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import numpy
from OpenGL.GL import *
from OpenGL.GL.shaders import compileShader, compileProgram
VERTEX_SHADER = """#version 120
attribute vec4 vertices;
varying vec2 coords;
void main() {
gl_Position = vertices;
coords = vertices.xy;
}
"""
FRAGMENT_SHADER = """#version 120
uniform float t;
varying vec2 coords;
void main() {
float i = 1. - (pow(abs(coords.x), 4.) + pow(abs(coords.y), 4.));
i = smoothstep(t - 0.8, t + 0.8, i);
i = floor(i * 20.) / 20.;
gl_FragColor = vec4(coords * .5 + .5, i, i);
}
"""
class Renderer(object):
def __init__(self):
self.t = 0.0
self.values = numpy.array([
-1.0, -1.0,
1.0, -1.0,
-1.0, 1.0,
1.0, 1.0
], dtype=numpy.float32)
def set_t(self, t):
self.t = t
def init(self):
self.vertexbuffer = glGenBuffers(1)
vertex_shader = compileShader(VERTEX_SHADER, GL_VERTEX_SHADER)
fragment_shader = compileShader(FRAGMENT_SHADER, GL_FRAGMENT_SHADER)
self.program = compileProgram(vertex_shader, fragment_shader)
self.vertices_attr = glGetAttribLocation(self.program, b'vertices')
self.t_attr = glGetUniformLocation(self.program, b't')
def reshape(self, x, y, width, height):
glViewport(x, y, width, height)
def render(self):
glUseProgram(self.program)
try:
glDisable(GL_DEPTH_TEST)
glClearColor(0, 0, 0, 1)
glClear(GL_COLOR_BUFFER_BIT)
glEnable(GL_BLEND)
glBlendFunc(GL_SRC_ALPHA, GL_ONE)
glBindBuffer(GL_ARRAY_BUFFER, self.vertexbuffer)
glEnableVertexAttribArray(self.vertices_attr)
glBufferData(GL_ARRAY_BUFFER, self.values, GL_STATIC_DRAW)
glVertexAttribPointer(self.vertices_attr, 2, GL_FLOAT, GL_FALSE, 0, None)
glUniform1f(self.t_attr, self.t)
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4)
finally:
glDisableVertexAttribArray(0)
glBindBuffer(GL_ARRAY_BUFFER, 0)
glUseProgram(0)
def cleanup(self):
glDeleteProgram(self.program)
glDeleteBuffers(1, [self.vertexbuffer])
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