René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Following rays along the way of their multiple intersections","articleBody":"Good day,\r\nI need to follow a ray along its path and acquire information of all its multiple intersections. To this end, I'm considering the following example involving the scattering from a corner reflector:\r\n\r\n```\r\nimport numpy as np\r\nfrom plotoptix import TkOptiX\r\nfrom plotoptix import NpOptiX\r\nimport matplotlib.pyplot as plt\r\n\r\nnu = 7\r\nnv = 7\r\n    \r\ndef displayResults(rt):\r\n\r\n    print(\"Launch finished.\")\r\n\r\n    hitPositionsData = rt._hit_pos\r\n    xHitPositions = hitPositionsData[:, :, 0]\r\n    yHitPositions = hitPositionsData[:, :, 1]\r\n    zHitPositions = hitPositionsData[:, :, 2]\r\n    dHitPositions = hitPositionsData[:, :, 3]\r\n\r\n    hitTriangle   = rt._geo_id[:, :, 1].reshape(rt._height, rt._width)\r\n\r\n    print(\"Shape of rays array is {}.\".format(xHitPositions.shape))\r\n\r\n    xHitPositions = xHitPositions[hitTriangle \u003c 0xFFFFFFFF]\r\n    yHitPositions = yHitPositions[hitTriangle \u003c 0xFFFFFFFF]\r\n    dHitPositions[np.where(hitTriangle \u003e= 0xFFFFFFFF)] = -1\r\n    hitTriangle[np.where(hitTriangle \u003e= 0xFFFFFFFF)] = 10\r\n\r\n    print(dHitPositions)\r\n    \r\n    print(\"Shape of hitting rays array is {}.\".format(xHitPositions.shape))\r\n\r\n    plt.plot(xHitPositions, yHitPositions, 'bo')\r\n    plt.show()\r\n\r\n    plt.imshow(dHitPositions)\r\n    plt.colorbar()\r\n    plt.show()\r\n\r\n    plt.imshow(hitTriangle)\r\n    plt.colorbar()\r\n    plt.show()\r\n\r\n    plt.draw()\r\n\r\n\r\n#verticesTriangle    = np.array([[-2, -2, 0], [2, -2, 0], [-2, 2, 0], [2,  2, 0]])\r\n#faceTriangle        = np.array([[0, 1, 2], [1, 2, 3]])\r\n#verticesTriangles   = np.array([[-1, -1, 0], [1, -1, 0], [-1, 1, 0], [1, 1, 0], [-1, 1, 2], [1, 1, 2]])\r\n#faceTriangles       = np.array([[0, 1, 2], [1, 2, 3], [2, 3, 4], [3, 4, 5]])\r\nverticesTriangles   = np.array([[0, 1, 0], [0, -1, 0], [0.5 * np.sqrt(2), 1, 0.5 * np.sqrt(2)], [0.5 * np.sqrt(2), -1, 0.5 * np.sqrt(2)], [-0.5 * np.sqrt(2), 1, 0.5 * np.sqrt(2)], [-0.5 * np.sqrt(2), -1, 0.5 * np.sqrt(2)]])\r\nfaceTriangles       = np.array([[0, 1, 2], [1, 2, 3], [0, 1, 4], [1, 4, 5]])\r\n\r\nrt                  = NpOptiX(on_rt_accum_done = displayResults, width = nu, height = nv)\r\n#rt                  = NpOptiX(width = nu, height = nv)\r\n\r\nrt.set_mesh(\"Mesh\", verticesTriangles, faceTriangles)\r\n\r\nu                   = np.linspace(-1.9, 2.1, nu)\r\nv                   = np.linspace(-2, 2, nv)\r\nV, U                = np.meshgrid(v, u)\r\nW                   = np.full((nu, nv), -1)\r\noriginsTexture      = np.stack((U, V, W, np.zeros((nu, nv)))).T\r\n\r\nrt.set_texture_2d(\"origins\", originsTexture)\r\n \r\ncx                  = np.zeros((nu, nv))\r\ncy                  = np.zeros((nu, nv))\r\ncz                  = np.ones((nu, nv))\r\nr                   = np.full((nu, nv), 200)\r\ndirectionsTexture   = np.stack((cx, cy, cz, r)).T\r\n\r\nrt.set_texture_2d(\"directions\", directionsTexture)\r\n \r\nrt.setup_camera(\"custom_cam\", cam_type = \"CustomProjXYZtoDir\", textures = [\"origins\", \"directions\"])\r\n\r\nrt.set_param(max_accumulation_frames = 1)\r\n\r\nrt.set_uint(\"path_seg_range\", 1, 4)\r\n\r\nrt.start()\r\n\r\n#rt.close()\r\n```\r\n\r\nI have the following questions:\r\n\r\n1) I'm setting `path_seg_range` to enable multiple reflections. However, it seems the line does not have an effect. If I comment it out, the results seem to be the same.\r\n2) I access the hit positions and hit distances by the `rt._hit_pos` array. However, for my purposes, I need to know all the hit positions and distances _per ray_. Is that possible by PlotOptiX?","author":{"url":"https://github.com/vitalitylearning2021","@type":"Person","name":"vitalitylearning2021"},"datePublished":"2023-02-08T18:29:40.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/41/plotoptix/issues/41"}