + (bglayer->tilemapWider ? 0x400 : 0) & 0x7fff]
};
int tileadr = ppu->bgLayer[layer].tileAdr, pixel;
int tileadr1 = tileadr + 7 - (y & 0x7), tileadr0 = tileadr + (y & 0x7);
const uint16 *addr;
for (size_t windex = 0; windex < win.nr; windex++) {
if (win.bits & (1 << windex))
continue; // layer is disabled for this window part
int sx = win.edges[windex];
PpuZbufType *dstz = ppu->bgBuffers[sub].data + sx + kPpuExtraLeftRight;
PpuZbufType *dstz_end = ppu->bgBuffers[sub].data + win.edges[windex + 1] + kPpuExtraLeftRight;
uint x = sx + bglayer->hScroll;
const uint16 *tp = tps[x >> 8 & 1] + ((x >> 3) & 0x1f);
const uint16 *tp_last = tps[x >> 8 & 1] + 31, *tp_next = tps[(x >> 8 & 1) ^ 1];
x &= 7;
int w = ppu->mosaicSize - (sx - ppu->mosaicModulo[sx]);
do {
w = IntMin(w, dstz_end - dstz);
uint32 tile = *tp;
int ta = (tile & 0x8000) ? tileadr1 : tileadr0;
PpuZbufType z = (tile & 0x2000) ? zhi : zlo;
uint32 bits = READ_BITS(ta, tile & 0x3ff);
if (tile & 0x4000) bits >>= x, GET_PIXEL(); else bits <<= x, GET_PIXEL_HFLIP();
if (pixel) {
pixel += (tile & 0x1c00) >> kPaletteShift;
uint i = 0;
do {
if (z > dstz[i])
dstz[i] = pixel + z;
} while (++i != w);
}
dstz += w, x += w;
for (; x >= 8; x -= 8)
tp = (tp != tp_last) ? tp + 1 : tp_next;
w = ppu->mosaicSize;
} while (dstz_end - dstz != 0);
}
#undef READ_BITS
#undef GET_PIXEL
#undef GET_PIXEL_HFLIP
}
// level6 should be set if it's from palette 0xc0 which means color math is not applied
#define SPRITE_PRIO_TO_PRIO(prio, level6) (((prio) * 4 + 2) * 16 + 4 + (level6 ? 2 : 0))
#define SPRITE_PRIO_TO_PRIO_HI(prio) ((prio) * 4 + 2)
static void PpuDrawSprites(Ppu *ppu, uint y, uint sub, bool clear_backdrop) {
int layer = 4;
if (!IS_SCREEN_ENABLED(ppu, sub, layer))
return; // layer is completely hidden
PpuWindows win;
IS_SCREEN_WINDOWED(ppu, sub, layer) ? PpuWindows_Calc(&win, ppu, layer) : PpuWindows_Clear(&win, ppu, layer);
for (size_t windex = 0; windex < win.nr; windex++) {
if (win.bits & (1 << windex))
continue; // layer is disabled for this window part
int left = win.edges[windex];
int width = win.edges[windex + 1] - left;
PpuZbufType *src = ppu->objBuffer.data + left + kPpuExtraLeftRight;
PpuZbufType *dst = ppu->bgBuffers[sub].data + left + kPpuExtraLeftRight;
if (clear_backdrop) {
memcpy(dst, src, width * sizeof(uint16));
} else {
do {
if (src[0] > dst[0])
dst[0] = src[0];
} while (src++, dst++, --width);
}
}
}
// Assumes it's drawn on an empty backdrop
static void PpuDrawBackground_mode7(Ppu *ppu, uint y, bool sub, PpuZbufType z) {
int layer = 0;
if (!IS_SCREEN_ENABLED(ppu, sub, layer))
return; // layer is completely hidden
PpuWindows win;
IS_SCREEN_WINDOWED(ppu, sub, layer) ? PpuWindows_Calc(&win, ppu, layer) : PpuWindows_Clear(&win, ppu, layer);
// expand 13-bit values to signed values
int hScroll = ((int16_t)(ppu->m7matrix[6] << 3)) >> 3;
int vScroll = ((int16_t)(ppu->m7matrix[7] << 3)) >> 3;
int xCenter = ((int16_t)(ppu->m7matrix[4] << 3)) >> 3;
int yCenter = ((int16_t)(ppu->m7matrix[5] << 3)) >> 3;
int clippedH = hScroll - xCenter;
int clippedV = vScroll - yCenter;
clippedH = (clippedH & 0x2000) ? (clippedH | ~1023) : (clippedH & 1023);
clippedV = (clippedV & 0x2000) ? (clippedV | ~1023) : (clippedV & 1023);
bool mosaic_enabled = IS_MOSAIC_ENABLED(ppu, 0);
if (mosaic_enabled)
y = ppu->mosaicModulo[y];
uint32 ry = ppu->m7yFlip ? 255 - y : y;
uint32 m7startX = (ppu->m7matrix[0] * clippedH & ~63) + (ppu->m7matrix[1] * ry & ~63) +
(ppu->m7matrix[1] * clippedV & ~63) + (xCenter << 8);
uint32 m7startY = (ppu->m7matrix[2] * clippedH & ~63) + (ppu->m7matrix[3] * ry & ~63) +
(ppu->m7matrix[3] * clippedV & ~63) + (yCenter << 8);
for (size_t windex = 0; windex < win.nr; windex++) {
if (win.bits & (1 << windex))
continue; // layer is disabled for this window part
int x = win.edges[windex], x2 = win.edges[windex + 1], tile;
PpuZbufType *dstz = ppu->bgBuffers[sub].data + x + kPpuExtraLeftRight;
PpuZbufType *dstz_end = ppu->bgBuffers[sub].data + x2 + kPpuExtraLeftRight;
uint32 rx = ppu->m7xFlip ? 255 - x : x;
uint32 xpos = m7startX + ppu->m7matrix[0] * rx;
uint32 ypos = m7startY + ppu->m7matrix[2] * rx;
uint32 dx = ppu->m7xFlip ? -ppu->m7matrix[0] : ppu->m7matrix[0];
uint32 dy = ppu->m7xFlip ? -ppu->m7matrix[2] : ppu->m7matrix[2];
uint32 outside_value = ppu->m7largeField ? 0x3ffff : 0xffffffff;
bool char_fill = ppu->m7charFill;
if (mosaic_enabled) {
int w = ppu->mosaicSize - (x - ppu->mosaicModulo[x]);
do {
w = IntMin(w, dstz_end - dstz);
if ((uint32)(xpos | ypos) > outside_value) {
if (!char_fill)
continue;
tile = 0;
} else {
tile = ppu->vram[(ypos >> 11 & 0x7f) * 128 + (xpos >> 11 & 0x7f)] & 0xff;
}
uint8 pixel = ppu->vram[tile * 64 + (ypos >> 8 & 7) * 8 + (xpos >> 8 & 7)] >> 8;
if (pixel) {
int i = 0;
do dstz[i] = pixel + z; while (++i != w);
}
} while (xpos += dx * w, ypos += dy * w, dstz += w, w = ppu->mosaicSize, dstz_end - dstz != 0);
} else {
do {
if ((uint32)(xpos | ypos) > outside_value) {
if (!char_fill)
continue;
tile = 0;
} else {
tile = ppu->vram[(ypos >> 11 & 0x7f) * 128 + (xpos >> 11 & 0x7f)] & 0xff;
}
uint8 pixel = ppu->vram[tile * 64 + (ypos >> 8 & 7) * 8 + (xpos >> 8 & 7)] >> 8;
if (pixel)
dstz[0] = pixel + z;
} while (xpos += dx, ypos += dy, ++dstz != dstz_end);
}
}
}
void PpuSetMode7PerspectiveCorrection(Ppu *ppu, int low, int high) {
ppu->mode7PerspectiveLow = low ? 1.0f / low : 0.0f;
ppu->mode7PerspectiveHigh = 1.0f / high;
}
void PpuSetExtraSideSpace(Ppu *ppu, int left, int right, int bottom) {
ppu->extraLeftCur = UintMin(left, ppu->extraLeftRight);
ppu->extraRightCur = UintMin(right, ppu->extraLeftRight);
ppu->extraBottomCur = UintMin(bottom, 16);
}
static FORCEINLINE float FloatInterpolate(float x, float xmin, float xmax, float ymin, float ymax) {
return ymin + (ymax - ymin) * (x - xmin) * (1.0f / (xmax - xmin));
}
// Upsampled version of mode7 rendering. Draws everything in 4x the normal resolution.
// Draws directly to the pixel buffer and bypasses any math, and supports only
// a subset of the normal features (all that zelda needs)
static void PpuDrawMode7Upsampled(Ppu *ppu, uint y) {
// expand 13-bit values to signed values
uint32 xCenter = ((int16_t)(ppu->m7matrix[4] << 3)) >> 3, yCenter = ((int16_t)(ppu->m7matrix[5] << 3)) >> 3;
uint32 clippedH = (((int16_t)(ppu->m7matrix[6] << 3)) >> 3) - xCenter;
uint32 clippedV = (((int16_t)(ppu->m7matrix[7] << 3)) >> 3) - yCenter;
int32 m0v[4];
if (*(uint32*)&ppu->mode7PerspectiveLow == 0) {
m0v[0] = m0v[1] = m0v[2] = m0v[3] = ppu->m7matrix[0] << 12;
} else {
static const float kInterpolateOffsets[4] = { -1, -1 + 0.25f, -1 + 0.5f, -1 + 0.75f };
for (int i = 0; i < 4; i++)
m0v[i] = 4096.0f / FloatInterpolate((int)y + kInterpolateOffsets[i], 0, 223, ppu->mode7PerspectiveLow, ppu->mode7PerspectiveHigh);
}
size_t pitch = ppu->renderPitch;
uint8 *render_buffer_ptr = &ppu->renderBuffer[(y - 1) * 4 * pitch];
uint8 *dst_start = render_buffer_ptr + (ppu->extraLeftRight - ppu->extraLeftCur) * 16;
size_t draw_width = 256 + ppu->extraLeftCur + ppu->extraRightCur;
uint8 *dst_curline = dst_start;
uint32 m1 = ppu->m7matrix[1] << 12; // xpos increment per vert movement
uint32 m2 = ppu->m7matrix[2] << 12; // ypos increment per horiz movement
for (int j = 0; j < 4; j++) {
uint32 m0 = m0v[j], m3 = m0;
uint32 xpos = m0 * clippedH + m1 * (clippedV + y) + (xCenter << 20), xcur;
uint32 ypos = m2 * clippedH + m3 * (clippedV + y) + (yCenter << 20), ycur;
uint32 tile, pixel;
xpos -= (m0 + m1) >> 1;
ypos -= (m2 + m3) >> 1;
xcur = (xpos << 2) + j * m1;
ycur = (ypos << 2) + j * m3;
xcur -= ppu->extraLeftCur * 4 * m0;
ycur -= ppu->extraLeftCur * 4 * m2;
uint8 *dst = dst_curline;
uint8 *dst_end = dst_curline + draw_width * 16;
#define DRAW_PIXEL(mode) \
tile = ppu->vram[(ycur >> 25 & 0x7f) * 128 + (xcur >> 25 & 0x7f)] & 0xff; \
pixel = ppu->vram[tile * 64 + (ycur >> 22 & 7) * 8 + (xcur >> 22 & 7)] >> 8; \
pixel = (xcur & 0x80000000) ? 0 : pixel; \
*(uint32*)dst = (mode ? (ppu->colorMapRgb[pixel] & 0xfefefe) >> 1 : ppu->colorMapRgb[pixel]); \
xcur += m0, ycur += m2, dst += 4;
if (!ppu->halfColor) {
do {
DRAW_PIXEL(0);
DRAW_PIXEL(0);
DRAW_PIXEL(0);
DRAW_PIXEL(0);
} while (dst != dst_end);
} else {
do {
DRAW_PIXEL(1);
DRAW_PIXEL(1);
DRAW_PIXEL(1);
DRAW_PIXEL(1);
} while (dst != dst_end);
}
#undef DRAW_PIXEL
dst_curline += pitch;
}
if (ppu->lineHasSprites) {
uint8 *dst = dst_start;
PpuZbufType *pixels = ppu->objBuffer.data + (kPpuExtraLeftRight - ppu->extraLeftCur);
for (size_t i = 0; i < draw_width; i++, dst += 16) {
uint32 pixel = pixels[i] & 0xff;
if (pixel) {
uint32 color = ppu->colorMapRgb[pixel];
((uint32 *)dst)[3] = ((uint32 *)dst)[2] = ((uint32 *)dst)[1] = ((uint32 *)dst)[0] = color;
((uint32 *)(dst + pitch * 1))[3] = ((uint32 *)(dst + pitch * 1))[2] = ((uint32 *)(dst + pitch * 1))[1] = ((uint32 *)(dst + pitch * 1))[0] = color;
((uint32 *)(dst + pitch * 2))[3] = ((uint32 *)(dst + pitch * 2))[2] = ((uint32 *)(dst + pitch * 2))[1] = ((uint32 *)(dst + pitch * 2))[0] = color;
((uint32 *)(dst + pitch * 3))[3] = ((uint32 *)(dst + pitch * 3))[2] = ((uint32 *)(dst + pitch * 3))[1] = ((uint32 *)(dst + pitch * 3))[0] = color;
}
}
}
if (ppu->extraLeftRight - ppu->extraLeftCur != 0) {
size_t n = 4 * sizeof(uint32) * (ppu->extraLeftRight - ppu->extraLeftCur);
for(int i = 0; i < 4; i++)
memset(render_buffer_ptr + pitch * i, 0, n);
}
if (ppu->extraLeftRight - ppu->extraRightCur != 0) {
size_t n = 4 * sizeof(uint32) * (ppu->extraLeftRight - ppu->extraRightCur);
for (int i = 0; i < 4; i++)
memset(render_buffer_ptr + pitch * i + (256 + ppu->extraLeftRight * 2 - (ppu->extraLeftRight - ppu->extraRightCur)) * 4 * sizeof(uint32), 0, n);
}
#undef DRAW_PIXEL
}
static void PpuDrawBackgrounds(Ppu *ppu, int y, bool sub) {
// Top 4 bits contain the prio level, and bottom 4 bits the layer type.
// SPRITE_PRIO_TO_PRIO can be used to convert from obj prio to this prio.
// 15: BG3 tiles with priority 1 if bit 3 of $2105 is set
// 14: Sprites with priority 3 (4 * sprite_prio + 2)
// 12: BG1 tiles with priority 1
// 11: BG2 tiles with priority 1
// 10: Sprites with priority 2 (4 * sprite_prio + 2)
// 8: BG1 tiles with priority 0
// 7: BG2 tiles with priority 0
// 6: Sprites with priority 1 (4 * sprite_prio + 2)
// 3: BG3 tiles with priority 1 if bit 3 of $2105 is clear
// 2: Sprites with priority 0 (4 * sprite_prio + 2)
// 1: BG3 tiles with priority 0
// 0: backdrop
if (ppu->mode == 1) {
if (ppu->lineHasSprites)
PpuDrawSprites(ppu, y, sub, true);
if (IS_MOSAIC_ENABLED(ppu, 0))
PpuDrawBackground_4bpp_mosaic(ppu, y, sub, 0, 0xc000, 0x8000);
else
PpuDrawBackground_4bpp(ppu, y, sub, 0, 0xc000, 0x8000);
if (IS_MOSAIC_ENABLED(ppu, 1))
PpuDrawBackground_4bpp_mosaic(ppu, y, sub, 1, 0xb100, 0x7100);
else
PpuDrawBackground_4bpp(ppu, y, sub, 1, 0xb100, 0x7100);
if (IS_MOSAIC_ENABLED(ppu, 2))
PpuDrawBackground_2bpp_mosaic(ppu, y, sub, 2, 0xf200, 0x1200);
else
PpuDrawBackground_2bpp(ppu, y, sub, 2, 0xf200, 0x1200);
} else {
// mode 7
PpuDrawBackground_mode7(ppu, y, sub, 0xc000);
if (ppu->lineHasSprites)
PpuDrawSprites(ppu, y, sub, false);
}
}
static NOINLINE void PpuDrawWholeLine(Ppu *ppu, uint y) {
if (ppu->forcedBlank) {
uint8 *dst = &ppu->renderBuffer[(y - 1) * ppu->renderPitch];
size_t n = sizeof(uint32) * (256 + ppu->extraLeftRight * 2);
memset(dst, 0, n);
return;
}
if (ppu->mode == 7 && (ppu->renderFlags & kPpuRenderFlags_4x4Mode7)) {
PpuDrawMode7Upsampled(ppu, y);
return;
}
// Default background is backdrop
ClearBackdrop(&ppu->bgBuffers[0]);
// Render main screen
PpuDrawBackgrounds(ppu, y, false);
// The 6:th bit is automatically zero, math is never applied to the first half of the sprites.
uint32 math_enabled = ppu->mathEnabled;
// Render also the subscreen?
bool rendered_subscreen = false;
if (ppu->preventMathMode != 3 && ppu->addSubscreen && math_enabled) {
ClearBackdrop(&ppu->bgBuffers[1]);
if (ppu->screenEnabled[1] != 0) {
PpuDrawBackgrounds(ppu, y, true);
rendered_subscreen = true;
}
}
// Color window affects the drawing mode in each region
PpuWindows cwin;
PpuWindows_Calc(&cwin, ppu, 5);
static const uint8 kCwBitsMod[8] = {
0x00, 0xff, 0xff, 0x00,
0xff, 0x00, 0xff, 0x00,
};
uint32 cw_clip_math = ((cwin.bits & kCwBitsMod[ppu->clipMode]) ^ kCwBitsMod[ppu->clipMode + 4]) |
((cwin.bits & kCwBitsMod[ppu->preventMathMode]) ^ kCwBitsMod[ppu->preventMathMode + 4]) << 8;
uint32 *dst = (uint32*)&ppu->renderBuffer[(y - 1) * ppu->renderPitch], *dst_org = dst;
dst += (ppu->extraLeftRight - ppu->extraLeftCur);
uint32 windex = 0;
do {
uint32 left = cwin.edges[windex] + kPpuExtraLeftRight, right = cwin.edges[windex + 1] + kPpuExtraLeftRight;
// If clip is set, then zero out the rgb values from the main screen.
uint32 clip_color_mask = (cw_clip_math & 1) ? 0x1f : 0;
uint32 math_enabled_cur = (cw_clip_math & 0x100) ? math_enabled : 0;
uint32 fixed_color = ppu->fixedColorR | ppu->fixedColorG << 5 | ppu->fixedColorB << 10;
if (math_enabled_cur == 0 || fixed_color == 0 && !ppu->halfColor && !rendered_subscreen) {
// Math is disabled (or has no effect), so can avoid the per-pixel maths check
uint32 i = left;
do {
uint32 color = ppu->cgram[ppu->bgBuffers[0].data[i] & 0xff];
dst[0] = ppu->brightnessMult[color & clip_color_mask] << 16 |
ppu->brightnessMult[(color >> 5) & clip_color_mask] << 8 |
ppu->brightnessMult[(color >> 10) & clip_color_mask];
} while (dst++, ++i < right);
} else {
uint8 *half_color_map = ppu->halfColor ? ppu->brightnessMultHalf : ppu->brightnessMult;
// Store this in locals
math_enabled_cur |= ppu->addSubscreen << 8 | ppu->subtractColor << 9;
// Need to check for each pixel whether to use math or not based on the main screen layer.
uint32 i = left;
do {
uint32 color = ppu->cgram[ppu->bgBuffers[0].data[i] & 0xff], color2;
uint8 main_layer = (ppu->bgBuffers[0].data[i] >> 8) & 0xf;
uint32 r = color & clip_color_mask;
uint32 g = (color >> 5) & clip_color_mask;
uint32 b = (color >> 10) & clip_color_mask;
uint8 *color_map = ppu->brightnessMult;
if (math_enabled_cur & (1 << main_layer)) {
if (math_enabled_cur & 0x100) { // addSubscreen ?
if ((ppu->bgBuffers[1].data[i] & 0xff) != 0)
color2 = ppu->cgram[ppu->bgBuffers[1].data[i] & 0xff], color_map = half_color_map;
else // Don't halve if ppu->addSubscreen && backdrop
color2 = fixed_color;
} else {
color2 = fixed_color, color_map = half_color_map;
}
uint32 r2 = (color2 & 0x1f), g2 = ((color2 >> 5) & 0x1f), b2 = ((color2 >> 10) & 0x1f);
if (math_enabled_cur & 0x200) { // subtractColor?
r = (r >= r2) ? r - r2 : 0;
g = (g >= g2) ? g - g2 : 0;
b = (b >= b2) ? b - b2 : 0;
} else {
r += r2;
g += g2;
b += b2;
}
}
dst[0] = color_map[b] | color_map[g] << 8 | color_map[r] << 16;
} while (dst++, ++i < right);
}
} while (cw_clip_math >>= 1, ++windex < cwin.nr);
// Clear out stuff on the sides.
if (ppu->extraLeftRight - ppu->extraLeftCur != 0)
memset(dst_org, 0, sizeof(uint32) * (ppu->extraLeftRight - ppu->extraLeftCur));
if (ppu->extraLeftRight - ppu->extraRightCur != 0)
memset(dst_org + (256 + ppu->extraLeftRight * 2 - (ppu->extraLeftRight - ppu->extraRightCur)), 0,
sizeof(uint32) * (ppu->extraLeftRight - ppu->extraRightCur));
}
static void ppu_handlePixel(Ppu* ppu, int x, int y) {
int r = 0, r2 = 0;
int g = 0, g2 = 0;
int b = 0, b2 = 0;
if (!ppu->forcedBlank) {
int mainLayer = ppu_getPixel(ppu, x, y, false, &r, &g, &b);
bool colorWindowState = ppu_getWindowState(ppu, 5, x);
if (
ppu->clipMode == 3 ||
(ppu->clipMode == 2 && colorWindowState) ||
(ppu->clipMode == 1 && !colorWindowState)
) {
r = g = b = 0;
}
int secondLayer = 5; // backdrop
bool mathEnabled = mainLayer < 6 && (ppu->mathEnabled & (1 << mainLayer)) && !(
ppu->preventMathMode == 3 ||
(ppu->preventMathMode == 2 && colorWindowState) ||
(ppu->preventMathMode == 1 && !colorWindowState)
);
if ((mathEnabled && ppu->addSubscreen) || ppu->mode == 5 || ppu->mode == 6) {
secondLayer = ppu_getPixel(ppu, x, y, true, &r2, &g2, &b2);
}
// TODO: subscreen pixels can be clipped to black as well
// TODO: math for subscreen pixels (add/sub sub to main)
if (mathEnabled) {
if (ppu->subtractColor) {
r -= (ppu->addSubscreen && secondLayer != 5) ? r2 : ppu->fixedColorR;
g -= (ppu->addSubscreen && secondLayer != 5) ? g2 : ppu->fixedColorG;
b -= (ppu->addSubscreen && secondLayer != 5) ? b2 : ppu->fixedColorB;
} else {
r += (ppu->addSubscreen && secondLayer != 5) ? r2 : ppu->fixedColorR;
g += (ppu->addSubscreen && secondLayer != 5) ? g2 : ppu->fixedColorG;
b += (ppu->addSubscreen && secondLayer != 5) ? b2 : ppu->fixedColorB;
}
if (ppu->halfColor && (secondLayer != 5 || !ppu->addSubscreen)) {
r >>= 1;
g >>= 1;
b >>= 1;
}
if (r > 31) r = 31;
if (g > 31) g = 31;
if (b > 31) b = 31;
if (r < 0) r = 0;
if (g < 0) g = 0;
if (b < 0) b = 0;
}
if (!(ppu->mode == 5 || ppu->mode == 6)) {
r2 = r; g2 = g; b2 = b;
}
}
int row = y - 1;
uint8 *pixelBuffer = (uint8*) &ppu->renderBuffer[row * ppu->renderPitch + (x + ppu->extraLeftRight) * 4];
pixelBuffer[0] = ((b << 3) | (b >> 2)) * ppu->brightness / 15;
pixelBuffer[1] = ((g << 3) | (g >> 2)) * ppu->brightness / 15;
pixelBuffer[2] = ((r << 3) | (r >> 2)) * ppu->brightness / 15;
pixelBuffer[3] = 0;
}
static const int bitDepthsPerMode[10][4] = {
{2, 2, 2, 2},
{4, 4, 2, 5},
{4, 4, 5, 5},
{8, 4, 5, 5},
{8, 2, 5, 5},
{4, 2, 5, 5},
{4, 5, 5, 5},
{8, 5, 5, 5},
{4, 4, 2, 5},
{8, 7, 5, 5}
};
static int ppu_getPixel(Ppu *ppu, int x, int y, bool sub, int *r, int *g, int *b) {
// array for layer definitions per mode:
// 0-7: mode 0-7; 8: mode 1 + l3prio; 9: mode 7 + extbg
// 0-3; layers 1-4; 4: sprites; 5: nonexistent
static const int layersPerMode[10][12] = {
{4, 0, 1, 4, 0, 1, 4, 2, 3, 4, 2, 3},
{4, 0, 1, 4, 0, 1, 4, 2, 4, 2, 5, 5},
{4, 0, 4, 1, 4, 0, 4, 1, 5, 5, 5, 5},
{4, 0, 4, 1, 4, 0, 4, 1, 5, 5, 5, 5},
{4, 0, 4, 1, 4, 0, 4, 1, 5, 5, 5, 5},
{4, 0, 4, 1, 4, 0, 4, 1, 5, 5, 5, 5},
{4, 0, 4, 4, 0, 4, 5, 5, 5, 5, 5, 5},
{4, 4, 4, 0, 4, 5, 5, 5, 5, 5, 5, 5},
{2, 4, 0, 1, 4, 0, 1, 4, 4, 2, 5, 5},
{4, 4, 1, 4, 0, 4, 1, 5, 5, 5, 5, 5}
};
static const int prioritysPerMode[10][12] = {
{3, 1, 1, 2, 0, 0, 1, 1, 1, 0, 0, 0},
{3, 1, 1, 2, 0, 0, 1, 1, 0, 0, 5, 5},
{3, 1, 2, 1, 1, 0, 0, 0, 5, 5, 5, 5},
{3, 1, 2, 1, 1, 0, 0, 0, 5, 5, 5, 5},
{3, 1, 2, 1, 1, 0, 0, 0, 5, 5, 5, 5},
{3, 1, 2, 1, 1, 0, 0, 0, 5, 5, 5, 5},
{3, 1, 2, 1, 0, 0, 5, 5, 5, 5, 5, 5},
{3, 2, 1, 0, 0, 5, 5, 5, 5, 5, 5, 5},
{1, 3, 1, 1, 2, 0, 0, 1, 0, 0, 5, 5},
{3, 2, 1, 1, 0, 0, 0, 5, 5, 5, 5, 5}
};
static const int layerCountPerMode[10] = {
12, 10, 8, 8, 8, 8, 6, 5, 10, 7
};
// figure out which color is on this location on main- or subscreen, sets it in r, g, b
// returns which layer it is: 0-3 for bg layer, 4 or 6 for sprites (depending on palette), 5 for backdrop
int actMode = ppu->mode == 1 ? 8 : ppu->mode;
actMode = ppu->mode == 7 && ppu->m7extBg_always_zero ? 9 : actMode;
int layer = 5;
int pixel = 0;
for (int i = 0; i < layerCountPerMode[actMode]; i++) {
int curLayer = layersPerMode[actMode][i];
int curPriority = prioritysPerMode[actMode][i];
bool layerActive = false;
if (!sub) {
layerActive = IS_SCREEN_ENABLED(ppu, 0, curLayer) && (
!IS_SCREEN_WINDOWED(ppu, 0, curLayer) || !ppu_getWindowState(ppu, curLayer, x)
);
} else {
layerActive = IS_SCREEN_ENABLED(ppu, 1, curLayer) && (
!IS_SCREEN_WINDOWED(ppu, 1, curLayer) || !ppu_getWindowState(ppu, curLayer, x)
);
}
if (layerActive) {
if (curLayer < 4) {
// bg layer
int lx = x;
int ly = y;
if (IS_MOSAIC_ENABLED(ppu, curLayer)) {
lx -= lx % ppu->mosaicSize;
ly -= (ly - 1) % ppu->mosaicSize;
}
if (ppu->mode == 7) {
pixel = ppu_getPixelForMode7(ppu, lx, curLayer, curPriority);
} else {
lx += ppu->bgLayer[curLayer].hScroll;
ly += ppu->bgLayer[curLayer].vScroll;
pixel = ppu_getPixelForBgLayer(
ppu, lx & 0x3ff, ly & 0x3ff,
curLayer, curPriority
);
}
} else {
// get a pixel from the sprite buffer
pixel = 0;
if ((ppu->objBuffer.data[x + kPpuExtraLeftRight] >> 12) == SPRITE_PRIO_TO_PRIO_HI(curPriority))
pixel = ppu->objBuffer.data[x + kPpuExtraLeftRight] & 0xff;
}
}
if (pixel > 0) {
layer = curLayer;
break;
}
}
uint16_t color = ppu->cgram[pixel & 0xff];
*r = color & 0x1f;
*g = (color >> 5) & 0x1f;
*b = (color >> 10) & 0x1f;
if (layer == 4 && pixel < 0xc0) layer = 6; // sprites with palette color < 0xc0
return layer;
}
static int ppu_getPixelForBgLayer(Ppu *ppu, int x, int y, int layer, bool priority) {
BgLayer *layerp = &ppu->bgLayer[layer];
// figure out address of tilemap word and read it
bool wideTiles = ppu->mode == 5 || ppu->mode == 6;
int tileBitsX = wideTiles ? 4 : 3;
int tileHighBitX = wideTiles ? 0x200 : 0x100;
int tileBitsY = 3;
int tileHighBitY = 0x100;
uint16_t tilemapAdr = layerp->tilemapAdr + (((y >> tileBitsY) & 0x1f) << 5 | ((x >> tileBitsX) & 0x1f));
if ((x & tileHighBitX) && layerp->tilemapWider) tilemapAdr += 0x400;
if ((y & tileHighBitY) && layerp->tilemapHigher) tilemapAdr += layerp->tilemapWider ? 0x800 : 0x400;
uint16_t tile = ppu->vram[tilemapAdr & 0x7fff];
// check priority, get palette
if (((bool)(tile & 0x2000)) != priority) return 0; // wrong priority
int paletteNum = (tile & 0x1c00) >> 10;
// figure out position within tile
int row = (tile & 0x8000) ? 7 - (y & 0x7) : (y & 0x7);
int col = (tile & 0x4000) ? (x & 0x7) : 7 - (x & 0x7);
int tileNum = tile & 0x3ff;
if (wideTiles) {
// if unflipped right half of tile, or flipped left half of tile
if (((bool)(x & 8)) ^ ((bool)(tile & 0x4000))) tileNum += 1;
}
// read tiledata, ajust palette for mode 0
int bitDepth = bitDepthsPerMode[ppu->mode][layer];
if (ppu->mode == 0) paletteNum += 8 * layer;
// plane 1 (always)
int paletteSize = 4;
uint16_t plane1 = ppu->vram[(layerp->tileAdr + ((tileNum & 0x3ff) * 4 * bitDepth) + row) & 0x7fff];
int pixel = (plane1 >> col) & 1;
pixel |= ((plane1 >> (8 + col)) & 1) << 1;
// plane 2 (for 4bpp, 8bpp)
if (bitDepth > 2) {
paletteSize = 16;
uint16_t plane2 = ppu->vram[(layerp->tileAdr + ((tileNum & 0x3ff) * 4 * bitDepth) + 8 + row) & 0x7fff];
pixel |= ((plane2 >> col) & 1) << 2;
pixel |= ((plane2 >> (8 + col)) & 1) << 3;
}
// plane 3 & 4 (for 8bpp)
if (bitDepth > 4) {
paletteSize = 256;
uint16_t plane3 = ppu->vram[(layerp->tileAdr + ((tileNum & 0x3ff) * 4 * bitDepth) + 16 + row) & 0x7fff];
pixel |= ((plane3 >> col) & 1) << 4;
pixel |= ((plane3 >> (8 + col)) & 1) << 5;
uint16_t plane4 = ppu->vram[(layerp->tileAdr + ((tileNum & 0x3ff) * 4 * bitDepth) + 24 + row) & 0x7fff];
pixel |= ((plane4 >> col) & 1) << 6;
pixel |= ((plane4 >> (8 + col)) & 1) << 7;
}
// return cgram index, or 0 if transparent, palette number in bits 10-8 for 8-color layers
return pixel == 0 ? 0 : paletteSize * paletteNum + pixel;
}
static void ppu_calculateMode7Starts(Ppu* ppu, int y) {
// expand 13-bit values to signed values
int hScroll = ((int16_t) (ppu->m7matrix[6] << 3)) >> 3;
int vScroll = ((int16_t) (ppu->m7matrix[7] << 3)) >> 3;
int xCenter = ((int16_t) (ppu->m7matrix[4] << 3)) >> 3;
int yCenter = ((int16_t) (ppu->m7matrix[5] << 3)) >> 3;
// do calculation
int clippedH = hScroll - xCenter;
int clippedV = vScroll - yCenter;
clippedH = (clippedH & 0x2000) ? (clippedH | ~1023) : (clippedH & 1023);
clippedV = (clippedV & 0x2000) ? (clippedV | ~1023) : (clippedV & 1023);
if(IS_MOSAIC_ENABLED(ppu, 0)) {
y -= (y - 1) % ppu->mosaicSize;
}
uint8_t ry = ppu->m7yFlip ? 255 - y : y;
ppu->m7startX = (
((ppu->m7matrix[0] * clippedH) & ~63) +
((ppu->m7matrix[1] * ry) & ~63) +
((ppu->m7matrix[1] * clippedV) & ~63) +
(xCenter << 8)
);
ppu->m7startY = (
((ppu->m7matrix[2] * clippedH) & ~63) +
((ppu->m7matrix[3] * ry) & ~63) +
((ppu->m7matrix[3] * clippedV) & ~63) +
(yCenter << 8)
);
}
static int ppu_getPixelForMode7(Ppu* ppu, int x, int layer, bool priority) {
if (IS_MOSAIC_ENABLED(ppu, layer))
x -= x % ppu->mosaicSize;
uint8_t rx = ppu->m7xFlip ? 255 - x : x;
int xPos = (ppu->m7startX + ppu->m7matrix[0] * rx) >> 8;
int yPos = (ppu->m7startY + ppu->m7matrix[2] * rx) >> 8;
bool outsideMap = xPos < 0 || xPos >= 1024 || yPos < 0 || yPos >= 1024;
xPos &= 0x3ff;
yPos &= 0x3ff;
if(!ppu->m7largeField) outsideMap = false;
uint8_t tile = outsideMap ? 0 : ppu->vram[(yPos >> 3) * 128 + (xPos >> 3)] & 0xff;
uint8_t pixel = outsideMap && !ppu->m7charFill ? 0 : ppu->vram[tile * 64 + (yPos & 7) * 8 + (xPos & 7)] >> 8;
if(layer == 1) {
if(((bool) (pixel & 0x80)) != priority) return 0;
return pixel & 0x7f;
}
return pixel;
}
static bool ppu_getWindowState(Ppu* ppu, int layer, int x) {
uint32 winflags = GET_WINDOW_FLAGS(ppu, layer);
if (!(winflags & kWindow1Enabled) && !(winflags & kWindow2Enabled)) {
return false;
}
if ((winflags & kWindow1Enabled) && !(winflags & kWindow2Enabled)) {
bool test = x >= ppu->window1left && x <= ppu->window1right;
return (winflags & kWindow1Inversed) ? !test : test;
}
if (!(winflags & kWindow1Enabled) && (winflags & kWindow2Enabled)) {
bool test = x >= ppu->window2left && x <= ppu->window2right;
return (winflags & kWindow2Inversed) ? !test : test;
}
bool test1 = x >= ppu->window1left && x <= ppu->window1right;
bool test2 = x >= ppu->window2left && x <= ppu->window2right;
if (winflags & kWindow1Inversed) test1 = !test1;
if (winflags & kWindow2Inversed) test2 = !test2;
return test1 || test2;
}
static bool ppu_evaluateSprites(Ppu* ppu, int line) {
// TODO: iterate over oam normally to determine in-range sprites,
// then iterate those in-range sprites in reverse for tile-fetching
// TODO: rectangular sprites, wierdness with sprites at -256
int index = 0, index_end = index;
int spritesLeft = 32 + 1, tilesLeft = 34 + 1;
uint8 spriteSizes[2] = { kSpriteSizes[ppu->objSize][0], kSpriteSizes[ppu->objSize][1] };
int extra_left_right = ppu->extraLeftRight;
if (ppu->renderFlags & kPpuRenderFlags_NoSpriteLimits)
spritesLeft = tilesLeft = 1024;
int tilesLeftOrg = tilesLeft;
do {
int yy = ppu->oam[index] >> 8;
if (yy == 0xf0)
continue; // this works for zelda because sprites are always 8 or 16.
// check if the sprite is on this line and get the sprite size
int row = (line - yy) & 0xff;
int highOam = ppu->oam[0x100 + (index >> 4)] >> (index & 15);
int spriteSize = spriteSizes[(highOam >> 1) & 1];
if (row >= spriteSize)
continue;
// in y-range, get the x location, using the high bit as well
int x = (ppu->oam[index] & 0xff) + (highOam & 1) * 256;
x -= (x >= 256 + extra_left_right) * 512;
// if in x-range
if (x <= -(spriteSize + extra_left_right))
continue;
// break if we found 32 sprites already
if (--spritesLeft == 0) {
break;
}
// get some data for the sprite and y-flip row if needed
int oam1 = ppu->oam[index + 1];
int objAdr = (oam1 & 0x100) ? ppu->objTileAdr2 : ppu->objTileAdr1;
if (oam1 & 0x8000)
row = spriteSize - 1 - row;
// fetch all tiles in x-range
int paletteBase = 0x80 + 16 * ((oam1 & 0xe00) >> 9);
int prio = SPRITE_PRIO_TO_PRIO((oam1 & 0x3000) >> 12, (oam1 & 0x800) == 0);
PpuZbufType z = paletteBase + (prio << 8);
for (int col = 0; col < spriteSize; col += 8) {
if (col + x > -8 - extra_left_right && col + x < 256 + extra_left_right) {
// break if we found 34 8*1 slivers already
if (--tilesLeft == 0) {
return true;
}
// figure out which tile this uses, looping within 16x16 pages, and get it's data
int usedCol = oam1 & 0x4000 ? spriteSize - 1 - col : col;
int usedTile = ((((oam1 & 0xff) >> 4) + (row >> 3)) << 4) | (((oam1 & 0xf) + (usedCol >> 3)) & 0xf);
uint16 *addr = &ppu->vram[(objAdr + usedTile * 16 + (row & 0x7)) & 0x7fff];
uint32 plane = addr[0] | addr[8] << 16;
// go over each pixel
int px_left = IntMax(-(col + x + kPpuExtraLeftRight), 0);
int px_right = IntMin(256 + kPpuExtraLeftRight - (col + x), 8);
PpuZbufType *dst = ppu->objBuffer.data + col + x + px_left + kPpuExtraLeftRight;
for (int px = px_left; px < px_right; px++, dst++) {
int shift = oam1 & 0x4000 ? px : 7 - px;
uint32 bits = plane >> shift;
int pixel = (bits >> 0) & 1 | (bits >> 7) & 2 | (bits >> 14) & 4 | (bits >> 21) & 8;
// draw it in the buffer if there is a pixel here, and the buffer there is still empty
if (pixel != 0 && (dst[0] & 0xff) == 0)
dst[0] = z + pixel;
}
}
}
} while ((index = (index + 2) & 0xff) != index_end);
return (tilesLeft != tilesLeftOrg);
}
uint8_t ppu_read(Ppu* ppu, uint8_t adr) {
switch (adr) {
case 0x34:
case 0x35:
case 0x36: {
int result = ppu->m7matrix[0] * (ppu->m7matrix[1] >> 8);
return (result >> (8 * (adr - 0x34))) & 0xff;
}
}
return 0xff;
}
void ppu_write(Ppu* ppu, uint8_t adr, uint8_t val) {
switch(adr) {
case 0x00: { // INIDISP
ppu->brightness = val & 0xf;
ppu->forcedBlank = val & 0x80;
break;
}
case 0x01: {
assert(val == 2);
break;
}
case 0x02: {
ppu->oamAdr = (ppu->oamAdr & ~0xff) | val;
ppu->oamSecondWrite = false;
break;
}
case 0x03: {
assert((val & 0x80) == 0);
ppu->oamAdr = (ppu->oamAdr & ~0xff00) | ((val & 1) << 8);
ppu->oamSecondWrite = false;
break;
}
case 0x04: {
if (!ppu->oamSecondWrite) {
ppu->oamBuffer = val;
} else {
if (ppu->oamAdr < 0x110)
ppu->oam[ppu->oamAdr++] = (val << 8) | ppu->oamBuffer;
}
ppu->oamSecondWrite = !ppu->oamSecondWrite;
break;
}
case 0x05: { // BGMODE
ppu->mode = val & 0x7;
assert(val == 7 || val == 9);
assert(ppu->mode == 1 || ppu->mode == 7);
assert((val & 0xf0) == 0);
break;
}
case 0x06: { // MOSAIC
ppu->mosaicSize = (val >> 4) + 1;
ppu->mosaicEnabled = (ppu->mosaicSize > 1) ? val : 0;
break;
}
case 0x07: // BG1SC
case 0x08:
case 0x09:
case 0x0a: {
// small tilemaps are used in attract intro
ppu->bgLayer[adr - 7].tilemapWider = val & 0x1;
ppu->bgLayer[adr - 7].tilemapHigher = val & 0x2;
ppu->bgLayer[adr - 7].tilemapAdr = (val & 0xfc) << 8;
break;
}
case 0x0b: { // BG12NBA
ppu->bgLayer[0].tileAdr = (val & 0xf) << 12;
ppu->bgLayer[1].tileAdr = (val & 0xf0) << 8;
break;
}
case 0x0c: { // BG34NBA
ppu->bgLayer[2].tileAdr = (val & 0xf) << 12;
ppu->bgLayer[3].tileAdr = (val & 0xf0) << 8;
break;
}
case 0x0d: { // BG1HOFS
ppu->m7matrix[6] = ((val << 8) | ppu->m7prev) & 0x1fff;
ppu->m7prev = val;
// fallthrough to normal layer BG-HOFS
}
case 0x0f:
case 0x11:
case 0x13: {
ppu->bgLayer[(adr - 0xd) / 2].hScroll = ((val << 8) | (ppu->scrollPrev & 0xf8) | (ppu->scrollPrev2 & 0x7)) & 0x3ff;
ppu->scrollPrev = val;
ppu->scrollPrev2 = val;
break;
}
case 0x0e: { // BG1VOFS
ppu->m7matrix[7] = ((val << 8) | ppu->m7prev) & 0x1fff;
ppu->m7prev = val;
// fallthrough to normal layer BG-VOFS
}
case 0x10:
case 0x12:
case 0x14: {
ppu->bgLayer[(adr - 0xe) / 2].vScroll = ((val << 8) | ppu->scrollPrev) & 0x3ff;
ppu->scrollPrev = val;
break;
}
case 0x15: { // VMAIN
if((val & 3) == 0) {
ppu->vramIncrement = 1;
} else if((val & 3) == 1) {
ppu->vramIncrement = 32;
} else {
ppu->vramIncrement = 128;
}
assert(((val & 0xc) >> 2) == 0);
ppu->vramIncrementOnHigh = val & 0x80;
break;
}
case 0x16: { // VMADDL
ppu->vramPointer = (ppu->vramPointer & 0xff00) | val;
break;
}
case 0x17: { // VMADDH
ppu->vramPointer = (ppu->vramPointer & 0x00ff) | (val << 8);
break;
}
case 0x18: { // VMDATAL
uint16_t vramAdr = ppu->vramPointer;
ppu->vram[vramAdr & 0x7fff] = (ppu->vram[vramAdr & 0x7fff] & 0xff00) | val;
if(!ppu->vramIncrementOnHigh) ppu->vramPointer += ppu->vramIncrement;
break;
}
case 0x19: { // VMDATAH
uint16_t vramAdr = ppu->vramPointer;
ppu->vram[vramAdr & 0x7fff] = (ppu->vram[vramAdr & 0x7fff] & 0x00ff) | (val << 8);
if(ppu->vramIncrementOnHigh) ppu->vramPointer += ppu->vramIncrement;
break;
}
case 0x1a: { // M7SEL
assert(val == 0x80);
ppu->m7largeField = val & 0x80;
ppu->m7charFill = val & 0x40;
ppu->m7yFlip = val & 0x2;
ppu->m7xFlip = val & 0x1;
break;
}
case 0x1b: // M7A etc
case 0x1c:
case 0x1d:
case 0x1e: {
ppu->m7matrix[adr - 0x1b] = (val << 8) | ppu->m7prev;
ppu->m7prev = val;
break;
}
case 0x1f:
case 0x20: {
ppu->m7matrix[adr - 0x1b] = ((val << 8) | ppu->m7prev) & 0x1fff;
ppu->m7prev = val;
break;
}
case 0x21: {
ppu->cgramPointer = val;
ppu->cgramSecondWrite = false;
break;
}
case 0x22: {
if(!ppu->cgramSecondWrite) {
ppu->cgramBuffer = val;
} else {
ppu->cgram[ppu->cgramPointer++] = (val << 8) | ppu->cgramBuffer;
}
ppu->cgramSecondWrite = !ppu->cgramSecondWrite;
break;
}
case 0x23: // W12SEL
ppu->windowsel = (ppu->windowsel & ~0xff) | val;
break;
case 0x24: // W34SEL
ppu->windowsel = (ppu->windowsel & ~0xff00) | (val << 8);
break;
case 0x25: // WOBJSEL
ppu->windowsel = (ppu->windowsel & ~0xff0000) | (val << 16);
break;
case 0x26:
ppu->window1left = val;
break;
case 0x27:
ppu->window1right = val;
break;
case 0x28:
ppu->window2left = val;
break;
case 0x29:
ppu->window2right = val;
break;
case 0x2a: // WBGLOG
assert(val == 0);
break;
case 0x2b: // WOBJLOG
assert(val == 0);
break;
case 0x2c: // TM
ppu->screenEnabled[0] = val;
break;
case 0x2d: // TS
ppu->screenEnabled[1] = val;
break;
case 0x2e: // TMW
ppu->screenWindowed[0] = val;
break;
case 0x2f: // TSW
ppu->screenWindowed[1] = val;
break;
case 0x30: { // CGWSEL
assert((val & 1) == 0); // directColor always zero
ppu->addSubscreen = val & 0x2;
ppu->preventMathMode = (val & 0x30) >> 4;
ppu->clipMode = (val & 0xc0) >> 6;
break;
}
case 0x31: { // CGADSUB
ppu->subtractColor = val & 0x80;
ppu->halfColor = val & 0x40;
ppu->mathEnabled = val & 0x3f;
break;
}
case 0x32: { // COLDATA
if(val & 0x80) ppu->fixedColorB = val & 0x1f;
if(val & 0x40) ppu->fixedColorG = val & 0x1f;
if(val & 0x20) ppu->fixedColorR = val & 0x1f;
break;
}
case 0x33: {
assert(val == 0);
ppu->m7extBg_always_zero = val & 0x40;
break;
}
default: {
break;
}
}
}