I have a 2-D numpy array that I have plotted in Pyopengl using Pyqt. Now I want to set The background of the plot greyscale such that when the line moves up or down, its background grey color changes intensity. I am attaching images for the behaviour I want.
but all I am able to create till now is with white background like this 
the code that I have written is
import OpenGL.GL as gl
import OpenGL.arrays.vbo as glvbo
from PyQt5.Qt import *
import numpy as np
import sys
VS = '''
#version 450
layout(location = 0) in vec2 position;
uniform float right;
uniform float bottom;
uniform float left;
uniform float top;
void main() {
const float far = 1.0;
const float near = -1.0;
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.x, position.y, 0., 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);
}
'''
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
class GLPlotWidget(QGLWidget):
def __init__(self, *args):
super(GLPlotWidget, self).__init__()
self.width, self.height = 100, 100
self.e = np.load('two.npy', mmap_mode='r')
self.vbo = glvbo.VBO(self.e)
self.count = self.vbo.shape[1]
self.right, self.left, self.top, self.bottom = self.e[0, -1, 0].min(), self.e[0, 0, 0].max(), self.e[0, :,
1].max(), self.e[-1,
:,
1].min()
# self.data = np.zeros((10, 2))
self.showMaximized()
def initializeGL(self):
vs = compile_vertex_shader(VS)
fs = compile_fragment_shader(FS)
self.shaders_program = link_shader_program(vs, fs)
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)
def paintGL(self):
self.resizeGL(self.width, self.height)
gl.glDisable(gl.GL_LINE_STIPPLE)
gl.glClearColor(1, 1,1, 0)
gl.glClear(gl.GL_COLOR_BUFFER_BIT)
self.vbo.bind()
gl.glEnableVertexAttribArray(0)
gl.glVertexAttribPointer(0, 2, gl.GL_FLOAT, gl.GL_FALSE, 0, None)
gl.glUseProgram(self.shaders_program)
self.ortho_view()
uni_color = gl.glGetUniformLocation(self.shaders_program, "triangleColor")
for i in range(0, self.vbo.data.shape[0]):
gl.glUniform3f(uni_color, 0, 0, 0)
# gl.glLineWidth(1.8)
gl.glDrawArrays(gl.GL_LINE_STRIP, i * self.count, self.count)
self.vbo.unbind()
def resizeGL(self, width, height):
self.width, self.height = width, height
gl.glViewport(0, 0, width, height)
def main():
app = QApplication(sys.argv)
editor = GLPlotWidget()
editor.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
Can anyone suggest me any method to solve this problem?
file link https://drive.google.com/file/d/1y6w35kuMguR1YczK7yMJpXU86T6qtGSv/view?usp=sharing
edit:- I tried to increase linewidth of points and set color to them but the result is not even close to satisfactory.
. and I am unable to understand how to pass color in triangles?
