Martino Ferrari
ed3a8ce645
The repository had no licence at all, so every source was all-rights-reserved by default. Add the verbatim MIT text at LICENSE (Copyright (c) 2026 Martino Ferrari) and a two-line SPDX header to each of the 113 first-party sources -- 48 include/plot, 26 src, 10 adapters, 5 examples, 21 tests, 3 tools -- so the grant travels with each file rather than relying on the root document alone. Scripts keep their shebang on line 1; the SPDX lines follow it. Genuinely vendored code is untouched: third_party/stb_truetype.h carries no header of ours. src/render/embedded_mono_font.cpp is generated, so tools/fonts/gen_atlas.py emit() now writes the two lines into its header comment and the file was regenerated -- gen_atlas.py --check passes and the regeneration adds only those comment lines to the previously committed file. README's provenance section now states MIT and links LICENSE. No code, test or public API change.
58 lines
2.9 KiB
C++
58 lines
2.9 KiB
C++
// SPDX-License-Identifier: MIT
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// SPDX-FileCopyrightText: 2026 Martino Ferrari
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#pragma once
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namespace plot::render {
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/// GLSL source of the instanced antialiased line pipeline.
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///
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/// The vertex shader takes one segment per instance (`a_p0` at location 0,
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/// `a_p1` at location 1, both with a vertex attribute divisor of 1), expands it
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/// in pixel space along its normal by `u_width * 0.5 + 1.0` pixels of AA fringe,
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/// and emits a four-vertex `GL_TRIANGLE_STRIP` quad whose corners come from
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/// `gl_VertexID` (0 and 1 are the two sides of `a_p0`, 2 and 3 of `a_p1`). It
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/// outputs `v_dist`, the signed distance from the segment axis in pixels, and
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/// `v_along`, the distance travelled from `a_p0` in pixels.
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///
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/// Uniforms: `u_scale` (vec2, data space to pixels), `u_offset` (vec2, pixels),
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/// `u_viewport` (vec2, pixels), `u_width` (float, pixels), `u_color` (vec4).
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/// `plot::Rect` is top-left origin while GL is bottom-left, so the y axis is
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/// flipped exactly once, here.
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///
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/// A degenerate segment (`a_p0 == a_p1`) keeps a finite normal and is stretched
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/// into a square mark one stroke width and fringe across, rather than
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/// collapsing to zero area and rasterising nothing — the dense path stages
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/// `min == max` buckets as exactly such segments.
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///
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/// The fragment shader discards outside the fringe and ramps alpha over the last
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/// pixel of the half width with `smoothstep`, which is what keeps a 1px trace
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/// from aliasing into dashes.
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extern const char* const kLineVS;
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extern const char* const kLineFS;
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/// GLSL source of the instanced text pipeline.
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///
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/// One glyph cell per instance, every attribute with a vertex attribute divisor
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/// of 1: `a_pos` at location 0 is the cell's top-left corner in Rect pixels,
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/// `a_uv` at location 1 is the glyph rect's normalised top-left in the atlas and
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/// `a_axis` at location 2 is the cell's local +x axis, a unit vector in pixels.
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///
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/// The vertex shader builds the cell from that basis and its perpendicular --
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/// the cell's own +v direction -- so `a_axis` of `(0, -1)` draws a run that
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/// advances up the screen, and it maps `a_uv` over the cell with the same
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/// handedness, so a glyph's top row stays its top row however the cell is
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/// turned. The fragment shader converts back to texels and samples the
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/// single-channel `GL_R8` atlas at the nearest texel centre, so `GL_NEAREST`
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/// never lands on a cell boundary. `u_color` tints the straight alpha.
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///
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/// Uniforms: `u_viewport` (vec2, pixels), `u_px_range` (vec2, the glyph cell's
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/// size on screen in pixels), `u_glyph_uv` (vec2, the glyph cell's size in
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/// normalised atlas coordinates -- one size for the whole draw, since every
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/// glyph of a frame comes from one atlas), `u_tex_size` (vec2, atlas size in
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/// texels), `u_atlas` (sampler2D, unit 0), `u_color` (vec4).
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extern const char* const kTextVS;
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extern const char* const kTextFS;
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} // namespace plot::render
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