images appearing upside down?
Author
how can i correct images appearing upside down i am using c++ is the only way to rotate the image 180 degrees?
If OGL is anything like DirectX regarding textures then cant u invert the texture coordinates?
ace
ace
just swap the t component of your tex coordinates (s, t) (swap 0s with 1s and vice versa)
it's been a long time sense i've played arround in OGL, but try something like
GL_MatrixMode(GL_TEXTURE);
GL_Scalef(-1,0,0);
GL_MatrixMode(GL_TEXTURE);
GL_Scalef(-1,0,0);
#first:
try to rotate the GL_TEXTURE like this
glMatrixMode(GL_TEXTURE);
glRotatef(180,0,0,1);
glMatrixMode(GL_MODELVIEW);
#second:
try to swap the array buffers like
unsigned char tmp=new unsigned char[image.size];
for (int i=0;i<image.size;i++)
tmp=image.data[(size-1)-i];
for (i=0;i<image.size;i++)
image.data=tmp;
delete []tmp;
something like this ..
i hope you get it :)
try to rotate the GL_TEXTURE like this
glMatrixMode(GL_TEXTURE);
glRotatef(180,0,0,1);
glMatrixMode(GL_MODELVIEW);
#second:
try to swap the array buffers like
unsigned char tmp=new unsigned char[image.size];
for (int i=0;i<image.size;i++)
tmp=image.data[(size-1)-i];
for (i=0;i<image.size;i++)
image.data=tmp;
delete []tmp;
something like this ..
i hope you get it :)
Are you sure they're upside down and not mirrored horizontally?
If they're mirrored horizontally it's because you haven't taken into account the fact that opengl coordinates conventionally put 0,0 at the bottom left of the screen.
You can fix this several ways
- Invert the y component of your texture coordinates
- Create the texture the other way up
The latter is often a nicer approach.
Mark
If they're mirrored horizontally it's because you haven't taken into account the fact that opengl coordinates conventionally put 0,0 at the bottom left of the screen.
You can fix this several ways
- Invert the y component of your texture coordinates
- Create the texture the other way up
The latter is often a nicer approach.
Mark
are you in ortho mode?
I read somewhere that textures are drawn from bottom to top.
GL_Scalef(0,-1,0); // X,Y,Z
will invert the screen
I read somewhere that textures are drawn from bottom to top.
GL_Scalef(0,-1,0); // X,Y,Z
will invert the screen
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