channel_3d_gl_interop.py

import numpy
from string import Template

from simulation         import Lattice, Geometry
from utility.particles  import Particles
from symbolic.generator import LBM

import symbolic.D3Q27 as D3Q27

from OpenGL.GL   import *
from OpenGL.GLUT import *

from OpenGL.GL import shaders

from geometry.sphere   import Sphere
from geometry.box      import Box
from geometry.cylinder import Cylinder

from utility.projection import Projection, Rotation
from utility.mouse      import MouseDragMonitor, MouseScrollMonitor

lattice_x = 256
lattice_y = 64
lattice_z = 64

updates_per_frame = 10
particle_count = 100000

lid_speed = 0.02
relaxation_time = 0.51

def get_cavity_material_map(g):
    return [
        (lambda x, y, z: x > 0 and x < g.size_x-1 and
                         y > 0 and y < g.size_y-1 and
                         z > 0 and z < g.size_z-1,            1), # bulk fluid
        (lambda x, y, z: x == 1 or x == g.size_x-2 or
                         y == 1 or y == g.size_y-2 or
                         z == 1 or z == g.size_z-2,           2), # walls
        (lambda x, y, z: x == 1,                                     3), # inflow
        (lambda x, y, z: x == g.size_x-2,                     4), # outflow

        (Box(g.size_x//10, 1.5*g.size_x//10, 0,             2*g.size_y//5, 0, g.size_z), 5),
        (Box(g.size_x//10, 1.5*g.size_x//10, 3*g.size_y//5, g.size_y,      0, g.size_z), 5),

        (Sphere(g.size_x//3, g.size_y//2, g.size_z//2, 16), 5),
        (Cylinder(g.size_x//3, 0, g.size_z//2, 5, l = g.size_y), 5),
        (Cylinder(g.size_x//3, g.size_y//2, 0, 5, h = g.size_z), 5),

        (lambda x, y, z: x == 0 or x == g.size_x-1 or
                         y == 0 or y == g.size_y-1 or
                         z == 0 or z == g.size_z-1,           0)  # ghost cells
    ]

boundary = Template("""
    if ( m == 2 || m == 5 ) {
        u_0 = 0.0;
        u_1 = 0.0;
        u_2 = 0.0;
    }
    if ( m == 3 ) {
        u_0 = min(time/5000.0 * $inflow, $inflow);
        u_1 = 0.0;
        u_2 = 0.0;
    }
    if ( m == 4 ) {
        rho = 1.0;
    }
""").substitute({
    "inflow": lid_speed
})

def glut_window(fullscreen = False):
    glutInit(sys.argv)
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)

    if fullscreen:
        window = glutEnterGameMode()
    else:
        glutInitWindowSize(800, 500)
        glutInitWindowPosition(0, 0)
        window = glutCreateWindow("LBM")

    return window

lbm = LBM(D3Q27)

window = glut_window(fullscreen = False)

particle_shader = shaders.compileShader("""
#version 430

layout (location=0) in vec4 particles;
                   out vec3 color;

uniform mat4 projection;
uniform mat4 rotation;

vec3 fire(float x) {
    return mix(
        vec3(1.0, 1.0, 0.0),
        vec3(1.0, 0.0, 0.0),
        x
    );
}

void main() {
    gl_Position = projection * rotation * vec4(
        particles[0],
        particles[1],
        particles[2],
        1.
    );

    color = fire(1.0-particles[3]);
}""", GL_VERTEX_SHADER)

vertex_shader = shaders.compileShader(Template("""
#version 430

layout (location=0) in vec4 vertex;
                   out vec3 color;

uniform mat4 projection;
uniform mat4 rotation;

void main() {
    gl_Position = projection * rotation * vertex;
    color = vec3(1.0,1.0,1.0);
}""").substitute({}), GL_VERTEX_SHADER)

fragment_shader = shaders.compileShader("""
#version 430

in vec3 color;

void main(){
    gl_FragColor = vec4(color.xyz, 0.0);
}""", GL_FRAGMENT_SHADER)

lighting_vertex_shader = shaders.compileShader("""
#version 430

layout (location=0) in vec4 vertex;
layout (location=2) in vec4 normal;
                   out vec3 color;
                   out vec3 frag_pos;
                   out vec3 frag_normal;

uniform mat4 projection;
uniform mat4 rotation;

void main() {
    gl_Position = projection * rotation * vertex;
    frag_pos    = vertex.xyz;
    frag_normal = normalize(normal.xyz);
    color = vec3(0.6,0.6,0.6);
}""", GL_VERTEX_SHADER)

lighting_fragment_shader = shaders.compileShader(Template("""
#version 430

in vec3 color;
in vec3 frag_pos;
in vec3 frag_normal;

uniform vec4 camera_pos;

out vec4 result;

void main(){
    const vec3 light_color = vec3(1.0,1.0,1.0);

    const vec3 ray = camera_pos.xyz - frag_pos;
    float brightness = dot(frag_normal, ray) / length(ray);
    brightness = clamp(brightness, 0, 1);

    result = vec4(max(0.4,brightness) * light_color * color.rgb, 1.0);
}
""").substitute({
    "size_x": lattice_x,
    "size_y": lattice_y,
    "size_z": lattice_z
}), GL_FRAGMENT_SHADER)

particle_program = shaders.compileProgram(particle_shader, fragment_shader)
particle_projection_id = shaders.glGetUniformLocation(particle_program, 'projection')
particle_rotation_id   = shaders.glGetUniformLocation(particle_program, 'rotation')

domain_program   = shaders.compileProgram(vertex_shader, fragment_shader)
domain_projection_id = shaders.glGetUniformLocation(domain_program, 'projection')
domain_rotation_id   = shaders.glGetUniformLocation(domain_program, 'rotation')

obstacle_program = shaders.compileProgram(lighting_vertex_shader, lighting_fragment_shader)
obstacle_projection_id = shaders.glGetUniformLocation(obstacle_program, 'projection')
obstacle_rotation_id   = shaders.glGetUniformLocation(obstacle_program, 'rotation')
obstacle_camera_pos_id = shaders.glGetUniformLocation(obstacle_program, 'camera_pos')

lattice = Lattice(
    descriptor   = D3Q27,
    geometry     = Geometry(lattice_x, lattice_y, lattice_z),
    moments      = lbm.moments(optimize = True),
    collide      = lbm.bgk(f_eq = lbm.equilibrium(), tau = relaxation_time),
    boundary_src = boundary,
    opengl       = True
)

material_map = get_cavity_material_map(lattice.geometry)
primitives   = list(map(lambda material: material[0], filter(lambda material: not callable(material[0]), material_map)))
lattice.apply_material_map(material_map)
lattice.sync_material()

particles = Particles(
    lattice,
    numpy.mgrid[
        2*lattice.geometry.size_x//100:4*lattice.geometry.size_x//100:particle_count/10000j,
        lattice.geometry.size_y//16:15*lattice.geometry.size_y//16:100j,
        lattice.geometry.size_z//16:15*lattice.geometry.size_z//16:100j,
    ].reshape(3,-1).T)

projection = Projection(distance = 2*lattice_x)
rotation = Rotation([-lattice_x/2, -lattice_y/2, -lattice_z/2])

cube_vertices, cube_edges = lattice.geometry.wireframe()

def on_display():
    for i in range(0,updates_per_frame):
        lattice.evolve()

    lattice.update_moments()

    for i in range(0,updates_per_frame):
        particles.update(aging = True)

    lattice.sync()

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

    glEnable(GL_DEPTH_TEST)
    glDepthFunc(GL_LESS)

    shaders.glUseProgram(particle_program)
    glUniformMatrix4fv(particle_projection_id, 1, False, numpy.ascontiguousarray(projection.get()))
    glUniformMatrix4fv(particle_rotation_id,   1, False, numpy.ascontiguousarray(rotation.get()))
    particles.bind()
    glEnable(GL_POINT_SMOOTH)
    glPointSize(1)
    glDrawArrays(GL_POINTS, 0, particles.count)

    shaders.glUseProgram(domain_program)
    glUniformMatrix4fv(domain_projection_id, 1, False, numpy.ascontiguousarray(projection.get()))
    glUniformMatrix4fv(domain_rotation_id,   1, False, numpy.ascontiguousarray(rotation.get()))
    glLineWidth(2)
    glBegin(GL_LINES)
    for i, j in cube_edges:
        glVertex(cube_vertices[i])
        glVertex(cube_vertices[j])
    glEnd()

    camera_pos = numpy.matmul([0,-projection.distance,0,1], rotation.get_inverse())

    shaders.glUseProgram(obstacle_program)
    glUniformMatrix4fv(obstacle_projection_id, 1, False, numpy.ascontiguousarray(projection.get()))
    glUniformMatrix4fv(obstacle_rotation_id,   1, False, numpy.ascontiguousarray(rotation.get()))
    glUniform4fv(obstacle_camera_pos_id,       1, camera_pos)

    for primitive in primitives:
        primitive.draw()

    glutSwapBuffers()

mouse_monitors = [
    MouseDragMonitor(GLUT_LEFT_BUTTON,  lambda dx, dy: rotation.update(0.005*dy, 0.005*dx)),
    MouseDragMonitor(GLUT_RIGHT_BUTTON, lambda dx, dy: rotation.shift(0.25*dx, 0.25*dy)),
    MouseScrollMonitor(lambda zoom: projection.update_distance(5*zoom))
]

def on_timer(t):
    glutTimerFunc(t, on_timer, t)
    glutPostRedisplay()

glutDisplayFunc(on_display)
glutReshapeFunc(lambda w, h: projection.update_ratio(w, h))
glutMouseFunc(lambda *args: list(map(lambda m: m.on_mouse(*args), mouse_monitors)))
glutMotionFunc(lambda *args: list(map(lambda m: m.on_mouse_move(*args), mouse_monitors)))
glutTimerFunc(10, on_timer, 10)

glutMainLoop()