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我想用opengl来制作等距图纸。使用Opengl的等距投影
据: http://en.wikipedia.org/wiki/Isometric_projection#Mathematics
“,这是通过首先寻找直朝向一个面进行下一步立方体旋转±45°围绕竖直轴线,随后的约±35.264°的旋转(准确地说反正弦。 (tan 30°)或arctan(sin 45°))。“
但很显然我错过了一些细节。这种代码虽然有些作品,但它却处于一个奇怪的角度。黄色应该是最底线。
import Graphics.UI.GLFW
import Graphics.Rendering.OpenGL
main :: IO()
main = do
initialize
openWindow (Size 800 600) [] Window
windowTitle $= "Test Projection"
clearColor $= Color4 0 0 0 1
pointSize $= 3
lineWidth $= 1
blend $= Enabled
blendFunc $= (SrcAlpha, OneMinusSrcAlpha)
viewport $= (Position 0 0, Size 800 600)
matrixMode $= Projection
loadIdentity
-- ortho (-2) (2) (-2) 2 (-20.0) 20.0
matrixMode $= Modelview 0
loadIdentity
rotate (35.264) (Vector3 1.0 0.0 0.0 :: Vector3 GLfloat)
rotate (-45) (Vector3 0.0 1.0 0.0 :: Vector3 GLfloat)
clear [ColorBuffer]
renderPrimitive Lines $ do
color $ Color3 1 zero zero
vertex' (0,0,0)
vertex' (1,0,0)
color $ Color3 zero 1 zero
vertex' (0,0,0)
vertex' (0,1,0)
color $ Color3 zero zero 1
vertex' (0,0,0)
vertex' (0,0,1)
color $ Color3 1 1 zero
vertex' (1,0,0)
vertex' (0,1,0)
swapBuffers
getChar
return()
vertex' :: Integral a => (a, a, a) -> IO()
vertex' (x, y, z) = vertex (Vertex3 (f x) (f y) (f z))
where f p = fromIntegral p :: GLint
zero :: GLfloat
zero = 0.0
谢谢了。事情现在变得更有意义。 – user1149863 2012-01-15 00:16:37
事实上,我昨晚一直熬到昨天晚上想弄清楚我做错了什么。 – user1149863 2012-01-15 00:18:12