C/C++ Programming Help Thread

[BigSanFrey]

How can i make it so that the cliffs have collision detection too? I know how to do it for the sides of the map but i was wondering how it can be done for various parts of the maps? I just want to know, now its in my head and i keep thinking about it lol. By the way i am using oslib and have just started to learn to code for the psp =\. would someone be kind enough to answer my question?

Look for Box-Line collision on Google.

Someone said that earlier, sorry forgot who :o

[morto]

I have got a error when i try to compile.

[Archaemic]

:facepalm:
You spelled debug wrong.

[Auraomega]

*Sigh* have you even tried seeing what the error is?

pspdebub does not exist, is exactly true, its pspdebug.

-Aura

EDIT: Archaemic beat me to it :Argh:

[Moose]

I think you spelt pspdebug.h wrong in the include, you wrote:

#include <pspdebub.h>

When it should be:

#include <pspdebug.h>

EDIT: Beaten...

[morto]

I think you spelt pspdebug.h wrong in the include, you wrote:

#include <pspdebub.h>

When it should be:

#include <pspdebug.h>

EDIT: Beaten...

Sorry for this stupid action of me i am just a starter but thanks.

[Auraomega]

I have the address of a function of mine which is not working, and I want to link a new function in its place. I think I found a post a while ago showing the same basic idea, where it replaced the address of the function in memory,and I've been searching for close to an hour to find it again with no luck. Can anyone give me some example code or link me to the post again if you somehow know the post? The post, IIRC, was about getting sceKernelExitGame to link to the devs shell, and to not exit to the XMB instead, incase thats of any help.

Thanks.
-Aura

[Judas]

I have the address of a function of mine which is not working, and I want to link a new function in its place. I think I found a post a while ago showing the same basic idea, where it replaced the address of the function in memory,and I've been searching for close to an hour to find it again with no luck. Can anyone give me some example code or link me to the post again if you somehow know the post? The post, IIRC, was about getting sceKernelExitGame to link to the devs shell, and to not exit to the XMB instead, incase thats of any help.

Thanks.
-Aura

I don't know how, but I remember that thread also.

I've got a couple questions

I think that's it.

[cruisx]

Someone said that earlier, sorry forgot who :o

ok thanks, ill see if box-line collision helps me and if i understand it =)

also someone else told me to use his, just wondering what you guys think..

typedef enum
   {
      TILE_PLAYER=1,
      TILE_GRASS=2...ETC
   }

inline int getCurrentTileType(const int& x,const int& y,const map& themap)
{

   return (((x>=themap.width() ||y>=themap.height() ||y<0||x<0)?-1 :themap.tiles[y][x]));
}

inline void getTilePos(const int& wanted_tile,int& px,int& py,const map& themap)
{
        px=-1,py=-1;
   int x=0,y=0;
        for (y=0;y<themap.height();y++)
   {
        for (x=0;x<themap.width();x++)
   {
      if ( getCurrentTileType(px,py,themap) != wanted_tile ) continue;
           px = x;
           py = y;
                return;
               
   }
   }


}



 

int main()
{
      map themap;

      while(running)
      {
 
               int player_x,player_y,current_tile;
     
         getTilePos(TILE_PLAYER,player_x,player_y,themap);
         current_tile = getCurrentTileType(player_x,player_y,themap);
         if(current_tile == TILE_GRASS)
         {
            //COLLISON! do whatever..
         }
          if(timer.diff() >= 10)..cleanup render etc..
         
      }
}

[Judas]

ok thanks, ill see if box-line collision helps me and if i understand it =)

also someone else told me to use his, just wondering what you guys think..

typedef enum
   {
      TILE_PLAYER=1,
      TILE_GRASS=2...ETC
   }

inline int getCurrentTileType(const int& x,const int& y,const map& themap)
{

   return (((x>=themap.width() ||y>=themap.height() ||y<0||x<0)?-1 :themap.tiles[y][x]));
}

inline void getTilePos(const int& wanted_tile,int& px,int& py,const map& themap)
{
        px=-1,py=-1;
   int x=0,y=0;
        for (y=0;y<themap.height();y++)
   {
        for (x=0;x<themap.width();x++)
   {
      if ( getCurrentTileType(px,py,themap) != wanted_tile ) continue;
           px = x;
           py = y;
                return;
               
   }
   }


}



 

int main()
{
      map themap;

      while(running)
      {
 
               int player_x,player_y,current_tile;
     
         getTilePos(TILE_PLAYER,player_x,player_y,themap);
         current_tile = getCurrentTileType(player_x,player_y,themap);
         if(current_tile == TILE_GRASS)
         {
            //COLLISON! do whatever..
         }
          if(timer.diff() >= 10)..cleanup render etc..
         
      }
}

In my Lua tile engine, that's how I did collision detection. And IMO, it's a very fast and easy way.

[Auraomega]

I don't know how, but I remember that thread also.

I've got a couple questions

I think that's it.

Yep, in one, thanks for that :)

@cruisx:
Thats, in my opinion, the easiest and quickest method of 2D collision, I only use Box-Line collision for 3D and the method you posted for 2D collisions.

-Aura

[cruisx]

Yep, in one, thanks for that :)

@cruisx:
Thats, in my opinion, the easiest and quickest method of 2D collision, I only use Box-Line collision for 3D and the method you posted for 2D collisions.

-Aura

ok sweet =p.this might sound noobish but can i use that in Oslib or do i have to convert it for it to work?

[Auraomega]

That method should work just fine in OSLib I believe, I use the method with graphics.c and OSLib is similar in the way it acts.

-Aura
-= Double Post =-
My code, in another module to my existing faulty code:

int load_MUSIC(char bpath[], int clockA, int clockB);

int load_MUSIC_patched(char bpath[], int clockA, int clockB)
{
	// Corrected code
}

int module_start()
{
	*((unsigned int *)load_MUSIC) = J(load_MUSIC_patched);
	return 0;
}

int module_stop(void)
{
	return 0;
}

The above code works if its directly done into the main Project4 code, but when its done from an external module it crashes the PSP. My assumption is that the address not correct.

I have used a stub file:

	.set noreorder

#include "pspstub.s"

	STUB_START "Project4Stub",0x40090000,0x00010005
	STUB_FUNC  0x7DD2EC2C,load_MUSIC
	STUB_END

is the underlined pointer the address in memory which the function will be loaded (I doubt because isn't the memory dynamic?), or is it the NID? If its the NID, is there a function to find the memory location using the NID?

-Aura

[cruisx]

can someone help me out with the collision detection? I made it so that it works for the walls but i am a bit confused on how to use this code for various parts of the map, sorry for all the questions, it is my first time and i don't understand some of the stuff.





like for example the wood fence.

typedef enum
   {
      TILE_PLAYER=1,
      TILE_GRASS=2...ETC
   }

inline int getCurrentTileType(const int& x,const int& y,const map& themap)
{

   return (((x>=themap.width() ||y>=themap.height() ||y<0||x<0)?-1 :themap.tiles[y][x]));
}

inline void getTilePos(const int& wanted_tile,int& px,int& py,const map& themap)
{
        px=-1,py=-1;
   int x=0,y=0;
        for (y=0;y<themap.height();y++)
   {
        for (x=0;x<themap.width();x++)
   {
      if ( getCurrentTileType(px,py,themap) != wanted_tile ) continue;
           px = x;
           py = y;
                return;
               
   }
   }


}



 

int main()
{
      map themap;

      while(running)
      {
 
               int player_x,player_y,current_tile;
     
         getTilePos(TILE_PLAYER,player_x,player_y,themap);
         current_tile = getCurrentTileType(player_x,player_y,themap);
         if(current_tile == TILE_GRASS)
         {
            //COLLISON! do whatever..
         }
          if(timer.diff() >= 10)..cleanup render etc..
         
      }
}

heres my code

//OSlib header file
#include <oslib/oslib.h>

//Include the Data part of the map
#include "Ocean.h"

//Necessary to create eboot
PSP_MODULE_INFO("OSLib Sample", 0, 1, 1);
PSP_MAIN_THREAD_ATTR(THREAD_ATTR_USER | THREAD_ATTR_VFPU);

//declaration of the pointers of our images
OSL_IMAGE *sprite, *Ocean_tileset;

//declaration of the pointers of our Map
OSL_MAP *Ocean;

//definitions
#define DOWN   0
#define UP     35
#define RIGHT  70
#define LEFT   105

//variables
int sprite_position;
int sprite_march;
int i;


//function declarations
void Buttons();
void SpriteAnimate();

int main()
{
    //Initialization of the Oslib library
    oslInit(0);

    //Initialization of the graphics mode
    oslInitGfx(OSL_PF_8888, 1);

        //Shows the psp-hacks hombrew competition splash screen
        oslShowPSPHacksLogo();

    //Sets the transparency color (pink)
    oslSetTransparentColor(RGB(255,0,255));

    //loads our images into memory
        Ocean_tileset = oslLoadImageFile("tileset.png", OSL_IN_RAM, OSL_PF_5551);
    sprite = oslLoadImageFile("sprite.png", OSL_IN_RAM, OSL_PF_5551);

    //Disables the transpaent color (pink)
    oslDisableTransparentColor();

    //verification that all files are present
    if (!sprite || !Ocean_tileset)
        oslDebug("It is impossible to load one or more of the images that are required in this program. Please make sure you have all the files required in the eboot folder");

//configuration of the Map
        Ocean = oslCreateMap(
        Ocean_tileset,                        //Tileset
        Ocean_map,                            //Map
        16,16,                                //Size of the tiles
        64,65,                                //Size of the Map
        OSL_MF_U16);                        //Format of the Map

        //Sets the sprite's original position on the screen
    sprite->x = 155;
    sprite->y = 95;
    sprite_position = DOWN;

    //main while loop
    while (!osl_quit)
    {
        //To be able to draw on the screen
        oslStartDrawing();        
        
        //calls the Buttons() function
        Buttons();

                //Draws the Map on the screen
        oslDrawMapSimple(Ocean);    

        //Draw the images to the screen
        oslDrawImage(sprite);

        //Ends drawing mode
        oslEndDrawing();

        //Synchronizes the screen
        oslSyncFrame();        
    }
    
    //Terminate the program
    oslEndGfx();
    oslQuit();
    return 0;
}


void Buttons()
{
    //initiate the PSP's buttons
    oslReadKeys();
   
     //Takes a screenshot of the PSP's screen 
     if (osl_keys->pressed.select)
    oslWriteImageFilePNG(OSL_SECONDARY_BUFFER, "screenshot.png", 0);

//Basic border collision
if (sprite->x <= 0)
 sprite->x = 0;

if (sprite->y <= 0)
 sprite->y = 0;

if (sprite->x >= 460)
 sprite->x = 460;

if (sprite->y >= 239)
 sprite->y = 239;

if (osl_keys->held.down)
    {
        Ocean->scrollY += 8;
        sprite->y += 1;
        sprite_position = DOWN;
        SpriteAnimate();
    }

    if (osl_keys->held.up)
    {
        Ocean->scrollY -= 8;
        sprite->y -= 1;
        sprite_position = UP;
        SpriteAnimate();
    }
    
    if (osl_keys->held.right)
    {
        Ocean->scrollX += 8;
        sprite->x += 1;
        sprite_position = RIGHT;
        SpriteAnimate();
    }
        if (osl_keys->held.left)
    {
        Ocean->scrollX -= 8;
        sprite->x -= 1;
        sprite_position = LEFT;
        SpriteAnimate();
    }
        
    

    //If a button is not pressed
    if (!osl_keys->held.value) 
    {
    //Start the variable over for when a button is pressed again
        sprite_march = 0; 

        //Sets the sprite's direction
        oslSetImageTileSize(sprite,0,sprite_position,22,35);
    }
}




void SpriteAnimate()
   {    
        //Moves the sprite in the row that it is in
        sprite_march++;


        //Moves the sprite constantly with no static position
        oslSetImageTileSize(sprite,(sprite_march * 22),sprite_position,22,35);

        //resets the sprite movement in that row
        if (sprite_march == 6) sprite_march = 0;
    
}

[Blackbelttcon]

hey if i wanted to splash an image, what kind of could would i use. this is for the computer. im having a real hard time finding it on google.

thanks

[eldiablov]

what lib are you using?

[Auraomega]

How can I set the formatting on a float? I have the presision set as high as I need it, but I was wondering if there was any way to remove the trailing zeros when they are not needed?

	.set noreorder

#include "pspstub.s"

	STUB_START "Project4Stub",0x40090000,0x00010005
	STUB_FUNC  0x7DD2EC2C,load_MUSIC
	STUB_END

is the underlined pointer the address in memory which the function will be loaded (I doubt because isn't the memory dynamic?), or is it the NID? If its the NID, is there a function to find the memory location using the NID?

-Aura

[Xsjado7]

How can I set the formatting on a float? I have the presision set as high as I need it, but I was wondering if there was any way to remove the trailing zeros when they are not needed?

Hey,
Im not sure i quite understand you but if you do 0.%f it will get rid of the 0's so the number is displayed like an integer. For example:

float a;
a = 10.0;
pspDebugScreenPrintf("0.%f", a);

will display 10 instead of 10.000...

Just a quick question, iv written a small function to remove a given colour from an image using graphics.h. Problem is that putPixelImage() doesnt support alpha colours so how else could i go about changing the pixel colour to transparent?

[yaustar]

From memory:

float a = 10.3425465577;
printf("0.%f", a); // 10
printf("0.2%f", a); // 10.34
printf("5.2%f", a); // 00010.34

[Auraomega]

Yeah, but doesn't that way remove them completely? I have presision set to what value I need, but when not all digits after the decimal point are being used I want to remove the trailing zeros, not completely remove them altogether. If theres no way to do this with formatting, would there be any way to check the significant figures, and make the length equal to this value? (I know you can change the length with a variable, I'm just not sure how to check the length).

-Aura

[yaustar]

Yeah, but doesn't that way remove them completely?

No, why would it if it isn't writing to the variable?

[Auraomega]

Hmm, let me put it another way now I have more time to explain:

float e = 2.71;

printf("%5.5f", e) // 2.71000
printf("%5.2f", e) // 2.71

The first output gives trailing zeros, the second output is what I am actually aiming for (without the trailing zeros), I can't set the presision to what is needed, as the value used will actually be dynamic.

(Oh, and 5.2%f is incorrect, the presision should go between the % and the f, not before, else you get 5.2[value], and the %5.2 doesn't appear to give zeros in front of the number).

-Aura

[yaustar]

Honestly, I don't think you can due the IEEE format. In addition, 2.71 might actually be 2.710000000000000001 due to the nature of floating points.

[Insert_Witty_Name]

First of all I have to ask why you need to do this, perhaps there is a better method to achieve your goal.

Also, I generally use fabs() for things like this.

[Auraomega]

I'm trying to throw together a basica calculator, and to keep it to some level of presision, I'm needing to use floats, when the answer has been found it becomes the next value, thus meaning the first and last value at least have to have presision. Theres probably a better way, but for the 10 odd minutes I've spent overall making it, I've not thought of one, and since creating it I've been working on other things.

Also, isn't fabs just modulus?

-Aura

[yaustar]

C or C++?

Edit: Actually, don't iostream and printf output float values up to the first trailing 0 by default?

[Auraomega]

I'm currently using C, and its a small tool in a big project, so I can't really turn it into C++ even if theres an easy solution.

-Aura

[yaustar]

One REALLY roundabout method I can think of is to convert the float to a char string and transverse from the end of the string to the front looking for '0's until it hits a non '0' character and place a null terminator there.

I see if I can whip up an example.

[Auraomega]

Hmm, that definatly seems a good idea, and I can't believe I hadn't thought of it myself, it wouldn't even be that hard to make, I'll get onto that right away.

Thanks.
-Aura

[yaustar]

Remember what I said about floats and precision? Well it is highlighted by what we are trying to do:

#include <stdio.h>
#include <string.h>

int main()
{
	const int BUFFER_SIZE = 128;
	char buffer[BUFFER_SIZE] = "";
	float aFloat = 3.65000f;
	snprintf( buffer, BUFFER_SIZE-1, "%.128f", aFloat );
	buffer[BUFFER_SIZE-1] = '\0';
	
	printf( buffer );
	printf( "\n" );
	
	for( int i = strlen(buffer) - 1; i >= 0 && buffer[i] == '0'; --i )
	{
		buffer[i] = '\0';		
	}
	
	printf( buffer );
	
	return 0;
}

Output:

3.6500000953674316406250000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
3.650000095367431640625