Hi,
I guess if I had a deep understanding of openGL I could find the answer,
but I am obviously looking for a shortcut (at the moment) to solve the
specific problem I'm facing which should be pretty simple.
In the attached patch I try to use a trivial shader to texture a
rectangle with an image; the uniform variable "curtex" tells the shader
which texture to use.
It works fine if all images have the same size; however, if the textures
have different sizes, no matter the value of "curtex", the texture
coords that are computed are correct for the image loaded by the
[pix_image] that immediately follows the [glsl_program], but are not
correct for other images.
So the question is: how should I change the vertex and/or fragment
shader code (or the patch maybe) so that the texture coordinates are
computed according to the dimensions of the texture that is actually
sampled?
It is important to NOT assume that the textures come from [pix_image]
objects, or at least, that they are loaded from image files: actually,
in real life, textures may be the video input generated by a [pix_film]
or an image captured by a [pix_snap].
Thanks a lot in advance
--
Matteo Sisti Sette
matteosistisette@gmail.com
http://www.matteosistisette.com
// porcodio
#extension GL_ARB_texture_rectangle : enable
uniform sampler2DRect curtex;
void main (void)
{
vec2 xy=gl_TexCoord[0].st;
vec4 frontcolor = texture2DRect(curtex, xy);
gl_FragColor = frontcolor;
}
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#X msg 114 259 open trivialshader.frag;
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#X obj 506 163 pix_image img2_.jpg;
#X obj 659 164 pix_image img3_.jpg;
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#X msg 229 387 curtex $1;
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