World Grid

Dimensions

The world has 200×200 cells (40 000 cells total). Internally stored as Cellule m_decor[100][100] — accessed via m_decor[x/2][y/2].

Viewport (Visible Area)

m_celCoin holds the cell corresponding to the top-left of the viewport (scroll position). m_celHome holds the default "Home key" position.

Isometric Projection

Planet Blupi uses a "diamond" isometric view:

Viewed from above (schematic):

           N (north)
           ^
    NW     |     NE
      \    |    /
       \   |   /
        \  |  /
    W ---(-+-)--- E
        /  |  \
       /   |   \
      /    |    \
    SW     |     SE
           v
           S (south)

Grid axis X points south-east (E), grid axis Y points south-west (S).

Coordinate Conversion

Cell → Pixel (ConvCelToPos)

POINT CDecor::ConvCelToPos(POINT cel) {
    POINT pos;
    pos.x = (cel.x - m_celCoin.x) * DIMCELX/2
          - (cel.y - m_celCoin.y) * DIMCELX/2
          + POSDRAWX + DIMDRAWX/2;
    pos.y = (cel.x - m_celCoin.x) * DIMCELY/2
          + (cel.y - m_celCoin.y) * DIMCELY/2
          + POSDRAWY;
    return pos;
}

Pixel → Cell (ConvPosToCel)

POINT CDecor::ConvPosToCel(POINT pos, BOOL bMap) {
    // Inverse of ConvCelToPos
    // bMap=TRUE: conversion for minimap clicks
    int relX = pos.x - POSDRAWX - DIMDRAWX/2;
    int relY = pos.y - POSDRAWY;
    // (approximate integer arithmetic)
    cel.x = m_celCoin.x + (relX + relY*2) / DIMCELX;
    cel.y = m_celCoin.y + (relY*2 - relX) / DIMCELX;
    return cel;
}

ConvPosToCel2(pos) — alternative more precise conversion used in the editor.

Cell Validation

BOOL IsValid(POINT cel) {
    return (cel.x >= 0 && cel.x < MAXCELX &&
            cel.y >= 0 && cel.y < MAXCELY);
}

Scrolling

Scrolling happens by moving the mouse to the screen edge: - Cursor sprites SPRITE_ARROWU/D/L/R/UL/UR/DL/DR indicate scroll direction - m_celCoin is incremented / decremented by cell steps - Minimum: (0, 0), maximum: (MAXCELX − visible, MAXCELY − visible)

Saved camera positions (m_memoPos[4]) are assigned via Shift+F5–F8, recalled via F5–F8.

Coordinate Helper Functions

POINT GetCel(int x, int y);               // create POINT{x, y}
POINT GetCel(POINT cel, int dx, int dy);  // cel + (dx, dy) cell offset
POINT GetVector(int direct);              // convert DIRECT_* → (dx, dy) vector

GetVector — Direction Vectors