shithub: zelda3

ref: 203a433a66633b726f92393efa42f168c0319755
dir: /snes/ppu.h/

#ifndef ZELDA3_SNES_PPU_H_
#define ZELDA3_SNES_PPU_H_

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>
#include "saveload.h"
typedef struct Ppu Ppu;

#include "../types.h"

typedef struct BgLayer {
  uint16_t hScroll;
  uint16_t vScroll;
  bool tilemapWider;
  bool tilemapHigher;
  uint16_t tilemapAdr;
  uint16_t tileAdr;
  bool bigTiles_always_zero;
  bool mosaicEnabled;
} BgLayer;

typedef struct Layer {
  bool screenEnabled[2];   // 0 = main, 1 = sub
  bool screenWindowed[2];  // 0 = main, 1 = sub
} Layer;

typedef struct WindowLayer {
  bool window1enabled;
  bool window2enabled;
  bool window1inversed;
  bool window2inversed;
  uint8_t maskLogic_always_zero;
} WindowLayer;

enum {
  kPpuXPixels = 256 + kPpuExtraLeftRight * 2,
};

typedef struct PpuPixelPrioBufs {
  uint8_t pixel[kPpuXPixels];
  uint8_t prio[kPpuXPixels];
} PpuPixelPrioBufs;

enum {
  kPpuRenderFlags_NewRenderer = 1,
  // Render mode7 upsampled by 4x4
  kPpuRenderFlags_4x4Mode7 = 2,
  // Use 240 height instead of 224
  kPpuRenderFlags_Height240 = 4,
  // Disable sprite render limits
  kPpuRenderFlags_NoSpriteLimits = 8,
};


struct Ppu {
  bool lineHasSprites;
  uint8_t lastBrightnessMult;
  uint8_t lastMosaicModulo;
  uint8_t renderFlags;
  uint32_t renderPitch;
  uint8_t *renderBuffer;
  uint8_t extraLeftCur, extraRightCur, extraLeftRight, extraBottomCur;
  float mode7PerspectiveLow, mode7PerspectiveHigh;
  // store 31 extra entries to remove the need for clamp
  uint8_t brightnessMult[32 + 31]; 
  uint8_t brightnessMultHalf[32 * 2];
  PpuPixelPrioBufs bgBuffers[2];
  // vram access
  uint16_t vram[0x8000];
  uint16_t vramPointer;
  bool vramIncrementOnHigh;
  uint16_t vramIncrement;
  uint8_t vramRemapMode;
  uint16_t vramReadBuffer;
  // cgram access
  uint16_t cgram[0x100];
  uint8_t cgramPointer;
  bool cgramSecondWrite;
  uint8_t cgramBuffer;
  // oam access
  uint16_t oam[0x100];
  uint8_t highOam[0x20];
  uint8_t oamAdr;
  uint8_t oamAdrWritten;
  bool oamInHigh;
  bool oamInHighWritten;
  bool oamSecondWrite;
  uint8_t oamBuffer;
  // object/sprites
  bool objPriority;
  uint16_t objTileAdr1;
  uint16_t objTileAdr2;
  uint8_t objSize;
  PpuPixelPrioBufs objBuffer;
  bool timeOver;
  bool rangeOver;
  bool objInterlace_always_zero;
  // background layers
  BgLayer bgLayer[4];
  uint8_t scrollPrev;
  uint8_t scrollPrev2;
  uint8_t mosaicSize;
  uint8_t mosaicStartLine;
  // layers
  Layer layer[5];
  // mode 7
  int16_t m7matrix[8]; // a, b, c, d, x, y, h, v
  uint8_t m7prev;
  bool m7largeField;
  bool m7charFill;
  bool m7xFlip;
  bool m7yFlip;
  bool m7extBg_always_zero;
  // mode 7 internal
  int32_t m7startX;
  int32_t m7startY;
  // windows
  WindowLayer windowLayer[6];
  uint8_t window1left;
  uint8_t window1right;
  uint8_t window2left;
  uint8_t window2right;
  // color math
  uint8_t clipMode;
  uint8_t preventMathMode;
  bool addSubscreen;
  bool subtractColor;
  bool halfColor;
  bool mathEnabled[6];
  uint8_t fixedColorR;
  uint8_t fixedColorG;
  uint8_t fixedColorB;
  // settings
  bool forcedBlank;
  uint8_t brightness;
  uint8_t mode;
  bool bg3priority;
  bool evenFrame;
  bool pseudoHires_always_zero;
  bool overscan_always_zero;
  bool frameOverscan_always_zero; // if we are overscanning this frame (determined at 0,225)
  bool interlace_always_zero;
  bool frameInterlace_always_zero; // if we are interlacing this frame (determined at start vblank)
  bool directColor_always_zero;
  // latching
  uint16_t hCount;
  uint16_t vCount;
  bool hCountSecond;
  bool vCountSecond;
  bool countersLatched;
  uint8_t ppu1openBus;
  uint8_t ppu2openBus;

  uint8_t mosaicModulo[kPpuXPixels];
  uint32_t colorMapRgb[256];
};

Ppu* ppu_init();
void ppu_free(Ppu* ppu);
void ppu_reset(Ppu* ppu);
void ppu_handleVblank(Ppu* ppu);
void ppu_runLine(Ppu* ppu, int line);
uint8_t ppu_read(Ppu* ppu, uint8_t adr);
void ppu_write(Ppu* ppu, uint8_t adr, uint8_t val);
void ppu_saveload(Ppu *ppu, SaveLoadFunc *func, void *ctx);
bool PpuBeginDrawing(Ppu *ppu, uint8_t *buffer, size_t pitch, uint32_t render_flags);

void PpuSetMode7PerspectiveCorrection(Ppu *ppu, int low, int high);
void PpuSetExtraSideSpace(Ppu *ppu, int left, int right, int bottom);

#endif  // ZELDA3_SNES_PPU_H_