[fpc-pascal] FPC Graphics options?

noreply at z505.com noreply at z505.com
Thu May 18 15:49:13 CEST 2017


On 2017-05-18 08:23, Graeme Geldenhuys wrote:
> On 2017-05-18 13:42, Reimar Grabowski wrote:
>>> The GPU also does clipping calculations
>>> based on the viewpoint (camera position) in the 3D scene.
>> Camera position?
>> OpenGL has no concept of a camera.
> 
> Yes, yes, but you know what I mean. Camera, View Point, Player View
> whatever. And yes I know there is no "real camera", its the scene that
> moves in the opposite direction to the user input.
> 
> 
>> Why do you have to *calculate* *all*?
> 
> My original project was to implement a _software_ raycaster, so no
> GPU, no OpenGL etc. Old old early 90's style programming.
> 
> This thread is getting a bit ridiculous - just like the Lazarus Forum
> thread did. Bottom line is, the exact same code (identical, just the
> language syntax that differed) produced acceptable results with GCC
> and Java. It didn't with FPC. We all now know FPC doesn't do such a
> great job at optimisation (I know the reasons why), and that the
> graphics API's is also not to blame. So lets leave it at that.
> 

No no you don't "leave" when you are trying to figure out a slow 
procedure that could be causing the problem, you stay here and find what 
is the bottlneck, then insert 3-234 lines of code to fix it so it's 
equal to the speed of x that you are comparing it to :-)

I just want to pinpoint why fpc is slow:
1.the math unit
2.nothing to do with the math unit
3.a wrapper around a graphics lib is slow, not the graphics lib itself 
just the wrapper in fpc
4. system.pp is slow
5. sysutils is slow
6.none of the above
7.magic (not an option. Leave thread..) ;-)



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