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* start GPU shit: draw BG0 16-color.

Browse Source 
* fix a few DMA bugs.
* fix a bug where some code could still run right after a halt instruction.
* fix VRAM mapping, too. I'm an idiot.
This commit is contained in:
StapleButter
2017-01-18 17:57:12 +01:00
parent d30e6956fa
commit d7c1d2a2cd
10 changed files with 244 additions and 65 deletions
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182
GPU2D.cpp
View File

@ -17,9 +17,9 @@
*/
#include <stdio.h>
#include <string.h>
#include "NDS.h"
#include "GPU.h"
#include "GPU2D.h"
GPU2D::GPU2D(u32 num)
@ -33,7 +33,8 @@ GPU2D::~GPU2D()
void GPU2D::Reset()
{
//
DispCnt = 0;
memset(BGCnt, 0, 4*2);
}
void GPU2D::SetFramebuffer(u16* buf)
@ -47,21 +48,31 @@ void GPU2D::SetFramebuffer(u16* buf)
u8 GPU2D::Read8(u32 addr)
{
printf("!! GPU2D READ8 %08X\n", addr);
return 0;
}
u16 GPU2D::Read16(u32 addr)
{
switch (addr & 0x00000FFF)
{
//
case 0x000: return DispCnt&0xFFFF;
case 0x002: return DispCnt>>16;
case 0x008: return BGCnt[0];
case 0x00A: return BGCnt[1];
case 0x00C: return BGCnt[2];
case 0x00E: return BGCnt[3];
}
printf("unknown GPU read16 %08X\n", addr);
return 0;
}
u32 GPU2D::Read32(u32 addr)
{
switch (addr & 0x00000FFF)
{
//
case 0x000: return DispCnt;
}
return Read16(addr) | (Read16(addr+2) << 16);
@ -76,15 +87,29 @@ void GPU2D::Write16(u32 addr, u16 val)
{
switch (addr & 0x00000FFF)
{
//
case 0x000:
DispCnt = (DispCnt & 0xFFFF0000) | val;
return;
case 0x002:
DispCnt = (DispCnt & 0x0000FFFF) | (val << 16);
return;
case 0x008: BGCnt[0] = val; return;
case 0x00A: BGCnt[1] = val; return;
case 0x00C: BGCnt[2] = val; return;
case 0x00E: BGCnt[3] = val; return;
}
printf("unknown GPU write16 %08X %04X\n", addr, val);
}
void GPU2D::Write32(u32 addr, u32 val)
{
switch (addr & 0x00000FFF)
{
//
case 0x000:
DispCnt = val;
return;
}
Write16(addr, val&0xFFFF);
@ -94,5 +119,148 @@ void GPU2D::Write32(u32 addr, u32 val)
void GPU2D::DrawScanline(u32 line)
{
//
u16* dst = &Framebuffer[256*line];
u32 dispmode = DispCnt >> 16;
dispmode &= (Num ? 0x1 : 0x3);
switch (dispmode)
{
case 0: // screen off
{
for (int i = 0; i < 256>>1; i++)
((u32*)dst)[i] = 0x7FFF7FFF;
}
break;
case 1: // regular display
{
DrawScanline_Mode1(line, dst);
}
break;
case 2: // VRAM display
{
u32* vram = (u32*)GPU::VRAM[(DispCnt >> 18) & 0x3];
vram = &vram[line << 7];
for (int i = 0; i < 256>>1; i++)
((u32*)dst)[i] = vram[i];
}
break;
case 3: // FIFO display
{
// uh, is there even anything that uses this?
}
break;
}
}
void GPU2D::DrawScanline_Mode1(u32 line, u16* dst)
{
for (int i = 0; i < 256>>1; i++)
((u32*)dst)[i] = 0; // TODO: backdrop
switch (DispCnt & 0x7)
{
case 0:
for (int i = 3; i >= 0; i--)
{
// TODO other BGs
if ((BGCnt[0] & 0x3) == i)
{
DrawBG_Text_4bpp(line, dst, 0);
// todo: sprites
}
}
break;
}
}
// char 06218000
// screen 06208000
void GPU2D::DrawBG_Text_4bpp(u32 line, u16* dst, u32 bgnum)
{
u16 bgcnt = BGCnt[bgnum];
u8* tileset;
u16* tilemap;
u16* pal;
// TODO scroll
u16 xoff = 0;
u16 yoff = line;
u32 widexmask = (bgcnt & 0x4000) ? 0x100 : 0;
//u32 ymask = (bgcnt & 0x8000) ? 0x1FF : 0xFF;
if (Num)
{
tileset = (u8*)GPU::VRAM_BBG[((bgcnt & 0x000C) >> 2)];
tilemap = (u16*)GPU::VRAM_BBG[((bgcnt & 0x1800) >> 11)];
tilemap += ((bgcnt & 0x0700) << 2);
pal = (u16*)&GPU::Palette[0x400];
}
else
{
tileset = (u8*)GPU::VRAM_ABG[((DispCnt & 0x07000000) >> 22) + ((bgcnt & 0x003C) >> 2)];
tilemap = (u16*)GPU::VRAM_ABG[((DispCnt & 0x38000000) >> 27) + ((bgcnt & 0x1800) >> 11)];
tilemap += ((bgcnt & 0x0700) << 2);
pal = (u16*)&GPU::Palette[0];
}
// adjust Y position in tilemap
if (bgcnt & 0x8000)
{
tilemap += ((yoff & 0x1F8) << 2);
if (bgcnt & 0x4000)
tilemap += ((yoff & 0x100) << 2);
}
else
tilemap += ((yoff & 0xF8) << 2);
u16 curtile;
u16* curpal;
u8* pixels;
// preload shit as needed
if (xoff & 0x7)
{
// load a new tile
curtile = tilemap[((xoff & 0xFF) >> 3) + ((xoff & widexmask) << 2)];
curpal = pal + ((curtile & 0xF000) >> 8);
pixels = tileset + ((curtile & 0x01FF) << 5) + ((yoff & 0x7) << 2);
pixels += ((xoff & 0x7) >> 1);
}
for (int i = 0; i < 256; i++)
{
if (!(xoff & 0x7))
{
// load a new tile
curtile = tilemap[((xoff & 0xFF) >> 3) + ((xoff & widexmask) << 2)];
curpal = pal + ((curtile & 0xF000) >> 8);
pixels = tileset + ((curtile & 0x01FF) << 5) + ((yoff & 0x7) << 2);
}
// draw pixel
u8 color;
if (xoff & 0x1)
{
color = *pixels >> 4;
pixels++;
}
else
{
color = *pixels & 0x0F;
}
//color = (i >> 4) + ((line >> 4) << 4);
//if (Num) color = 0;
dst[i] = curpal[color];
xoff++;
}
}