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Messages - MichaelJPCT

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Support / Re: gpu bug ?
« on: January 11, 2019, 01:42:42 pm »
i don't know the size of the flickering squares, but might be 32. the width of screen is 1920. the squares are axis-aligned to  screen.
but the patterns of flicker are multiple, sometimes i see narrow bands. pattern changes with camera position and angle, not by time.
i tried setting usePowerVRTweaks to false, and the whole device hanged. i had to turn off power to reset it.

Support / Re: gpu bug ?
« on: January 11, 2019, 12:59:43 pm »
i don't have a way to take screenshots on that device yet, so i use real camera to shoot the imgs.
2 shadows are overlapping in these screenshots(the meshes holding the texture is much larger than the dark area of  shadow).
shadows are at exact same height.
the shadow closer to camera flickers(always true).

Support / gpu bug ?
« on: January 11, 2019, 04:36:14 am »
my project sometimes has 2 transparent objects(shadows) overlapping but at the same height.
on Powervr 6250 gpu , the objects flicker, like the behavior of Z-fighting. on maliT720, it doesn't happen.
it shouldn't happen because they are transparent, they should co-exist.
what might be the cause of Z-fighting and can it be fixed?

Projects / Re: my project - Vehicle Simulation
« on: January 04, 2019, 03:53:54 pm »
at early stage there are only aircrafts, but if i have enough time , it can have other vehicles, mainly wheeled vehicles (cars).
also human(like fps game) , weapons(bullets , missiles) etc.
the focus is on physics simulation.

Projects / Re: my project - Vehicle Simulation
« on: December 28, 2018, 06:33:56 pm »
more imgs can be found on

Projects / my project - Vehicle Simulation
« on: December 28, 2018, 06:28:35 pm »
this project uses JPCT-AE.
so far i can only post screenshots.

Support / Re: about the strength of specular light
« on: November 12, 2018, 12:16:35 pm »
i see. the built-in shaders are complex enough already. thanks.

Support / about the strength of specular light
« on: November 11, 2018, 07:00:01 pm »
Hi Egon,
i found the reflected light color is related to texture color - the light on white object is whiter than that on dark color  objects.
but in reality, some dark colored object can reflect very bright light, such as dark colored glass.
i don't aim for complex graphics so that's not very important by now.
in some engines, there is concept of " material " - not just texture, but how strong do ambient light, diffuse light, specular light affect an object.
would you consider having this in JPCT? or people need to write new shaders if necessary.

Support / Re: about Light Discard Distance
« on: November 06, 2018, 12:29:28 pm »
that makes sense , thanks.

Support / about Light Discard Distance
« on: November 06, 2018, 03:28:16 am »
Hi again.
i recently found that discard distance of Light means the distance between Light and origin of an Object3D.
if an object3D(such as a ball) has radius of 10, placed 15 from light, discard distance is 10, then the object is not lit. but in reality the light should lit a part of the object at that distance.
when the light move closer to the object , down to 9.9 unit away, the object is suddenly lit.
would it be better if discard distance takes into account the radius of object3d?
that's just a thought, there may be downside too.

Support / to delete an Object3D
« on: October 28, 2018, 09:03:18 am »
Hi Egon, long time no see. i am still using JPCT for my hobby project , and i'm happy with it so far.
now i need to add/delete Object3D , like a lot. i see dispose() of Light , but no such thing of Object3D. does it mean it's safe to just remove it from World and set the field to null and let JVM do garbage collection?
and for other object types, are they all safe if there is no dispose() method?

Support / Re: Changing world and all objects
« on: November 09, 2017, 03:05:14 am »
glsurfaceview has a rendermode: WHEN_DIRTY. use this mode and request render every frame.
or put all operations in OnDrawFrame() method.

Support / Re: 3D object from 2D drawing
« on: November 07, 2017, 02:59:39 am »
these all can be done. but much maths calculation is involved, if you don't know how to calculate distance between points, you should find someone who is good in maths, geometry, computer graphics, java programming to do this. it takes a lot to do the work, you can't learn all these in a few weeks.

Support / Re: variable shadow bias ?
« on: November 06, 2017, 05:37:13 pm »
sorry i can't connect to google server. is it Naroth the RPG game ?
i tested Naroth. in the game the visual range is not large and FOV doesn't change. so in a sense it's like an indoor game.
think of a flight simulation with visual range of 20km and FOV angle range of 1 to 90 degree, the scene in view can be very large(many objects and large terrain area) or very small(need high detail of objects). the 2 extreme situations make things more complicated.
such as shadow mapping, the shadow texture can't be big enough while at the same time detailed enough. so a simple shadow mapping technique doesn't work.
i don't aim for complex graphics, i'm just telling example that some situations are difficult to handle.

Support / Re: variable shadow bias ?
« on: November 06, 2017, 05:44:51 am »
Hi thanks. i don't need it, for now.
but this is something that an engine user can't(or very difficult to) get around if the situation is met, while at engine level it is easy(technically speaking) to do.
i wish JPCT engine can handle most situations (some problems can be solved by tricks without too much trouble) , but some features would require much effort from you, those are not what i would ask for , such as ortho camera.
if some features can be easily achieved from engine level, then having them would make JPCT engine better - less limitation, wider use.

i have a feeling that JPCT engine was designed and tested mostly for small scene, like indoor scene. while i mostly do open world scene. so i encounter (or fore-see) some situations that are difficult to solve, shadow bias is an example.
but i like JPCT most, and my main hobby project is made with JPCT (mostly physics simulation , with simple graphics)

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