void project(float x, float y, float z, int* dx, int *dy) {
        *dx = x * (TILE_W/2) - y * (TILE_W/2);
        *dy = x * (TILE_H/2) + y * (TILE_H/2) - z;
    }
    void invProject(float x, float y, float z, int* dx, int* dy) {
        float tw = TILE_W/2, th = TILE_H/2;
        *dx = x / tw + ((y + z) / th - x / tw) / 2;
        *dy = ((y + z) / th - x / tw) / 2;
    }