C/C++ Programming Help Thread

[psphacker12.]

I've found what I was doing wrong !
I was using the tiff changeBuffer function...

[Raphael]

Raphael & Insomniac [& yaustar] - This gives me a slow, dark green (from cube i drew after it ) blob it looks like. Im sure it is theh sky box, but doesnt have hte texture and doesnt look right as it is dark green, even with GL_DECAL or GL_REPLACE....

...

Im thinking of getting rid of the scaling, along with translation call in the function, and using the verticies points for where to place them, and to 'scale' them (i wont actually scale htem, rather just build the sky box the size it is, without scaling a 1x1x1 cube).

You really should change that code. As it is, it is predestinated to be slow (even on PC) and cause problems.
Do the tesselation for each side of the skybox, so that you avoid all those texture swaps. They are very costly and should be avoided whereever possible!
Also I'm not sure about your tesselation algorithm, since I don't know what STEP is supposed to be as well as why you step i and j by 5. Also your coordinates seem off.
Say you want to subdivide a big QUAD into 4x4 parts with constant z (front or back of skybox):

glBindTexture(GL_TEXTURE_2D,mytex);
glScalef( width, height, length );
glBegin(GL_QUADS); // dunno if multi-quads within one GL_QUADS block is possible on PSPGL
for (i=0;i<4;i++)
 for (j=0;j<4;j++)
 {
    glTexture2f( j/4.0f, i/4.0f ); glVertex3f( j/4.0f, i/4.0f, 1.0f );
    glTexture2f( (j+1)/4.0f, i/4.0f ); glVertex3f( (j+1)/4.0f, i/4.0f, 1.0f );
    glTexture2f( (j+1)/4.0f, (i+1)/4.0f ); glVertex3f( (j+1)/4.0f, (i+1)/4.0f, 1.0f );
    glTexture2f( j/4.0f, (i+1)/4.0f ); glVertex3f( j/4.0f, (i+1)/4.0f, 1.0f );
 }
glEnd();

You should be able to adopt that code to create side and top/bottom quads too and also change the subdivision depth. To optimize that for drawing speed, you could also use TRIANGLE_STRIP to create one row of the subdivision, but I'll leave that to you to figure out if you want.

[hallo007]

I am trying to make my first prx , but i he isnt working , no errors or warnings

Spoiler for main:

#include <pspdebug.h>
#include <pspctrl.h>
#include <string.h>
#include <malloc.h>
#include <stdio.h>
#include <pspdisplay.h>
#include <pspkernel.h>
#include <assert.h>
#include <stdlib.h>
#include <psppower.h>

#define printf pspDebugScreenPrintf


PSP_MODULE_INFO("hello world", 0x1000, 1, 1);


int main()
{
    pspDebugScreenInit();
    
while(1)
{
        pspDebugScreenSetXY(0,0);
        printf("hello");
        }
	return 0;
            }
void* getModuleInfo(void)
{
	return (void *) &module_info;
}

Spoiler for exports:

# Define the exports for the prx
PSP_BEGIN_EXPORTS

# These four lines are mandatory (although you can add other functions like module_stop)
# syslib is a psynonym for the single mandatory export.
PSP_EXPORT_START(syslib, 0, 0x8000)
PSP_EXPORT_FUNC_HASH(modu le_start)
PSP_EXPORT_VAR_HASH(modul e_info)
PSP_EXPORT_END

# Export our function
PSP_EXPORT_START(MyLib, 0, 0x0001)
PSP_EXPORT_FUNC_HASH(getM oduleInfo)
PSP_EXPORT_END

PSP_END_EXPORTS

Spoiler for makefile:

TARGET = file1
OBJS = main.o
BUILD_PRX=1
# Define the name of our custom exports (minus the .exp extension)

PRX_EXPORTS=exports.exp
USE_KERNEL_LIBS=[1,0]
USE_PSPSDK_LIBC = 1
CFLAGS = -O2 -G0 -Wall
CXXFLAGS = $(CFLAGS) -fno-exceptions -fno-rtti
ASFLAGS = $(CFLAGS)
LIBS = -lpsppower




PSPSDK=$(shell psp-config --pspsdk-path)
include $(PSPSDK)/lib/build.mak

[SG57]

RAphael -

#define STEP (1.0f/256.0f)

My textures are 256x256, and I had 5 as an interval, because it was slow, and still is, and doesnt work. Ill use your code their and adopt it to fit my needswhen i get home from school. But honestly, shouldn't I just be able to make some minor number tweaks to that right there. For each side of the cube, id change values, but that right there is a base framework to use? Or should I change that to be exact andforget about scaling? My first skybox function did that... MAde huge quads, they culled very easily.

[Mr305]

int i; 
char* tempstr;
char number;
tempstr= "Trial and error since 2 days";
initGraphics();
for(i=0;i<255;i++)
{
Color mycolor=RGB(i,i,i);
printTextCentered(136,tempstr,mycolor);
sprintf(number,"The value of I must be shown here but it doesn't %i",i);
}
flipScreen();

Compiles fine. I either get a black screen or Just the centered text in white colorNO CHANGE IN COLOR DURING LOOP happens! but what I want [Go from black to white using RGB. Doesn't happen].

sprintf yields no result.
Please Help :Cry: ASAP,better.
I've already charged psp 2wice for this.

[Waterbottle]

int i; 
char* tempstr;
char number;
tempstr= "Trial and error since 2 days";
initGraphics();
for(i=0;i<255;i++)
{
Color mycolor=RGB(i,i,i);
printTextCentered(136,tempstr,mycolor);
sprintf(number,"The value of I must be shown here but it doesn't %i",i);
}
flipScreen();

Compiles fine. I either get a black screen or Just the centered text in white colorNO CHANGE IN COLOR DURING LOOP happens! but what I want [Go from black to white using RGB. Doesn't happen].

sprintf yields no result.
Please Help :Cry: ASAP,better.
I've already charged psp 2wice for this.

The first argument of sprintf is char*, therefor you need to pass the address of number (&number). But you would get an overflow. You should use an array.

I believe it doesn't change color because you only flip the screen after drawing all of them, therefore only the last one drawn will be shown.

Also sprintf won't print anything to the screen, printf does that.

try

int i; 
char* tempstr;
tempstr= "Trial and error since 2 days";
initGraphics();
for(i=0;i<255;i++)
{
Color mycolor=RGB(i,i,i);
printTextCentered(136,tempstr,mycolor);
printf("The value of I must be shown here but it doesn't %i",i);
flipScreen();
}

[Mr305]

The first argument of sprintf is char*, therefor you need to pass the address of number (&number). But you would get an overflow. You should use an array.

I believe it doesn't change color because you only flip the screen after drawing all of them, therefore only the last one drawn will be shown.

Also sprintf won't print anything to the screen, printf does that.

try

int i; 
char* tempstr;
tempstr= "Trial and error since 2 days";
initGraphics();
for(i=0;i<255;i++)
{
Color mycolor=RGB(i,i,i);
printTextCentered(136,tempstr,mycolor);
printf("The value of I must be shown here but it doesn't %i",i);
flipScreen();
}

Thanx for reply, be here I'll post the result. PLEASE :o
Q: i don think DebugScreenPrintf, which needs debugscreeninit, works after initgraphics.

[Dream_Team]

Ok, so here is my problem :

I've just began learning C++ for the PSP.

I've been playing around and having succesfull attempts (making the USB Mass Storage example as a prx as I still don't know anything concerning threads ^^)

But i've saw that the prx loader calls "void *getModuleInfo(void);" to import getModuleInfo from the loaded prx.

I need the prx to clear the screen.
But if i call pspDebugScreenClear(); withtout calling pspDebugScreenInit(); , the screen isn't cleared.
The problem if that if i call pspDebugScreenInit(); , the prx loader can't take back the control of the debug screen.

So I created a function in the prx_loader :

Spoiler for function:

void* clearDebugScreen(void)
{
pspDebugScreenSetXY(0, 0);
pspDebugScreenClear();
}

and then, in the prx i add "void *clearDebugScreen(void);" and then in my main procedure, i call "clearDebugScreen()" somewhere. This is what the prx loader does. Ok ?
Now here's the problem, the prx_loader compiles fine, but the prx complains about : "main.c.text+0x230): undefined reference to `clearDebugScreen'"
I tought this was due to the fact that I was trying to compile as a prx, but I tried changing the makefile so it can be an elf, but I get the same error

Any idea ?

[tommydanger]

int i; 
char* tempstr;
char number;
tempstr= "Trial and error since 2 days";
initGraphics();
for(i=0;i<255;i++)
{
Color mycolor=RGB(i,i,i);
printTextCentered(136,tempstr,mycolor);
sprintf(number,"The value of I must be shown here but it doesn't %i",i);
}
flipScreen();

Compiles fine. I either get a black screen or Just the centered text in white colorNO CHANGE IN COLOR DURING LOOP happens! but what I want [Go from black to white using RGB. Doesn't happen].

sprintf yields no result.
Please Help :Cry: ASAP,better.
I've already charged psp 2wice for this.

int i; 
char tempstr[] = "Trial and error since 2 days";
char number[100];
Color mycolor;
initGraphics();
for(i=0;i<255;i++)
{
color=RGB(i,i,i);
printTextCentered(136,tempstr,mycolor);
sprintf(number,"The value of I must be shown here but it doesn't %d",i);
}
flipScreen();

1.)char* tempstr; is a pointer to a char, to output your tempstr you need to allocate memory for it, like:char tempstr[] = "Trial and error since 2 days";
which is now a char _array_!
2.)char number; how is it supposed to store a string? you have to allocate memory for it to to store your string
3.) Do never declare variables inside a loop! never it's very bad programming behaviour, declare it before the loop
4.) to show an int, use %d

[Mr305]

1.)char* tempstr; is a pointer to a char, to output your tempstr you need to allocate memory for it, like:char tempstr[] = "Trial and error since 2 days";
which is now a char _array_!
2.)char number; how is it supposed to store a string? you have to allocate memory for it to to store your string
3.) Do never declare variables inside a loop! never it's very bad programming behaviour, declare it before the loop
4.) to show an int, use %d

I tried to resolve issues:

int main(void)
{
int i; 
SceCtrlData pad;
char* tempstr= "text here"; 


	
	
IF I TRY , char* tempstr[100 ]= "text here";
main.c:22: error: invalid initializer
main.c:29: warning: passing argument 2 of 'printTextCentered' from incompatible
pointer type
main.c:30: warning: passing argument 1 of 'sprintf' makes pointer from integer without a cast

int number;
Color mycolor;
initGraphics();
for(i=0;i<255;i++)
{
mycolor=RGB(i,i,i);
printTextCentered(136,tempstr,mycolor);
sprintf(number,"The number i is %d",i);
}
flipScreen();
}
}

All I get is a BLACK screeen! :Argh:

[Dream_Team]

Ok, nevermind, I figured it out with lookking at the MyLib.s

I created a file MyLib2.s

Does having that line (STUB_START "MyLib",0x00090000,0x0001 0005) in both files can conflict (for the second I only changed "MyLib" to "MyLib2") ?

EDIT : Oh noes, it compile, but it doesn't run the function

[tommydanger]

well, how you are supposed to see the text "The number i is $anynumber" without printing to the screen? :P
hint: read the usage of sprintf again ;)

[Raphael]

#define STEP (1.0f/256.0f)

My textures are 256x256, and I had 5 as an interval, because it was slow, and still is, and doesnt work. Ill use your code their and adopt it to fit my needswhen i get home from school. But honestly, shouldn't I just be able to make some minor number tweaks to that right there. For each side of the cube, id change values, but that right there is a base framework to use? Or should I change that to be exact andforget about scaling? My first skybox function did that... MAde huge quads, they culled very easily.

Well, that would obviously be slow with 255x255 = 65k subdivisions, since you'd render 6x 65k = 360k+ quads = 700k triangles... too much for the PSP.
Even with a step of 5 you have 51x51 = 250 divisions, meaning 250x6x2 = 3k triangles. Pretty much for just a skybox. Try something lower, like 16x16 and step up until the culling problems disappear. Just use the code as I gave you and make that 4's a #define to easily change the subdivision depth.
Then do that code snippet 6 times for each of the cube faces (apply the coordinates accordingly). It should work.

[SG57]

That's what i am planning to do. As for a skybox texture, I was wondering...

If I do use a 16x16 skybox texture, than rather than have a horribly pixelated and blurry 'sky', I should probably make it reptitivly place the texture upon the object, instead of scaling it. I know how to do it, change the properties of the texture from GL_LINEAR to something else, ill google it when i code later today...

[Insert_Witty_Name]

I think Raphael meant 16x16 subdivisions with your 256x256 texture...

[Xylem]

Hey guys. I have a question (first question at qj! please respond kindly!). Currently, i am on the 4th tutorial at psp-programming.com (very good site), and i wanted to know, is there an easier way for image processing? This is my code (with comments i added to help me); please respond by telling me which part is not necessary (besides the comments of course):

Spoiler for Spoiler for Simple Image Processing:

#include <pspdisplay.h>
#include <pspctrl.h>
#include <pspkernel.h>
#include <pspdebug.h>
#include <pspgu.h>
#include <png.h>
#include <stdio.h>
#include "graphics.h"
#define printf pspDebugScreenPrintf
#define MAX(X, Y) ((X) > (Y) ? (X) : (Y))
PSP_MODULE_INFO("Image Display Program", 0, 1, 1);
/* Same as:
int Max(int X, int Y) {
if(X>Y) {
return X
} else {
return Y
}
} */

/* Exit callback */
int exit_callback(int arg1, int arg2, void *common) {
sceKernelExitGame();
return 0;
}
/* Callback thread */
int CallbackThread(SceSize args, void *argp) {
int cbid;

cbid = sceKernelCreateCallback(" Exit Callback", exit_callback, NULL);
sceKernelRegisterExitCall back(cbid);

sceKernelSleepThreadCB();

return 0;
}
/* Sets up the callback thread and returns its thread id */
int SetupCallbacks(void) {
int thid = 0;

thid = sceKernelCreateThread("up date_thread", CallbackThread, 0x11, 0xFA0, 0, 0);
if(thid >= 0) {
sceKernelStartThread(thid , 0, 0);
}

return thid;
}



/* Main Loop */

int main() {
char buffer[200];
Image* black;

pspDebugScreenInit();
SetupCallbacks();
initGraphics();

/* Load your images */
sprintf(buffer, "black.png");
black = loadImage(buffer);
/* If image loading fails, print out result of failure */
if (!black) {
//Image load failed
printf("Image load failed!\n");
} else {

int x = 0;
int y = 0;
sceDisplayWaitVblankStart ();

while (x < 480) {
while (y < 272) {
/* Blit your variable image on the screen. First two for loading parts of image,
second two for length and width of image, third variable, last two set x and y*/
blitAlphaImageToScreen(0 ,0 ,480 , 272, black, x, y);
/* Define height of image */
y += 272;
}
/* Define length of image */
x += 480;
/* This line used to reset Y for letting X be alone*/
y = 0;
}
/* Print out image memory; put image memory in effect */
flipScreen();
}

sceKernelSleepThread();
return 0;
}

Edit: Never mind. I fixed it. Wasn't hard. Sorry. However, now i have a newer question. How do i use a background for a counter? What i mean is, how do i combine the 3rd and 4th tutorial to use a simple image while having a counter? Thanks, help is appreciated. :)

[SG57]

Xylem - Either set the Debug console's framebuffer address to match that of the graphic's library, or just use the graphics library text porinting function:

printTextScreen( x,y, string, color);

An example:

#define green 0x0000FF00L

int main() {
  Image * background = Image.load("background.png");
  int counter = 0;
  char counter_buffer[5];

  for(;;) { // indefinate loop
    screen:blit(0,0,background);
    printTextScreen( 227,131,counter_buffer, green);

    sceDisplayWaitVblank(); // or w/e the function is called
    flipScreen();

    if(counter>9999) { counter=0; } else { counter++; } // this prevents a buffer overflow, as well with the next line
    snprintf(counter_buffer,4,"%i",counter);
  }
  return 0;
}

[1337PSPer]

how do you get txt to print on the xmb, tryed the testprx but nothing seems to happen when loaded in the xmb. can any one help??

[Mr305]

#include <stdio.h>
#include <stdlib.h>
----other code---
TRIED this buffer = itoa (rand,status,10);
Tried this too itoa (rand,status,10);

--other code that uses status---

How do I convert a int type to a char or char*?
I get these errors:
[CODE]
main.o: In function `main':
main.c.text+0x168): undefined reference to `itoa'
main.c.text+0x1c4): undefined reference to `itoa'
collect2: ld returned 1 exit status
[CODE]

I also tried

extern "C"
{
#include <stdio.h> 
#include <stdlib.h>
}

Please help!

[MaTiAz]

how do you get txt to print on the xmb, tryed the testprx but nothing seems to happen when loaded in the xmb. can any one help??

Use the text blitter from the devhook VSHEX.

[Mr305]

#include <stdio.h>
#include <stdlib.h>
----other code---
TRIED this buffer = itoa (rand,status,10);
Tried this too itoa (rand,status,10);

--other code that uses status---

How do I convert a int type to a char or char*?
I get these errors:
[CODE]
main.o: In function `main':
main.c.text+0x168): undefined reference to `itoa'
main.c.text+0x1c4): undefined reference to `itoa'
collect2: ld returned 1 exit status
[CODE]

I also tried

extern "C"
{
#include <stdio.h> 
#include <stdlib.h>
}

Please help!

Google misleads !! :Argh: :Argh: :Argh:
sprintf() 's the king.
I guess done with scoring system!

[jsharrad]

itoa won't work in Linux/Cygwin because it's not ANSI C so their stdlib doesn't have it.

If you really need itoa though, like if you are working with non-base 10 numbers, you can just write your own and include it in your program.

/**
	
 * Ansi C "itoa" based on Kernighan & Ritchie's "Ansi C"
	
 */
	
void strreverse(char* begin, char* end) {
	
	char aux;
	
	while(end>begin)
	
		aux=*end, *end--=*begin, *begin++=aux;
	
}
	
void itoa(int value, char* str, int base) {
	
	static char num[] = "0123456789abcdefghijklmnopqrstuvwxyz";
	
	char* wstr=str;
	
	int sign;
	

	
	// Validate base
	
	if (base<2 || base>35){ *wstr='\0'; return; }
	

	
	// Take care of sign
	
	if ((sign=value) < 0) value = -value;
	

	
	// Conversion. Number is reversed.
	
	do *wstr++ = num[value%base]; while(value/=base);
	
	if(sign<0) *wstr++='-';
	
	*wstr='\0';
	

	
	// Reverse string
	
	strreverse(str,wstr-1);
	
}

[hallo007]

how do you instal the psp-newlib
the normal
./bootstrap; ./configure; make; make install
isnt working

[1337PSPer]

Use the text blitter from the devhook VSHEX.

can some plz give me a hello world exemple, that would be great because i don't realy understand what you mean by use the text blitter from devhook.

[hallo007]

just download the source and you will see

[1337PSPer]

where can i download the source?

[hallo007]

it is within the devhook SDK

[BlackShark]

hello, guys, I'm pretty new to C so please go easy on me (or not, what ever is cool) im trying to compile using Dev-CPP but when I do i get but one error

*** No rule to make target `main.o', needed by `irda.elf'.  Stop.

as you might see, im just trying to compile one of the examples in the SDK, it DOES compile from command line so I'm pretty sure my environment is set up right, any suggestions?

[hallo007]

there isnt a main.c

[BlackShark]

mmm, weird, maybe Cygwin cant see it from Dev-CPP or something... Thanks hallo007

EDIT sweet, got it to work, (stupid me, didn't have the project.dev in the same directory as the main.c and makefile. just draged and droped that in, made sure the that Dev-CPP could find the makefile again, hit the compile and boom, got an eboot (and others) thanks again Hallo007
-= Double Post =-
here I go again with another crazy n00b question...

im trying to follow this tut here...http://www.psp-programming.com/tutorials/c/lesson04.htm
and i need to download the zlib and libpng using cygwin and
svn checkout svn://svn.pspdev.org/psp/trunk/libpng
command but cygwin doesn't seem to reconize the svn command, is there any other place i can get these two libraries?