/* Copyright 2016-2022 melonDS team This file is part of melonDS. melonDS is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. melonDS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with melonDS. If not, see http://www.gnu.org/licenses/. */ #include #include #include "NDS.h" #include "GPU.h" // notes on color conversion // // * BLDCNT special effects are applied on 18bit colors // -> layers are converted to 18bit before being composited // -> 'brightness up' effect does: x = x + (63-x)*factor // * colors are converted as follows: 18bit = 15bit * 2 // -> white comes out as 62,62,62 and not 63,63,63 // * VRAM/FIFO display modes convert colors the same way // * 3D engine converts colors differently (18bit = 15bit * 2 + 1, except 0 = 0) // * 'screen disabled' white is 63,63,63 // * [Gericom] bit15 is used as bottom green bit for palettes. TODO: check where this applies. // tested on the normal BG palette and applies there // // for VRAM display mode, VRAM must be mapped to LCDC // // FIFO display mode: // * the 'FIFO' is a circular buffer of 32 bytes (16 pixels) // * the buffer doesn't get empty, the display controller keeps reading from it // -> if it isn't updated, the contents will be repeated every 16 pixels // * the write pointer is incremented when writing to the higher 16 bits of the FIFO register (0x04000068) // * the write pointer is reset upon VBlank // * FIFO DMA (mode 4) is triggered every 8 pixels. start bit is cleared upon VBlank. // // sprite blending rules // * destination must be selected as 2nd target // * sprite must be semitransparent or bitmap sprite // * blending is applied instead of the selected color effect, even if it is 'none'. // * for bitmap sprites: EVA = alpha+1, EVB = 16-EVA // * for bitmap sprites: alpha=0 is always transparent, even if blending doesn't apply // // 3D blending rules // // 3D/3D blending seems to follow these equations: // dstColor = srcColor*srcAlpha + dstColor*(1-srcAlpha) // dstAlpha = max(srcAlpha, dstAlpha) // blending isn't applied if dstAlpha is zero. // // 3D/2D blending rules // * if destination selected as 2nd target: // blending is applied instead of the selected color effect, using full 5bit alpha from 3D layer // this even if the selected color effect is 'none'. // apparently this works even if BG0 isn't selected as 1st target // * if BG0 is selected as 1st target, destination not selected as 2nd target: // brightness up/down effect is applied if selected. if blending is selected, it doesn't apply. // * 3D layer pixels with alpha=0 are always transparent. // // mosaic: // * mosaic grid starts at 0,0 regardless of the BG/sprite position // * when changing it midframe: new X setting is applied immediately, new Y setting is applied only // after the end of the current mosaic row (when Y counter needs reloaded) // * for rotscaled sprites: coordinates that are inside the sprite are clamped to the sprite region // after being transformed for mosaic // TODO: master brightness, display capture and mainmem FIFO are separate circuitry, distinct from // the tile renderers. // for example these aren't affected by POWCNT GPU-disable bits. // to model the hardware more accurately, the relevant logic should be moved to GPU.cpp. namespace GPU2D { Unit::Unit(u32 num) { Num = num; } void Unit::Reset() { Enabled = false; DispCnt = 0; memset(BGCnt, 0, 4*2); memset(BGXPos, 0, 4*2); memset(BGYPos, 0, 4*2); memset(BGXRef, 0, 2*4); memset(BGYRef, 0, 2*4); memset(BGXRefInternal, 0, 2*4); memset(BGYRefInternal, 0, 2*4); memset(BGRotA, 0, 2*2); memset(BGRotB, 0, 2*2); memset(BGRotC, 0, 2*2); memset(BGRotD, 0, 2*2); memset(Win0Coords, 0, 4); memset(Win1Coords, 0, 4); memset(WinCnt, 0, 4); Win0Active = 0; Win1Active = 0; BGMosaicSize[0] = 0; BGMosaicSize[1] = 0; OBJMosaicSize[0] = 0; OBJMosaicSize[1] = 0; BGMosaicY = 0; BGMosaicYMax = 0; OBJMosaicY = 0; OBJMosaicYMax = 0; OBJMosaicYCount = 0; BlendCnt = 0; EVA = 16; EVB = 0; EVY = 0; memset(DispFIFO, 0, 16*2); DispFIFOReadPtr = 0; DispFIFOWritePtr = 0; memset(DispFIFOBuffer, 0, 256*2); CaptureCnt = 0; CaptureLatch = false; MasterBrightness = 0; } void Unit::DoSavestate(Savestate* file) { file->Section((char*)(Num ? "GP2B" : "GP2A")); file->Var32(&DispCnt); file->VarArray(BGCnt, 4*2); file->VarArray(BGXPos, 4*2); file->VarArray(BGYPos, 4*2); file->VarArray(BGXRef, 2*4); file->VarArray(BGYRef, 2*4); file->VarArray(BGXRefInternal, 2*4); file->VarArray(BGYRefInternal, 2*4); file->VarArray(BGRotA, 2*2); file->VarArray(BGRotB, 2*2); file->VarArray(BGRotC, 2*2); file->VarArray(BGRotD, 2*2); file->VarArray(Win0Coords, 4); file->VarArray(Win1Coords, 4); file->VarArray(WinCnt, 4); file->VarArray(BGMosaicSize, 2); file->VarArray(OBJMosaicSize, 2); file->Var8(&BGMosaicY); file->Var8(&BGMosaicYMax); file->Var8(&OBJMosaicY); file->Var8(&OBJMosaicYMax); file->Var16(&BlendCnt); file->Var16(&BlendAlpha); file->Var8(&EVA); file->Var8(&EVB); file->Var8(&EVY); file->Var16(&MasterBrightness); if (!Num) { file->VarArray(DispFIFO, 16*2); file->Var32(&DispFIFOReadPtr); file->Var32(&DispFIFOWritePtr); file->VarArray(DispFIFOBuffer, 256*2); file->Var32(&CaptureCnt); } file->Var32(&Win0Active); file->Var32(&Win1Active); } u8 Unit::Read8(u32 addr) { switch (addr & 0x00000FFF) { case 0x000: return DispCnt & 0xFF; case 0x001: return (DispCnt >> 8) & 0xFF; case 0x002: return (DispCnt >> 16) & 0xFF; case 0x003: return DispCnt >> 24; case 0x008: return BGCnt[0] & 0xFF; case 0x009: return BGCnt[0] >> 8; case 0x00A: return BGCnt[1] & 0xFF; case 0x00B: return BGCnt[1] >> 8; case 0x00C: return BGCnt[2] & 0xFF; case 0x00D: return BGCnt[2] >> 8; case 0x00E: return BGCnt[3] & 0xFF; case 0x00F: return BGCnt[3] >> 8; case 0x048: return WinCnt[0]; case 0x049: return WinCnt[1]; case 0x04A: return WinCnt[2]; case 0x04B: return WinCnt[3]; // there are games accidentally trying to read those // those are write-only case 0x04C: case 0x04D: return 0; } printf("unknown GPU read8 %08X\n", addr); return 0; } u16 Unit::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]; case 0x048: return WinCnt[0] | (WinCnt[1] << 8); case 0x04A: return WinCnt[2] | (WinCnt[3] << 8); case 0x050: return BlendCnt; case 0x052: return BlendAlpha; // BLDY is write-only case 0x064: return CaptureCnt & 0xFFFF; case 0x066: return CaptureCnt >> 16; case 0x06C: return MasterBrightness; } printf("unknown GPU read16 %08X\n", addr); return 0; } u32 Unit::Read32(u32 addr) { switch (addr & 0x00000FFF) { case 0x000: return DispCnt; case 0x064: return CaptureCnt; } return Read16(addr) | (Read16(addr+2) << 16); } void Unit::Write8(u32 addr, u8 val) { switch (addr & 0x00000FFF) { case 0x000: DispCnt = (DispCnt & 0xFFFFFF00) | val; if (Num) DispCnt &= 0xC0B1FFF7; return; case 0x001: DispCnt = (DispCnt & 0xFFFF00FF) | (val << 8); if (Num) DispCnt &= 0xC0B1FFF7; return; case 0x002: DispCnt = (DispCnt & 0xFF00FFFF) | (val << 16); if (Num) DispCnt &= 0xC0B1FFF7; return; case 0x003: DispCnt = (DispCnt & 0x00FFFFFF) | (val << 24); if (Num) DispCnt &= 0xC0B1FFF7; return; case 0x10: if (!Num) GPU3D::SetRenderXPos((GPU3D::RenderXPos & 0xFF00) | val); break; case 0x11: if (!Num) GPU3D::SetRenderXPos((GPU3D::RenderXPos & 0x00FF) | (val << 8)); break; } if (!Enabled) return; switch (addr & 0x00000FFF) { case 0x008: BGCnt[0] = (BGCnt[0] & 0xFF00) | val; return; case 0x009: BGCnt[0] = (BGCnt[0] & 0x00FF) | (val << 8); return; case 0x00A: BGCnt[1] = (BGCnt[1] & 0xFF00) | val; return; case 0x00B: BGCnt[1] = (BGCnt[1] & 0x00FF) | (val << 8); return; case 0x00C: BGCnt[2] = (BGCnt[2] & 0xFF00) | val; return; case 0x00D: BGCnt[2] = (BGCnt[2] & 0x00FF) | (val << 8); return; case 0x00E: BGCnt[3] = (BGCnt[3] & 0xFF00) | val; return; case 0x00F: BGCnt[3] = (BGCnt[3] & 0x00FF) | (val << 8); return; case 0x010: BGXPos[0] = (BGXPos[0] & 0xFF00) | val; return; case 0x011: BGXPos[0] = (BGXPos[0] & 0x00FF) | (val << 8); return; case 0x012: BGYPos[0] = (BGYPos[0] & 0xFF00) | val; return; case 0x013: BGYPos[0] = (BGYPos[0] & 0x00FF) | (val << 8); return; case 0x014: BGXPos[1] = (BGXPos[1] & 0xFF00) | val; return; case 0x015: BGXPos[1] = (BGXPos[1] & 0x00FF) | (val << 8); return; case 0x016: BGYPos[1] = (BGYPos[1] & 0xFF00) | val; return; case 0x017: BGYPos[1] = (BGYPos[1] & 0x00FF) | (val << 8); return; case 0x018: BGXPos[2] = (BGXPos[2] & 0xFF00) | val; return; case 0x019: BGXPos[2] = (BGXPos[2] & 0x00FF) | (val << 8); return; case 0x01A: BGYPos[2] = (BGYPos[2] & 0xFF00) | val; return; case 0x01B: BGYPos[2] = (BGYPos[2] & 0x00FF) | (val << 8); return; case 0x01C: BGXPos[3] = (BGXPos[3] & 0xFF00) | val; return; case 0x01D: BGXPos[3] = (BGXPos[3] & 0x00FF) | (val << 8); return; case 0x01E: BGYPos[3] = (BGYPos[3] & 0xFF00) | val; return; case 0x01F: BGYPos[3] = (BGYPos[3] & 0x00FF) | (val << 8); return; case 0x040: Win0Coords[1] = val; return; case 0x041: Win0Coords[0] = val; return; case 0x042: Win1Coords[1] = val; return; case 0x043: Win1Coords[0] = val; return; case 0x044: Win0Coords[3] = val; return; case 0x045: Win0Coords[2] = val; return; case 0x046: Win1Coords[3] = val; return; case 0x047: Win1Coords[2] = val; return; case 0x048: WinCnt[0] = val; return; case 0x049: WinCnt[1] = val; return; case 0x04A: WinCnt[2] = val; return; case 0x04B: WinCnt[3] = val; return; case 0x04C: BGMosaicSize[0] = val & 0xF; BGMosaicSize[1] = val >> 4; return; case 0x04D: OBJMosaicSize[0] = val & 0xF; OBJMosaicSize[1] = val >> 4; return; case 0x050: BlendCnt = (BlendCnt & 0x3F00) | val; return; case 0x051: BlendCnt = (BlendCnt & 0x00FF) | (val << 8); return; case 0x052: BlendAlpha = (BlendAlpha & 0x1F00) | (val & 0x1F); EVA = val & 0x1F; if (EVA > 16) EVA = 16; return; case 0x053: BlendAlpha = (BlendAlpha & 0x001F) | ((val & 0x1F) << 8); EVB = val & 0x1F; if (EVB > 16) EVB = 16; return; case 0x054: EVY = val & 0x1F; if (EVY > 16) EVY = 16; return; } printf("unknown GPU write8 %08X %02X\n", addr, val); } void Unit::Write16(u32 addr, u16 val) { switch (addr & 0x00000FFF) { case 0x000: DispCnt = (DispCnt & 0xFFFF0000) | val; if (Num) DispCnt &= 0xC0B1FFF7; return; case 0x002: DispCnt = (DispCnt & 0x0000FFFF) | (val << 16); if (Num) DispCnt &= 0xC0B1FFF7; return; case 0x010: if (!Num) GPU3D::SetRenderXPos(val); break; case 0x068: DispFIFO[DispFIFOWritePtr] = val; return; case 0x06A: DispFIFO[DispFIFOWritePtr+1] = val; DispFIFOWritePtr += 2; DispFIFOWritePtr &= 0xF; return; case 0x06C: MasterBrightness = val; return; } if (!Enabled) return; switch (addr & 0x00000FFF) { case 0x008: BGCnt[0] = val; return; case 0x00A: BGCnt[1] = val; return; case 0x00C: BGCnt[2] = val; return; case 0x00E: BGCnt[3] = val; return; case 0x010: BGXPos[0] = val; return; case 0x012: BGYPos[0] = val; return; case 0x014: BGXPos[1] = val; return; case 0x016: BGYPos[1] = val; return; case 0x018: BGXPos[2] = val; return; case 0x01A: BGYPos[2] = val; return; case 0x01C: BGXPos[3] = val; return; case 0x01E: BGYPos[3] = val; return; case 0x020: BGRotA[0] = val; return; case 0x022: BGRotB[0] = val; return; case 0x024: BGRotC[0] = val; return; case 0x026: BGRotD[0] = val; return; case 0x028: BGXRef[0] = (BGXRef[0] & 0xFFFF0000) | val; if (GPU::VCount < 192) BGXRefInternal[0] = BGXRef[0]; return; case 0x02A: if (val & 0x0800) val |= 0xF000; BGXRef[0] = (BGXRef[0] & 0xFFFF) | (val << 16); if (GPU::VCount < 192) BGXRefInternal[0] = BGXRef[0]; return; case 0x02C: BGYRef[0] = (BGYRef[0] & 0xFFFF0000) | val; if (GPU::VCount < 192) BGYRefInternal[0] = BGYRef[0]; return; case 0x02E: if (val & 0x0800) val |= 0xF000; BGYRef[0] = (BGYRef[0] & 0xFFFF) | (val << 16); if (GPU::VCount < 192) BGYRefInternal[0] = BGYRef[0]; return; case 0x030: BGRotA[1] = val; return; case 0x032: BGRotB[1] = val; return; case 0x034: BGRotC[1] = val; return; case 0x036: BGRotD[1] = val; return; case 0x038: BGXRef[1] = (BGXRef[1] & 0xFFFF0000) | val; if (GPU::VCount < 192) BGXRefInternal[1] = BGXRef[1]; return; case 0x03A: if (val & 0x0800) val |= 0xF000; BGXRef[1] = (BGXRef[1] & 0xFFFF) | (val << 16); if (GPU::VCount < 192) BGXRefInternal[1] = BGXRef[1]; return; case 0x03C: BGYRef[1] = (BGYRef[1] & 0xFFFF0000) | val; if (GPU::VCount < 192) BGYRefInternal[1] = BGYRef[1]; return; case 0x03E: if (val & 0x0800) val |= 0xF000; BGYRef[1] = (BGYRef[1] & 0xFFFF) | (val << 16); if (GPU::VCount < 192) BGYRefInternal[1] = BGYRef[1]; return; case 0x040: Win0Coords[1] = val & 0xFF; Win0Coords[0] = val >> 8; return; case 0x042: Win1Coords[1] = val & 0xFF; Win1Coords[0] = val >> 8; return; case 0x044: Win0Coords[3] = val & 0xFF; Win0Coords[2] = val >> 8; return; case 0x046: Win1Coords[3] = val & 0xFF; Win1Coords[2] = val >> 8; return; case 0x048: WinCnt[0] = val & 0xFF; WinCnt[1] = val >> 8; return; case 0x04A: WinCnt[2] = val & 0xFF; WinCnt[3] = val >> 8; return; case 0x04C: BGMosaicSize[0] = val & 0xF; BGMosaicSize[1] = (val >> 4) & 0xF; OBJMosaicSize[0] = (val >> 8) & 0xF; OBJMosaicSize[1] = val >> 12; return; case 0x050: BlendCnt = val & 0x3FFF; return; case 0x052: BlendAlpha = val & 0x1F1F; EVA = val & 0x1F; if (EVA > 16) EVA = 16; EVB = (val >> 8) & 0x1F; if (EVB > 16) EVB = 16; return; case 0x054: EVY = val & 0x1F; if (EVY > 16) EVY = 16; return; } //printf("unknown GPU write16 %08X %04X\n", addr, val); } void Unit::Write32(u32 addr, u32 val) { switch (addr & 0x00000FFF) { case 0x000: DispCnt = val; if (Num) DispCnt &= 0xC0B1FFF7; return; case 0x064: CaptureCnt = val & 0xEF3F1F1F; return; case 0x068: DispFIFO[DispFIFOWritePtr] = val & 0xFFFF; DispFIFO[DispFIFOWritePtr+1] = val >> 16; DispFIFOWritePtr += 2; DispFIFOWritePtr &= 0xF; return; } if (Enabled) { switch (addr & 0x00000FFF) { case 0x028: if (val & 0x08000000) val |= 0xF0000000; BGXRef[0] = val; if (GPU::VCount < 192) BGXRefInternal[0] = BGXRef[0]; return; case 0x02C: if (val & 0x08000000) val |= 0xF0000000; BGYRef[0] = val; if (GPU::VCount < 192) BGYRefInternal[0] = BGYRef[0]; return; case 0x038: if (val & 0x08000000) val |= 0xF0000000; BGXRef[1] = val; if (GPU::VCount < 192) BGXRefInternal[1] = BGXRef[1]; return; case 0x03C: if (val & 0x08000000) val |= 0xF0000000; BGYRef[1] = val; if (GPU::VCount < 192) BGYRefInternal[1] = BGYRef[1]; return; } } Write16(addr, val&0xFFFF); Write16(addr+2, val>>16); } void Unit::UpdateMosaicCounters(u32 line) { // Y mosaic uses incrementing 4-bit counters // the transformed Y position is updated every time the counter matches the MOSAIC register if (OBJMosaicYCount == OBJMosaicSize[1]) { OBJMosaicYCount = 0; OBJMosaicY = line + 1; } else { OBJMosaicYCount++; OBJMosaicYCount &= 0xF; } } void Unit::VBlank() { if (CaptureLatch) { CaptureCnt &= ~(1<<31); CaptureLatch = false; } DispFIFOReadPtr = 0; DispFIFOWritePtr = 0; } void Unit::VBlankEnd() { // TODO: find out the exact time this happens BGXRefInternal[0] = BGXRef[0]; BGXRefInternal[1] = BGXRef[1]; BGYRefInternal[0] = BGYRef[0]; BGYRefInternal[1] = BGYRef[1]; BGMosaicY = 0; BGMosaicYMax = BGMosaicSize[1]; //OBJMosaicY = 0; //OBJMosaicYMax = OBJMosaicSize[1]; //OBJMosaicY = 0; //OBJMosaicYCount = 0; } void Unit::SampleFIFO(u32 offset, u32 num) { for (u32 i = 0; i < num; i++) { u16 val = DispFIFO[DispFIFOReadPtr]; DispFIFOReadPtr++; DispFIFOReadPtr &= 0xF; DispFIFOBuffer[offset+i] = val; } } u16* Unit::GetBGExtPal(u32 slot, u32 pal) { const u32 PaletteSize = 256 * 2; const u32 SlotSize = PaletteSize * 16; return (u16*)&(Num == 0 ? GPU::VRAMFlat_ABGExtPal : GPU::VRAMFlat_BBGExtPal)[slot * SlotSize + pal * PaletteSize]; } u16* Unit::GetOBJExtPal() { return Num == 0 ? (u16*)GPU::VRAMFlat_AOBJExtPal : (u16*)GPU::VRAMFlat_BOBJExtPal; } void Unit::CheckWindows(u32 line) { line &= 0xFF; if (line == Win0Coords[3]) Win0Active &= ~0x1; else if (line == Win0Coords[2]) Win0Active |= 0x1; if (line == Win1Coords[3]) Win1Active &= ~0x1; else if (line == Win1Coords[2]) Win1Active |= 0x1; } void Unit::CalculateWindowMask(u32 line, u8* windowMask, u8* objWindow) { for (u32 i = 0; i < 256; i++) windowMask[i] = WinCnt[2]; // window outside if (DispCnt & (1<<15)) { // OBJ window for (int i = 0; i < 256; i++) { if (objWindow[i]) windowMask[i] = WinCnt[3]; } } if (DispCnt & (1<<14)) { // window 1 u8 x1 = Win1Coords[0]; u8 x2 = Win1Coords[1]; for (int i = 0; i < 256; i++) { if (i == x2) Win1Active &= ~0x2; else if (i == x1) Win1Active |= 0x2; if (Win1Active == 0x3) windowMask[i] = WinCnt[1]; } } if (DispCnt & (1<<13)) { // window 0 u8 x1 = Win0Coords[0]; u8 x2 = Win0Coords[1]; for (int i = 0; i < 256; i++) { if (i == x2) Win0Active &= ~0x2; else if (i == x1) Win0Active |= 0x2; if (Win0Active == 0x3) windowMask[i] = WinCnt[0]; } } } void Unit::GetBGVRAM(u8*& data, u32& mask) { if (Num == 0) { data = GPU::VRAMFlat_ABG; mask = 0x7FFFF; } else { data = GPU::VRAMFlat_BBG; mask = 0x1FFFF; } } void Unit::GetOBJVRAM(u8*& data, u32& mask) { if (Num == 0) { data = GPU::VRAMFlat_AOBJ; mask = 0x3FFFF; } else { data = GPU::VRAMFlat_BOBJ; mask = 0x1FFFF; } } }