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gluScaleImage, HELP?!?!

Started by drago Apr 28, 2000 at 7:43 PM 0 replies 1.6k views

Original Post

Apr 28, 2000 at 7:43 PM

Can anyone explain me how to use the gluScaleImage function? Let me get more specific. gluScaleImage(GLenum format, GLint widthin, GLint heightin, GLenum typein, const void *datain, GLint widthout, GLint heightout, GLenum typeout, void *dataout); The problem is that i want to be able to load an image with wrong dimensions e.g 144x200 and scale it to e.g 256 x 256 , so that the image data can be uploaded into a texture object. What i do is this (in pseudo code): - Copy texture data - Calculate closest valid dimensions (64 x 64, 128 x 128, etc.) - Delete the original texture data - Allocate memory for the original texture data - call gluScaleImage() This doesn't work, I only see one line at the bottom of the quad (that line seems the be correct). After copying the texture data, I check if(pCopiedTextureData[100] == pOriginalTextureData[100]) to see if the copying worked, it does. Then I checked if the calculated valid dimensions were really valid, so I did and they were. So no problem there. So now I checked if(pCopiedTextureData[100] == pOriginalTextureData[100]) after i deleted and allocated new memory for the pOriginalTextureData, AND THEY EQUAL?!?! So I believe that the problem lies there. ---------- Drago Edited by - drago on 4/29/00 7:51:30 AM

drago

Apr 29, 2000 at 8:09 AM

Here is the modified code:


typedef unsigned char byte;
typedef unsigned int uint;

void CTexture::ScaleTexture(byte *pTexData, uint nTexWidth, uint nTexHeight, uint nTexColorDepth, GLenum format)
{
   // Copy the original texture data
   uint nTempTexWidth = nTexWidth;
   uint nTempTexHeight = nTexHeight;
   uint nTempTexColorDepth = nTexColorDepth;
   uint nTempTexMemSpace = nTempTexWidth * nTempTexHeight * (nTempTexColorDepth / 8);
   byte *pTempTexData = new byte[nTexMemSpace];
   memcpy(pTempTexData, pTexData, nTexMemSpace);

   // Set new texture properties for the original texture data
   nTexWidth = nTexHeight = 256;

   // Delete the original texture data and allocate new memory for the scaled texture
   delete [] pTexData;
   uint nScaledTexMemSpace = nTexWidth * nTexHeight * (nTexColorDepth / 8);
   pTexData = new byte[nScaledTexMemSpace];

   // Scale the texture
   gluScaleImage(format, nTempTexWidth, nTempTexHeight, GL_UNSIGNED_BYTE, pTempTexData, nTexWidth, nTexHeight, GL_UNSIGNED_BYTE, pTexData);
}

----------
Drago

Edited by - drago on 4/29/00 10:31:54 AM

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