如何从Pyopengl中的3-D numpy数组创建曲面？

问题描述 投票：1回答：1

我创建了一个由X，Y和Z轴坐标组成的3-d numpy数组。现在，我正在尝试使用opengl中的这些点来创建曲面，但我成功完成的工作就是在model下创建线模型。谁能建议我对代码进行更改以根据数据形成实际的3D表面？数据文件使用链接https://drive.google.com/open?id=1PWbNIt3xbchtQ9HIIS96k7ZjblzPO_wO

代码：-

import OpenGL.GL as gl
import OpenGL.arrays.vbo as glvbo
from PyQt5.Qt import *
import numpy as np
import Backend_algo as Sb
import sys
import ctypes


def compile_vertex_shader(source):
    """Compile a vertex shader from source."""
    vertex_shader = gl.glCreateShader(gl.GL_VERTEX_SHADER)
    gl.glShaderSource(vertex_shader, source)
    gl.glCompileShader(vertex_shader)
    # check compilation error
    result = gl.glGetShaderiv(vertex_shader, gl.GL_COMPILE_STATUS)
    if not (result):
        raise RuntimeError(gl.glGetShaderInfoLog(vertex_shader))
    return vertex_shader


def compile_fragment_shader(source):
    """Compile a fragment shader from source."""
    fragment_shader = gl.glCreateShader(gl.GL_FRAGMENT_SHADER)
    gl.glShaderSource(fragment_shader, source)
    gl.glCompileShader(fragment_shader)
    result = gl.glGetShaderiv(fragment_shader, gl.GL_COMPILE_STATUS)
    if not (result):
        raise RuntimeError(gl.glGetShaderInfoLog(fragment_shader))
    return fragment_shader


def link_shader_program(vertex_shader, fragment_shader):
    """Create a shader program with from compiled shaders."""
    program = gl.glCreateProgram()
    gl.glAttachShader(program, vertex_shader)
    gl.glAttachShader(program, fragment_shader)
    gl.glLinkProgram(program)

    result = gl.glGetProgramiv(program, gl.GL_LINK_STATUS)
    if not (result):
        raise RuntimeError(gl.glGetProgramInfoLog(program))
    return program


VS = '''

attribute vec3 position;


uniform float right;
uniform float bottom;
uniform float left;
uniform float top;
uniform float far;
uniform float near;

void main() {

    mat4 testmat = mat4(
            vec4(2.0 / (right - left), 0, 0, 0),
            vec4(0, 2.0 / (top - bottom), 0, 0),
            vec4(0, 0, -2.0 / (far - near), 0),
            vec4(-(right + left) / (right - left), -(top + bottom) / (top - bottom), -(far + near) / (far - near), 1)
    );

    gl_Position = testmat * vec4(position, 1.);

}

'''
FS = '''
#version 450
// Output variable of the fragment shader, which is a 4D vector containing the
// RGBA components of the pixel color.
uniform vec3 triangleColor;
out vec4 outColor;

void main()
{
    outColor = vec4(triangleColor, 1.0);
}
'''


class GLPlotWidget3D(QGLWidget):

    def __init__(self, *args):
        # QGLWidget.__init__(self)
        super(GLPlotWidget3D, self).__init__()
        # self.parent = args[0]
        self.width, self.height = 100, 100
        self.right, self.left, self.top, self.bottom = 21000, -21000, 10, -10
        self.data = np.zeros((3, 10, 2))
        self.vbo = glvbo.VBO(self.data)

        self.showMaximized()

    def initializeGL(self):
        vs = Sb.compile_vertex_shader(VS)
        fs = Sb.compile_fragment_shader(FS)
        self.shaders_program = link_shader_program(vs, fs)
        self.e = np.load(('three.npy'), mmap_mode='r')
        self.e = np.array(self.e, dtype=np.float32)

        self.right, self.left, self.top, self.bottom, self.far, self.near = self.e[:, :, 1].min(), self.e[:, : , 1].max(), self.e[:, : , 0].min(), self.e[:, : , 0].max(), self.e[:, : , 2].max(), self.e[:, : , 2].min()

    def ortho_view(self):
        right = gl.glGetUniformLocation(self.shaders_program, "right")
        gl.glUniform1f(right, self.right)

        left = gl.glGetUniformLocation(self.shaders_program, "left")
        gl.glUniform1f(left, self.left)

        top = gl.glGetUniformLocation(self.shaders_program, "top")
        gl.glUniform1f(top, self.top)

        bottom = gl.glGetUniformLocation(self.shaders_program, "bottom")
        gl.glUniform1f(bottom, self.bottom)

        far = gl.glGetUniformLocation(self.shaders_program, "far")
        gl.glUniform1f(far, self.far)

        near = gl.glGetUniformLocation(self.shaders_program, "near")
        gl.glUniform1f(near, self.near)


    def paintGL(self):
        self.resizeGL(self.width, self.height)
        gl.glClearColor(0.2, 0.2, 0.2, 0)
        gl.glClear(gl.GL_COLOR_BUFFER_BIT)
        gl.glUseProgram(self.shaders_program)

        buffer = gl.glGenBuffers(1)

        gl.glBindBuffer(gl.GL_ARRAY_BUFFER, buffer)
        stride = self.e.strides[0]
        offset = ctypes.c_void_p(1)
        loc = gl.glGetAttribLocation(self.shaders_program, "position")
        gl.glEnableVertexAttribArray(loc)
        gl.glVertexAttribPointer(loc, 3, gl.GL_FLOAT, False, stride, offset)
        gl.glBufferData(gl.GL_ARRAY_BUFFER, self.e.nbytes, self.e, gl.GL_DYNAMIC_DRAW)

        gl.glDrawArrays(gl.GL_LINE_LOOP, 0, self.e.shape[0])

        self.ortho_view()
        uni_color = gl.glGetUniformLocation(self.shaders_program, "triangleColor")
        gl.glUniform3f(uni_color, 0.9, 0.9, 0.9)


    def resizeGL(self, width, height):
        self.width, self.height = width, height
        gl.glViewport(0, 0, width, height)


def main():
    app = QApplication(sys.argv)
    editor = GLPlotWidget3D()
    editor.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()
python-3.x numpy pyqt5 pyopengl python-moderngl
1个回答
1
投票

'three.npy'包含一个3维数组（7782 x 24 x3），具有管的顶点坐标。尺寸为3的第3维包含顶点的x，y和z坐标。顶点以7782环的形式组织，圆周周围有24个点。

将顶点坐标读取到展平缓冲区（numpy数组由glBufferData自动展平）。生成索引数组（顶点缓冲区的索引）。索引描述堆积了7781个环的glBufferData原语。每个环由圆周上的24个四边形组成。

GL_TRIANGLE_STRIP
顶点的

x和y分量在[-10，10]范围内，但是z分量在[3，29724672]范围内。 

GL_TRIANGLE_STRIP

我建议为z坐标定义比例尺：

self.e = np.load(('three.npy'), mmap_mode='r')
self.e = np.array(self.e, dtype=np.float32)

self.elems = []
ring_c = self.e.shape[1]
slice_c = self.e.shape[0]
for si in range(slice_c-1):
    self.elems += [si*ring_c, si*ring_c]
    for ri in range(ring_c+1):
        ie = ri % ring_c
        self.elems += [ie+si*ring_c, ie+(si+1)*ring_c]
self.elems = np.array(self.elems, dtype=np.int32)

为顶点创建x min x max y min y max z min z max -10.589109 10.517833 -10.464569 10.594374 29724672.0 3.1618009 （self.scaleZ = 0.000001 ），为索引创建Vertex Buffer Object（GL_ARRAY_BUFFER）：

Index buffer Object

指定顶点坐标数组。参见GL_ELEMENT_ARRAY_BUFFER。self.vertexbuffer = gl.glGenBuffers(1) gl.glBindBuffer(gl.GL_ARRAY_BUFFER, self.vertexbuffer) gl.glBufferData(gl.GL_ARRAY_BUFFER, self.e, gl.GL_DYNAMIC_DRAW) self.elementbuffer = gl.glGenBuffers(1) gl.glBindBuffer(gl.GL_ELEMENT_ARRAY_BUFFER, self.elementbuffer) gl.glBufferData(gl.GL_ELEMENT_ARRAY_BUFFER, self.elems, gl.GL_DYNAMIC_DRAW) 的stride和偏移量parameter必须为0。stride指定连续通用顶点属性之间的字节偏移，它必须为Vertex Specification（12）或glVertexAttribPointer。 0具有特殊含义，并且会将属性解释为紧密包装。如果stride为0，则由size和type参数计算。offset不必为glVertexAttribPointer或3*self.e.itemsize，因为数组中1属性的偏移量为0。在任何情况下，stride和offset的单位都是字节。

0

ctypes.c_void_p(0)类型为None，并且必须先绑定索引缓冲区，然后才能用gl.glBindBuffer(gl.GL_ARRAY_BUFFER, self.vertexbuffer) stride = 0 # 3*self.e.itemsize offset = None # ctypes.c_void_p(0) loc = self.attrib['position'] gl.glEnableVertexAttribArray(loc) gl.glVertexAttribPointer(loc, 3, gl.GL_FLOAT, False, stride, offset) 绘制元素：

primitive

而不是在顶点着色器中指定GL_TRIANGLE_STRIP矩阵，我建议对投影，模型转换和视图转换分别使用矩阵glDrawElements。投影矩阵定义了3D视区到2D视口的投影。视图矩阵定义了视图的观看位置和场景上的观看方向。模型矩阵定义了模式的比例和动画。

glDrawElements

链接着色器程序后获取属性索引和统一位置：

gl.glBindBuffer(gl.GL_ELEMENT_ARRAY_BUFFER, self.elementbuffer)

self.perspective_view()
gl.glUniform3f(self.uniform['triangleColor'], 1, 1, 1)
gl.glDrawElements(gl.GL_TRIANGLE_STRIP, self.elems.size, gl.GL_UNSIGNED_INT, None)

对于3D外观，我建议使用Orthographic projection而不是Uniform variable。使用attribute vec3 position; uniform mat4 u_proj; uniform mat4 u_view; uniform mat4 u_model; void main() { gl_Position = u_proj * u_view * u_model * vec4(position, 1.0); } 或vs = compile_vertex_shader(VS) fs = compile_fragment_shader(FS) self.shaders_program = link_shader_program(vs, fs) self.attrib = { a : gl.glGetAttribLocation (self.shaders_program, a) for a in ['position'] } print(self.attrib) self.uniform = { u : gl.glGetUniformLocation (self.shaders_program, u) for u in ['u_model', 'u_view', 'u_proj', "triangleColor"] } print(self.uniform) 设置矩阵。

Perspective projection

完整示例：（片段着色器根据片段的深度来着色片段）

Orthographic projection

numpy.array
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