Testing use of OpenGL 3.2 and 2.1 shaders simultaneously

gltest.py

# -*- coding: utf-8 -*-
import numpy as np
from vispy.gloo import gl
from vispy.app import Canvas

v1 = """
#version 120
attribute vec2 pos; attribute vec3 color; varying vec4 f_color;
void main() {
    gl_Position = vec4(pos, 0, 1.0);
    f_color = vec4(color, 1.0);
}
"""

v2 = """
#version 150
in vec2 pos; in vec3 color; out vec4 f_color;
void main() {
    gl_Position = vec4(pos + vec2(1, 0), 0, 1.0);
    f_color = vec4(color, 1.0);
}
"""

f1 = ("#version 120\n"
      "attribute vec4 f_color; void main() {gl_FragColor = f_color;}")
f2 = ("#version 150\n"
      "in vec4 f_color; void main() {gl_FragColor = f_color;}")


c = Canvas(close_keys='escape', show=True)
c.__enter__()
gl.use('pyopengl')


def create_prog(v, f):
    hprog = gl.glCreateProgram()
    for tt, src in ((gl.GL_VERTEX_SHADER, v), (gl.GL_FRAGMENT_SHADER, f)):
        shader = gl.glCreateShader(tt)
        gl.glShaderSource_compat(shader, src)
        gl.glCompileShader(shader)
        gl.glAttachShader(hprog, shader)
    gl.glLinkProgram(hprog)
    gl.glValidateProgram(hprog)
    return hprog

prog1 = create_prog(v1, f1)
prog2 = create_prog(v2, f2)

pos = np.array([(-1, -1), (0, 1), (1, -1)], np.float32)
color = np.array([(1, 0, 0), (0, 1, 0), (0, 0, 1)], np.float32)
pos_buf = gl.glCreateBuffer()
gl.glBindBuffer(gl.GL_ARRAY_BUFFER, pos_buf)
gl.glBufferData(gl.GL_ARRAY_BUFFER, pos, gl.GL_STATIC_DRAW)
col_buf = gl.glCreateBuffer()
gl.glBindBuffer(gl.GL_ARRAY_BUFFER, col_buf)
gl.glBufferData(gl.GL_ARRAY_BUFFER, color, gl.GL_STATIC_DRAW)
gl.glBindBuffer(gl.GL_ARRAY_BUFFER, 0)
assert gl.glGetError() == 0


@c.events.paint.connect
def paint(event):
    for prog in (prog1, prog2):
        gl.glUseProgram(prog)
        loc = gl.glGetAttribLocation(prog, 'pos')
        gl.glEnableVertexAttribArray(loc)
        gl.glBindBuffer(gl.GL_ARRAY_BUFFER, pos_buf)
        gl.glVertexAttribPointer(loc, 2, gl.GL_FLOAT, gl.GL_FALSE, 0, 0)
        loc = gl.glGetAttribLocation(prog, 'color')
        gl.glEnableVertexAttribArray(loc)
        gl.glBindBuffer(gl.GL_ARRAY_BUFFER, col_buf)
        gl.glVertexAttribPointer(loc, 3, gl.GL_FLOAT, gl.GL_FALSE, 0, 0)
        gl.glDrawArrays(gl.GL_TRIANGLES, 0, 3)
        assert gl.glGetError() == 0

c.show()
c.update()
c.app.run()