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CuPy/OpenGL interop example
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# MIT License | |
# Copyright (c) 2024 Jean-Baptiste Keck | |
#Permission is hereby granted, free of charge, to any person obtaining a copy | |
#of this software and associated documentation files (the "Software"), to deal | |
#in the Software without restriction, including without limitation the rights | |
#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
#copies of the Software, and to permit persons to whom the Software is | |
#furnished to do so, subject to the following conditions: | |
#The above copyright notice and this permission notice shall be included in all | |
#copies or substantial portions of the Software. | |
#THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
#SOFTWARE. | |
import sys | |
from cuda import cudart | |
import numpy as np | |
import cupy as cp | |
import pyrr | |
import glfw | |
from OpenGL.GL import * # noqa F403 | |
import OpenGL.GL.shaders | |
def format_cudart_err(err): | |
return ( | |
f"{cudart.cudaGetErrorName(err)[1].decode('utf-8')}({int(err)}): " | |
f"{cudart.cudaGetErrorString(err)[1].decode('utf-8')}" | |
) | |
def check_cudart_err(args): | |
if isinstance(args, tuple): | |
assert len(args) >= 1 | |
err = args[0] | |
if len(args) == 1: | |
ret = None | |
elif len(args) == 2: | |
ret = args[1] | |
else: | |
ret = args[1:] | |
else: | |
err = args | |
ret = None | |
assert isinstance(err, cudart.cudaError_t), type(err) | |
if err != cudart.cudaError_t.cudaSuccess: | |
raise RuntimeError(format_cudart_err(err)) | |
return ret | |
class CudaOpenGLMappedBuffer: | |
def __init__(self, gl_buffer, flags=0): | |
self._gl_buffer = int(gl_buffer) | |
self._flags = int(flags) | |
self._graphics_ressource = None | |
self._cuda_buffer = None | |
self.register() | |
@property | |
def gl_buffer(self): | |
return self._gl_buffer | |
@property | |
def cuda_buffer(self): | |
assert self.mapped | |
return self._cuda_buffer | |
@property | |
def graphics_ressource(self): | |
assert self.registered | |
return self._graphics_ressource | |
@property | |
def registered(self): | |
return self._graphics_ressource is not None | |
@property | |
def mapped(self): | |
return self._cuda_buffer is not None | |
def __enter__(self): | |
return self.map() | |
def __exit__(self, exc_type, exc_value, trace): | |
self.unmap() | |
return False | |
def __del__(self): | |
self.unregister() | |
def register(self): | |
if self.registered: | |
return self._graphics_ressource | |
self._graphics_ressource = check_cudart_err( | |
cudart.cudaGraphicsGLRegisterBuffer(self._gl_buffer, self._flags) | |
) | |
return self._graphics_ressource | |
def unregister(self): | |
if not self.registered: | |
return self | |
self.unmap() | |
self._graphics_ressource = check_cudart_err( | |
cudart.cudaGraphicsUnregisterResource(self._graphics_ressource) | |
) | |
return self | |
def map(self, stream=None): | |
if not self.registered: | |
raise RuntimeError("Cannot map an unregistered buffer.") | |
if self.mapped: | |
return self._cuda_buffer | |
check_cudart_err( | |
cudart.cudaGraphicsMapResources(1, self._graphics_ressource, stream) | |
) | |
ptr, size = check_cudart_err( | |
cudart.cudaGraphicsResourceGetMappedPointer(self._graphics_ressource) | |
) | |
self._cuda_buffer = cp.cuda.MemoryPointer( | |
cp.cuda.UnownedMemory(ptr, size, self), 0 | |
) | |
return self._cuda_buffer | |
def unmap(self, stream=None): | |
if not self.registered: | |
raise RuntimeError("Cannot unmap an unregistered buffer.") | |
if not self.mapped: | |
return self | |
self._cuda_buffer = check_cudart_err( | |
cudart.cudaGraphicsUnmapResources(1, self._graphics_ressource, stream) | |
) | |
return self | |
class CudaOpenGLMappedArray(CudaOpenGLMappedBuffer): | |
def __init__(self, dtype, shape, gl_buffer, flags=0, strides=None, order='C'): | |
super().__init__(gl_buffer, flags) | |
self._dtype = dtype | |
self._shape = shape | |
self._strides = strides | |
self._order = order | |
@property | |
def cuda_array(self): | |
assert self.mapped | |
return cp.ndarray( | |
shape=self._shape, | |
dtype=self._dtype, | |
strides=self._strides, | |
order=self._order, | |
memptr=self._cuda_buffer, | |
) | |
def map(self, *args, **kwargs): | |
super().map(*args, **kwargs) | |
return self.cuda_array | |
VERTEX_SHADER = """ | |
#version 330 | |
in vec3 position; | |
uniform mat4 transform; | |
void main() { | |
gl_Position = transform * vec4(position, 1.0f); | |
} | |
""" | |
FRAGMENT_SHADER = """ | |
#version 330 | |
out vec4 outColor; | |
void main() { | |
outColor = vec4(1.0f, 0.0f, 0.0f, 1.0f); | |
} | |
""" | |
def setup_buffers(Nx, Ny): | |
max_vertices = Nx*Ny | |
max_triangles = 2*(Nx-1)*(Ny-1) | |
ftype = np.float32 | |
itype = np.uint32 | |
vertex_bytes = 3 * max_vertices * ftype().nbytes | |
index_bytes = 3 * max_triangles * itype().nbytes | |
flags = cudart.cudaGraphicsRegisterFlags.cudaGraphicsRegisterFlagsWriteDiscard | |
VBO = glGenBuffers(1) | |
glBindBuffer(GL_ARRAY_BUFFER, VBO) | |
glBufferData(GL_ARRAY_BUFFER, vertex_bytes, None, GL_DYNAMIC_DRAW) | |
vertex_buffer = CudaOpenGLMappedArray(ftype, (Ny, Nx, 3), VBO, flags) | |
EBO = glGenBuffers(1) | |
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO) | |
glBufferData(GL_ELEMENT_ARRAY_BUFFER, index_bytes, None, GL_DYNAMIC_DRAW) | |
index_buffer = CudaOpenGLMappedArray(itype, (Ny-1, Nx-1, 2, 3), EBO, flags) | |
Ix = cp.arange(Nx-1)[None,:] | |
Iy = cp.arange(Ny-1)[:,None] | |
I = index_buffer.map() | |
I[...,0,0] = Iy*Nx+Ix | |
I[...,0,1] = Iy*Nx+Ix+Nx | |
I[...,0,2] = Iy*Nx+Ix+Nx+1 | |
I[...,1,0] = Iy*Nx+Ix+Nx+1 | |
I[...,1,1] = Iy*Nx+Ix+1 | |
I[...,1,2] = Iy*Nx+Ix | |
index_buffer.unmap() | |
return vertex_buffer, index_buffer, max_triangles | |
def update_vertices(t, vertex_buffer): | |
r = (t / 10.0) % 1.0 | |
r = (1 - r) if r > 0.5 else r | |
with vertex_buffer as V: | |
(Ny, Nx, _) = V.shape | |
θ = cp.linspace(0, np.pi, Nx)[None,:] | |
φ = cp.linspace(0, 2*np.pi, Ny)[:,None] | |
V[..., 0] = r * cp.cos(φ) * cp.sin(θ) | |
V[..., 1] = r * cp.sin(φ) * cp.sin(θ) | |
V[..., 2] = r * cp.cos(θ) | |
def main(): | |
if not glfw.init(): | |
return | |
title = "CuPy Cuda/OpenGL interop example" | |
window = glfw.create_window(800, 800, title, None, None) | |
if not window: | |
glfw.terminate() | |
return | |
glfw.make_context_current(window) | |
glfw.swap_interval(0) | |
shader = OpenGL.GL.shaders.compileProgram( | |
OpenGL.GL.shaders.compileShader(VERTEX_SHADER, GL_VERTEX_SHADER), | |
OpenGL.GL.shaders.compileShader(FRAGMENT_SHADER, GL_FRAGMENT_SHADER), | |
) | |
positionLoc = glGetAttribLocation(shader, "position") | |
transformLoc = glGetUniformLocation(shader, "transform") | |
Nx, Ny = 32, 32 | |
vertex_buffer, index_buffer, Ntriangles = setup_buffers(Nx, Ny) | |
fps = 0 | |
nframes = 0 | |
last_time = glfw.get_time() | |
glUseProgram(shader) | |
glEnable(GL_DEPTH_TEST) | |
while not glfw.window_should_close(window): | |
t = glfw.get_time() | |
dt = t - last_time | |
if dt >= 1.0: | |
fps = nframes / dt | |
last_time = t | |
nframes = 0 | |
update_vertices(t, vertex_buffer) | |
width, height = glfw.get_window_size(window) | |
glViewport(0, 0, width, height) | |
glClearColor(0.0, 0.0, 0.0, 1.0) | |
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) | |
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE) | |
rot_x = pyrr.Matrix44.from_x_rotation(0) | |
rot_y = pyrr.Matrix44.from_y_rotation(t) | |
glUniformMatrix4fv(transformLoc, 1, GL_FALSE, rot_x * rot_y) | |
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer.gl_buffer) | |
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer.gl_buffer) | |
glEnableVertexAttribArray(positionLoc) | |
glVertexAttribPointer(positionLoc, 3, GL_FLOAT, GL_FALSE, 12, ctypes.c_void_p(0)) | |
glDrawElements(GL_TRIANGLES, int(3 * Ntriangles), GL_UNSIGNED_INT, None) | |
glfw.swap_buffers(window) | |
glfw.poll_events() | |
glfw.set_window_title(window, f"{title} ({fps:.1f} fps)") | |
nframes += 1 | |
index_buffer.unregister() | |
vertex_buffer.unregister() | |
glfw.terminate() | |
if __name__ == "__main__": | |
sys.exit(main()) |
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Thanks for asking to clarify the license @martinResearch, I added the MIT license directly into the sources.