Function oldCastLight

tests/shadowcasting_test.cpp:26–79

NOLINTNEXTLINE(cata-xy)

// NOLINTNEXTLINE(cata-xy)
static void oldCastLight( float ( &output_cache )[MAPSIZE * SEEX][MAPSIZE * SEEY],
                          const float ( &input_array )[MAPSIZE * SEEX][MAPSIZE * SEEY],
                          const int xx, const int xy, const int yx, const int yy,
                          const int offsetX, const int offsetY, const int offsetDistance,
                          const int row = 1, float start = 1.0f, const float end = 0.0f )
{

    float newStart = 0.0f;
    const float radius = 60.0f - offsetDistance;
    if( start < end ) {
        return;
    }
    bool blocked = false;
    tripoint delta;
    for( int distance = row; distance <= radius && !blocked; distance++ ) {
        delta.y = -distance;
        for( delta.x = -distance; delta.x <= 0; delta.x++ ) {
            const point current( offsetX + delta.x * xx + delta.y * xy, offsetY + delta.x * yx + delta.y * yy );
            const float leftSlope = ( delta.x - 0.5f ) / ( delta.y + 0.5f );
            const float rightSlope = ( delta.x + 0.5f ) / ( delta.y - 0.5f );

            if( start < rightSlope ) {
                continue;
            } else if( end > leftSlope ) {
                break;
            }

            //check if it's within the visible area and mark visible if so
            if( rl_dist( tripoint_zero, delta ) <= radius ) {
                output_cache[current.x][current.y] = VISIBILITY_FULL;
            }

            if( blocked ) {
                //previous cell was a blocking one
                if( input_array[current.x][current.y] == LIGHT_TRANSPARENCY_SOLID ) {
                    //hit a wall
                    newStart = rightSlope;
                } else {
                    blocked = false;
                    start = newStart;
                }
            } else {
                if( input_array[current.x][current.y] == LIGHT_TRANSPARENCY_SOLID &&
                    distance < radius ) {
                    //hit a wall within sight line
                    blocked = true;
                    oldCastLight( output_cache, input_array, xx, xy, yx, yy,
                                  offsetX, offsetY, offsetDistance,  distance + 1, start, leftSlope );
                    newStart = rightSlope;
                }
            }
        }
    }
}

/*
 * This is checking whether bresenham visibility checks match shadowcasting (they don't).