Licar/renderer.h

/**
  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_PERSPECTIVE_CORRECTION 2
#define S3L_NEAR_CROSS_STRATEGY 0

#define S3L_Z_BUFFER 1

#include "small3dlib.h"

/// Renderer specific unit, length of one map square.
#define LCR_RENDERER_UNIT S3L_FRACTIONS_PER_UNIT

struct
{
  S3L_Scene scene;
  S3L_Model3D models[3]; // TODO

  S3L_Model3D *mapModel;
  S3L_Unit mapVerts[LCR_SETTING_MAX_MAP_VERTICES * 3];
  S3L_Index mapTris[LCR_SETTING_MAX_MAP_TRIANGLES * 3];

  /**
    Additional data for triangles. 4 higher bits hold direction (for lighting):
    0 is floor, 1 is wall, 2 is wall (90 degrees). 4 lower bits hold the
    texture index.
  */
  uint8_t mapTriangleData[LCR_SETTING_MAX_MAP_TRIANGLES];

  // pixel function precomputed values:
  int previousTriID;
  int triUVs[6];
} LCR_renderer;

void LCR_pixelFunc3D(S3L_PixelInfo *pixel)
{
  // once we get a new triangle, we precompute things for it:
  if (pixel->triangleIndex != LCR_renderer.previousTriID)
  {
    S3L_Index *t = LCR_renderer.mapTris + 3 * pixel->triangleIndex;
    S3L_Unit *v[3];

    for (int i = 0; i < 3; ++i)
      v[i] = LCR_renderer.mapVerts + 3 * t[i];

    uint8_t type = LCR_renderer.mapTriangleData[pixel->triangleID] >> 4;

    LCR_loadImage(LCR_renderer.mapTriangleData[pixel->triangleID] & 0x0f);

    if (type == 0) // floor?
    {
      if (v[0][1] != v[1][1] || v[1][1] != v[2][1]) // angled floor?
        LCR_imageChangeBrightness(1);

      for (int i = 0; i < 6; ++i)
        LCR_renderer.triUVs[i] = ((
          (v[i / 2][(i % 2) * 2]) *
            LCR_IMAGE_SIZE) / LCR_RENDERER_UNIT);
    }
    else
    {
      if (type == 1)
        LCR_imageChangeBrightness(0);

      for (int i = 0; i < 6; ++i)
      {
        LCR_renderer.triUVs[i] = ((
          (v[i / 2][i % 2 ? 1 : (type == 1 ? 2 : 0)]) *
            LCR_IMAGE_SIZE) / LCR_RENDERER_UNIT);

        if (i % 2)
          LCR_renderer.triUVs[i] = LCR_IMAGE_SIZE -
            LCR_renderer.triUVs[i];
      }
    }

    // shift the UVs to the origin (prevent high values of UV coords)
    for (int i = 0; i < 2; ++i)
    {
      uint8_t minCoord = LCR_renderer.triUVs[i] <
        LCR_renderer.triUVs[2 + i] ? (0 + i) : (2 + i);

      if (LCR_renderer.triUVs[4 + i] < LCR_renderer.triUVs[minCoord])
        minCoord = 4 + i;

      S3L_Unit shiftBy = LCR_renderer.triUVs[minCoord] % LCR_IMAGE_SIZE;

      if (shiftBy < 0)
        shiftBy += LCR_IMAGE_SIZE;

      shiftBy -= LCR_renderer.triUVs[minCoord];

      LCR_renderer.triUVs[i] += shiftBy;
      LCR_renderer.triUVs[2 + i] += shiftBy;
      LCR_renderer.triUVs[4 + i] += shiftBy;
    }

    LCR_renderer.previousTriID = pixel->triangleIndex;
  }

  int barycentric[3];

  barycentric[0] = pixel->barycentric[0] / 8;
  barycentric[1] = pixel->barycentric[1] / 8;
  barycentric[2] = pixel->barycentric[2] / 8;

  uint16_t color = LCR_sampleImage(
    (barycentric[0] * LCR_renderer.triUVs[0] +
     barycentric[1] * LCR_renderer.triUVs[2] +
     barycentric[2] * LCR_renderer.triUVs[4])
     / (S3L_FRACTIONS_PER_UNIT / 8),
    (barycentric[0] * LCR_renderer.triUVs[1] +
     barycentric[1] * LCR_renderer.triUVs[3] +
     barycentric[2] * LCR_renderer.triUVs[5])
     / (S3L_FRACTIONS_PER_UNIT / 8));

  LCR_drawPixelXYUnsafe(pixel->x,pixel->y,color);
}

S3L_Index _LCR_addMapVert(S3L_Unit x, S3L_Unit y, S3L_Unit z)
{
  S3L_Index index = 0;
  S3L_Unit *verts = LCR_renderer.mapVerts;

  while (index < LCR_renderer.mapModel->vertexCount) // if exists, return index
  {
    if (verts[0] == x && verts[1] == y && verts[2] == z)
      return index;

    verts += 3;
    index++;
  }

  // if it doesn't exist, add it
  if (LCR_renderer.mapModel->vertexCount < LCR_SETTING_MAX_MAP_VERTICES)
  {
    *verts = x; verts++;
    *verts = y; verts++;
    *verts = z;
    LCR_renderer.mapModel->vertexCount++;
    return LCR_renderer.mapModel->vertexCount - 1;
  }

  LCR_log("couldn't add map vertex!");

  return 0;  
}

void _LCR_addMapTri(S3L_Index a, S3L_Index b, S3L_Index c, uint8_t mat)
{
  if (LCR_renderer.mapModel->triangleCount < LCR_SETTING_MAX_MAP_TRIANGLES)
  {
    S3L_Index *t =
      &(LCR_renderer.mapTris[LCR_renderer.mapModel->triangleCount * 3]);

    *t = a; t++;
    *t = b; t++;
    *t = c;

    LCR_renderer.mapTriangleData[LCR_renderer.mapModel->triangleCount] =
      mat;

    LCR_renderer.mapModel->triangleCount++;
  }
}

void _LCR_swapMapTris(unsigned int index1, unsigned int index2)
{
  uint8_t tmpMat;
  S3L_Index tmpIndex,
    *t1 = LCR_renderer.mapTris + index1 * 3,
    *t2 = LCR_renderer.mapTris + index2 * 3;

  for (int i = 0; i < 3; ++i)
  {
    tmpIndex = t1[i];
    t1[i] = t2[i];
    t2[i] = tmpIndex;
  }

  tmpMat = LCR_renderer.mapTriangleData[index1];
  LCR_renderer.mapTriangleData[index1] = LCR_renderer.mapTriangleData[index2];
  LCR_renderer.mapTriangleData[index2] = tmpMat;
}

int _LCR_quadCoversTri(const S3L_Unit quad[8], const S3L_Unit tri[6])
{
  for (int i = 0; i < 3; ++i) // for each triangle point
  {
    int covered = 0;

    for (int j = 0; j < 3; ++j) // for each quad subtriangle
    {
      uint8_t winds = 0;

      for (int k = 0; k < 3; ++k) // for each subtriangle side
      {
         S3L_Unit w = // triangle winding
          (quad[(2 * (j + ((k + 1) % 3))) % 8 + 1] -
            quad[(2 * (j + k)) % 8 + 1]) *
          (tri[2 * i] - quad[(2 * (j + (k + 1) % 3)) % 8]) -
          (quad[(2 * (j + ((k + 1) % 3))) % 8] - quad[(2 * (j + k)) % 8])
          * (tri[2 * i + 1] - quad[(2 * (j + (k + 1) % 3)) % 8 + 1]);

         if (w > 0)
           winds |= 1;
         else if (w < 0)
           winds |= 2;
      }

      if (winds != 3) // no opposite winds?
      {
        covered = 1;
        break;
      }
    }

    if (!covered)
      return 0;
  }

  return 1;
}

/**
  Checks whether two triangles (and potenrially their neighbors) cover each
  other, in return values lowest bit means whether t1 is covered and the second
  lowest bit means whether t2 is covered.
*/
uint8_t _LCR_checkMapTriCover(const S3L_Index *t1,
  const S3L_Index *t2)
{
  if ((t1[0] == t2[0] || t1[0] == t2[1] || t1[0] == t2[2]) &&
    (t1[1] == t2[0] || t1[1] == t2[1] || t1[1] == t2[2]) &&
    (t1[2] == t2[0] || t1[2] == t2[1] || t1[2] == t2[2]))
    return 0x03;

  uint8_t result = 0;
  int plane = -1;
  S3L_Unit *vertices[6];

  for (int i = 0; i < 3; ++i)
  {
    vertices[i] = LCR_renderer.mapVerts + 3 * t1[i];
    vertices[3 + i] = LCR_renderer.mapVerts + 3 * t2[i];
  }

  for (int i = 0; i < 3; ++i)
    if (vertices[0][i] == vertices[1][i] && vertices[1][i] == vertices[2][i] &&
        vertices[2][i] == vertices[3][i] && vertices[3][i] == vertices[4][i] &&
        vertices[4][i] == vertices[5][i])
    {
      plane = i;
      break;
    }

  if (plane >= 0) // both triangles in the same plane => then do more checks
  {
    if (S3L_abs(vertices[0][0] - vertices[3][0]) +
        S3L_abs(vertices[0][1] - vertices[3][1]) +
        S3L_abs(vertices[0][2] - vertices[3][2]) >
        2 * LCR_RENDERER_UNIT)
      return 0; // quick manhattan distance bailout condition

    for (int j = 0; j < 2; ++j)
    {
      S3L_Unit points2D[14]; // tri1, quad (tri2 + 1 extra vert)

      int coordX = plane == 0 ? 1 : 0,
          coordY = plane == 2 ? 1 : 2;

      for (int i = 0; i < 3; ++i)
      {
        points2D[i * 2]         = vertices[i][coordX];
        points2D[i * 2 + 1]     = vertices[i][coordY];
        points2D[6 + i * 2]     = vertices[3 + i][coordX];
        points2D[6 + i * 2 + 1] = vertices[3 + i][coordY];
      }

      points2D[12] = (4 * points2D[6] + 3 * points2D[8] + points2D[10]) / 8;
      points2D[13] = (4 * points2D[7] + 3 * points2D[9] + points2D[11]) / 8;

      // first: does the triangle alone cover the other one?
      if (_LCR_quadCoversTri(points2D + 6,points2D))
        result |= 1 << j;
      else
      {
        // now check if this triangle along with a neighbor cover the other one

        S3L_Index *t3 = LCR_renderer.mapTris;

        for (int i = 0; i < LCR_renderer.mapModel->triangleCount; ++i)
        {
          uint8_t sharedVerts =
            (t3[0] == t2[0] || t3[0] == t2[1] || t3[0] == t2[2]) |
            ((t3[1] == t2[0] || t3[1] == t2[1] || t3[1] == t2[2]) << 1) |
            ((t3[2] == t2[0] || t3[2] == t2[1] || t3[2] == t2[2]) << 2);

          if (
            t3 != t1 && t3 != t2 &&
            (sharedVerts == 3 || sharedVerts == 5 || sharedVerts == 6) &&
            LCR_renderer.mapVerts[3 * t3[0] + plane] ==
            LCR_renderer.mapVerts[3 * t3[1] + plane] &&
            LCR_renderer.mapVerts[3 * t3[1] + plane] ==
            LCR_renderer.mapVerts[3 * t3[2] + plane] &&
            LCR_renderer.mapVerts[3 * t3[0] + plane] ==
            LCR_renderer.mapVerts[3 * t1[0] + plane]
            )
          {
            // here shares exactly two vertices and is in the same plane

            uint8_t freeVert =
              sharedVerts == 3 ? 2 : (sharedVerts == 5 ? 1 : 0);

            points2D[12] = LCR_renderer.mapVerts[3 * t3[freeVert] + coordX];
            points2D[13] = LCR_renderer.mapVerts[3 * t3[freeVert] + coordY];
           
            if (_LCR_quadCoversTri(points2D + 6,points2D))
            {
              result |= 1 << j;
              break;
            }
          }

          t3 += 3;
        }
      }

      // now swap both triangles and do it all again:

      const S3L_Index *tmp = t1;
      t1 = t2;
      t2 = tmp;

      for (int i = 0; i < 3; ++i)
      {
        S3L_Unit *tmpCoord = vertices[i];
        vertices[i] = vertices[3 + i];
        vertices[3 + i] = tmpCoord;
      }
    }
  }

  return result;
}

/**
  Removes map triangles that are covered by other triangles (and also vertices
  that by this become unused). This makes the map model smaller, faster and
  prevents bleeding through due to z-bugger imprecisions.
*/
void _LCR_cullHiddenMapTris(void)
{
  LCR_log("culling invisible triangles");

  int n = 0; // number of removed elements
  int i = 0;

  S3L_Index *t1 = LCR_renderer.mapTris, *t2;

  /*
    We'll be moving the covered triangles to the end of the array, then at the
    end we'll just shorten the array by number of removed triangles.
  */
  while (i < LCR_renderer.mapModel->triangleCount - n)
  {
    t2 = t1 + 3; // t2 is the the other triangle against which we check

    int t1Covered = 0;

    for (int j = i + 1; j < LCR_renderer.mapModel->triangleCount; ++j)
    {
      uint8_t cover = _LCR_checkMapTriCover(t1,t2);

      t1Covered |= cover & 0x01;

      if (cover & 0x02)
      {
        if (j < LCR_renderer.mapModel->triangleCount - n)
        {
          _LCR_swapMapTris(j,
            LCR_renderer.mapModel->triangleCount - 1 - n);

          n++;
        }
      }
 
      t2 += 3; // check next triangle
    }

    if (t1Covered)
    {
      _LCR_swapMapTris(i,
        LCR_renderer.mapModel->triangleCount - 1 - n);

      n++;
      // we stay at this position because we've swapped the triangle here
    }
    else
    {
      t1 += 3;
      i++;
    }
  }

  LCR_renderer.mapModel->triangleCount -= n; // cut off the removed triangles

  // remove unused vertices:

  i = 0;

  while (i < LCR_renderer.mapModel->vertexCount)
  {
    int used = 0;

    for (int j = 0; j < LCR_renderer.mapModel->triangleCount * 3; ++j)
      if (LCR_renderer.mapTris[j] == i)
      {
        used = 1;
        break;
      }

    if (used)
      i++;
    else
    {
      for (int j = 0; j < 3; ++j)
        LCR_renderer.mapVerts[3 * i + j] =
          LCR_renderer.mapVerts[(LCR_renderer.mapModel->vertexCount - 1) * 3 + j];

      for (int j = 0; j < LCR_renderer.mapModel->triangleCount * 3; ++j)
        if (LCR_renderer.mapTris[j] == LCR_renderer.mapModel->vertexCount - 1)
          LCR_renderer.mapTris[j] = i;

      LCR_renderer.mapModel->vertexCount--;
    }
  }
}

/**
  Builds the internal 3D model of the currently loaded map. Returns 1 on
  success, 0 otherwise (e.g. not enough space).
*/
uint8_t _LCR_buildMapModel(void)
{
  LCR_log("building map model");

  uint8_t blockShapeBytes[LCR_MAP_BLOCK_SHAPE_MAX_BYTES];
  uint8_t blockShapeByteCount;

  S3L_model3DInit(LCR_renderer.mapVerts,0,LCR_renderer.mapTris,0,LCR_renderer.mapModel);

  for (int j = 0; j < LCR_currentMap.blockCount; ++j)
  {
    if ((j + 1) % LCR_SETTING_TRIANGLE_CULLING_PERIOD == 0)
      _LCR_cullHiddenMapTris();

    S3L_Unit originOffset = -1 * LCR_MAP_SIZE_BLOCKS / 2 * LCR_RENDERER_UNIT;
    S3L_Index triIndices[3];
    const uint8_t *block = LCR_currentMap.blocks + j * LCR_BLOCK_SIZE;
    uint8_t
      blockType = block[0],
      edgeBits,   // bottom, top, left, right, front, bottom
      bx, by, bz, // block coords
      vx, vy, vz, // vertex coords
      vi = 0;     // vertex index (0, 1 or 2)

    LCR_mapBlockGetCoords(block,&bx,&by,&bz);

    LCR_mapGetBlockShape(blockType,LCR_mapBlockGetTransform(block),
      blockShapeBytes,&blockShapeByteCount);

    for (int i = 0; i < blockShapeByteCount; ++i)
    {
      if (vi == 0)
        edgeBits = (by == 0) |
          ((by == LCR_MAP_SIZE_BLOCKS - 1) << 1) |
          ((bx == 0) << 2) |
          ((bx == LCR_MAP_SIZE_BLOCKS - 1) << 3) |
          ((bz == 0) << 4) |
          ((bz == LCR_MAP_SIZE_BLOCKS - 1) << 5);

      LCR_decodeMapBlockCoords(blockShapeBytes[i],&vx,&vy,&vz);

      edgeBits &= (vy == 0) | ((vy == LCR_BLOCK_SHAPE_COORD_MAX) << 1) |
        ((vx == 0) << 2) | ((vx == LCR_BLOCK_SHAPE_COORD_MAX) << 3) |
        ((vz == 0) << 4) | ((vz == LCR_BLOCK_SHAPE_COORD_MAX) << 5);

      triIndices[vi] = _LCR_addMapVert(
        originOffset + (((S3L_Unit) bx) * LCR_RENDERER_UNIT) +
          (LCR_RENDERER_UNIT * ((S3L_Unit) vx)) / LCR_BLOCK_SHAPE_COORD_MAX,
        (originOffset + (((S3L_Unit) by) * LCR_RENDERER_UNIT)) / 2 +
          (LCR_RENDERER_UNIT / 2 * ((S3L_Unit) vy)) / LCR_BLOCK_SHAPE_COORD_MAX,
        originOffset + (((S3L_Unit) bz) * LCR_RENDERER_UNIT) +
          (LCR_RENDERER_UNIT * ((S3L_Unit) vz)) / LCR_BLOCK_SHAPE_COORD_MAX);

      if (vi < 2)
        vi++;
      else
      {
        // don't add triangles completely at the floor or ceiling of the map
        if (!edgeBits)
        {
#define VERT(n,c) LCR_renderer.mapVerts[3 * n + c]
          uint8_t blockMat = LCR_mapBlockGetMaterial(block);
          uint8_t triData =
            (((VERT(triIndices[0],0) == VERT(triIndices[1],0)) &&
            (VERT(triIndices[1],0) == VERT(triIndices[2],0))) << 4) |
            (((VERT(triIndices[0],2) == VERT(triIndices[1],2)) &&
            (VERT(triIndices[1],2) == VERT(triIndices[2],2))) << 5);
#undef VERT

          if (triData & 0xf0) // wall?
          {
            triData |= 
              ((blockMat == LCR_BLOCK_MATERIAL_CONCRETE) ||
              (blockMat == LCR_BLOCK_MATERIAL_ICE) ||
              (blockType == LCR_BLOCK_FULL_ACCEL) ||
              (blockType == LCR_BLOCK_FULL_STICKER)) ?
              LCR_IMAGE_WALL_CONCRETE : LCR_IMAGE_WALL_WOOD;
          }
          else
          { // TODO: tidy this mess?
            if (blockType == LCR_BLOCK_FULL_ACCEL)
              triData |= LCR_IMAGE_GROUND_ACCEL;
            else if (blockType == LCR_BLOCK_FULL_STICKER)
              triData |= LCR_IMAGE_GROUND_STICKER;
            else
              switch (blockMat)
              {
                case LCR_BLOCK_MATERIAL_CONCRETE:
                  triData |= LCR_IMAGE_GROUND_CONCRETE;
                  break;

                case LCR_BLOCK_MATERIAL_GRASS:
                  triData |= LCR_IMAGE_GROUND_GRASS;
                  break;

                case LCR_BLOCK_MATERIAL_DIRT:
                  triData |= LCR_IMAGE_GROUND_DIRT;
                  break;

                case LCR_BLOCK_MATERIAL_ICE:
                  triData |= LCR_IMAGE_GROUND_ICE;
                  break;

                default:
                  break;
              }
          }

          _LCR_addMapTri(triIndices[0],triIndices[1],triIndices[2],triData);
        }      
     
        vi = 0;
      }
    }
  }

  // TODO: also cull the triangles in the loop by some N steps

  _LCR_cullHiddenMapTris();

  LCR_log("map model built");

  return 1;
}

uint8_t LCR_rendererInit(void)
{
  LCR_log("initializing renderer");

  LCR_renderer.mapModel = LCR_renderer.models;

  if (!_LCR_buildMapModel())
    return 0;

  S3L_sceneInit(LCR_renderer.models,1,&LCR_renderer.scene);

  return 1;
}

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

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

  LCR_renderer.scene.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_renderer.scene.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_renderer.scene.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_renderer.scene.camera.transform.rotation.y +=
    (yawPitchOffset[0] * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;
  
  LCR_renderer.scene.camera.transform.rotation.x +=
    (yawPitchOffset[1] * S3L_FRACTIONS_PER_UNIT) / LCR_SQUARE_SIDE_LEN;

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

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

/**
  Draws background sky, offsets are in multiples of screen dimensions
  (e.g. S3L_FRACTIONS_PER_UNIT / 2 for offsetH means half the screen width).
*/
void LCR_rendererDrawSky(int sky, S3L_Unit offsetH, S3L_Unit offsetV)
{
  int anchorPoint[2], y;
  unsigned long pixelIndex;
  unsigned int topColor, bottomColor;

  sky = 8 + 4 * sky;

  LCR_loadImage(sky);
  topColor = LCR_sampleImage(0,0);

  LCR_loadImage(sky + 3);
  bottomColor = LCR_sampleImage(LCR_IMAGE_SIZE - 1,LCR_IMAGE_SIZE - 1);

  anchorPoint[0] = ((LCR_EFFECTIVE_RESOLUTION_X * offsetH)
    / S3L_FRACTIONS_PER_UNIT) %
    (2 * LCR_IMAGE_SIZE * LCR_SETTING_SKY_SIZE);

  if (anchorPoint[0] < 0)
    anchorPoint[0] += 2 * LCR_IMAGE_SIZE * LCR_SETTING_SKY_SIZE;

  anchorPoint[1] = 
    (LCR_EFFECTIVE_RESOLUTION_Y) / 3 - // 3: we place the center a bit more up
    (LCR_EFFECTIVE_RESOLUTION_Y * offsetV) / S3L_FRACTIONS_PER_UNIT
    - LCR_IMAGE_SIZE * LCR_SETTING_SKY_SIZE;
  
  pixelIndex = 0;
  y = anchorPoint[1] < 0 ? anchorPoint[1] : 0;

  while (y < anchorPoint[1] && y < LCR_EFFECTIVE_RESOLUTION_Y) // top strip
  {
    for (int x = 0; x < LCR_EFFECTIVE_RESOLUTION_X; ++x)
    {
      LCR_drawPixel(pixelIndex,topColor);
      pixelIndex++;
    }

    y++;
  }

  anchorPoint[1] += 2 * LCR_IMAGE_SIZE * LCR_SETTING_SKY_SIZE;
    
  int linesLeft = 0;
  int skyPart = 0;

  while (y < anchorPoint[1] && y < LCR_EFFECTIVE_RESOLUTION_Y) // image strip
  {
    if (!linesLeft)
    {
      LCR_loadImage(sky + skyPart);
      linesLeft = LCR_IMAGE_SIZE / 2;
      skyPart++;
    }

    if (y >= 0)
    {
      for (int ix = 0; ix < 2 * LCR_IMAGE_SIZE * LCR_SETTING_SKY_SIZE;
        ix += LCR_SETTING_SKY_SIZE)
      {
        unsigned int color = LCR_getNextImagePixel();
        unsigned long startIndex = pixelIndex;

        for (int k = 0; k < LCR_SETTING_SKY_SIZE; ++k)
        {
          if (y + k >= LCR_EFFECTIVE_RESOLUTION_Y)
            break;

          for (int j = 0; j < LCR_SETTING_SKY_SIZE; ++j)
          {
            int x = anchorPoint[0] + ix + j;

            if (x >= 2 * LCR_IMAGE_SIZE * LCR_SETTING_SKY_SIZE)
              x -= 2 * LCR_IMAGE_SIZE * LCR_SETTING_SKY_SIZE;

            while (x < LCR_EFFECTIVE_RESOLUTION_X)
            {
              LCR_drawPixel(startIndex + x,color);
              x += 2 * LCR_IMAGE_SIZE * LCR_SETTING_SKY_SIZE;
            }
          }

          startIndex += LCR_EFFECTIVE_RESOLUTION_X;
        }
      }
    
      pixelIndex += LCR_EFFECTIVE_RESOLUTION_X * LCR_SETTING_SKY_SIZE;
      y += LCR_SETTING_SKY_SIZE;
    }
    else
    {
      for (int ix = 0; ix < 2 * LCR_IMAGE_SIZE; ++ix)
        LCR_getNextImagePixel();
   
      for (int i = 0; i < LCR_SETTING_SKY_SIZE; ++i)
      {
        if (y >= 0)
          for (int x = 0; x < LCR_EFFECTIVE_RESOLUTION_X; ++x)
          {
            LCR_drawPixel(pixelIndex,topColor);
            pixelIndex++;
          }

        y++;
      }
    }

    linesLeft--;
  }

  while (y < 0) // can still be the case
    y = 0;

  while (y < LCR_EFFECTIVE_RESOLUTION_Y) // bottom strip
  {
    for (int x = 0; x < LCR_EFFECTIVE_RESOLUTION_X; ++x)
    {
      LCR_drawPixel(pixelIndex,bottomColor);
      pixelIndex++;
    }

    y++;
  }
}

void LCR_rendererDraw(void)
{
  LCR_renderer.previousTriID = -1;
  S3L_newFrame();

  LCR_rendererDrawSky(2,
    LCR_renderer.scene.camera.transform.rotation.y,
    -4 * LCR_renderer.scene.camera.transform.rotation.x);

  S3L_drawScene(LCR_renderer.scene);
}

#endif // guard