Talk:Rectangle Texture

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Texel center

What's meaning of 'the CENTER of 13th texel'? Isn't a texel the minimal unit for sampling?

The sentence in question is attempting to explain where a particular non-normalized texture coordinate goes to in texel space. Because rectangle textures can undergo filtering, they are not discrete spaces. So if the coordinate means "the center of the 13th texel", that can give a different value from "the left edge of the 13th texel" depending on the filtering mode. The latter will filter against the 12th texel; the former will not. Alfonse (talk) 18:05, 26 November 2019 (UTC)
Assuming the filtering mode is GL_NEAREST, for the given texture cooordinate (13.0, 0.0), will the 12th texel color be sampled? But the distance from the coordinate that the value (13.0, 0.0) represents to the center of 12th texel is same with that to the center of 13th texel. According to Textures Filtering--Lucmaa (talk) 08:37, 27 November 2019 (UTC)
A texture coordinate of exactly 13.0 maps to the edge between the 13th and 14th texels (the first texel being the 1st texel). I don't recall exactly what the standard says about which one is favored when you land exactly on the edge, but it will be one of those two. Alfonse (talk) 14:41, 27 November 2019 (UTC)