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fullscreen_quad.py
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125 lines (110 loc) · 4.32 KB
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# Copyright 2018 The dm_control Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ============================================================================
"""OpenGL utility for rendering numpy arrays as images on a quad surface."""
import ctypes
import numpy as np
from OpenGL import GL
from OpenGL.GL import shaders
# This array contains packed position and texture cooridnates of a fullscreen
# quad.
# It contains definition of 4 vertices that will be rendered as a triangle
# strip. Each vertex is described by a tuple:
# (VertexPosition.X, VertexPosition.Y, TextureCoord.U, TextureCoord.V)
_FULLSCREEN_QUAD_VERTEX_POSITONS_AND_TEXTURE_COORDS = np.array([
-1, -1, 0, 1,
-1, 1, 0, 0,
1, -1, 1, 1,
1, 1, 1, 0], dtype=np.float32)
_FLOATS_PER_XY = 2
_FLOATS_PER_VERTEX = 4
_SIZE_OF_FLOAT = ctypes.sizeof(ctypes.c_float)
_VERTEX_SHADER = """
#version 120
attribute vec2 position;
attribute vec2 uv;
void main() {
gl_Position = vec4(position, 0, 1);
gl_TexCoord[0].st = uv;
}
"""
_FRAGMENT_SHADER = """
#version 120
uniform sampler2D tex;
void main() {
gl_FragColor = texture2D(tex, gl_TexCoord[0].st);
}
"""
_VAR_POSITION = 'position'
_VAR_UV = 'uv'
_VAR_TEXTURE_SAMPLER = 'tex'
class FullscreenQuadRenderer:
"""Renders pixmaps on a fullscreen quad using OpenGL."""
def __init__(self):
"""Initializes the fullscreen quad renderer."""
GL.glClearColor(0, 0, 0, 0)
self._init_geometry()
self._init_texture()
self._init_shaders()
def _init_geometry(self):
"""Initializes the fullscreen quad geometry."""
vertex_buffer = GL.glGenBuffers(1)
GL.glBindBuffer(GL.GL_ARRAY_BUFFER, vertex_buffer)
GL.glBufferData(
GL.GL_ARRAY_BUFFER,
_FULLSCREEN_QUAD_VERTEX_POSITONS_AND_TEXTURE_COORDS.nbytes,
_FULLSCREEN_QUAD_VERTEX_POSITONS_AND_TEXTURE_COORDS, GL.GL_STATIC_DRAW)
def _init_texture(self):
"""Initializes the texture storage."""
self._texture = GL.glGenTextures(1)
GL.glBindTexture(GL.GL_TEXTURE_2D, self._texture)
GL.glTexParameteri(
GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_NEAREST)
GL.glTexParameteri(
GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_NEAREST)
def _init_shaders(self):
"""Initializes the shaders used to render the textures fullscreen quad."""
vs = shaders.compileShader(_VERTEX_SHADER, GL.GL_VERTEX_SHADER)
fs = shaders.compileShader(_FRAGMENT_SHADER, GL.GL_FRAGMENT_SHADER)
self._shader = shaders.compileProgram(vs, fs)
stride = _FLOATS_PER_VERTEX * _SIZE_OF_FLOAT
var_position = GL.glGetAttribLocation(self._shader, _VAR_POSITION)
GL.glVertexAttribPointer(
var_position, 2, GL.GL_FLOAT, GL.GL_FALSE, stride, None)
GL.glEnableVertexAttribArray(var_position)
var_uv = GL.glGetAttribLocation(self._shader, _VAR_UV)
uv_offset = ctypes.c_void_p(_FLOATS_PER_XY * _SIZE_OF_FLOAT)
GL.glVertexAttribPointer(
var_uv, 2, GL.GL_FLOAT, GL.GL_FALSE, stride, uv_offset)
GL.glEnableVertexAttribArray(var_uv)
self._var_texture_sampler = GL.glGetUniformLocation(
self._shader, _VAR_TEXTURE_SAMPLER)
def render(self, pixmap, viewport_shape):
"""Renders the pixmap on a fullscreen quad.
Args:
pixmap: A 3D numpy array of bytes (np.uint8), with dimensions
(width, height, 3).
viewport_shape: A tuple of two elements, (width, height).
"""
GL.glClear(GL.GL_COLOR_BUFFER_BIT)
GL.glViewport(0, 0, *viewport_shape)
GL.glUseProgram(self._shader)
GL.glActiveTexture(GL.GL_TEXTURE0)
GL.glBindTexture(GL.GL_TEXTURE_2D, self._texture)
GL.glPixelStorei(GL.GL_UNPACK_ALIGNMENT, 1)
GL.glTexImage2D(GL.GL_TEXTURE_2D, 0, GL.GL_RGB, pixmap.shape[1],
pixmap.shape[0], 0, GL.GL_RGB, GL.GL_UNSIGNED_BYTE,
pixmap)
GL.glUniform1i(self._var_texture_sampler, 0)
GL.glDrawArrays(GL.GL_TRIANGLE_STRIP, 0, 4)