Am 21.11.12 17:41, schrieb Christopher Wright:
rough pseudo-code:
glGenTextures(1, &scaledTexture);// make the destination scaled texture
// TODO: set up texture dimensions via glTexImage2D
glGenFramebuffers(1, &myFBO);// make the drawing FBO to perform the
scaling
glBindFramebuffer(GL_FRAMEBUFFER_EXT, myFBO);
glFramebufferTexture2D(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
GL_TEXTURE_2D, scaledTexture, 0);
glDrawBuffer(GL_COLOR_ATTACHMENT0);
// bind source texture -- you might just use the bindTextureRep call here?
glBindTexture(GL_TEXTURE_2D (or rect?), yourInputTexture);
// set up projection -- pixel-for-pixel orthographic
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0,0,width,0,height, -1, 1);
// draw the source to the destination
// TODO: if better-than-bilinear-scaling is desired, add a shader here
to do bicubic or something
glBegin(GL_QUADS);
glTexCoord2f(0,0);
glVertex2f(0,0);
glTexCoord2f(1,0);
glVertex2f(width,0);
glTexCoord2f(1,1);
glVertex2f(width,height);
glTexCoord2f(0,1);
glVertex(0, height);
This barfed at me - I presume this is meant to be glVertex2D, right?
glEnd();
// done! scaledTexture now has the scaled contents using bilinear
scaling in hardware
// make sure to delete fbos and texture when done.
// ALSO: RESTORE ALL THE GL STATE! NOT DOING SO WILL BLOW UP!
Sorry for my ignorance, but what is the GL state and how do I restore it?
Thanks,
--
Christophe Leske
multimedial.de
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www.multimedial.de - i...@multimedial.de
Hohler Strasse 17 - 51645 Gummersbach
+49(0)2261-99824540 // +49(0)177-2497031
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