OpenGL对象没有照明答案

【问题标题】：OpenGL object no lightingOpenGL对象没有照明
【发布时间】：2018-08-19 09:21:22
【问题描述】：

我无法让我的模型正确点亮。我正在制作一个由小立方体/体素组成的物体，并且所有侧面都具有相同的光强度。我正在用 Python 编写代码并将 numpy 用于数组。我的点数组是三角形角点的平面/一维数组。我的法线数组是每个三角形的法线 3d 向量的平面/一维数组。

下面的代码在一个初始化过程中：

# ===============================================
# First add points to buffer
# ===============================================
points = numpy.array(points,dtype=numpy.float32)
points=points * scale
self.voxelPtBufferLen = len(points) // 3

glEnableClientState(GL_VERTEX_ARRAY)
self.voxelPtBufferIdx = glGenBuffers(1)
dataSizePt = arrays.ArrayDatatype.arrayByteCount(points)

# print ("datasize",dataSize)
glBindBuffer(GL_ARRAY_BUFFER, self.voxelPtBufferIdx)
glBufferData(GL_ARRAY_BUFFER, dataSizePt, points, GL_STATIC_DRAW)

glDisableClientState(GL_VERTEX_ARRAY)

# ===============================================
# Second add normals for each triangle to buffer
# ===============================================
normals = numpy.array(normals, dtype=numpy.float32)
self.voxelNmBufferLen = len(normals)

glEnableClientState(GL_NORMAL_ARRAY)
self.voxelNmBufferIdx = glGenBuffers(1)
dataSizeNm = arrays.ArrayDatatype.arrayByteCount(normals)

glBindBuffer(GL_ARRAY_BUFFER, self.voxelNmBufferIdx)
glBufferData(GL_ARRAY_BUFFER, dataSizeNm, normals, GL_STATIC_DRAW)

glDisableClientState(GL_NORMAL_ARRAY)

然后绘制这个我有以下代码

colorFront = (0.1, 0.3, 0.6)
colorBack = (1, 0.3, 0.3)
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, (0.2, 0.2, 0.2))
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, (0.8, 0.8, 1.0))
glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, 50.0)

glEnable(GL_DEPTH_TEST)
glEnable(GL_NORMALIZE)


glLight(GL_LIGHT1, GL_AMBIENT, (0.3, 0.0, 0.0, 1))
glLight(GL_LIGHT1, GL_DIFFUSE, (0.6, 0.0, 0.0, 1))
glLight(GL_LIGHT1, GL_SPECULAR, (0.9, 0.0, 0.0, 1))
glLight(GL_LIGHT1, GL_POSITION, (10,10,10))
glLight(GL_LIGHT1, GL_SPOT_DIRECTION, (-10,-10,-10))
glEnable(GL_LIGHT1)

glBegin(GL_QUADS)
glColor3f(1.0,1.0,0)
glVertex3f(10, 10, 10)
glVertex3f(12, 12, 12)
glVertex3f(10, 12, 12)
glVertex3f(12, 10, 12)
glEnd()

glPolygonMode(GL_FRONT_AND_BACK, GL_FILL)
glColor3fv(colorFront)

# DRAW VOXELS
glEnableClientState(GL_VERTEX_ARRAY)
glBindBuffer(GL_ARRAY_BUFFER, self.voxelPtBufferIdx)
glVertexPointer(3,GL_FLOAT,0,None)

glEnableClientState(GL_NORMAL_ARRAY)
glBindBuffer(GL_ARRAY_BUFFER, self.voxelNmBufferIdx)
glNormalPointer(GL_FLOAT, 0, 0)

glDrawArrays(GL_TRIANGLES, 0, self.voxelPtBufferLen)

glDisableClientState(GL_VERTEX_ARRAY)
glDisableClientState(GL_NORMAL_ARRAY)

【问题讨论】：

标签： python opengl buffer light normals

【解决方案1】：

主要问题是您必须启用光照。见glEnable：

glEnable(GL_LIGHTING)

启用照明后，网格的颜色由材质参数 (glMaterial) 决定。另见Basic OpenGL Lighting。

您没有设置环境材质参数 (GL_AMBIENT) 和漫反射材质参数 (GL_DIFFUSE) 似乎很弱。尝试类似：

glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, (0.3, 0.3, 0.3))
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, (1.0, 1.0, 1.0))

【讨论】：