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Merge pull request #1 from Lauchmelder23/graphics

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The PPU should be finished now
This commit is contained in:
Lauchmelder 2021-07-12 19:55:08 +02:00 committed by GitHub
parent f931ccaac9 9b9a17928b
commit 094f2ca8f4
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 133 additions and 64 deletions
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21
include/lcd.hpp
View file

@ -48,6 +48,7 @@ typedef union
typedef struct
{
WORD spritePalette;
WORD sprite;
WORD highByte, lowByte;
WORD full;
@ -82,6 +83,19 @@ typedef union
} b;
} OAMEntry;
typedef union
{
BYTE b;
struct
{
BYTE idx0 : 2;
BYTE idx1 : 2;
BYTE idx2 : 2;
BYTE idx3 : 2;
} colors;
} Palette;
// The screen. With emphasis on ree
class LCD
{
@ -115,9 +129,9 @@ public:
BYTE lyc;
BYTE wy;
BYTE wx;
BYTE bgp;
BYTE obp0;
BYTE obp1;
Palette bgp;
Palette obp0;
Palette obp1;
BYTE dma;
PixelFetcher fetcher;
@ -126,4 +140,5 @@ public:
BYTE x;
BYTE dmaCycles;
bool windowMode;
};

172
src/lcd.cpp
View file

@ -4,7 +4,8 @@
#include "bus.hpp"
static BYTE colormap[4] = { 0b00000000, 0b00100101, 0b01001010, 0b10010011 };
static BYTE colormap[4] = { 0b10010011, 0b01001010, 0b00100101, 0b00000000 };
static WORD lastX = 0xFFFF;
// Reverses a Byte (0111010 -> 0101110)
BYTE Reverse(BYTE b) {
@ -36,12 +37,18 @@ void LCD::Setup()
bgFIFO.full = 0x00;
spriteFIFO.full = 0x00;
windowMode = false;
}
// One LCD tick. Or clock? cycles? who even knows, the wiki uses all of
// those terms interchangeably while still insisting they're all different
void LCD::Tick()
{
if (lcdc.w.window)
{
volatile int jdkds = 3;
}
// Update cycles
scanlineCycles++;
cycles++;
@ -87,7 +94,10 @@ void LCD::Tick()
{
// If we just started this scanline then start the OAM search phase
if (scanlineCycles == 0)
{
windowMode = false;
stat.w.mode = 2;
}
// Else if we entered screen space, go to the rendering phase
else if (scanlineCycles == 81) {
@ -121,75 +131,87 @@ void LCD::Tick()
}
}
}
// Pixel Fetcher (oh lord)
else if (stat.w.mode == 3)
{
if (lcdc.w.obj_enable) // IF sprite rendering is enabled
{
OAMEntry* entry;
for (int i = 0; i < 40; i++) // Go through all sprites
if (x != lastX) // If we already checked this pixel then skip
{
entry = (OAMEntry*)(oam.data() + i * 4);
if (x == entry->b.x - 8 && entry->b.y <= ly + 16 && ly + 8 + (8 * lcdc.w.obj_size) < entry->b.y) // and if the sprite is rendered on the current coordinate
lastX = x;
OAMEntry* entry;
for (int i = 0; i < 40; i++) // Go through all sprites
{
// Fetch Sprite!
WORD yOffset = (ly - entry->b.y + 16); // offset of the tile data in vram
if (entry->b.attr.yFlip)
entry = (OAMEntry*)(oam.data() + i * 4);
if (x + 8 == entry->b.x && entry->b.y <= ly + 16 && ly + 16 < entry->b.y + 8 + (8 * lcdc.w.obj_size)) // and if the sprite is rendered on the current coordinate
{
yOffset = 8 * (1 + lcdc.w.obj_size) - yOffset; // flip vertically by just doing this
}
if (entry->b.idx == 0x82)
volatile int jdsfklsd = 4;
BYTE lo = vram[2 * yOffset + (entry->b.idx * 16 * (1 + lcdc.w.obj_size))]; // get lo and hi byte of tile data
BYTE hi = vram[2 * yOffset + (entry->b.idx * 16 * (1 + lcdc.w.obj_size)) + 1];
if (entry->b.attr.xFlip)
{
lo = Reverse(lo);
hi = Reverse(hi);
}
// Feed it all into the spriteFIFO
spriteFIFO.lowByte = lo;
spriteFIFO.highByte = hi;
spriteFIFO.full = 0xFF;
BYTE counter = 0;
while (spriteFIFO.full) // While theres data in the fifo
{
BYTE color = ((spriteFIFO.highByte & 0x80) >> 6) | ((spriteFIFO.lowByte & 0x80) >> 7); // Get color of sprite at that pixel
if (color != 0x00) // if its not transparent
// Fetch Sprite!
WORD yOffset = (ly - entry->b.y + 16) * 2; // offset of the tile data in vram
if (entry->b.attr.yFlip)
{
BYTE bgPriority = (bgFIFO.sprite & (0x80 >> counter)) >> 6; // See if there is already a sprite rendered at this pixel (if yes,
// then dont render over it because sprites with the LOWER x coord get priority)
if (!bgPriority)
yOffset = 16 * (1 + lcdc.w.obj_size) - 2 - yOffset; // flip vertically by just doing this
}
BYTE lo = vram[yOffset + (entry->b.idx * 16 * (1 + lcdc.w.obj_size))]; // get lo and hi byte of tile data
BYTE hi = vram[yOffset + (entry->b.idx * 16 * (1 + lcdc.w.obj_size)) + 1];
if (entry->b.attr.xFlip)
{
lo = Reverse(lo);
hi = Reverse(hi);
}
// Feed it all into the spriteFIFO
spriteFIFO.lowByte = lo;
spriteFIFO.highByte = hi;
spriteFIFO.full = 0xFF;
BYTE counter = 0;
while (spriteFIFO.full) // While theres data in the fifo
{
BYTE color = ((spriteFIFO.highByte & 0x80) >> 6) | ((spriteFIFO.lowByte & 0x80) >> 7); // Get color of sprite at that pixel
if (color != 0x00) // if its not transparent
{
BYTE bgColor = ((bgFIFO.highByte & (0x80 >> counter)) >> 6) | ((bgFIFO.lowByte & (0x80 >> counter)) >> 7); // Get the color of the background at this pixel
if (entry->b.attr.bgPriority) // If the background/window are supposed to have priority do this
BYTE bgPriority = (bgFIFO.sprite & (0x80 >> counter)) >> 6; // See if there is already a sprite rendered at this pixel (if yes,
// then dont render over it because sprites with the LOWER x coord get priority)
if (!bgPriority)
{
if (bgColor == 0x00)
BYTE bgColor = ((bgFIFO.highByte & (0x80 >> counter)) >> 6) | ((bgFIFO.lowByte & (0x80 >> counter)) >> 7); // Get the color of the background at this pixel
if (entry->b.attr.bgPriority) // If the background/window are supposed to have priority do this
{
if (bgColor == 0x00)
{
bgFIFO.highByte ^= ((-((spriteFIFO.highByte & 0x80) >> 7) ^ bgFIFO.highByte) & (0x80 >> counter));
bgFIFO.lowByte ^= ((-((spriteFIFO.lowByte & 0x80) >> 7) ^ bgFIFO.lowByte) & (0x80 >> counter));
bgFIFO.spritePalette ^= ((-entry->b.attr.palette ^ bgFIFO.lowByte) & (0x80 >> counter));
bgFIFO.sprite |= (0x80 >> counter);
}
}
else
{
bgFIFO.highByte ^= ((-((spriteFIFO.highByte & 0x80) >> 7) ^ bgFIFO.highByte) & (0x80 >> counter));
bgFIFO.lowByte ^= ((-((spriteFIFO.lowByte & 0x80) >> 7) ^ bgFIFO.lowByte) & (0x80 >> counter));
bgFIFO.spritePalette ^= ((-entry->b.attr.palette ^ bgFIFO.lowByte) & (0x80 >> counter));
bgFIFO.sprite |= (0x80 >> counter);
}
}
else
{
bgFIFO.highByte ^= ((((spriteFIFO.highByte & 0x80) >> 7) ^ bgFIFO.highByte) & (0x80 >> counter));
bgFIFO.lowByte ^= ((((spriteFIFO.lowByte & 0x80) >> 7) ^ bgFIFO.lowByte) & (0x80 >> counter));
bgFIFO.sprite |= (0x80 >> counter);
}
}
}
// Advance FIFOs
spriteFIFO.full <<= 1;
spriteFIFO.highByte <<= 1;
spriteFIFO.lowByte <<= 1;
counter++;
// Advance FIFOs
spriteFIFO.full <<= 1;
spriteFIFO.highByte <<= 1;
spriteFIFO.lowByte <<= 1;
counter++;
}
}
}
}
@ -201,7 +223,12 @@ void LCD::Tick()
case 0: // Get Tile
{
// TODO: Implement the window
WORD baseAddr = (lcdc.w.bg_tilemap ? 0x1C00 : 0x1800);
WORD baseAddr = 0x00;
if(windowMode)
baseAddr = (lcdc.w.window_tilemap ? 0x1C00 : 0x1800);
else
baseAddr = (lcdc.w.bg_tilemap ? 0x1C00 : 0x1800);
BYTE fetcherX = ((scx + fetcher.x) & 0xFF) / 8;
BYTE fetcherY = ((ly + scy) & 0xFF) / 8;
fetcher.tile = vram[baseAddr + (0x20 * fetcherY) + fetcherX];
@ -212,6 +239,7 @@ void LCD::Tick()
{
WORD baseAddr = (lcdc.w.tiledata ? 0x0000 : 0x0800);
fetcher.lo = vram[baseAddr + 2 * ((fetcher.y + scy) % 8) + (fetcher.tile * 16)];
fetcher.lo *= lcdc.w.enable;
}
break;
@ -220,6 +248,7 @@ void LCD::Tick()
// TODO: Check LCDC.4
WORD baseAddr = (lcdc.w.tiledata ? 0x0000 : 0x0800);
fetcher.hi = vram[baseAddr + 2 * ((fetcher.y + scy) % 8) + (fetcher.tile * 16) + 1];
fetcher.hi *= lcdc.w.enable;
}
break;
@ -245,14 +274,38 @@ void LCD::Tick()
fetcher.cycle++;
fetcher.x++;
// Draw pixels
// Draw pixels
if (lcdc.w.window && x + 7 == wx && ly >= wy)
{
bgFIFO.full = 0x00;
fetcher.cycle = 0;
fetcher.x = x;
windowMode = true;
}
if (bgFIFO.full & 0x00FF) // If Data in FIFO
{
// calculate color
BYTE color = ((bgFIFO.highByte & 0x80) >> 6) | ((bgFIFO.lowByte & 0x80) >> 7);
Palette* p = &bgp;
if (bgFIFO.sprite & 0x80)
p = (bgFIFO.spritePalette & 0x80) ? &obp1 : &obp0;
// set color (pretty easy huh)
display[ly * 160 + x] = colormap[color];
BYTE displayColor = 0x00;
switch (color)
{
case 0x00: displayColor = colormap[p->colors.idx0]; break;
case 0x01: displayColor = colormap[p->colors.idx1]; break;
case 0x02: displayColor = colormap[p->colors.idx2]; break;
case 0x03: displayColor = colormap[p->colors.idx3]; break;
}
if ((bgFIFO.sprite & 0x80) && color == 0x00)
displayColor = 0x00;
display[ly * 160 + x] = displayColor;
x++;
// advance fifo
@ -260,6 +313,7 @@ void LCD::Tick()
bgFIFO.lowByte <<= 1;
bgFIFO.full <<= 1;
bgFIFO.sprite <<= 1;
bgFIFO.spritePalette <<= 1;
}
if (x == 160) // if we reached the end of the scanline, enable hblank
@ -306,9 +360,9 @@ bool LCD::Read(WORD addr, BYTE& val)
case 0xFF43: val = scx; return true;
case 0xFF44: val = ly; return true;
case 0xFF45: val = lyc; return true;
case 0xFF47: val = bgp; return true;
case 0xFF48: val = obp0; return true;
case 0xFF49: val = obp1; return true;
case 0xFF47: val = bgp.b; return true;
case 0xFF48: val = obp0.b; return true;
case 0xFF49: val = obp1.b; return true;
case 0xFF4A: val = wy; return true;
case 0xFF4B: val = wx; return true;
@ -345,9 +399,9 @@ bool LCD::Write(WORD addr, BYTE val)
case 0xFF43: scx = val; return true;
case 0xFF44: ly = val; return true;
case 0xFF45: lyc = val; return true;
case 0xFF47: bgp = val; return true;
case 0xFF48: obp0 = val; return true;
case 0xFF49: obp1 = val; return true;
case 0xFF47: bgp.b = val; return true;
case 0xFF48: obp0.b = val; return true;
case 0xFF49: obp1.b = val; return true;
case 0xFF4A: wy = val; return true;
case 0xFF4B: wx = val; return true;

4
src/main.cpp
View file

@ -208,8 +208,8 @@ int main(int argc, char** argv)
BYTE loVal2 = (lo2 & (0x80 >> x)) >> (7 - x);
BYTE hiVal2 = (hi2 & (0x80 >> x)) >> (7 - x);
tilemappixels1[(tileX * 8 + x) + (32 * 8) * (tileY * 8 + y)] = colormap[loVal1 + hiVal1];
tilemappixels2[(tileX * 8 + x) + (32 * 8) * (tileY * 8 + y)] = colormap[loVal2 + hiVal2];
tilemappixels1[(tileX * 8 + x) + (32 * 8) * (tileY * 8 + y)] = colormap[loVal1 + (hiVal1 << 1)];
tilemappixels2[(tileX * 8 + x) + (32 * 8) * (tileY * 8 + y)] = colormap[loVal2 + (hiVal2 << 2)];
}
}
}