所以我对 Lua 相当陌生,在其他语言中我已经能够创建一个 2D 变量数组并简单地通过该数组进行索引以创建一个平铺地图。每当我在 lua 中尝试这个时,我都会收到一个错误(特别是一个错误,指出我正在索引一个 nil 值)。我怎样才能解决这个问题?
function love.load()
love.graphics.setColor(255,255,0)
tile = love.graphics.newImage("lightGrass.png")
map = { {1,1,0,0,0,0,0,0,0,0},
{0,1,0,0,0,0,0,0,0,0},
{0,1,0,0,0,0,0,0,0,0},
{1,1,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,0,0,0,0,0,0}
}
end
function love.draw()
for i = 0, 10 do
for j = 0, 10 do
newPos = map[i][j]
if newPos == 0 then -- this is where the error is!!!!!!!!!!!!!!!
love.graphics.draw(tile,j * 32, i * 32)
end
end
end
end
function love.update(dt)
end
Run Code Online (Sandbox Code Playgroud) 我正在尝试为我的游戏做一些计算,我正在尝试计算两点之间的距离.基本上,我正在使用圆的方程来查看这些点是否在我定义的半径范围内.
(x - x1)^2 + (y - y1)^2 <= r^2
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我的问题是:如何用SSE评估条件语句并解释结果?到目前为止我有这个:
float distSqr4 = (pow(x4 - k->getPosition().x, 2) + pow(y4 - k->getPosition().y, 2));
float distSqr3 = (pow(x3 - k->getPosition().x, 2) + pow(y3 - k->getPosition().y, 2));
float distSqr2 = (pow(x2 - k->getPosition().x, 2) + pow(y2 - k->getPosition().y, 2));
float distSqr1 = (pow(x1 - k->getPosition().x, 2) + pow(y1 - k->getPosition().y, 2));
__m128 distances = _mm_set_ps(distSqr1, distSqr2, distSqr3, distSqr4);
__m128 maxDistSqr = _mm_set1_ps(k->getMaxDistance() * k->getMaxDistance());
__m128 result = _mm_cmple_ps(distances, maxDistSqr);
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一旦我得到结果变量,我就迷路了.我如何使用刚刚得到的结果变量?我的计划是,如果评估的条件证明是真的,做一些光照计算,然后在屏幕上绘制像素.在这种情况下,我如何解释真实与虚假?
任何有关正确方向的帮助都非常感谢!
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