import enum
from OpenGL import GL
from OpenGL.GL import shaders
import numpy as np
from ...Qt import QtGui, QtOpenGL
from ... import functions as fn
from ..GLGraphicsItem import GLGraphicsItem
__all__ = ['GLLinePlotItem']
class DirtyFlag(enum.Flag):
POSITION = enum.auto()
COLOR = enum.auto()
[docs]
class GLLinePlotItem(GLGraphicsItem):
"""Draws line plots in 3D."""
_shaderProgram = None
[docs]
def __init__(self, parentItem=None, **kwds):
"""All keyword arguments are passed to setData()"""
super().__init__()
glopts = kwds.pop('glOptions', 'additive')
self.setGLOptions(glopts)
self.pos = None
self.mode = 'line_strip'
self.width = 1.
self.color = (1.0,1.0,1.0,1.0)
self.antialias = False
self.m_vbo_position = QtOpenGL.QOpenGLBuffer(QtOpenGL.QOpenGLBuffer.Type.VertexBuffer)
self.m_vbo_color = QtOpenGL.QOpenGLBuffer(QtOpenGL.QOpenGLBuffer.Type.VertexBuffer)
self.dirty_bits = DirtyFlag(0)
self.setParentItem(parentItem)
self.setData(**kwds)
[docs]
def setData(self, **kwds):
"""
Update the data displayed by this item. All arguments are optional;
for example it is allowed to update vertex positions while leaving
colors unchanged, etc.
==================== ==================================================
**Arguments:**
------------------------------------------------------------------------
pos (N,3) array of floats specifying point locations.
color (N,4) array of floats (0.0-1.0) or
tuple of floats specifying
a single color for the entire item.
width float specifying line width
antialias enables smooth line drawing
mode 'lines': Each pair of vertexes draws a single line
segment.
'line_strip': All vertexes are drawn as a
continuous set of line segments.
==================== ==================================================
"""
args = ['pos', 'color', 'width', 'mode', 'antialias']
for k in kwds.keys():
if k not in args:
raise Exception('Invalid keyword argument: %s (allowed arguments are %s)' % (k, str(args)))
if 'pos' in kwds:
pos = kwds.pop('pos')
self.pos = np.ascontiguousarray(pos, dtype=np.float32)
self.dirty_bits |= DirtyFlag.POSITION
if 'color' in kwds:
color = kwds.pop('color')
if isinstance(color, np.ndarray):
color = np.ascontiguousarray(color, dtype=np.float32)
self.dirty_bits |= DirtyFlag.COLOR
if isinstance(color, str):
color = fn.mkColor(color)
if isinstance(color, QtGui.QColor):
color = color.getRgbF()
self.color = color
for k, v in kwds.items():
setattr(self, k, v)
if self.mode not in ['line_strip', 'lines']:
raise ValueError("Unknown line mode '%s'. (must be 'lines' or 'line_strip')" % self.mode)
self.update()
def upload_vbo(self, vbo, arr):
if arr is None:
vbo.destroy()
return
if not vbo.isCreated():
vbo.create()
vbo.bind()
if vbo.size() != arr.nbytes:
vbo.allocate(arr, arr.nbytes)
else:
vbo.write(0, arr, arr.nbytes)
vbo.release()
@staticmethod
def getShaderProgram():
klass = GLLinePlotItem
if klass._shaderProgram is not None:
return klass._shaderProgram
ctx = QtGui.QOpenGLContext.currentContext()
fmt = ctx.format()
if ctx.isOpenGLES():
if fmt.version() >= (3, 0):
glsl_version = "#version 300 es\n"
sources = SHADER_CORE
else:
glsl_version = ""
sources = SHADER_LEGACY
else:
if fmt.version() >= (3, 1):
glsl_version = "#version 140\n"
sources = SHADER_CORE
else:
glsl_version = ""
sources = SHADER_LEGACY
compiled = [shaders.compileShader([glsl_version, v], k) for k, v in sources.items()]
program = shaders.compileProgram(*compiled)
# bind generic vertex attrib 0 to "a_position" so that
# vertex attrib 0 definitely gets enabled later.
GL.glBindAttribLocation(program, 0, "a_position")
GL.glBindAttribLocation(program, 1, "a_color")
GL.glLinkProgram(program)
klass._shaderProgram = program
return program
def paint(self):
if self.pos is None:
return
self.setupGLState()
mat_mvp = self.mvpMatrix()
mat_mvp = np.array(mat_mvp.data(), dtype=np.float32)
context = QtGui.QOpenGLContext.currentContext()
if DirtyFlag.POSITION in self.dirty_bits:
self.upload_vbo(self.m_vbo_position, self.pos)
if DirtyFlag.COLOR in self.dirty_bits:
self.upload_vbo(self.m_vbo_color, self.color)
self.dirty_bits = DirtyFlag(0)
program = self.getShaderProgram()
enabled_locs = []
loc = 0
self.m_vbo_position.bind()
GL.glVertexAttribPointer(loc, 3, GL.GL_FLOAT, False, 0, None)
self.m_vbo_position.release()
enabled_locs.append(loc)
loc = 1
if isinstance(self.color, np.ndarray):
self.m_vbo_color.bind()
GL.glVertexAttribPointer(loc, 4, GL.GL_FLOAT, False, 0, None)
self.m_vbo_color.release()
enabled_locs.append(loc)
else:
GL.glVertexAttrib4f(loc, *self.color)
enable_aa = self.antialias and not context.isOpenGLES()
if enable_aa:
GL.glEnable(GL.GL_LINE_SMOOTH)
GL.glEnable(GL.GL_BLEND)
GL.glBlendFuncSeparate(GL.GL_SRC_ALPHA, GL.GL_ONE_MINUS_SRC_ALPHA,
GL.GL_ONE, GL.GL_ONE_MINUS_SRC_ALPHA)
GL.glHint(GL.GL_LINE_SMOOTH_HINT, GL.GL_NICEST)
sfmt = context.format()
core_forward_compatible = (
sfmt.profile() == sfmt.OpenGLContextProfile.CoreProfile
and not sfmt.testOption(sfmt.FormatOption.DeprecatedFunctions)
)
if not core_forward_compatible:
# Core Forward Compatible profiles will return error for
# any width that is not 1.0
GL.glLineWidth(self.width)
for loc in enabled_locs:
GL.glEnableVertexAttribArray(loc)
with program:
loc = GL.glGetUniformLocation(program, "u_mvp")
GL.glUniformMatrix4fv(loc, 1, False, mat_mvp)
if self.mode == 'line_strip':
GL.glDrawArrays(GL.GL_LINE_STRIP, 0, len(self.pos))
elif self.mode == 'lines':
GL.glDrawArrays(GL.GL_LINES, 0, len(self.pos))
for loc in enabled_locs:
GL.glDisableVertexAttribArray(loc)
if enable_aa:
GL.glDisable(GL.GL_LINE_SMOOTH)
GL.glDisable(GL.GL_BLEND)
GL.glLineWidth(1.0)
SHADER_LEGACY = {
GL.GL_VERTEX_SHADER : """
uniform mat4 u_mvp;
attribute vec4 a_position;
attribute vec4 a_color;
varying vec4 v_color;
void main() {
v_color = a_color;
gl_Position = u_mvp * a_position;
}
""",
GL.GL_FRAGMENT_SHADER : """
#ifdef GL_ES
precision mediump float;
#endif
varying vec4 v_color;
void main() {
gl_FragColor = v_color;
}
""",
}
SHADER_CORE = {
GL.GL_VERTEX_SHADER : """
uniform mat4 u_mvp;
in vec4 a_position;
in vec4 a_color;
out vec4 v_color;
void main() {
v_color = a_color;
gl_Position = u_mvp * a_position;
}
""",
GL.GL_FRAGMENT_SHADER : """
#ifdef GL_ES
precision mediump float;
#endif
in vec4 v_color;
out vec4 fragColor;
void main() {
fragColor = v_color;
}
""",
}
