add an option to output raw depth and an unprojection example

examples/unproj_example.py

@@ -0,0 +1,114 @@
+"""Examples of using pyrender for viewing and offscreen rendering.
+"""
+import pyglet
+pyglet.options['shadow_window'] = False
+import os
+import numpy as np
+import trimesh
+
+import pyrender
+from pyrender import PerspectiveCamera,\
+                     DirectionalLight, SpotLight, PointLight,\
+                     MetallicRoughnessMaterial,\
+                     Primitive, Mesh, Node, Scene,\
+                     Viewer, OffscreenRenderer
+
+def unproj( inv_mvp , raw_depth):	
+	im_z = raw_depth[:].copy()
+
+	height, width = raw_depth.shape
+	im_y, im_x = np.indices((height, width))
+
+	# opengl is bottom-left 
+	im_y = height-1 - im_y 
+
+	x0 = 0 
+	y0 = 0 
+	x_nd = (1.0*im_x - x0) / (width/2.0)-1
+	y_nd = (1.0*im_y - y0) / (height/2.0)-1
+
+	# https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/gluUnProject.xml
+	# 2*depth-1
+	x = x_nd  
+	y = y_nd  
+	z = im_z*2-1
+	w = np.ones(x.shape)
+
+	xyzw = np.array([x[:],y[:],z[:],w])
+
+	valid_mask = im_z!=1
+	xyzw=xyzw[:,valid_mask] 
+
+	xyzw = inv_mvp @ xyzw
+	xyz = xyzw[:3,:].copy()
+	xyz = xyz / xyzw[3]
+	xyz = np.transpose(xyz)
+	# N,3
+	return xyz
+
+if __name__ =='__main__':
+
+	#==============================================================================
+	# Mesh creation
+	#==============================================================================
+
+	# Drill trimesh
+	drill_trimesh = trimesh.load('./models/drill.obj')
+	drill_trimesh.visual.vertex_colors = np.array((1,0,0,1))
+	drill_trimesh.visual.face_colors = np.array((1,0,0,1))
+	drill_mesh = Mesh.from_trimesh(drill_trimesh)
+
+	#drill_pose = np.eye(4)
+	#drill_pose[0,3] = 0.1
+	#drill_pose[2,3] = -np.min(drill_trimesh.vertices[:,2])
+
+
+	#==============================================================================
+	# Camera creation
+	#==============================================================================
+
+	cam = PerspectiveCamera(yfov=(np.pi / 3.0), aspectRatio=1.0*640/480, znear=0.1, zfar=6)
+	cam_pose = np.array([
+	    [0.0,  -np.sqrt(2)/2, np.sqrt(2)/2, 0.5],
+	    [1.0, 0.0,           0.0,           0.0],
+	    [0.0,  np.sqrt(2)/2,  np.sqrt(2)/2, 0.4],
+	    [0.0,  0.0,           0.0,          1.0]
+	])
+
+	proj = cam.get_projection_matrix()
+	mvp = proj @ np.linalg.inv(cam_pose)
+	inv_mvp = np.linalg.inv(mvp)
+	#==============================================================================
+	# Scene creation
+	#==============================================================================
+
+	scene = Scene(ambient_light=np.array([0.02, 0.02, 0.02, 1.0]))
+	cam_node = scene.add(cam, pose=cam_pose)
+
+	scene.main_camera_node= cam_node
+
+	#==============================================================================
+	drill_node = scene.add(drill_mesh)
+	r = OffscreenRenderer(viewport_width=640, viewport_height=480)
+
+	rf  = pyrender.RenderFlags.NONE 
+	rf |= pyrender.RenderFlags.USE_RAW_DEPTH
+	color, raw_depth = r.render(scene, flags=rf)
+	r.delete()
+
+	# unproject to get point cloud  
+	pcd = unproj( inv_mvp , raw_depth)
+
+	#==============================================================================
+	#------------------------------------------------------------------------------
+	# Creating meshes from point clouds
+	#------------------------------------------------------------------------------
+	points_mesh = Mesh.from_points(pcd, colors=np.array((0.0,1.0,0.0,1.0)))
+	pcd_node = scene.add(points_mesh)
+
+	#==============================================================================
+	# Using the viewer with a pre-specified camera
+	#==============================================================================
+	v = Viewer(scene, render_flags={'point_size':5})
+
+

pyrender/constants.py

@@ -51,7 +51,8 @@ class RenderFlags(object):
     """Render the color buffer with the alpha channel enabled."""
     FLAT = 4096
     """Render the color buffer flat, with no lighting computations."""
-
+    USE_RAW_DEPTH = 8192
+    """Disable depth output preprocessing"""
 
 class TextAlign:
     """Text alignment options for captions.

pyrender/renderer.py

@@ -1117,18 +1117,24 @@ def _read_main_framebuffer(self, scene, flags):
         depth_im = np.frombuffer(depth_buf, dtype=np.float32)
         depth_im = depth_im.reshape((height, width))
         depth_im = np.flip(depth_im, axis=0)
-        inf_inds = (depth_im == 1.0)
-        depth_im = 2.0 * depth_im - 1.0
-        z_near = scene.main_camera_node.camera.znear
-        z_far = scene.main_camera_node.camera.zfar
-        noninf = np.logical_not(inf_inds)
-        if z_far is None:
-            depth_im[noninf] = 2 * z_near / (1.0 - depth_im[noninf])
+
+
+        if not (flags & RenderFlags.USE_RAW_DEPTH):
+            inf_inds = (depth_im == 1.0)
+            depth_im = 2.0 * depth_im - 1.0
+            z_near = scene.main_camera_node.camera.znear
+            z_far = scene.main_camera_node.camera.zfar
+            noninf = np.logical_not(inf_inds)
+            if z_far is None:
+                depth_im[noninf] = 2 * z_near / (1.0 - depth_im[noninf])
+            else:
+                depth_im[noninf] = ((2.0 * z_near * z_far) /
+                                    (z_far + z_near - depth_im[noninf] *
+                                    (z_far - z_near)))
+            depth_im[inf_inds] = 0.0
         else:
-            depth_im[noninf] = ((2.0 * z_near * z_far) /
-                                (z_far + z_near - depth_im[noninf] *
-                                (z_far - z_near)))
-        depth_im[inf_inds] = 0.0
+            pass
+
 
         # Resize for macos if needed
         if sys.platform == 'darwin':