Tile Grid

Snapping objects to a grid, or just visualizing a regular layout on screen for debugging, doesn't need the full weight of a real TileMap with its textures and physics.

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Overview

TileGrid is contained in the header "remake2d/tilegrid.hpp". It only computes and stores the Area of each cell in a grid, given a center, a size, and a number of divisions, without carrying any texture or physics data.

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Methods

void move(const Vec2d&)   noexcept; // move grid center
void cut(const Grid2d&)   noexcept; // change grid divisions
void resize(const Dim2d&) noexcept; // resize grid

usize  count(void)              const noexcept; // total number of cells
Dim2d  size(void)               const noexcept; // grid size
Grid2d cut(void)                const noexcept; // current grid divisions
Vec2d  center(void)             const noexcept; // grid center
Area   cell(const Grid2d&)      const noexcept; // get a specific cell area by (col, row)
std::vector<Area> cells(void)   const noexcept; // get all cell areas

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Usage

Creating a grid

The constructor takes a center, a size, and a Grid2d defining the number of columns and rows:

Grid2d(const Vec2d&, const Dim2d&, const Grid2d&);

rmk::TileGrid grid({400, 300}, {800, 600}, {8, 6});

Drawing a grid

Like any Geometry, TileGrid draws directly through Window::draw, handy for visualizing an alignment during development:

// In render loop
win.draw(grid, rmk::color::gray);

#include <remake2d/window.hpp>
#include <remake2d/loop.hpp>
#include <remake2d/tilegrid.hpp>

int main(void) {
    rmk::Window win;
    rmk::TileGrid grid({400, 300}, {800, 600}, {8, 6});

    rmk::loop.execute(win, [&](void) {
        win.draw(grid, rmk::color::gray);
    });

    rmk::loop.update();
}

Retrieving cells

Finding which cell the mouse is in, or iterating the whole grid, works by (col, row) coordinate, or by grabbing everything at once:

rmk::Area cell = grid.cell({2, 1}); // 3rd column, 2nd row
std::vector<rmk::Area> all = grid.cells();

Info

Count returns cut.x * cut.y, the total number of cells in the grid.

Modifying a grid

Move, cut and resize all rebuild the internal cell cache automatically, no manual recalculation needed:

grid.move({500, 300});
grid.cut({10, 8});
grid.resize({1000, 700});

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