/**
  3D renderer: implements 3D rendering.
*/

#ifndef _LCR_RENDERER_H
#define _LCR_RENDERER_H

#define S3L_RESOLUTION_X LCR_SETTING_RESOLUTION_X
#define S3L_RESOLUTION_Y LCR_SETTING_RESOLUTION_Y
#define S3L_PIXEL_FUNCTION LCR_pixelFunc3D

#define S3L_Z_BUFFER 2

#include "small3dlib.h"

struct LCR_Renderer
{
  // TODO

  
};

S3L_Scene LCR_scene3D;
S3L_Model3D LCR_models3D[3]; // TODO

S3L_Unit LCR_vertices3D[LCR_SETTING_MAX_VERTICES * 3];
S3L_Index LCR_triangles3D[LCR_SETTING_MAX_TRIANGLES * 3];

void LCR_pixelFunc3D(S3L_PixelInfo *pixel)
{
  LCR_drawPixelSafe(pixel->x,pixel->y,0xff00);
}

/** Builds an internal 3D model of the currently loaded map. Returns 1 on
  success, otherwise 0 (e.g. not enough space). */
uint8_t LCR_buildMapModel(void)
{
  // TODO

  LCR_vertices3D[0] = -2000;
  LCR_vertices3D[1] = -100;
  LCR_vertices3D[2] = 1000;

  LCR_vertices3D[3] = 400;
  LCR_vertices3D[4] = -100;
  LCR_vertices3D[5] = 2000;

  LCR_vertices3D[6] = 0;
  LCR_vertices3D[7] = 400;
  LCR_vertices3D[8] = 2000;

  LCR_triangles3D[0] = 0;
  LCR_triangles3D[1] = 1;
  LCR_triangles3D[2] = 2;

  return 1;
}

uint8_t LCR_rendererInit(void)
{
  if (!LCR_buildMapModel())
    return 0;

  S3L_model3DInit(LCR_vertices3D,3,LCR_triangles3D,1,LCR_models3D);
  S3L_sceneInit(LCR_models3D,1,&LCR_scene3D);

  return 1;
}

void LCR_rendererMoveCamera(LCR_SpaceUnit forwRightUpOffset[3],
  LCR_SpaceUnit yawPitchOffset[2])
{  
  S3L_Vec4 f, r, u;

  S3L_rotationToDirections(LCR_scene3D.camera.transform.rotation,
    S3L_FRACTIONS_PER_UNIT,&f,&r,&u);

  LCR_scene3D.camera.transform.translation.x +=
    ((f.x * forwRightUpOffset[0] + r.x * forwRightUpOffset[1] + 
    u.x * forwRightUpOffset[2]) * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;      
 
  LCR_scene3D.camera.transform.translation.y +=
    ((f.y * forwRightUpOffset[0] + r.y * forwRightUpOffset[1] + 
    u.y * forwRightUpOffset[2]) * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;      

  LCR_scene3D.camera.transform.translation.z +=
    ((f.z * forwRightUpOffset[0] + r.z * forwRightUpOffset[1] + 
    u.z * forwRightUpOffset[2]) * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;      
  
  LCR_scene3D.camera.transform.rotation.y +=
    (yawPitchOffset[0] * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;
  
  LCR_scene3D.camera.transform.rotation.x +=
    (yawPitchOffset[1] * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;

  if (LCR_scene3D.camera.transform.rotation.x > S3L_FRACTIONS_PER_UNIT / 4)
    LCR_scene3D.camera.transform.rotation.x = S3L_FRACTIONS_PER_UNIT / 4;

  if (LCR_scene3D.camera.transform.rotation.x < -1 * S3L_FRACTIONS_PER_UNIT / 4)
    LCR_scene3D.camera.transform.rotation.x = -1 * S3L_FRACTIONS_PER_UNIT / 4;
}

void LCR_rendererDraw(void)
{
  S3L_newFrame();
  S3L_drawScene(LCR_scene3D);
}

void LCR_drawBackground(int verticalOffset)
{
  uint16_t color = LCR_skyImages[LCR_skyImages[256] & 0x00ff]  ; // TODO
  int limit = verticalOffset - LCR_SETTING_SKY_SIZE * LCR_SKY_IMAGE_SIZE / 2;

  if (limit >= LCR_EFFECTIVE_RESOLUTION_Y)
    limit = LCR_EFFECTIVE_RESOLUTION_Y - 1;

  for (int y = 0; y <= limit; ++y)
    for (int x = 0; x < LCR_EFFECTIVE_RESOLUTION_X; ++x)
      LCR_drawPixelUnsafe(x,y,color);

  color = LCR_skyImages[LCR_skyImages[255 + (128 * 128) / 2] >> 8]; // TODO
  limit = verticalOffset + LCR_SETTING_SKY_SIZE * LCR_SKY_IMAGE_SIZE / 2 -
    LCR_SETTING_SKY_SIZE;

  if (limit < 0)
    limit = 0;

  for (int y = LCR_EFFECTIVE_RESOLUTION_Y - 1; y >= limit; --y)
    for (int x = 0; x < LCR_EFFECTIVE_RESOLUTION_X; ++x)
      LCR_drawPixelUnsafe(x,y,color);
}

void LCR_drawSkyStrip(int verticalOffset, uint8_t horizontalOffset)
{
#if LCR_SETTING_SKY_SIZE != 0
  verticalOffset -= (LCR_SETTING_SKY_SIZE * LCR_SKY_IMAGE_SIZE) / 2; 

  int finalY = verticalOffset + LCR_SETTING_SKY_SIZE * LCR_SKY_IMAGE_SIZE;

  finalY = (finalY / LCR_SETTING_SKY_SIZE) * LCR_SETTING_SKY_SIZE;

  if (finalY >= LCR_EFFECTIVE_RESOLUTION_Y)
    finalY = LCR_EFFECTIVE_RESOLUTION_Y - 1;

  const uint16_t *skyLine = LCR_skyImages + 256;

  if (verticalOffset < 0)
  {
    skyLine += (-1 * verticalOffset / LCR_SETTING_SKY_SIZE) * (LCR_SKY_IMAGE_SIZE / 2);
    verticalOffset = 0;
  }

  while (verticalOffset < finalY)
  {
    for (int i = 0; i < LCR_EFFECTIVE_RESOLUTION_X; ++i)
    {
      // only diraw background on empty pixels
      if (S3L_zBufferRead(i,verticalOffset) == S3L_MAX_DEPTH)
      {
        int offsetX = (i / LCR_SETTING_SKY_SIZE + horizontalOffset)
          % LCR_SKY_IMAGE_SIZE;

        uint16_t pixel = *(skyLine + offsetX / 2);

        pixel = offsetX % 2 ? (pixel >> 8) : (pixel & 0x00ff);

        LCR_drawPixelUnsafe(i,verticalOffset,LCR_skyImages[pixel]); 
      }
    }

    verticalOffset++;

    if (verticalOffset % LCR_SETTING_SKY_SIZE == 0)
      skyLine += LCR_SKY_IMAGE_SIZE / 2;
  }

#endif
}

LCR_SpaceUnit LCR_rendererGetCameraYaw(void)
{
  return (LCR_scene3D.camera.transform.rotation.y * LCR_SQUARE_SIDE_LEN) /
    S3L_FRACTIONS_PER_UNIT;
}

LCR_SpaceUnit LCR_rendererGetCameraPitch(void)
{
  return (LCR_scene3D.camera.transform.rotation.x * LCR_SQUARE_SIDE_LEN) /
    S3L_FRACTIONS_PER_UNIT;
}

#endif // guard