C/C++ Programming Help Thread

[Access_Denied]

The power switch is in the psppower.h file. Look at the PSPSDK sample on how to use it.

(lol @ access_denied suggesting pspctrl)

I assumed that he was talking about the hold switch, which is in pspctrl.h.

[youresam]

How can I make a code that says some thin like if the power switch is pressed up then do whatever i want. how would i do that?

Pressing it UP is power access.

[Access_Denied]

Pressing it UP is power access.

Wouldn't that just turn off the PSP though? Or can you override that?

[youresam]

Exactly, he wants to know when that happens. You get about a 1/2 second to detect the power switch before it powers down. This is useful because if youre reading a file...constantly....then you know you NEED_TO stop when power is pressed.

[pspfreak9]

Ok but how would I make an if statement when the power switch is pulled up?
Would it be like this:

 if (pwrflags & PSP_POWER_CB_POWER_SWITCH || pwrflags & PSP_POWER_CB_SUSPENDING) {

[Moca]

to generate a random number u can just use

number = rand() % 100 + 1;

[youresam]

Ok but how would I make an if statement when the power switch is pulled up?
Would it be like this:

 if (pwrflags & PSP_POWER_CB_POWER_SWITCH || pwrflags & PSP_POWER_CB_SUSPENDING) {

Correct,
But note that it must be running in a power thread.

[hallo007]

the size is 13900225 bytes

then
int buffer = malloc(size);

but buffer returns NULL , is the file to big to store to an int?(i guess but need to be sure)
-= Double Post =-
no need any more
ported all functions to pspIo and fixed it;)
-= Double Post =-
another problem

i am 99% sure the fault is here
fread(&header, sizeof(HEADER), 1, infile);

to

sceIoRead(infile,&header, sizeof(HEADER));


what did I wrong

more info:

typedef struct
{
	char signature[4];

	int version;

	int offset[8];

} HEADER;

HEADER header; 

infile=sceIoOpen(path, PSP_O_RDONLY, 0777);

I hope someone can help me

[Grimfate126]

to generate a random number u can just use

number = rand() % 100 + 1;

yes, but keep in mind that you will also have to the the random seed. also, read up on the mersenne twister. its much more random.

[Flame4e]

umm i was wondering if anyone knows some great basic c tutorials (i did the 6 on psp-prog and already have one homwbrew release but its very basic) so yea i want to get better but i need help with a lot of thing and motly makefiles i just dont get how to set them up

[Access_Denied]

umm i was wondering if anyone knows some great basic c tutorials (i did the 6 on psp-prog and already have one homwbrew release but its very basic) so yea i want to get better but i need help with a lot of thing and motly makefiles i just dont get how to set them up

Go to my site. (Link in my sig) I think the C tutorials are all around easier than Yeldarb's. As for Makefile's, you just simply have to understand what the compiler does, and what the linker does. You can look in a general C tutorial for that.

@Hallo0007-

This will not do anything:

int buffer = malloc(size);

malloc is used to set the size of a buffer. You'd have to do something like this

char* buffer = malloc(size);

[hallo007]

but smaller files were working , i stiil think the fault is here

fread(&header, sizeof(HEADER), 1, infile);

to

sceIoRead(infile,&header, sizeof(HEADER));


what did I wrong

more info:


	
	
typedef struct
{
	char signature[4];

	int version;

	int offset[8];

} HEADER;

HEADER header; 

infile=sceIoOpen(path, PSP_O_RDONLY, 0777);

I hope someone can help me

[Access_Denied]

I didn't even look at your code. I was just skimming the page and saw that, so I pointed it out.

[yaustar]

umm i was wondering if anyone knows some great basic c tutorials (i did the 6 on psp-prog and already have one homwbrew release but its very basic) so yea i want to get better but i need help with a lot of thing and motly makefiles i just dont get how to set them up

In that case, just learn the language on the easiest development platform you have access which is the PC. Don't start developing on the PSP yet. Plenty of links can be find in the document here:

http://parabellumgames.no-ip.org/art...c-programming/

Access_Denied: Some quick comments on your tutorials. You don't explain the difference between various datatypes or what a variable actually does in the program. (ie variable represents a chunk of memory on the stack) or what it abstractly represents. It gets worst as you actually use pointers without explaining what they are.

You also don't cover all areas of functions. Return types, parameter passing, what void means, the difference between a function definiton and declaration.

There are also lot of other things but those two are most important as they are basics.

[pspfreak9]

Ok I modded the sdk sample of power to this:

Spoiler for Mod:

/************************* *******
************************* ******* PSP Software Development Kit - http://www.pspdev.org
************************* ******* -----------------------------------------------------------------------
************************* ******* Licensed under the BSD license, see LICENSE in PSPSDK root for details.
************************* *******
************************* ******* main.c - Sample to demonstrate proper use of the power library
************************* *******
************************* ******* Copyright (c) 2005 John Kelley <[email protected]>
************************* *******
************************* ******* $Id: main.c 1869 2006-04-09 14:21:59Z tyranid $
************************* *******/
#include <stdlib.h>
#include <pspkernel.h>
#include <pspdebug.h>
#include <pspctrl.h>
#include <pspdisplay.h>
#include <stdio.h>
#include <pspmoduleinfo.h>
#include <psppower.h>

/************************* ******* Define the module info section ************************* *******/
PSP_MODULE_INFO("PowerTes t", 0, 0, 71);

char powerCBMessage[256];

/************************* ******* Define printf, just to make typing easier ************************* *******/
#define printf pspDebugScreenPrintf

/************************* ******* Exit callback ************************* *******/
int exit_callback(int arg1, int arg2, void ************************* *******common)
{
sceKernelExitGame();

return 0;
}
FILE ************************* ******* pFile;
int x = 24;
/************************* ******* Power Callback ************************* *******/
int power_callback(int unknown, int pwrflags, void ************************* *******common)
{
/************************* ******* check for power switch and suspending as one is manual and the other automatic ************************* *******/
if (pwrflags & PSP_POWER_CB_POWER_SWITCH || pwrflags & PSP_POWER_CB_SUSPENDING) {
x = x + 1;
}
sceDisplayWaitVblankStart ();
return 0;
}

/************************* ******* Callback thread ************************* *******/
int CallbackThread(SceSize args, void ************************* *******argp)
{
int cbid;
cbid = sceKernelCreateCallback(" Exit Callback", exit_callback, NULL);
sceKernelRegisterExitCall back(cbid);
cbid = sceKernelCreateCallback(" Power Callback", power_callback, NULL);
scePowerRegisterCallback( 0, 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 routine ************************* *******/
int main(int argc, char ************************* *******argv[])
{
SceCtrlData pad;
int i = 0;
int powerLocked = 0;
int powerTicks = 0;
u32 oldButtons = 0;
int batteryLifeTime = 0;

//init screen and callbacks
pspDebugScreenInit();
pspDebugScreenClear();
SetupCallbacks();

// Setup Pad
sceCtrlSetSamplingCycle(0 );
sceCtrlSetSamplingMode(0) ;

//fetch and print out power and battery information
for (;;) {
/************************* ******* fix so the screen lines up right if the battery disappears ************************* *******/
if (!scePowerIsBatteryExist( )) {
pspDebugScreenClear();
}

pspDebugScreenSetXY(0, 0);
printf("PSP Power Sample v1.0 by John_K\n\n");
sceCtrlReadBufferPositive (&pad, 1);

printf("External Power: %s\n", scePowerIsPowerOnline()? "yes" : "no ");
printf("%-14s: %s\n", "Battery", scePowerIsBatteryExist()? "present" : "absent ");

if (scePowerIsBatteryExist() ) {
printf("%-14s: %s\n", "Low Charge", scePowerIsLowBattery()? "yes" : "no ");
printf("%-14s: %s\n", "Charging", scePowerIsBatteryCharging ()? "yes" : "no ");
batteryLifeTime = scePowerGetBatteryLifeTim e();
printf("%-14s: %d%% (%02dh%02dm) \n", "Charge",
scePowerGetBatteryLifePer cent(), batteryLifeTime/60, batteryLifeTime-(batteryLifeTime/60*********************** *********60));
printf("%-14s: %0.3fV\n", "Volts", (float) scePowerGetBatteryVolt() / 1000.0);
printf("%-14s: %d deg C\n", "Battery Temp", scePowerGetBatteryTemp()) ;
} else
printf("Battery stats unavailable\n");

printf("%-14s: %d mHz\n", "CPU Speed", scePowerGetCpuClockFreque ncy());
printf("%-14s: %d mHz\n", "Bus Speed", scePowerGetBusClockFreque ncy());
printf("%-14s: %s \n", "Power Switch", powerLocked == 0 ? "unlocked" : "locked");
printf("%-14s: %s \n", "Send Ticks", powerTicks == 1 ? "yes" : "no");
printf("\nPress X to switch CPU between 333 and 222 mHz\n");
printf("Press O to toggle power switch lock\n");
printf("Press [] to toggle sending power ticks\n");
//send powerTicks if enabled
if (powerTicks == 1)
if (scePowerTick(0) != 0)
printf("Error calling scePowerTick(0)\n");

//only check buttons if they've changed since last frame
if (oldButtons != pad.Buttons) {
//check to see if the user pressed X to toggle CPU speed
if (pad.Buttons & PSP_CTRL_CROSS) {
if (i == 0) {
i = scePowerSetClockFrequency (333, 333, 166);
if (i == 0) {
i = 1;
} else {
printf("\nCould not set CPU to 333mHz (0x%08X)\n", i);
i = 0;
}
} else {
i = scePowerSetClockFrequency (222, 222, 111);
if (i != 0) {
printf("\nCould not set CPU to 222mHz (0x%08X)\n", i);
i = 1;
}
}
}
//check to see if the user pressed O to toggle power locking
if (pad.Buttons & PSP_CTRL_CIRCLE) {
if (powerLocked == 0) {
if (scePowerLock(0) == 0)
powerLocked = 1;
else
printf("Error locking power switch\n");
} else {
if (scePowerUnlock(0) == 0)
powerLocked = 0;
else
printf("Error unlocking power switch\n");
}
}
//check to see if the user pressed [] to toggle PowerTicks
if (pad.Buttons & PSP_CTRL_SQUARE)
powerTicks = powerTicks == 1 ? 0 : 1;
}

pspDebugScreenSetXY(0, 30);
printf("Power callback messages appear below:");
pFile = fopen ("myfile.txt" , "w");
fwrite (x , 1 , 29 , pFile);
fclose (pFile);
oldButtons = pad.Buttons;

sceDisplayWaitVblankStart ();
}

sceKernelSleepThread();
sceKernelExitGame();

return 0;
}

When I run it it works fine so i went to test it out by just flicking up my poweswitch and then the memory stick light blinked (it was getting ready to write to the txt file) and the it just froze. Why would that happen? Is it beacuse I gave it too much to do before powering down?

[BlackShark]

Ok Im having a problem with my bullet system, when I press X, no matter what direction im facing it changes my player's position to face north west and fire the bullet south west for some reason,

heres the bulletFire function

Spoiler for function:

//BULLET SYSTEM

void bulletFire() {
if (firing == true) {
if(Pdir == 1) {
by = by - 10;
}

if (Pdir == 2) {
bx = bx + 10;
by = by - 10;
}
if (Pdir == 3) {
bx = bx + 10;
}
if (Pdir = 4) {
bx = bx + 10;
by = by + 10;
}
if(Pdir = 5) {
by = by + 10;
}
if(Pdir = 6) {
bx = bx - 10;
by = by + 10;
}
if(Pdir = 7) {
bx = bx - 10;
}
if(Pdir = 8) {
bx = bx - 10;
by = by - 10;
}
blitAlphaImageToScreen(0, 0, 12, 12, Bulletpic, bx, by);
//bullet goes of screen...
if(bx > 480) {
firing = false;
}else if(bx < 0) {
firing = false;
}else if(by > 272) {
firing = false;
}else if(by < 0) {
firing = false;
}
}

}

Then I call it like this,

//Weapon firering 
         if(pad.Buttons & PSP_CTRL_CROSS && (autof == 100) && (firing == false)) {           
                        autof = 0;
                           bx = playerX - 15;
                           by = playerY - 16; 
                           firing = true; 
               }

Any ideas?




EDIT: Can't believe this, while reviewing my post i finally found what was wrong, Sorry for wasting post space

[SG57]

I have a question, sorta. What is a reasonable value for fog density so the fog has a large range of area to go from no fog, to light light fog, to light fog, to medium fog, to dense fog, to complete fog... Its hard to explain, so if you dont understand, just say so :o

BS - Just to take a crack at it, even though you fixed it - looks to me like somewhere in your other code your setting Pdir to 4, with out knowing it... Thats all i could really gather from your little snippet.

also, a little otimization trick:

if(bx > 480) {
firing = false;
}else if(bx < 0) {
firing = false;
}else if(by > 272) {
firing = false;
}else if(by < 0) {
firing = false;
}

Can be converted to:

if(bx > 480 || bx < 0 || by > 272 || by < 0) firing = false;

You need to make more usage of the logical operators.

Also, another optimization, use a switch case statement instead of:

if(Pdir == 1) {
by = by - 10;
}

if (Pdir == 2) {
bx = bx + 10;
by = by - 10;
}
if (Pdir == 3) {
bx = bx + 10;
}
if (Pdir = 4) {
bx = bx + 10;
by = by + 10;
}
if(Pdir = 5) {
by = by + 10;
}
if(Pdir = 6) {
bx = bx - 10;
by = by + 10;
}
if(Pdir = 7) {
bx = bx - 10;
}
if(Pdir = 8) {
bx = bx - 10;
by = by - 10;
}

Via:

switch(Pdir) {
   case 1: { by -= 1; break; }
   case 2: { bx += 1; by -= 1; break; }
   case 3: { bx += 1; break; }
   case 4: { bx += 1; by += 1; break; }
   case 5: { by += 1; break; }
   case 6: { bx -= 1; by += 1;break; }
   case 7: { bx -= 1; break; } 
   case 8: { bx -= 1; by -= 1; break; }
   default: { Pdir = some_default_value; break; }
}

[BlackShark]

ok thank you, turns out i also set Pdir to 5, 6, and 7 as well, (thats y i was getting such a weird step,

also thanks for the optimization tips, was trying to figure out what the C equivelent of "or" was to lua, now i know its ||, much helpful :), I knew about switch case but wasn't sure I knew enough to implement them, I can study that to use more if needed, thanks again SG

[SG57]

Switch case statements confused me at first as well. I simply skipped them. But later, I learned to love them ;) Hell, i made that TIFF Pixel Repair app just as an excuse to use switch statements ;) If you dive into emulator developing, youll find switch case statements everywhere.

[BlackShark]

Now i just need to figure out how to make the image "rotate" when L or R is pressed (like CsPSP)

[SG57]

You have 2, efficient, options for that.

1. Use hardware rotation, but this will require knowledge of the PSPs GU function calls and how to use them effectively.

2. Pre-defined image rotation by using an image editor and applying the rotation to it, but this can eat up alot of memory if you have 360** of rotation and/or a large image. Your best bet for this would be to place all angles of rotation of the sprite you want, onto a sprite sheet, and also get rid of any unimportant angles of rotation (example, to cut your amount of sprites in 1/2, increment your angles of rotation by 2. This will significantly reduce hte amount of memory taken up (depending on sprite size) and not be 100% noticeable.

I believe CSPSP uses the GU.

[BlackShark]

yes, he used the GU (got some help from him earlier and thats what he used) My main concern is that if I managed to do the image rotation, how would i do the bullet system? he used a bullet class in C++ so that option is out for me :S

[SG57]

Use TP's little bullet sustem guide thing. Have L and R rotate a point around in a circle, and use those X and Y coordinates with TP's guide (instead of the cursor thing).

[BlackShark]

Where can i find this guide? I remember seeing somewhere not sure were though, (if all else fails ill google it)

[Psilocybeing]

For image rotation a software solution really won't cut it unless you can optimise on the usual rotation method. (see attachment)

Your other option is to use OpenGL to render your textures onto a flat surface, after which you can use the basic matrix transformations to rotate the image. Using this method rendering around 180 entities I have got FPS up to 40 or so I believe; certainly alot faster than the software rotation method which trundled along at approx .5 FPS ;)

As SG57 said you have the option of using a tileset of rotations of the original image at intervals of say 15 degrees, however I find this method gives a somewhat static feel to it.

For the OpenGL method read up on the ported "Nehes" OpenGL tutorials for the PSP, in particular Lesson 6(for loading/rendering a texture to a face), Lesson 12(for display lists and rotation) and Lesson 20(for masking/blending).

Links:
Nehe Tutorials 1-10 http://www.qj.net/portage-of-nehe-tu...g/49/aid/47390
Nehe Tutorials 11-20 http://pspupdates.qj.net/Portage-of-...g/49/aid/59254

[coolguy5678]

vLib does image rotation with the GU for you, but if you're already quite far into your project you're gonna need a lot of changes...

[pspfreak9]

Can some please answer my PSP Power problem on the last page. Thx :)

[youresam]

Can some please answer my PSP Power problem on the last page. Thx :)

Tell me why you need to know if the PSP is turning off.

[pspfreak9]

Well because using the code in netlib, if your player 1 and waiting for player 2 and if you turn off the power switch the game wont work any more. I need it to netsend "empty" to the room before powering down, and maybe netunreg.
-= Double Post =-
i was just testing it by writing to a txt file

[Glynnder]

wait, netlib = lua, isnt this the C/C++ help thread?