# Tag Info

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When your GPU displays a new frame on the screen, it transfers the image over the HDMI cable (or whatever kind) in a process called "scanout". The pixels are sent out in linear order, usually left-to-right and top-to-bottom. The process is timed so that it takes most of the duration of a refresh interval to do this. For instance, at 60Hz, one frame is ~17 ...

9

All conics (including rotated ellipses) can be described by an implicit equation of the form H(x, y) = A x² + B xy + C y² + D x + E y + F = 0 The basic principle of the incremental line tracing algorithms (I wouldn't call them scanline) is to follow the pixels that fulfill the equation as much as possible. Depending on the local slope of the line, you ...

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The classic book Computer Graphics: Principles and Practice (second edition) by Foley, van Dam, et al. describes such an algorithm in section 19.2. The explanation in the book seems to come from an MSc thesis, Raster Algorithms for 2D Primitives by Dilip Da Silva. See also these papers: Curve-drawing algorithms for raster displays by Van Aken and Novak (...

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The scan-line algorithm (as described on Wikipedia for instance) is concerned with generating the pixels in order, left-to-right and top-to-bottom, with each pixel needing to be touched only once. It was developed in the late 1960s, for devices with no framebuffer memory—so it has to generate each pixel just-in-time as it scans out to the display. The ...

2

Congratulations for having progressed so far. Context, first analysis Your explanation: I am using a z-buffer, with one stored length to a wall for the x coordinate of each ray. Means the z-buffer is currently one-dimension. One dimension is enough in the first case (your first two images) but not in the second case. To see why, imagine that the red tomato ...

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The great thing is we can finally predict scan-line exact raster accuracy with no access to a per-scanline query: https://www.youtube.com/watch?v=OZ7Loh830Ec I have come up with the exact microsecond-accurate formulas as a VSYNC offset, to predict the position of a tearline. Tearlines during VSYNC OFF are always raster-exact, so you can steer them out of ...

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