ref: 376b5d1c799e82e24dbe2bccce2135f2443752fa
dir: /snes/ppu.c/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>
#include "ppu.h"
#include "snes.h"
// 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
};
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 const int spriteSizes[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 uint16_t ppu_getOffsetValue(Ppu* ppu, int col, int row);
static int ppu_getPixelForBgLayer(Ppu* ppu, int x, int y, int layer, bool priority);
static void ppu_handleOPT(Ppu* ppu, int layer, int* lx, int* ly);
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 void ppu_evaluateSprites(Ppu* ppu, int line);
static uint16_t ppu_getVramRemap(Ppu* ppu);
Ppu* ppu_init(Snes* snes) {
Ppu* ppu = (Ppu * )malloc(sizeof(Ppu));
ppu->snes = snes;
return ppu;
}
void ppu_free(Ppu* ppu) {
free(ppu);
}
void ppu_reset(Ppu* ppu) {
memset(ppu->vram, 0, sizeof(ppu->vram));
ppu->vramPointer = 0;
ppu->vramIncrementOnHigh = false;
ppu->vramIncrement = 1;
ppu->vramRemapMode = 0;
ppu->vramReadBuffer = 0;
memset(ppu->cgram, 0, sizeof(ppu->cgram));
ppu->cgramPointer = 0;
ppu->cgramSecondWrite = false;
ppu->cgramBuffer = 0;
memset(ppu->oam, 0, sizeof(ppu->oam));
memset(ppu->highOam, 0, sizeof(ppu->highOam));
ppu->oamAdr = 0;
ppu->oamAdrWritten = 0;
ppu->oamInHigh = false;
ppu->oamInHighWritten = false;
ppu->oamSecondWrite = false;
ppu->oamBuffer = 0;
ppu->objPriority = false;
ppu->objTileAdr1 = 0;
ppu->objTileAdr2 = 0;
ppu->objSize = 0;
memset(ppu->objPixelBuffer, 0, sizeof(ppu->objPixelBuffer));
memset(ppu->objPriorityBuffer, 0, sizeof(ppu->objPriorityBuffer));
ppu->timeOver = false;
ppu->rangeOver = false;
ppu->objInterlace = false;
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->bgLayer[i].bigTiles = false;
ppu->bgLayer[i].mosaicEnabled = false;
}
ppu->scrollPrev = 0;
ppu->scrollPrev2 = 0;
ppu->mosaicSize = 1;
ppu->mosaicStartLine = 1;
for(int i = 0; i < 5; i++) {
ppu->layer[i].mainScreenEnabled = false;
ppu->layer[i].subScreenEnabled = false;
ppu->layer[i].mainScreenWindowed = false;
ppu->layer[i].subScreenWindowed = false;
}
memset(ppu->m7matrix, 0, sizeof(ppu->m7matrix));
ppu->m7prev = 0;
ppu->m7largeField = false;
ppu->m7charFill = false;
ppu->m7xFlip = false;
ppu->m7yFlip = false;
ppu->m7extBg = false;
ppu->m7startX = 0;
ppu->m7startY = 0;
for(int i = 0; i < 6; i++) {
ppu->windowLayer[i].window1enabled = false;
ppu->windowLayer[i].window2enabled = false;
ppu->windowLayer[i].window1inversed = false;
ppu->windowLayer[i].window2inversed = false;
ppu->windowLayer[i].maskLogic = 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;
memset(ppu->mathEnabled, 0, sizeof(ppu->mathEnabled));
ppu->fixedColorR = 0;
ppu->fixedColorG = 0;
ppu->fixedColorB = 0;
ppu->forcedBlank = true;
ppu->brightness = 0;
ppu->mode = 0;
ppu->bg3priority = false;
ppu->evenFrame = false;
ppu->pseudoHires = false;
ppu->overscan = false;
ppu->frameOverscan = false;
ppu->interlace = false;
ppu->frameInterlace = false;
ppu->directColor = false;
ppu->hCount = 0;
ppu->vCount = 0;
ppu->hCountSecond = false;
ppu->vCountSecond = false;
ppu->countersLatched = false;
ppu->ppu1openBus = 0;
ppu->ppu2openBus = 0;
memset(ppu->pixelBuffer, 0, sizeof(ppu->pixelBuffer));
}
void ppu_saveload(Ppu *ppu, SaveLoadFunc *func, void *ctx) {
func(ctx, &ppu->vram, offsetof(Ppu, pixelBuffer) - offsetof(Ppu, vram));
}
bool ppu_checkOverscan(Ppu* ppu) {
// called at (0,225)
ppu->frameOverscan = ppu->overscan; // set if we have a overscan-frame
return ppu->frameOverscan;
}
void ppu_handleVblank(Ppu* ppu) {
// called either right after ppu_checkOverscan at (0,225), or at (0,240)
if(!ppu->forcedBlank) {
ppu->oamAdr = ppu->oamAdrWritten;
ppu->oamInHigh = ppu->oamInHighWritten;
ppu->oamSecondWrite = false;
}
ppu->frameInterlace = ppu->interlace; // set if we have a interlaced frame
}
void ppu_runLine(Ppu* ppu, int line) {
if(line == 0) {
// pre-render line
// TODO: this now happens halfway into the first line
ppu->mosaicStartLine = 1;
ppu->rangeOver = false;
ppu->timeOver = false;
ppu->evenFrame = !ppu->evenFrame;
} else {
// evaluate sprites
memset(ppu->objPixelBuffer, 0, sizeof(ppu->objPixelBuffer));
if(!ppu->forcedBlank) ppu_evaluateSprites(ppu, line - 1);
// actual line
if(ppu->mode == 7) ppu_calculateMode7Starts(ppu, line);
for(int x = 0; x < 256; x++) {
ppu_handlePixel(ppu, x, line);
}
}
}
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[mainLayer] && !(
ppu->preventMathMode == 3 ||
(ppu->preventMathMode == 2 && colorWindowState) ||
(ppu->preventMathMode == 1 && !colorWindowState)
);
if((mathEnabled && ppu->addSubscreen) || ppu->pseudoHires || 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->pseudoHires || ppu->mode == 5 || ppu->mode == 6)) {
r2 = r; g2 = g; b2 = b;
}
}
int row = (y - 1) + (ppu->evenFrame ? 0 : 239);
ppu->pixelBuffer[row * 2048 + x * 8 + 1] = ((b2 << 3) | (b2 >> 2)) * ppu->brightness / 15;
ppu->pixelBuffer[row * 2048 + x * 8 + 2] = ((g2 << 3) | (g2 >> 2)) * ppu->brightness / 15;
ppu->pixelBuffer[row * 2048 + x * 8 + 3] = ((r2 << 3) | (r2 >> 2)) * ppu->brightness / 15;
ppu->pixelBuffer[row * 2048 + x * 8 + 5] = ((b << 3) | (b >> 2)) * ppu->brightness / 15;
ppu->pixelBuffer[row * 2048 + x * 8 + 6] = ((g << 3) | (g >> 2)) * ppu->brightness / 15;
ppu->pixelBuffer[row * 2048 + x * 8 + 7] = ((r << 3) | (r >> 2)) * ppu->brightness / 15;
}
static int ppu_getPixel(Ppu* ppu, int x, int y, bool sub, int* r, int* g, int* b) {
// 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 && ppu->bg3priority ? 8 : ppu->mode;
actMode = ppu->mode == 7 && ppu->m7extBg ? 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 = ppu->layer[curLayer].mainScreenEnabled && (
!ppu->layer[curLayer].mainScreenWindowed || !ppu_getWindowState(ppu, curLayer, x)
);
} else {
layerActive = ppu->layer[curLayer].subScreenEnabled && (
!ppu->layer[curLayer].subScreenWindowed || !ppu_getWindowState(ppu, curLayer, x)
);
}
if(layerActive) {
if(curLayer < 4) {
// bg layer
int lx = x;
int ly = y;
if(ppu->bgLayer[curLayer].mosaicEnabled && ppu->mosaicSize > 1) {
lx -= lx % ppu->mosaicSize;
ly -= (ly - ppu->mosaicStartLine) % ppu->mosaicSize;
}
if(ppu->mode == 7) {
pixel = ppu_getPixelForMode7(ppu, lx, curLayer, curPriority);
} else {
lx += ppu->bgLayer[curLayer].hScroll;
if(ppu->mode == 5 || ppu->mode == 6) {
lx *= 2;
lx += (sub || ppu->bgLayer[curLayer].mosaicEnabled) ? 0 : 1;
if(ppu->interlace) {
ly *= 2;
ly += (ppu->evenFrame || ppu->bgLayer[curLayer].mosaicEnabled) ? 0 : 1;
}
}
ly += ppu->bgLayer[curLayer].vScroll;
if(ppu->mode == 2 || ppu->mode == 4 || ppu->mode == 6) {
ppu_handleOPT(ppu, curLayer, &lx, &ly);
}
pixel = ppu_getPixelForBgLayer(
ppu, lx & 0x3ff, ly & 0x3ff,
curLayer, curPriority
);
}
} else {
// get a pixel from the sprite buffer
pixel = 0;
if(ppu->objPriorityBuffer[x] == curPriority) pixel = ppu->objPixelBuffer[x];
}
}
if(pixel > 0) {
layer = curLayer;
break;
}
}
if(ppu->directColor && layer < 4 && bitDepthsPerMode[actMode][layer] == 8) {
*r = ((pixel & 0x7) << 2) | ((pixel & 0x100) >> 7);
*g = ((pixel & 0x38) >> 1) | ((pixel & 0x200) >> 8);
*b = ((pixel & 0xc0) >> 3) | ((pixel & 0x400) >> 8);
} else {
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 void ppu_handleOPT(Ppu* ppu, int layer, int* lx, int* ly) {
int x = *lx;
int y = *ly;
int column = 0;
if(ppu->mode == 6) {
column = ((x - (x & 0xf)) - ((ppu->bgLayer[layer].hScroll * 2) & 0xfff0)) >> 4;
} else {
column = ((x - (x & 0x7)) - (ppu->bgLayer[layer].hScroll & 0xfff8)) >> 3;
}
if(column > 0) {
// fetch offset values from layer 3 tilemap
int valid = layer == 0 ? 0x2000 : 0x4000;
uint16_t hOffset = ppu_getOffsetValue(ppu, column - 1, 0);
uint16_t vOffset = 0;
if(ppu->mode == 4) {
if(hOffset & 0x8000) {
vOffset = hOffset;
hOffset = 0;
}
} else {
vOffset = ppu_getOffsetValue(ppu, column - 1, 1);
}
if(ppu->mode == 6) {
// TODO: not sure if correct
if(hOffset & valid) *lx = (((hOffset & 0x3f8) + (column * 8)) * 2) | (x & 0xf);
} else {
if(hOffset & valid) *lx = ((hOffset & 0x3f8) + (column * 8)) | (x & 0x7);
}
// TODO: not sure if correct for interlace
if(vOffset & valid) *ly = (vOffset & 0x3ff) + (y - ppu->bgLayer[layer].vScroll);
}
}
static uint16_t ppu_getOffsetValue(Ppu* ppu, int col, int row) {
int x = col * 8 + ppu->bgLayer[2].hScroll;
int y = row * 8 + ppu->bgLayer[2].vScroll;
int tileBits = ppu->bgLayer[2].bigTiles ? 4 : 3;
int tileHighBit = ppu->bgLayer[2].bigTiles ? 0x200 : 0x100;
uint16_t tilemapAdr = ppu->bgLayer[2].tilemapAdr + (((y >> tileBits) & 0x1f) << 5 | ((x >> tileBits) & 0x1f));
if((x & tileHighBit) && ppu->bgLayer[2].tilemapWider) tilemapAdr += 0x400;
if((y & tileHighBit) && ppu->bgLayer[2].tilemapHigher) tilemapAdr += ppu->bgLayer[2].tilemapWider ? 0x800 : 0x400;
return ppu->vram[tilemapAdr & 0x7fff];
}
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 = layerp->bigTiles || ppu->mode == 5 || ppu->mode == 6;
int tileBitsX = wideTiles ? 4 : 3;
int tileHighBitX = wideTiles ? 0x200 : 0x100;
int tileBitsY = layerp->bigTiles ? 4 : 3;
int tileHighBitY = layerp->bigTiles ? 0x200 : 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;
}
if(layerp->bigTiles) {
// if unflipped bottom half of tile, or flipped upper half of tile
if(((bool) (y & 8)) ^ ((bool) (tile & 0x8000))) tileNum += 0x10;
}
// 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(ppu->bgLayer[0].mosaicEnabled && ppu->mosaicSize > 1) {
y -= (y - ppu->mosaicStartLine) % 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) {
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) {
if(!ppu->windowLayer[layer].window1enabled && !ppu->windowLayer[layer].window2enabled) {
return false;
}
if(ppu->windowLayer[layer].window1enabled && !ppu->windowLayer[layer].window2enabled) {
bool test = x >= ppu->window1left && x <= ppu->window1right;
return ppu->windowLayer[layer].window1inversed ? !test : test;
}
if(!ppu->windowLayer[layer].window1enabled && ppu->windowLayer[layer].window2enabled) {
bool test = x >= ppu->window2left && x <= ppu->window2right;
return ppu->windowLayer[layer].window2inversed ? !test : test;
}
bool test1 = x >= ppu->window1left && x <= ppu->window1right;
bool test2 = x >= ppu->window2left && x <= ppu->window2right;
if(ppu->windowLayer[layer].window1inversed) test1 = !test1;
if(ppu->windowLayer[layer].window2inversed) test2 = !test2;
switch(ppu->windowLayer[layer].maskLogic) {
case 0: return test1 || test2;
case 1: return test1 && test2;
case 2: return test1 != test2;
case 3: return test1 == test2;
}
return false;
}
static void 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
uint8_t index = ppu->objPriority ? (ppu->oamAdr & 0xfe) : 0;
int spritesFound = 0;
int tilesFound = 0;
for(int i = 0; i < 128; i++) {
uint8_t y = ppu->oam[index] >> 8;
// check if the sprite is on this line and get the sprite size
uint8_t row = line - y;
int spriteSize = spriteSizes[ppu->objSize][(ppu->highOam[index >> 3] >> ((index & 7) + 1)) & 1];
int spriteHeight = ppu->objInterlace ? spriteSize / 2 : spriteSize;
if(row < spriteHeight) {
// in y-range, get the x location, using the high bit as well
int x = ppu->oam[index] & 0xff;
x |= ((ppu->highOam[index >> 3] >> (index & 7)) & 1) << 8;
if(x > 255) x -= 512;
// if in x-range
if(x > -spriteSize) {
// break if we found 32 sprites already
spritesFound++;
if(spritesFound > 32) {
ppu->rangeOver = true;
break;
}
// update row according to obj-interlace
if(ppu->objInterlace) row = row * 2 + (ppu->evenFrame ? 0 : 1);
// get some data for the sprite and y-flip row if needed
int tile = ppu->oam[index + 1] & 0xff;
int palette = (ppu->oam[index + 1] & 0xe00) >> 9;
bool hFlipped = ppu->oam[index + 1] & 0x4000;
if(ppu->oam[index + 1] & 0x8000) row = spriteSize - 1 - row;
// fetch all tiles in x-range
for(int col = 0; col < spriteSize; col += 8) {
if(col + x > -8 && col + x < 256) {
// break if we found 34 8*1 slivers already
tilesFound++;
if(tilesFound > 34) {
ppu->timeOver = true;
break;
}
// figure out which tile this uses, looping within 16x16 pages, and get it's data
int usedCol = hFlipped ? spriteSize - 1 - col : col;
uint8_t usedTile = (((tile >> 4) + (row / 8)) << 4) | (((tile & 0xf) + (usedCol / 8)) & 0xf);
uint16_t objAdr = (ppu->oam[index + 1] & 0x100) ? ppu->objTileAdr2 : ppu->objTileAdr1;
uint16_t plane1 = ppu->vram[(objAdr + usedTile * 16 + (row & 0x7)) & 0x7fff];
uint16_t plane2 = ppu->vram[(objAdr + usedTile * 16 + 8 + (row & 0x7)) & 0x7fff];
// go over each pixel
for(int px = 0; px < 8; px++) {
int shift = hFlipped ? px : 7 - px;
int pixel = (plane1 >> shift) & 1;
pixel |= ((plane1 >> (8 + shift)) & 1) << 1;
pixel |= ((plane2 >> shift) & 1) << 2;
pixel |= ((plane2 >> (8 + shift)) & 1) << 3;
// draw it in the buffer if there is a pixel here, and the buffer there is still empty
int screenCol = col + x + px;
if(pixel > 0 && screenCol >= 0 && screenCol < 256 && ppu->objPixelBuffer[screenCol] == 0) {
ppu->objPixelBuffer[screenCol] = 0x80 + 16 * palette + pixel;
ppu->objPriorityBuffer[screenCol] = (ppu->oam[index + 1] & 0x3000) >> 12;
}
}
}
}
if(tilesFound > 34) break; // break out of sprite-loop if max tiles found
}
}
index += 2;
}
}
static uint16_t ppu_getVramRemap(Ppu* ppu) {
uint16_t adr = ppu->vramPointer;
switch(ppu->vramRemapMode) {
case 0: return adr;
case 1: return (adr & 0xff00) | ((adr & 0xe0) >> 5) | ((adr & 0x1f) << 3);
case 2: return (adr & 0xfe00) | ((adr & 0x1c0) >> 6) | ((adr & 0x3f) << 3);
case 3: return (adr & 0xfc00) | ((adr & 0x380) >> 7) | ((adr & 0x7f) << 3);
}
return adr;
}
uint8_t ppu_read(Ppu* ppu, uint8_t adr) {
switch(adr) {
case 0x04: case 0x14: case 0x24:
case 0x05: case 0x15: case 0x25:
case 0x06: case 0x16: case 0x26:
case 0x08: case 0x18: case 0x28:
case 0x09: case 0x19: case 0x29:
case 0x0a: case 0x1a: case 0x2a: {
return ppu->ppu1openBus;
}
case 0x34:
case 0x35:
case 0x36: {
int result = ppu->m7matrix[0] * (ppu->m7matrix[1] >> 8);
ppu->ppu1openBus = (result >> (8 * (adr - 0x34))) & 0xff;
return ppu->ppu1openBus;
}
case 0x37: {
// TODO: only when ppulatch is set
ppu->hCount = ppu->snes->hPos / 4;
ppu->vCount = ppu->snes->vPos;
ppu->countersLatched = true;
if (ppu->snes->disableHpos)
ppu->vCount = 192;
return ppu->snes->openBus;
}
case 0x38: {
uint8_t ret = 0;
if(ppu->oamInHigh) {
ret = ppu->highOam[((ppu->oamAdr & 0xf) << 1) | (uint8_t)ppu->oamSecondWrite];
if(ppu->oamSecondWrite) {
ppu->oamAdr++;
if(ppu->oamAdr == 0) ppu->oamInHigh = false;
}
} else {
if(!ppu->oamSecondWrite) {
ret = ppu->oam[ppu->oamAdr] & 0xff;
} else {
ret = ppu->oam[ppu->oamAdr++] >> 8;
if(ppu->oamAdr == 0) ppu->oamInHigh = true;
}
}
ppu->oamSecondWrite = !ppu->oamSecondWrite;
ppu->ppu1openBus = ret;
return ret;
}
case 0x39: {
uint16_t val = ppu->vramReadBuffer;
if(!ppu->vramIncrementOnHigh) {
ppu->vramReadBuffer = ppu->vram[ppu_getVramRemap(ppu) & 0x7fff];
ppu->vramPointer += ppu->vramIncrement;
}
ppu->ppu1openBus = val & 0xff;
return val & 0xff;
}
case 0x3a: {
uint16_t val = ppu->vramReadBuffer;
if(ppu->vramIncrementOnHigh) {
ppu->vramReadBuffer = ppu->vram[ppu_getVramRemap(ppu) & 0x7fff];
ppu->vramPointer += ppu->vramIncrement;
}
ppu->ppu1openBus = val >> 8;
return val >> 8;
}
case 0x3b: {
uint8_t ret = 0;
if(!ppu->cgramSecondWrite) {
ret = ppu->cgram[ppu->cgramPointer] & 0xff;
} else {
ret = ((ppu->cgram[ppu->cgramPointer++] >> 8) & 0x7f) | (ppu->ppu2openBus & 0x80);
}
ppu->cgramSecondWrite = !ppu->cgramSecondWrite;
ppu->ppu2openBus = ret;
return ret;
}
case 0x3c: {
#if 0
uint8_t val = 0;
if(ppu->hCountSecond) {
val = ((ppu->hCount >> 8) & 1) | (ppu->ppu2openBus & 0xfe);
} else {
val = ppu->hCount & 0xff;
}
#else
uint8_t val = 0x17;// (ppu->ppu2openBus + ppu->cgramPointer * 7) * 0x31337 >> 8;
#endif
ppu->hCountSecond = !ppu->hCountSecond;
ppu->ppu2openBus = val;
return val;
}
case 0x3d: {
uint8_t val = 0;
uint16_t vCount = 192;// ppu->vCount
if(ppu->vCountSecond) {
val = ((vCount >> 8) & 1) | (ppu->ppu2openBus & 0xfe);
} else {
val = vCount & 0xff;
}
ppu->vCountSecond = !ppu->vCountSecond;
ppu->ppu2openBus = val;
return val;
}
case 0x3e: {
uint8_t val = 0x1; // ppu1 version (4 bit)
val |= ppu->ppu1openBus & 0x10;
val |= ppu->rangeOver << 6;
val |= ppu->timeOver << 7;
ppu->ppu1openBus = val;
return val;
}
case 0x3f: {
uint8_t val = 0x3; // ppu2 version (4 bit), bit 4: ntsc/pal
val |= ppu->ppu2openBus & 0x20;
val |= ppu->countersLatched << 6;
val |= ppu->evenFrame << 7;
ppu->countersLatched = false; // TODO: only when ppulatch is set
ppu->hCountSecond = false;
ppu->vCountSecond = false;
ppu->ppu2openBus = val;
return val;
}
default: {
return ppu->snes->openBus;
}
}
}
void ppu_write(Ppu* ppu, uint8_t adr, uint8_t val) {
switch(adr) {
case 0x00: {
// TODO: oam address reset when written on first line of vblank, (and when forced blank is disabled?)
ppu->brightness = val & 0xf;
ppu->forcedBlank = val & 0x80;
break;
}
case 0x01: {
ppu->objSize = val >> 5;
ppu->objTileAdr1 = (val & 7) << 13;
ppu->objTileAdr2 = ppu->objTileAdr1 + (((val & 0x18) + 8) << 9);
break;
}
case 0x02: {
ppu->oamAdr = val;
ppu->oamAdrWritten = ppu->oamAdr;
ppu->oamInHigh = ppu->oamInHighWritten;
ppu->oamSecondWrite = false;
break;
}
case 0x03: {
ppu->objPriority = val & 0x80;
ppu->oamInHigh = val & 1;
ppu->oamInHighWritten = ppu->oamInHigh;
ppu->oamAdr = ppu->oamAdrWritten;
ppu->oamSecondWrite = false;
break;
}
case 0x04: {
if(ppu->oamInHigh) {
ppu->highOam[((ppu->oamAdr & 0xf) << 1) | (uint8_t)ppu->oamSecondWrite] = val;
if(ppu->oamSecondWrite) {
ppu->oamAdr++;
if(ppu->oamAdr == 0) ppu->oamInHigh = false;
}
} else {
if(!ppu->oamSecondWrite) {
ppu->oamBuffer = val;
} else {
ppu->oam[ppu->oamAdr++] = (val << 8) | ppu->oamBuffer;
if(ppu->oamAdr == 0) ppu->oamInHigh = true;
}
}
ppu->oamSecondWrite = !ppu->oamSecondWrite;
break;
}
case 0x05: {
ppu->mode = val & 0x7;
ppu->bg3priority = val & 0x8;
ppu->bgLayer[0].bigTiles = val & 0x10;
ppu->bgLayer[1].bigTiles = val & 0x20;
ppu->bgLayer[2].bigTiles = val & 0x40;
ppu->bgLayer[3].bigTiles = val & 0x80;
break;
}
case 0x06: {
// TODO: mosaic line reset specifics
ppu->bgLayer[0].mosaicEnabled = val & 0x1;
ppu->bgLayer[1].mosaicEnabled = val & 0x2;
ppu->bgLayer[2].mosaicEnabled = val & 0x4;
ppu->bgLayer[3].mosaicEnabled = val & 0x8;
ppu->mosaicSize = (val >> 4) + 1;
ppu->mosaicStartLine = 0;// ppu->snes->vPos;
break;
}
case 0x07:
case 0x08:
case 0x09:
case 0x0a: {
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: {
ppu->bgLayer[0].tileAdr = (val & 0xf) << 12;
ppu->bgLayer[1].tileAdr = (val & 0xf0) << 8;
break;
}
case 0x0c: {
ppu->bgLayer[2].tileAdr = (val & 0xf) << 12;
ppu->bgLayer[3].tileAdr = (val & 0xf0) << 8;
break;
}
case 0x0d: {
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: {
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: {
if((val & 3) == 0) {
ppu->vramIncrement = 1;
} else if((val & 3) == 1) {
ppu->vramIncrement = 32;
} else {
ppu->vramIncrement = 128;
}
ppu->vramRemapMode = (val & 0xc) >> 2;
ppu->vramIncrementOnHigh = val & 0x80;
break;
}
case 0x16: {
ppu->vramPointer = (ppu->vramPointer & 0xff00) | val;
ppu->vramReadBuffer = ppu->vram[ppu_getVramRemap(ppu) & 0x7fff];
break;
}
case 0x17: {
ppu->vramPointer = (ppu->vramPointer & 0x00ff) | (val << 8);
ppu->vramReadBuffer = ppu->vram[ppu_getVramRemap(ppu) & 0x7fff];
break;
}
case 0x18: {
// TODO: vram access during rendering (also cgram and oam)
uint16_t vramAdr = ppu_getVramRemap(ppu);
if (val != 0xef) {
val += 0;
}
ppu->vram[vramAdr & 0x7fff] = (ppu->vram[vramAdr & 0x7fff] & 0xff00) | val;
if(!ppu->vramIncrementOnHigh) ppu->vramPointer += ppu->vramIncrement;
break;
}
case 0x19: {
uint16_t vramAdr = ppu_getVramRemap(ppu);
ppu->vram[vramAdr & 0x7fff] = (ppu->vram[vramAdr & 0x7fff] & 0x00ff) | (val << 8);
if(ppu->vramIncrementOnHigh) ppu->vramPointer += ppu->vramIncrement;
break;
}
case 0x1a: {
ppu->m7largeField = val & 0x80;
ppu->m7charFill = val & 0x40;
ppu->m7yFlip = val & 0x2;
ppu->m7xFlip = val & 0x1;
break;
}
case 0x1b:
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:
case 0x24:
case 0x25: {
ppu->windowLayer[(adr - 0x23) * 2].window1inversed = val & 0x1;
ppu->windowLayer[(adr - 0x23) * 2].window1enabled = val & 0x2;
ppu->windowLayer[(adr - 0x23) * 2].window2inversed = val & 0x4;
ppu->windowLayer[(adr - 0x23) * 2].window2enabled = val & 0x8;
ppu->windowLayer[(adr - 0x23) * 2 + 1].window1inversed = val & 0x10;
ppu->windowLayer[(adr - 0x23) * 2 + 1].window1enabled = val & 0x20;
ppu->windowLayer[(adr - 0x23) * 2 + 1].window2inversed = val & 0x40;
ppu->windowLayer[(adr - 0x23) * 2 + 1].window2enabled = val & 0x80;
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: {
ppu->windowLayer[0].maskLogic = val & 0x3;
ppu->windowLayer[1].maskLogic = (val >> 2) & 0x3;
ppu->windowLayer[2].maskLogic = (val >> 4) & 0x3;
ppu->windowLayer[3].maskLogic = (val >> 6) & 0x3;
break;
}
case 0x2b: {
ppu->windowLayer[4].maskLogic = val & 0x3;
ppu->windowLayer[5].maskLogic = (val >> 2) & 0x3;
break;
}
case 0x2c: {
ppu->layer[0].mainScreenEnabled = val & 0x1;
ppu->layer[1].mainScreenEnabled = val & 0x2;
ppu->layer[2].mainScreenEnabled = val & 0x4;
ppu->layer[3].mainScreenEnabled = val & 0x8;
ppu->layer[4].mainScreenEnabled = val & 0x10;
break;
}
case 0x2d: {
ppu->layer[0].subScreenEnabled = val & 0x1;
ppu->layer[1].subScreenEnabled = val & 0x2;
ppu->layer[2].subScreenEnabled = val & 0x4;
ppu->layer[3].subScreenEnabled = val & 0x8;
ppu->layer[4].subScreenEnabled = val & 0x10;
break;
}
case 0x2e: {
ppu->layer[0].mainScreenWindowed = val & 0x1;
ppu->layer[1].mainScreenWindowed = val & 0x2;
ppu->layer[2].mainScreenWindowed = val & 0x4;
ppu->layer[3].mainScreenWindowed = val & 0x8;
ppu->layer[4].mainScreenWindowed = val & 0x10;
break;
}
case 0x2f: {
ppu->layer[0].subScreenWindowed = val & 0x1;
ppu->layer[1].subScreenWindowed = val & 0x2;
ppu->layer[2].subScreenWindowed = val & 0x4;
ppu->layer[3].subScreenWindowed = val & 0x8;
ppu->layer[4].subScreenWindowed = val & 0x10;
break;
}
case 0x30: {
ppu->directColor = val & 0x1;
ppu->addSubscreen = val & 0x2;
ppu->preventMathMode = (val & 0x30) >> 4;
ppu->clipMode = (val & 0xc0) >> 6;
break;
}
case 0x31: {
ppu->subtractColor = val & 0x80;
ppu->halfColor = val & 0x40;
for(int i = 0; i < 6; i++) {
ppu->mathEnabled[i] = val & (1 << i);
}
break;
}
case 0x32: {
if(val & 0x80) ppu->fixedColorB = val & 0x1f;
if(val & 0x40) ppu->fixedColorG = val & 0x1f;
if(val & 0x20) ppu->fixedColorR = val & 0x1f;
break;
}
case 0x33: {
ppu->interlace = val & 0x1;
ppu->objInterlace = val & 0x2;
ppu->overscan = val & 0x4;
ppu->pseudoHires = val & 0x8;
ppu->m7extBg = val & 0x40;
break;
}
default: {
break;
}
}
}
void ppu_putPixels(Ppu* ppu, uint8_t* pixels) {
for(int y = 0; y < (ppu->frameOverscan ? 239 : 224); y++) {
int dest = y * 2 + (ppu->frameOverscan ? 2 : 16);
int y1 = y, y2 = y + 239;
if(!ppu->frameInterlace) {
y1 = y + (ppu->evenFrame ? 0 : 239);
y2 = y1;
}
memcpy(pixels + (dest * 2048), &ppu->pixelBuffer[y1 * 2048], 2048);
memcpy(pixels + ((dest + 1) * 2048), &ppu->pixelBuffer[y2 * 2048], 2048);
}
// clear top 2 lines, and following 14 and last 16 lines if not overscanning
memset(pixels, 0, 2048 * 2);
if(!ppu->frameOverscan) {
memset(pixels + (2 * 2048), 0, 2048 * 14);
memset(pixels + (464 * 2048), 0, 2048 * 16);
}
}