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Please help me with Interface Stuff

BlitzMax Forums/BlitzMax Programming/Please help me with Interface Stuff

Suco-X(Posted 2005) [#1]
Hi.
At moment i test my first Interface with the SDL Lib. But i had some unexplainable(for me) problems with Correctly Structur Import.
Letīs begin :
The SDL_Surface Structure http://www.libsdl.org/cgi/docwiki.cgi/SDL_5fSurface

My Test Code

Import "-lsdl.dll"

extern "C"

type SDL_Surface

  field flags:int                           
  field format:byte ptr            
  field w:int,h:int                              
  field pitch:short                           
  field pixels:byte ptr                          
  field clip_rect:byte ptr                    
  field refcount:int  
end type


Function SDL_Init(Flags:Int)
Function SDL_SetVideoMode:SDL_Surface(Width:Int, Height:Int, Depth:Int, Flags:Int)
Function SDL_Flip(Screen:SDL_Surface)
Function SDL_FillRect(dst:SDL_Surface, dstrect:byte ptr, color:Int)
end extern


Const SDL_INIT_VIDEO              = $00000020
Const SDL_HWSURFACE               = $00000001
Const SDL_DOUBLEBUF               = $40000000
Const SDL_FULLSCREEN              = $80000000



if SDL_Init(SDL_INIT_VIDEO)=-1
	end
endif

local ScreenSurface:SDL_Surface = SDL_SetVideoMode(800,600,32,SDL_HWSURFACE|SDL_DOUBLEBUF)
print ScreenSurface.w
print ScreenSurface.h 

Repeat
SDL_FillRect(ScreenSurface,null,$FFFFFF)
SDL_Flip(ScreenSurface)
FlushMem()
Until KeyHit(KEY_ESCAPE)


The Problem :
This Code works without Errors.
But the ScreenSurface Data are wrong. Prints :
w: 600
h: 3200

I Think the Data is in disorder. But i dont know what i can do. Please help me a bit.
Mfg Suco


Dreamora(Posted 2005) [#2]
According the headers or SDL 1.2 SDL_video.h, the surface should look like this: 
struct SDL_Surface {
	Uint32 flags;				/* Read-only */
	SDL_PixelFormat *format;		/* Read-only */
	int w, h;				/* Read-only */
	Uint16 pitch;				/* Read-only */
	void *pixels;				/* Read-write */
	int offset;				/* Private */

	/* Hardware-specific surface info */
	struct private_hwdata *hwdata;

	/* clipping information */
	SDL_Rect clip_rect;			/* Read-only */
	Uint32 unused1;				/* for binary compatibility */

	/* Allow recursive locks */
	Uint32 locked;				/* Private */

	/* info for fast blit mapping to other surfaces */
	struct SDL_BlitMap *map;		/* Private */

	/* format version, bumped at every change to invalidate blit maps */
	unsigned int format_version;		/* Private */

	/* Reference count -- used when freeing surface */
	int refcount;				/* Read-mostly */
}



According that, the first 4 fields should be correct but after that, there are quite some fields missing.


Suco-X(Posted 2005) [#3]
hi.
Thats not the Problem. 

Type SDL_Surface 

    Field flags:Int 
                     
    Field format:Byte Ptr 
    
    Field w:Int, h:Int 
    Field pitch:Short                 
    Field __unused_align_1:Short       
    Field pixels:Byte Ptr 
    Field offset:Int 
    Field hwdata:Byte Ptr 
             
    Field clip_rect_x:Short 
    Field clip_rect_y:Short 
    Field clip_rect_w:Short 
    Field clip_rect_h:Short 

    Field unused1:Int 
    Field locked:Int 
    Field map:Byte Ptr     
    Field format_version:Int 
    Field refcount:Int             
     
End Type


The Structur on my normal Version. But its the Same problem.........
It runs if i work with Byte Ptr and Memcopy to a Surface Instance like : 
local tmp:byte ptr = SDL_SetVideoMode(..)
local ScreenSurface:SDL_Surface = new SDL_Surface
memcopy ScreenSurface,tmp,sizeof(ScreenSurface)

Works good. But not the best Solution i think.
Mfg Suco


StuC(Posted 2005) [#4]
Your problem is the SDL_SetVideoMode function returns a pointer to that structure.

For some reason, this doesn't work (I get an unhandled memory exception in the catch):




StuC(Posted 2005) [#5]
This does work, but makes no sense. There seems to be a problem with dereferencing a pointer of a user defined type.




Mirko(Posted 2005) [#6]
@suco-x: Do you have any plans on releasing a sdl BM-Module?

I ask this because my carpc does support opengl only in some kind of compatibility mode which means if i create a program which only uses one DrawImage command the flip takes about 2 seconds to render ;-)
Less then 1 fps is unusable even though i am not programming a game ;-)

As i read, sdl uses DirectX on a Windows Pc, right?
DirectX works fine on my carpc.
Maybe that would be a solution for me, as my program only has to draw a few bitmapts on the screen ( a user interface), that's all.


Suco-X(Posted 2005) [#7]
Hi
I provided a first Version of one SDL Module some month ago. But i hate the Structure handling and stopped the development. I thought Mark say me a better way...
Mfg Suco


TeaVirus(Posted 2005) [#8]
Hey Mirko, I'm into car PC as well! I've written the interface that I'm currently using in Blitz3D but am working on an improved version in Max. OpenGL seems to work fine on the Epia M10000. Don't they have the same graphics subsystem? Anyway, sorry to go off topic Suco...