{"action":"created","issue":{"url":"https://api.github.com/repos/tangrams/tangram/issues/577","repository_url":"https://api.github.com/repos/tangrams/tangram","labels_url":"https://api.github.com/repos/tangrams/tangram/issues/577/labels{/name}","comments_url":"https://api.github.com/repos/tangrams/tangram/issues/577/comments","events_url":"https://api.github.com/repos/tangrams/tangram/issues/577/events","html_url":"https://github.com/tangrams/tangram/issues/577","id":249825842,"number":577,"title":"Point outline width is not sharp","user":{"login":"nvkelso","id":853051,"avatar_url":"https://avatars0.githubusercontent.com/u/853051?v=4","gravatar_id":"","url":"https://api.github.com/users/nvkelso","html_url":"https://github.com/nvkelso","followers_url":"https://api.github.com/users/nvkelso/followers","following_url":"https://api.github.com/users/nvkelso/following{/other_user}","gists_url":"https://api.github.com/users/nvkelso/gists{/gist_id}","starred_url":"https://api.github.com/users/nvkelso/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nvkelso/subscriptions","organizations_url":"https://api.github.com/users/nvkelso/orgs","repos_url":"https://api.github.com/users/nvkelso/repos","events_url":"https://api.github.com/users/nvkelso/events{/privacy}","received_events_url":"https://api.github.com/users/nvkelso/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":2,"created_at":"2017-08-12T17:50:01Z","updated_at":"2017-08-14T15:58:34Z","closed_at":null,"body":"Following up on a PR comment https://github.com/tangrams/tangram/pull/508#discussion_r131962936 after it was closed:\r\n\r\nFrom @javisantana:\r\n\r\nHey, sorry to open this conversation but I don't fully understand this.\r\n\r\n`v_aa_factor` is calculated taking like `TANGRAM_PX_FADE_RANGE * 1.0/ length(a_shape.xy / 256.)`. \r\n\r\nThis opens some questions:\r\n- even `v_aa_factor` is a varying, does it vary? the v_aa_factor calculated for each vertex should be the same (I'm talking just about the quads used to render a point)\r\n- when point size is <= 2px `v_aa_factor` is greater than 1 so the `smoothstep(1. - v_aa_factor, 1., point_dist)` is kind of misleading\r\n- if `a_shape` is [+-128, +-128], then should n't be `TANGRAM_PX_FADE_RANGE * 1.0/ length(a_shape.xy / 128.)` or something like `max(1.0, TANGRAM_PX_FADE_RANGE * 1.0/ length(a_shape.xy / 256.))` to avoid aliasing on 1px points? \r\n\r\nAm I misunderstanding `v_aa_factor` usage?\r\n\r\nthanks!\r\n"},"comment":{"url":"https://api.github.com/repos/tangrams/tangram/issues/comments/322230720","html_url":"https://github.com/tangrams/tangram/issues/577#issuecomment-322230720","issue_url":"https://api.github.com/repos/tangrams/tangram/issues/577","id":322230720,"user":{"login":"javisantana","id":30147,"avatar_url":"https://avatars1.githubusercontent.com/u/30147?v=4","gravatar_id":"","url":"https://api.github.com/users/javisantana","html_url":"https://github.com/javisantana","followers_url":"https://api.github.com/users/javisantana/followers","following_url":"https://api.github.com/users/javisantana/following{/other_user}","gists_url":"https://api.github.com/users/javisantana/gists{/gist_id}","starred_url":"https://api.github.com/users/javisantana/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/javisantana/subscriptions","organizations_url":"https://api.github.com/users/javisantana/orgs","repos_url":"https://api.github.com/users/javisantana/repos","events_url":"https://api.github.com/users/javisantana/events{/privacy}","received_events_url":"https://api.github.com/users/javisantana/received_events","type":"User","site_admin":false},"created_at":"2017-08-14T15:58:34Z","updated_at":"2017-08-14T15:58:34Z","body":"ok, thanks for the update. I tried some stuff but I needed to know a little bit more about the rationale behind it.\r\n\r\nI've been comparing with the way mapnik (cairo) does things and there are differenteces. I tried to tweak the values to get the same but it's tricky without knowing the internal details. \r\n\r\nI will send a PR with some proposed fixes and we can discuss things there. "}}
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