# ----------------------------------------------------------------------------- # Python & OpenGL for Scientific Visualization # www.labri.fr/perso/nrougier/python+opengl # Copyright (c) 2017, Nicolas P. Rougier # Distributed under the 2-Clause BSD License. # ----------------------------------------------------------------------------- import numpy as np from glumpy import app, gloo, gl vertex = """ attribute vec2 position; varying vec2 v_position; void main(){ v_position = position; gl_Position = vec4(position, 0.0, 1.0); } """ fragment = """ float SDF_fake_triangle(vec2 p0, vec2 p1, vec2 p2, vec2 p) { vec2 e0 = p1 - p0; vec2 e1 = p2 - p1; vec2 e2 = p0 - p2; vec2 v0 = p - p0; vec2 v1 = p - p1; vec2 v2 = p - p2; vec2 o0 = normalize(vec2(e0.y, -e0.x)); vec2 o1 = normalize(vec2(e1.y, -e1.x)); vec2 o2 = normalize(vec2(e2.y, -e2.x)); return max(max(dot(o0,v0), dot(o1,v1)), dot(o2,v2)); } vec4 color(float d) { vec3 white = vec3(1.0, 1.0, 1.0); vec3 blue = vec3(0.1, 0.4, 0.7); vec3 color = white - sign(d)*blue; color *= (1.0 - exp(-4.0*abs(d))) * (0.8 + 0.2*cos(140.0*d)); color = mix(color, white, 1.0-smoothstep(0.0,0.02,abs(d)) ); return vec4(color, 1.0); } varying vec2 v_position; uniform vec2 p0, p1, p2; void main() { float d = SDF_fake_triangle(p0, p1, p2, v_position); gl_FragColor = color(d); } """ window = app.Window(512, 512) quad = gloo.Program(vertex, fragment, count=4) quad['position'] = (-1,+1), (+1,+1), (-1,-1), (+1,-1) phi = 0 @window.event def on_draw(dt): global phi phi0 = np.pi*phi/180.0 phi1 = np.pi*(phi+120)/180.0 phi2 = np.pi*(phi+240)/180.0 rho0 = rho1 = rho2 = 0.75 quad["p0"] = rho0*np.cos(phi0), rho0*np.sin(phi0) quad["p1"] = rho1*np.cos(phi1), rho1*np.sin(phi1) quad["p2"] = rho2*np.cos(phi2), rho2*np.sin(phi2) window.clear() quad.draw(gl.GL_TRIANGLE_STRIP) phi += 1.0 app.run(framerate=60, framecount=360)