{"id":866,"date":"2009-11-21T13:14:00","date_gmt":"2009-11-21T12:14:00","guid":{"rendered":"http:\/\/it4bus.vn\/itersdesktop\/2009\/11\/21\/opengl-gl_select-problems-with-ati-nvidia\/"},"modified":"2009-11-21T13:14:00","modified_gmt":"2009-11-21T12:14:00","slug":"opengl-gl_select-problems-with-ati-nvidia","status":"publish","type":"post","link":"https:\/\/www.itersdesktop.com\/fr\/2009\/11\/21\/opengl-gl_select-problems-with-ati-nvidia\/","title":{"rendered":"OpenGL GL_Select problems with ATI, NVidia"},"content":{"rendered":"<ul>\n<li>C\u00e1c gi\u1ea3i th\u00edch v\u1ec1 c\u00e1ch install v\u00e0 uninstall c\u00e1c ATI drivers. See <a href=\"https:\/\/help.ubuntu.com\/community\/RadeonDriver\">here<\/a>\n<\/li>\n<\/ul>\n<div>\n<span>select and pick object up<\/span><\/p>\n<\/div>\n<p><span>The 1st explaination:<\/span> see <a href=\"http:\/\/www.openframeworks.cc\/forum\/viewtopic.php?f=9&#038;t=2143\">here<\/a>. B\u00ean d\u01b0\u1edbi l\u00e0 m\u1ed9t copy c\u1ee7a gi\u1ea3i th\u00edch.<\/p>\n<blockquote><p>Beware that a BIG drop in performance will exist in ATI or NVIDIA GPUs<\/p>\n<p>The hardware acceleration for GL_Select is only in full power on the high end graphics cards specially for graphics workstation.<\/p>\n<p>The Bad Thing, that&rsquo;s only a matter of drivers, (some folks have hacked the drivers) but not a good solution.<\/p>\n<p>So, if u have lots of objects to pick (like i have , > 10000) it&rsquo;s better that you don&rsquo;t rely on that method for object picking.\n<\/p><\/blockquote>\n<p><span>The 2nd explaination<\/span>: see <a href=\"http:\/\/www.delphigl.de\/tutorials\/selection.html\">here<\/a>. B\u00ean d\u01b0\u1edbi l\u00e0 m\u1ed9t phi\u00ean b\u1ea3n copy l\u1ea1i<\/p>\n<blockquote><p>As mentioned above, this is very easy to implement.But there&rsquo;s a big drawback,namely the maximum size of the Name Stack.Every OpenGL implementation must at least offer a Name Stack size of 64 names (My GeForce4 Ti4400 with NVidia&rsquo;s Detonator 28.80 offers a Name Stack depth of 128 names).This is not enough,especially for complex scenes.If you need to retrieve information on more objects than your Name Stack is deep,then you&rsquo;ll have to use another method like casting a ray on where your mousecursor is.<\/p><\/blockquote>\n<p><span>The 3nd explaination<\/span>: see <a href=\"http:\/\/www.it.usyd.edu.au\/~tapted\/slow_glselect.html\">here<\/a>. B\u00ean d\u01b0\u1edbi l\u00e0 m\u1ed9t copy l\u1ea1i<\/p>\n<blockquote>\n<p> I&rsquo;ve started noticing a dramatic drop in the performance of OpenGL rendering in SELECT mode. That is, after a call glRenderMode(GL_SELECT);. GL_SELECT is meant to be <em>faster<\/em> than regular rendering, because it only needs to render the geometry, and not shading or textures but recent drivers (since July 2007) have started slowing this operation down dramatically. <\/p>\n<p> So far, it only appears to affect ATI graphics drivers. I haven&rsquo;t tested any HD cards &#8212; if you have one, please consider contributing some numbers, using the test program below. Also, the numbers below indicate that GL_RENDER performance may very well also be affected &#8212; <em>by half!<\/em>. Clearly something has screwed up.<\/p>\n<p>&#8230;.<\/p>\n<p>Nvidia drivers seem to be unaffected &#8212; if they were doing it too, I might be lead to believe a: <\/p>\n<h3>Conspiracy Theory<\/h3>\n<p> There&rsquo;s a chance that ATI\/AMD (and nvidia) are deliberately disabling this feature of their graphics cards. Games often get by without using it, while high-end graphics workstation applications like Maya depend on it heavily. There&rsquo;s a chance the card manufacturers want you to shell out for a workstation card, like Quadro, if you want to use this feature. But, clearly, the cards can support it just fine!<\/p>\n<\/blockquote>\n<\/p>\n<p><span>The 4th explaination:<\/span> See <a href=\"http:\/\/3dnature.com\/glprobs.html\">here<\/a>.<\/p>\n<p>Those are very clear for us to stop testing on Francois&rsquo;s computer.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>C\u00e1c gi\u1ea3i th\u00edch v\u1ec1 c\u00e1ch install v\u00e0 uninstall c\u00e1c ATI drivers. See here select and pick object up The 1st explaination: see here. B\u00ean d\u01b0\u1edbi l\u00e0 m\u1ed9t copy c\u1ee7a gi\u1ea3i&hellip; <\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-866","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.itersdesktop.com\/fr\/wp-json\/wp\/v2\/posts\/866","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.itersdesktop.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.itersdesktop.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.itersdesktop.com\/fr\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.itersdesktop.com\/fr\/wp-json\/wp\/v2\/comments?post=866"}],"version-history":[{"count":0,"href":"https:\/\/www.itersdesktop.com\/fr\/wp-json\/wp\/v2\/posts\/866\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.itersdesktop.com\/fr\/wp-json\/wp\/v2\/media?parent=866"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.itersdesktop.com\/fr\/wp-json\/wp\/v2\/categories?post=866"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.itersdesktop.com\/fr\/wp-json\/wp\/v2\/tags?post=866"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}