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OpenGL纹理投影穿过曲面

projection textures opengl python

Resindra Aji · 技术社区 · 7 年前

我是新来的,我也是openGL新手。我想开发一种查看器,加载.ply文件,图像作为纹理,并将其投影到网格。我想问一下纹理投影。加载纹理和设置纹理投影的代码如下所示:

def loadTexture():
   # load the image
   imdata = 0
   imname = 'Cropped_Image26904_2.jpg'
   texture = glGenTextures(1)
   im = cv2.imread(imname)
   imdata = cv2.cvtColor(im, cv2.COLOR_BGR2RGB)
   # bind texture
   glBindTexture(GL_TEXTURE_2D, texture)
   glTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, imdata.shape[1],
   imdata.shape[0], 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, imdata)
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, 
   GL_CLAMP_TO_BORDER)
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, 
   GL_CLAMP_TO_BORDER)
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, 
   GL_CLAMP_TO_BORDER)
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, 
   GL_CLAMP_TO_BORDER)
   gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGB, imdata.shape[1], 
   imdata.shape[0], GL_RGB, GL_UNSIGNED_BYTE, imdata)
   # set the 'projector' location that project the texture
   glMatrixMode(GL_PROJECTION)
   glPushMatrix()
   glLoadIdentity()
   gluPerspective(fov, 
   float(glutGet(GLUT_WINDOW_WIDTH))/glutGet(GLUT_WINDOW_HEIGHT), .1, 
   1e8)
   gluLookAt(0,0,1, 0,0,0, 0,1,0)
   mat3 = glGetFloatv(GL_PROJECTION_MATRIX)
   # mapping the texture
   glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR)
   glTexGenfv(GL_S, GL_EYE_PLANE, mat3[0])
   glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR)
   glTexGenfv(GL_T, GL_EYE_PLANE, mat3[1])
   glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR)
   glTexGenfv(GL_R, GL_EYE_PLANE, mat3[2])
   glTexGeni(GL_Q, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR)
   glTexGenfv(GL_Q, GL_EYE_PLANE, mat3[3])
   # enable the texture
   glEnable(GL_TEXTURE_2D)
   glEnable(GL_TEXTURE_GEN_S)
   glEnable(GL_TEXTURE_GEN_T)
   glEnable(GL_TEXTURE_GEN_R)
   glEnable(GL_TEXTURE_GEN_Q)

The viewer form front. The pink ball is the 'projector' position

问题是,投影纹理穿过了长方体,并且在长方体的背面留下了一个投影: The texture also projected to the backside of the cube

所以,问题是,如何使纹理的投影只出现在“投影仪”可见的脸上?非常感谢你。