shithub: zelda3

ref: e463564ffe1d86ce13f722e88cfe1154708ed7d2
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;
  // -- snapshot starts here
  bool tilemapWider;
  bool tilemapHigher;
  uint16_t tilemapAdr;
  // -- snapshot ends here
  uint16_t tileAdr;
} BgLayer;

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

typedef uint16_t PpuZbufType;

typedef struct PpuPixelPrioBufs {
  // This holds the prio in the upper 8 bits and the color in the lower 8 bits.
  PpuZbufType data[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;

  // TMW / TSW etc
  uint8 screenEnabled[2];
  uint8 screenWindowed[2];
  uint8 mosaicEnabled;
  uint8 mosaicSize;
  // object/sprites
  uint16_t objTileAdr1;
  uint16_t objTileAdr2;
  uint8_t objSize;
  // Window
  uint8_t window1left;
  uint8_t window1right;
  uint8_t window2left;
  uint8_t window2right;
  uint32_t windowsel;

  // color math
  uint8_t clipMode;
  uint8_t preventMathMode;
  bool addSubscreen;
  bool subtractColor;
  bool halfColor;
  uint8 mathEnabled;
  uint8_t fixedColorR, fixedColorG, fixedColorB;
  // settings
  bool forcedBlank;
  uint8_t brightness;
  uint8_t mode;

  // vram access
  uint16_t vramPointer;
  uint16_t vramIncrement;
  bool vramIncrementOnHigh;
  // cgram access
  uint8_t cgramPointer;
  bool cgramSecondWrite;
  uint8_t cgramBuffer;
  // oam access
  uint16_t oamAdr;
  bool oamSecondWrite;
  uint8_t oamBuffer;

  // background layers
  BgLayer bgLayer[4];
  uint8_t scrollPrev;
  uint8_t scrollPrev2;
  
  // 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;

  uint16_t oam[0x110];
  
  // store 31 extra entries to remove the need for clamp
  uint8_t brightnessMult[32 + 31];
  uint8_t brightnessMultHalf[32 * 2];
  uint16_t cgram[0x100];
  uint8_t mosaicModulo[kPpuXPixels];
  uint32_t colorMapRgb[256];
  PpuPixelPrioBufs bgBuffers[2];
  PpuPixelPrioBufs objBuffer;
  uint16_t vram[0x8000];
};

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);
void PpuBeginDrawing(Ppu *ppu, uint8_t *buffer, size_t pitch, uint32_t render_flags);

// Returns the current render scale, 1x = 256px, 2x=512px, 4x=1024px
int PpuGetCurrentRenderScale(Ppu *ppu, 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_