#include <eekernel.h>
#include <stdio.h>
#include <libdev.h>
#include <eeregs.h>
#include <libgraph.h>
#include <libdma.h>
#include <math.h>




struct DrawSetup {
  sceGifTag giftag;
  sceGsDrawEnv1 de;
} __attribute__((aligned(16)));


void print_draw_env(sceGsDrawEnv1& env) {
  printf("DRAW ENV\n");
  printf(" frame\n");
  printf("  FBP: 0x%lx\n", env.frame1.FBP);
  printf("  FBW: 0x%lx\n", env.frame1.FBW);
  printf("  PSM: 0x%lx\n", env.frame1.PSM);
  printf("  FBMSK: 0x%lx\n", env.frame1.FBMSK);
  printf(" zbuf\n");
  printf("  ZBP: 0x%lx\n", env.zbuf1.ZBP);
  printf("  PSM: 0x%lx\n", env.zbuf1.PSM);
  printf("  ZMSK: 0x%lx\n", env.zbuf1.ZMSK);
  printf(" xyoffset\n");
  printf("  OFX: 0x%lx\n", env.xyoffset1.OFX);
  printf("  OFY: 0x%lx\n", env.xyoffset1.OFY);
  printf(" scissor\n");
  printf("  SCAX0: 0x%lx\n", env.scissor1.SCAX0);
  printf("  SCAX1: 0x%lx\n", env.scissor1.SCAX1);
  printf("  SCAY0: 0x%lx\n", env.scissor1.SCAY0);
  printf("  SCAY1: 0x%lx\n", env.scissor1.SCAY1);
  printf(" prmodecont\n");
  printf("  AC: 0x%lx\n", env.prmodecont.AC);
  printf(" colclamp\n");
  printf("  CLAMP: 0x%lx\n", env.colclamp.CLAMP);
  printf(" dthe\n");
  printf("  DTHE: 0x%lx\n", env.dthe.DTHE);
  printf(" test\n");
  printf("  ATE: 0x%lx\n", env.test1.ATE);
  printf("  ATST: 0x%lx\n", env.test1.ATST);
  printf("  AREF: 0x%lx\n", env.test1.AREF);
  printf("  AFAIL: 0x%lx\n", env.test1.AFAIL);
  printf("  DATE: 0x%lx\n", env.test1.DATE);
  printf("  DATM: 0x%lx\n", env.test1.DATM);
  printf("  ZTE: 0x%lx\n", env.test1.ZTE);
  printf("  ZTST: 0x%lx\n", env.test1.ZTST);
}

struct SpriteDrawData {
  sceGifTag giftag;
  sceGifPackRgbaq rgba0;
  sceGifPackXyz   xyz0;
  sceGifPackXyz   xyz1;
} __attribute__((aligned(16)));

SpriteDrawData sprite;
sceDmaChan* gifChan;
sceGsDispEnv disp_e;
DrawSetup draw_setup;

void init_gs() {
  printf("GS Init!\n");
  sceGsResetPath();
  sceDmaReset(1);
  gifChan = sceDmaGetChan(SCE_DMA_GIF);

  // Sony GS Setup Stuff
  sceGsResetGraph(0, SCE_GS_INTERLACE, SCE_GS_NTSC, SCE_GS_FRAME);
  // this will set up two draw and disp envs.
  //sceGsSetDefDBuff(&db, SCE_GS_PSMCT32, 640, 224, SCE_GS_ZGREATER, SCE_GS_PSMZ24, 1);
  sceGsSetDefDrawEnv(&draw_setup.de, SCE_GS_PSMCT32, 640, 240, 2, SCE_GS_PSMZ32);
  draw_setup.de.xyoffset1.OFX = 0;
  draw_setup.de.xyoffset1.OFY = 0;
  sceGsSetDefDispEnv(&disp_e, SCE_GS_PSMCT32, 640, 240, 0, 0);
  print_draw_env(draw_setup.de);
  sceGsPutDispEnv(&disp_e);
  SCE_GIF_CLEAR_TAG(&draw_setup.giftag);
  draw_setup.giftag.NLOOP = 8;
  draw_setup.giftag.EOP = 1;
  draw_setup.giftag.PRE = 0;
  draw_setup.giftag.FLG = 0;
  draw_setup.giftag.NREG = 1;
  draw_setup.giftag.REGS0 = 0xe; // A+D
  FlushCache(0);
  sceGsPutDrawEnv(&draw_setup.giftag);
  sceGsSyncPath(0,0);
}

void build_column(SpriteDrawData& asprite, int r, int g, int b, int z, int i) {
  SCE_GIF_CLEAR_TAG(&asprite.giftag);
  asprite.giftag.NLOOP = 1;
  asprite.giftag.EOP = 1;
  asprite.giftag.PRE = 1;
  asprite.giftag.PRIM = 6;
  asprite.giftag.FLG = 0; // packed
  asprite.giftag.NREG = 3;
  asprite.giftag.REGS0 = 1; // rgbaq
  asprite.giftag.REGS1 = 5; // xyz2
  asprite.giftag.REGS2 = 5; // xyz2

  asprite.rgba0.R = r;
  asprite.rgba0.G = g;
  asprite.rgba0.B = b;
  asprite.rgba0.A = (z == 0) ? 0 : 0x80;


  asprite.xyz0.X = 16 * 32 * i;
  asprite.xyz0.Y = 0;
  asprite.xyz0.Z = z;
  asprite.xyz0.ADC = 1;

  asprite.xyz1.X = 16 * 32 * (i + 1);
  asprite.xyz1.Y = 0x1e8 << 4 ;
  asprite.xyz1.Z = z;
  asprite.xyz1.ADC = 0;
}

void step_1() {
  printf("STEP 1: draw screen in 32 wide columns with Z = 0xffffffff\n");
  for(int i = 0; i < 20; i++) {
    build_column(sprite, i*2, i*4, i*8, 0xffffffff, i);
    FlushCache(0);
    sceDmaSendN(gifChan, &sprite, sizeof(SpriteDrawData) / 16);
    sceGsSyncPath(0,0);
  }
}

void print_zbp_fb_zte(sceGsDrawEnv1& de) {
  printf("ZBP: 0x%lx\n", de.zbuf1.ZBP);
  printf("FBP: 0x%lx\n", de.frame1.FBP);
  printf("ZTE: 0x%lx\n", de.test1.ZTE);
  printf("ZTST: 0x%lx\n", de.test1.ZTST);
  printf("PSM: 0x%lx\n", de.frame1.PSM);
}

void step_2() {
  printf("STEP 2: change settings\n");
  printf("Original settings:\n");
  print_zbp_fb_zte(draw_setup.de);
  printf("\n");

  draw_setup.de.frame1.FBP = draw_setup.de.zbuf1.ZBP;
  draw_setup.de.test1.ZTE = 1;
  draw_setup.de.test1.ZTST = 1;
  draw_setup.de.frame1.PSM = 48;
  FlushCache(0);
  sceGsPutDrawEnv(&draw_setup.giftag);
  sceGsSyncPath(0,0);
  sceGsSyncV(0);
  printf("New settings:\n");
  print_zbp_fb_zte(draw_setup.de);
  printf("\n");
  print_draw_env(draw_setup.de);
}

void step_3() {
  printf("STEP 3: repeat of step 1 draw, with all zeros\n");
  for(int i = 0; i < 20; i+=2) {
    build_column(sprite, 0, 0, 0, 0, i);
    FlushCache(0);
    sceDmaSendN(gifChan, &sprite, sizeof(SpriteDrawData) / 16);
    sceGsSyncPath(0,0);
  }
}

void step_4() {
  printf("display the Z buffer.\n");
  disp_e.dispfb.FBP = draw_setup.de.zbuf1.ZBP;
  sceGsPutDispEnv(&disp_e);
}



void draw_run() {
  step_1();
  step_2();
  step_3();
  step_4();
}

int frame = 0;
int odd_even = 0;
void frame_end() {
  sceGsSyncPath(0,0);
  //sceGsSetHalfOffset((frame&1) ? &db.draw1 : &db.draw0, 2048, 2048, odd_even);
  frame++;
  odd_even = !sceGsSyncV(0);

  if(!(frame % 128)) {
    printf("frame %d\n", frame);
  }
}



int main() {
  init_gs();
  printf("GS init done\n");
  printf("starting loop!\n");
    FlushCache(0);
    //sceGsSwapDBuff(&db, frame);
    draw_run();
    frame_end();
    for(;;) { }
  return 0;
}