OpenGL python绘图圈缺少一些细节吗？

问题描述

我实现了一个绘制圆形功能，差不多完成了，但这是这样的：

def drawCicrcle(x,y,z,radius,numSides):
    numVertices = numSides + 2
    doublePi = 2.0 * math.pi
    circLeverticesX = np.array([],dtype='f')
    circLeverticesY = np.array([],dtype='f')
    circLeverticesZ = np.array([],dtype='f')

    circLeverticesX = np.insert(circLeverticesX,x)
    circLeverticesY = np.insert(circLeverticesX,y)
    circLeverticesZ = np.insert(circLeverticesX,z)


    for i in range(1,numVertices):
        circLeverticesX = np.append(
            circLeverticesX,x + (radius * math.cos(i * doublePi / numSides)))
        circLeverticesY = np.append(
            circLeverticesY,y + (radius * math.sin(i * doublePi / numSides)))
        circLeverticesZ = np.append(circLeverticesZ,z)

    allCircLevertices = np.array([],dtype='f')

    for i in range(0,numVertices):
        allCircLevertices = np.insert(
            allCircLevertices,i*3,circLeverticesX[i])
        allCircLevertices = np.insert(
            allCircLevertices,(i*3) + 1,circLeverticesY[i])
        allCircLevertices = np.insert(
            allCircLevertices,(i*3) + 2,circLeverticesZ[i])

    vboc = glGenBuffers(1)
    glBindBuffer(GL_ARRAY_BUFFER,vboc)
    glBufferData(GL_ARRAY_BUFFER,allCircLevertices,GL_STATIC_DRAW)
    glVertexAttribPointer(0,3,GL_FLOAT,False,sizeof(ctypes.c_float)*9,ctypes.c_void_p(36))
    glDrawArrays(GL_TRIANGLE_FAN,numVertices)

然后我拨打我的主drawCicrcle(-0.5,0.5,0.0,0.18,360) 我想念什么？

解决方法

circleVerticesX = np.array([numVertices],dtype='f')并没有达到您的期望。它会创建一个 numpy 数组，其中的单个元素的值为numVertices（请参见numpy.array）。

使用顶点坐标创建一个列表，并从该列表创建一个numpy数组：

vertex_list = [...]
# [...]

allCircleVertices = np.array([vertex_list],dtype='f')

功能drawCicrcle：

def drawCicrcle(x,y,z,radius,numSides):
    numVertices = numSides + 2
    doublePi = 2.0 * math.pi

    vertex_list = [x,z]
    for i in range(1,numVertices):
        vertex_list.append(x + (radius * math.cos(i * doublePi / numSides)))
        vertex_list.append(y + (radius * math.sin(i * doublePi / numSides)))
        vertex_list.append(z)
    allCircleVertices = np.array([vertex_list],dtype='f')

    vboc = glGenBuffers(1)
    glBindBuffer(GL_ARRAY_BUFFER,vboc)
    glBufferData(GL_ARRAY_BUFFER,allCircleVertices,GL_STATIC_DRAW)
    glVertexAttribPointer(0,3,GL_FLOAT,False,3*sizeof(ctypes.c_float),ctypes.c_void_p(0))
    glDrawArrays(GL_TRIANGLE_FAN,numVertices)

---

或者使用numVertices*3个元素（参见numpy.empty）创建一个空的 numpy 数组，并将顶点坐标分配给该数组的字段：

allCircleVertices = np.array([vertex_list],dtype='f')

allCircleVertices[0:3] = [x,z]
# [...]

功能drawCicrcle：

def drawCicrcle(x,numSides):
    numVertices = numSides + 2
    doublePi = 2.0 * math.pi

    allCircleVertices = np.empty((numVertices*3),dtype='f')
    allCircleVertices[0:3] = [x,numVertices):
        vx = x + (radius * math.cos(i * doublePi / numSides))
        vy = y + (radius * math.sin(i * doublePi / numSides))
        allCircleVertices[i*3:i*3+3] = [vx,vy,z]

    vboc = glGenBuffers(1)
    glBindBuffer(GL_ARRAY_BUFFER,numVertices)

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