// Copyright 2008 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <cmath>
#include <cstring>

#include "Common/ChunkFile.h"
#include "Common/CommonTypes.h"
#include "VideoCommon/PixelShaderManager.h"
#include "VideoCommon/RenderBase.h"
#include "VideoCommon/VideoCommon.h"
#include "VideoCommon/VideoConfig.h"
#include "VideoCommon/XFMemory.h"

bool PixelShaderManager::s_bFogRangeAdjustChanged;
bool PixelShaderManager::s_bViewPortChanged;

PixelShaderConstants PixelShaderManager::constants;
bool PixelShaderManager::dirty;

void PixelShaderManager::Init()
{
  memset(&constants, 0, sizeof(constants));

  // Init any intial constants which aren't zero when bpmem is zero.
  s_bFogRangeAdjustChanged = true;
  s_bViewPortChanged = false;

  SetEfbScaleChanged();
  SetIndMatrixChanged(0);
  SetIndMatrixChanged(1);
  SetIndMatrixChanged(2);
  SetZTextureTypeChanged();
  SetTexCoordChanged(0);
  SetTexCoordChanged(1);
  SetTexCoordChanged(2);
  SetTexCoordChanged(3);
  SetTexCoordChanged(4);
  SetTexCoordChanged(5);
  SetTexCoordChanged(6);
  SetTexCoordChanged(7);

  dirty = true;
}

void PixelShaderManager::Dirty()
{
  // This function is called after a savestate is loaded.
  // Any constants that can changed based on settings should be re-calculated
  s_bFogRangeAdjustChanged = true;

  SetEfbScaleChanged();
  SetFogParamChanged();

  dirty = true;
}

void PixelShaderManager::SetConstants()
{
  if (s_bFogRangeAdjustChanged)
  {
    // set by two components, so keep changed flag here
    // TODO: try to split both registers and move this logic to the shader
    if (!g_ActiveConfig.bDisableFog && bpmem.fogRange.Base.Enabled == 1)
    {
      // bpmem.fogRange.Base.Center : center of the viewport in x axis. observation:
      // bpmem.fogRange.Base.Center = realcenter + 342;
      int center = ((u32)bpmem.fogRange.Base.Center) - 342;
      // normalize center to make calculations easy
      float ScreenSpaceCenter = center / (2.0f * xfmem.viewport.wd);
      ScreenSpaceCenter = (ScreenSpaceCenter * 2.0f) - 1.0f;
      // bpmem.fogRange.K seems to be  a table of precalculated coefficients for the adjust factor
      // observations: bpmem.fogRange.K[0].LO appears to be the lowest value and
      // bpmem.fogRange.K[4].HI the largest
      // they always seems to be larger than 256 so my theory is :
      // they are the coefficients from the center to the border of the screen
      // so to simplify I use the hi coefficient as K in the shader taking 256 as the scale
      // TODO: Shouldn't this be EFBToScaledXf?
      constants.fogf[0][0] = ScreenSpaceCenter;
      constants.fogf[0][1] = (float)Renderer::EFBToScaledX((int)(2.0f * xfmem.viewport.wd));
      constants.fogf[0][2] = bpmem.fogRange.K[4].HI / 256.0f;
    }
    else
    {
      constants.fogf[0][0] = 0;
      constants.fogf[0][1] = 1;
      constants.fogf[0][2] = 1;
    }
    dirty = true;

    s_bFogRangeAdjustChanged = false;
  }

  if (s_bViewPortChanged)
  {
    constants.zbias[1][0] = (u32)xfmem.viewport.farZ;
    constants.zbias[1][1] = (u32)xfmem.viewport.zRange;
    dirty = true;
    s_bViewPortChanged = false;
  }
}

void PixelShaderManager::SetTevColor(int index, int component, s32 value)
{
  auto& c = constants.colors[index];
  c[component] = value;
  dirty = true;

  PRIM_LOG("tev color%d: %d %d %d %d\n", index, c[0], c[1], c[2], c[3]);
}

void PixelShaderManager::SetTevKonstColor(int index, int component, s32 value)
{
  auto& c = constants.kcolors[index];
  c[component] = value;
  dirty = true;

  PRIM_LOG("tev konst color%d: %d %d %d %d\n", index, c[0], c[1], c[2], c[3]);
}

void PixelShaderManager::SetAlpha()
{
  constants.alpha[0] = bpmem.alpha_test.ref0;
  constants.alpha[1] = bpmem.alpha_test.ref1;
  dirty = true;
}

void PixelShaderManager::SetDestAlpha()
{
  constants.alpha[3] = bpmem.dstalpha.alpha;
  dirty = true;
}

void PixelShaderManager::SetTexDims(int texmapid, u32 width, u32 height)
{
  float rwidth = 1.0f / (width * 128.0f);
  float rheight = 1.0f / (height * 128.0f);

  // TODO: move this check out to callee. There we could just call this function on texture changes
  // or better, use textureSize() in glsl
  if (constants.texdims[texmapid][0] != rwidth || constants.texdims[texmapid][1] != rheight)
    dirty = true;

  constants.texdims[texmapid][0] = rwidth;
  constants.texdims[texmapid][1] = rheight;
}

void PixelShaderManager::SetZTextureBias()
{
  constants.zbias[1][3] = bpmem.ztex1.bias;
  dirty = true;
}

void PixelShaderManager::SetViewportChanged()
{
  s_bViewPortChanged = true;
  s_bFogRangeAdjustChanged =
      true;  // TODO: Shouldn't be necessary with an accurate fog range adjust implementation
}

void PixelShaderManager::SetEfbScaleChanged()
{
  constants.efbscale[0] = 1.0f / Renderer::EFBToScaledXf(1);
  constants.efbscale[1] = 1.0f / Renderer::EFBToScaledYf(1);
  dirty = true;
}

void PixelShaderManager::SetZSlope(float dfdx, float dfdy, float f0)
{
  constants.zslope[0] = dfdx;
  constants.zslope[1] = dfdy;
  constants.zslope[2] = f0;
  dirty = true;
}

void PixelShaderManager::SetIndTexScaleChanged(bool high)
{
  constants.indtexscale[high][0] = bpmem.texscale[high].ss0;
  constants.indtexscale[high][1] = bpmem.texscale[high].ts0;
  constants.indtexscale[high][2] = bpmem.texscale[high].ss1;
  constants.indtexscale[high][3] = bpmem.texscale[high].ts1;
  dirty = true;
}

void PixelShaderManager::SetIndMatrixChanged(int matrixidx)
{
  int scale = ((u32)bpmem.indmtx[matrixidx].col0.s0 << 0) |
              ((u32)bpmem.indmtx[matrixidx].col1.s1 << 2) |
              ((u32)bpmem.indmtx[matrixidx].col2.s2 << 4);

  // xyz - static matrix
  // w - dynamic matrix scale / 128
  constants.indtexmtx[2 * matrixidx][0] = bpmem.indmtx[matrixidx].col0.ma;
  constants.indtexmtx[2 * matrixidx][1] = bpmem.indmtx[matrixidx].col1.mc;
  constants.indtexmtx[2 * matrixidx][2] = bpmem.indmtx[matrixidx].col2.me;
  constants.indtexmtx[2 * matrixidx][3] = 17 - scale;
  constants.indtexmtx[2 * matrixidx + 1][0] = bpmem.indmtx[matrixidx].col0.mb;
  constants.indtexmtx[2 * matrixidx + 1][1] = bpmem.indmtx[matrixidx].col1.md;
  constants.indtexmtx[2 * matrixidx + 1][2] = bpmem.indmtx[matrixidx].col2.mf;
  constants.indtexmtx[2 * matrixidx + 1][3] = 17 - scale;
  dirty = true;

  PRIM_LOG("indmtx%d: scale=%d, mat=(%d %d %d; %d %d %d)\n", matrixidx, scale,
           bpmem.indmtx[matrixidx].col0.ma, bpmem.indmtx[matrixidx].col1.mc,
           bpmem.indmtx[matrixidx].col2.me, bpmem.indmtx[matrixidx].col0.mb,
           bpmem.indmtx[matrixidx].col1.md, bpmem.indmtx[matrixidx].col2.mf);
}

void PixelShaderManager::SetZTextureTypeChanged()
{
  switch (bpmem.ztex2.type)
  {
  case TEV_ZTEX_TYPE_U8:
    constants.zbias[0][0] = 0;
    constants.zbias[0][1] = 0;
    constants.zbias[0][2] = 0;
    constants.zbias[0][3] = 1;
    break;
  case TEV_ZTEX_TYPE_U16:
    constants.zbias[0][0] = 1;
    constants.zbias[0][1] = 0;
    constants.zbias[0][2] = 0;
    constants.zbias[0][3] = 256;
    break;
  case TEV_ZTEX_TYPE_U24:
    constants.zbias[0][0] = 65536;
    constants.zbias[0][1] = 256;
    constants.zbias[0][2] = 1;
    constants.zbias[0][3] = 0;
    break;
  default:
    break;
  }
  dirty = true;
}

void PixelShaderManager::SetTexCoordChanged(u8 texmapid)
{
  TCoordInfo& tc = bpmem.texcoords[texmapid];
  constants.texdims[texmapid][2] = (float)(tc.s.scale_minus_1 + 1) * 128.0f;
  constants.texdims[texmapid][3] = (float)(tc.t.scale_minus_1 + 1) * 128.0f;
  dirty = true;
}

void PixelShaderManager::SetFogColorChanged()
{
  if (g_ActiveConfig.bDisableFog)
    return;

  constants.fogcolor[0] = bpmem.fog.color.r;
  constants.fogcolor[1] = bpmem.fog.color.g;
  constants.fogcolor[2] = bpmem.fog.color.b;
  dirty = true;
}

void PixelShaderManager::SetFogParamChanged()
{
  if (!g_ActiveConfig.bDisableFog)
  {
    constants.fogf[1][0] = bpmem.fog.a.GetA();
    constants.fogi[1] = bpmem.fog.b_magnitude;
    constants.fogf[1][2] = bpmem.fog.c_proj_fsel.GetC();
    constants.fogi[3] = bpmem.fog.b_shift;
  }
  else
  {
    constants.fogf[1][0] = 0.f;
    constants.fogi[1] = 1;
    constants.fogf[1][2] = 0.f;
    constants.fogi[3] = 1;
  }
  dirty = true;
}

void PixelShaderManager::SetFogRangeAdjustChanged()
{
  if (g_ActiveConfig.bDisableFog)
    return;

  s_bFogRangeAdjustChanged = true;
}

void PixelShaderManager::DoState(PointerWrap& p)
{
  p.Do(s_bFogRangeAdjustChanged);
  p.Do(s_bViewPortChanged);

  p.Do(constants);

  if (p.GetMode() == PointerWrap::MODE_READ)
  {
    // Fixup the current state from global GPU state
    // NOTE: This requires that all GPU memory has been loaded already.
    Dirty();
  }
}
