From:	enigma AT erols DOT com (enigma)
Newsgroups:	comp.os.msdos.djgpp,comp.graphics.algorithms
Subject:	Re: VESA 2.0 and NEAR PTR
Date:	Thu, 13 Mar 1997 03:51:06 GMT
Organization:	djgpp, i luv u ;)
Lines:	128
Message-ID:	<3327780b.7631253@news.erols.com>
References:	<33232BE7 DOT 2F3D AT nada DOT kth DOT se>
NNTP-Posting-Host:	dam-as14s68.erols.com
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

>int VBE_detect(VBE_VgaInfo *vbeinfo) {
>  __dpmi_regs regs;
>  
>  assert(sizeof(*vbeinfo) < _go32_info_block.size_of_transfer_buffer);
>  regs.x.ax = 0x4F00;
>  regs.x.di = __tb & 0x0F;
>  regs.x.es = (__tb >> 4) & 0xFFFF;
>  dosmemput(vbeinfo,sizeof(*vbeinfo),__tb);
>  __dpmi_int(0x10, &regs);
>  dosmemget(__tb, sizeof(*vbeinfo), vbeinfo);
>  if(strncmp(vbeinfo->VESASignature,"VESA",4) != 0) return 0;
>  else return vbeinfo->VESAVersion;
>}
^^^ First problem: You never told the VESA driver you wanted VBE 2.0
Info.  You should send 'VBE2' in the vesa signature on the struct.

>
>
>
>void VBE_getmodeinfo(unsigned short mode, VBE_ModeInfo *modeinfo) {
>  __dpmi_regs regs;
>  
>  assert(sizeof(*modeinfo) < _go32_info_block.size_of_transfer_buffer);
>  regs.x.ax = 0x4F01;
>  regs.x.cx = mode;
>  regs.x.di = __tb & 0x0F;
>  regs.x.es = (__tb >> 4) & 0xFFFF;
>  __dpmi_int(0x10, &regs);
>  dosmemget(__tb, sizeof(*modeinfo), modeinfo);
>  return;
>}
^^ I always CHECK this bios call, cause it returns false 15% of the
time.

>/*
>#define SUPPORTED 1
>#define NOT_SUPPORTED	0
>
>int check_640x480x256(void) {
>  __dpmi_regs regs;
>  regs.x.ax = 0x4F02;
>  regs.x.bx = 0x4101;
>  __dpmi_int(0x10, &regs);
>  if(regs.x.ax == 0x4F) return SUPPORTED;
>  else return NOT_SUPPORTED;
		^^ This does not check if it's supported.  Only if the
function returned without any errors.  check the high byte..
>
>
>unsigned int linear_address;
>
>void VBE_get_linear_address(int mode) {
>  VBE_ModeInfo modeinfo;
>  __dpmi_meminfo mem;
>  
>  VBE_getmodeinfo(mode, &modeinfo);
>  mem.size = (unsigned long)(modeinfo.XResolution * modeinfo.YResolution
>* modeinfo.BitsPerPixel/8);
>  mem.address = modeinfo.PhysBasePtr;
>  __dpmi_physical_address_mapping(&mem);
>  linear_address = mem.address;
>  return;
>}
>
>
>VBE_ModeInfo modeinfo;
>
>
>void VBE_setmode(int mode) {
>  __dpmi_regs regs;
>  regs.x.ax = 0x4f02;
>  regs.x.bx = mode | 0x8000;
>  __dpmi_int(0x10, &regs);
>  return;
>}
check these, man.. VBE 2.0 sux
>void settext() {
>  __dpmi_regs regs;
>  regs.x.ax = 3;
>  __dpmi_int(0x10, &regs);
>  return;
>}
>
>
>int main(void) {
>  /*if(VBE_detect(&vbeinfo) < 0x200) {
>    printf("Your card does not support VESA 2.0\n");
>    exit(1);
>  }*/
why commented?
>  int mode = 0x4101;
actually .. send in 101.. much better..
>  VBE_getmodeinfo(mode, &modeinfo);
>  if(modeinfo.ModeAttributes & 0x8)
>    printf("Linear frame buffer found\n");
>  else {
>    printf("Linear frame buffer not found\n");
>    exit(1);
>  }
>
>  VBE_get_linear_address(mode);
>  char* video = (char*)linear_address;
>  VBE_setmode(mode);                                    // 640x480x256
>
>  getch();
>
>  __djgpp_nearptr_enable();
>  video += __djgpp_conventional_base;
>  for(int i=0;i<640*480;i++)
>    video[ i ] = (unsigned char)(i&255);
>  __djgpp_nearptr_disable();
>
>  getch();
>  settext();
>  cout << modeinfo.PhysBasePtr << endl;
>  cout << int(video) << endl;
>  return 0;
>}
>
>------------------------------
>please reply to newsgroup and mail...
>d95-nlu AT nada DOT kth DOT se
>------------------------------
tell me if i'm wrong. its late. i'm tired. i hate VBE 2.0, the docs
are pages and pages.. 

mint
enigma AT erols DOT com

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