get_intersection is inaccurate with a near horizontal camera

MilesRomanum commented 1 month ago

Terrain3D version

v.0.9.3-beta

System information

Godot 4.3 - Windows 10 - RTX 3080 TI - Vulkan Forward+

Is the issue reproducable in the demo?

Yes

Issue description

get_intersection is inaccurate when trying to use click detection on a flat/horizontal camera. Here is a trail of logs that show the potential deviation

https://github.com/user-attachments/assets/35236db1-2696-46b5-89ed-e00a5df61bb1

Below is my project (if you run with console and right click on the map, you will get reports of error, distance etc)

Hearts.of.Steel.zip

Logs


Error: 4.172072    Dist: 47.907257
Error: 31.103138    Dist: 78.95521
Error: 26.155058    Dist: 105.19489
Error: 59.366867    Dist: 164.7356
Error: 41.345886    Dist: 206.0743
Error: 37.026024    Dist: 169.3499
Error: 94.67689    Dist: 74.74287```

TokisanGames commented 1 month ago

The calculation for our GPU mouse was changed in #500 fdbdd3620c685fcfacda39c605dd3b2e82c51283, which increased the bit depth. You could rerun your accuracy tests with get_intersection() to see if it helps if you like.

MilesRomanum commented 1 month ago

Hi, I updated to the latest build, but I think it isnt better.

Error: 195.10928    Dist: 96.99999  Estimate: (-50.490257, 2.1923776, -59.30308)    get_intersection: (-152.04807, -27.234423, -223.2778)
Error: 70.21573 Dist: 167.00017 Estimate: (141.91121, 6.1355257, -65.47567) get_intersection: (80.26688, 10.628754, -32.158478)
Error: 59.644417    Dist: 107.00001 Estimate: (109.21683, 3.863419, -121.39816) get_intersection: (125.72325, -3.360117, -178.25601)
Error: 14.938561    Dist: 92.00023  Estimate: (180.57889, 9.896137, -91.63437)  get_intersection: (195.31886, 8.771511, -89.482864)
Error: 54.439037    Dist: 145.99986 Estimate: (30.42535, 4.030425, -121.96139)  get_intersection: (84.48676, 8.800047, -117.692535)

Ill share a video in a second. I added a debug marker to show the two collision position to demonstrate better. red is estimate, green is get_intersection

MilesRomanum commented 1 month ago

Sharing the debug log, this is mapped to every click recorded in the video. red marker is where the estimate returned, versus green for get_intersection Part1:

https://github.com/user-attachments/assets/62fa582b-7ac3-449c-8c94-073123b4a335

part2: https://github.com/user-attachments/assets/8d3f9e6c-5bf8-4f0e-b641-d3b9cf21e574

Error: 125.99021    Dist: 167.99976 Estimate: (139.78886, 5.582857, -65.41576)  get_intersection: (23.650845, 14.011656, -17.307026)
Error: 71.474724    Dist: 95.99963  Estimate: (186.11154, 8.179788, -16.108404) get_intersection: (254.5876, 1.7453604, 3.3406029)
Error: 54.875015    Dist: 149.99963 Estimate: (294.80597, 4.0693984, -124.0558) get_intersection: (268.88422, 8.73481, -75.91472)
Error: 44.654305    Dist: 105.00113 Estimate: (360.26288, 4.7399936, -93.67245) get_intersection: (404.6128, -0.39843178, -94.50224)
Error: 10.400347    Dist: 93.99986  Estimate: (357.36133, -0.010972619, 8.01142)    get_intersection: (356.1135, -1.8733864, 18.167282)
Error: 70.68224 Dist: 164.00052 Estimate: (240.01453, 5.2122087, 90.925644) get_intersection: (301.24237, 10.215933, 55.9672)
Error: 76.33255 Dist: 239.99902 Estimate: (107.84906, 4.3857574, 221.78114) get_intersection: (167.60542, 8.341199, 174.4505)
Error: 220.4336 Dist: 18.99996  Estimate: (114.441505, 12.430712, 42.566242)    get_intersection: (20.843628, -38.51715, -150.39677)
Error: 34.081936    Dist: 53.000088 Estimate: (128.70679, 1.3547925, -10.902894)    get_intersection: (105.18446, 11.3011, 11.665879)
Error: 9.250448 Dist: 62.000168 Estimate: (74.84858, 2.1242995, -28.525751) get_intersection: (81.24271, 4.31719, -22.210915)
Error: 10.195393    Dist: 51    Estimate: (35.5852, 7.427745, -0.9930133)   get_intersection: (26.717762, 5.54974, 3.6747112)
Error: 27.455229    Dist: 22.999996 Estimate: (4.323099, 6.734419, 11.310597)   get_intersection: (-12.11165, -5.3073006, -7.0928154)
Error: 93.42034 Dist: 115.99991 Estimate: (-96.08584, 3.8323512, -30.210556)    get_intersection: (-5.355257, 14.293623, -10.566666)

Had to compress/downsample/lower the framerate, but as you can see, green (get_intersection) can be very far off where the mouse meets the terrain. red (iterative approximation) is not perfect, but it is much closer to the reference point so the error estimate is legitimate.

I think the reason why this may not have been massive in the editor is because the camera angle is almost vertical, whereas here it is horizontal.

let me know if you'd like to look at my source code, ill edit out the unnecessary stuff and upload the project files upon request

TokisanGames / Terrain3D