114 lines
4.9 KiB
C
114 lines
4.9 KiB
C
// Copyright Contributors to the Open Shading Language project.
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// SPDX-License-Identifier: BSD-3-Clause
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// https://github.com/AcademySoftwareFoundation/OpenShadingLanguage
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#ifndef OSLUTIL_H
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#define OSLUTIL_H
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// Return wireframe opacity factor [0, 1] given a geometry type in
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// ("triangles", "polygons" or "patches"), and a line_width in raster
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// or world space depending on the last (raster) boolean argument.
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//
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float wireframe(string edge_type, float line_width, int raster)
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{
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// ray differentials are so big in diffuse context that this function would always return "wire"
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if (raytype("path:diffuse")) return 0.0;
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int np = 0;
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point p[64];
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float pixelWidth = 1;
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if (edge_type == "triangles")
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{
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np = 3;
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if (!getattribute("geom:trianglevertices", p))
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return 0.0;
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}
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else if (edge_type == "polygons" || edge_type == "patches")
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{
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getattribute("geom:numpolyvertices", np);
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if (np < 3 || !getattribute("geom:polyvertices", p))
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return 0.0;
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}
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if (raster)
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{
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// Project the derivatives of P to the viewing plane defined
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// by I so we have a measure of how big is a pixel at this point
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float pixelWidthX = length(Dx(P) - dot(Dx(P), I) * I);
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float pixelWidthY = length(Dy(P) - dot(Dy(P), I) * I);
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// Take the average of both axis' length
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pixelWidth = (pixelWidthX + pixelWidthY) / 2;
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}
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// Use half the width as the neighbor face will render the
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// other half. And take the square for fast comparison
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pixelWidth *= 0.5 * line_width;
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pixelWidth *= pixelWidth;
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for (int i = 0; i < np; i++)
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{
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int i2 = i ? i - 1 : np - 1;
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vector dir = P - p[i];
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vector edge = p[i] - p[i2];
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vector crs = cross(edge, dir);
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// At this point dot(crs, crs) / dot(edge, edge) is
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// the square of area / length(edge) == square of the
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// distance to the edge.
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if (dot(crs, crs) < (dot(edge, edge) * pixelWidth))
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return 1;
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}
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return 0;
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}
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float wireframe(string edge_type, float line_width) { return wireframe(edge_type, line_width, 1); }
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float wireframe(string edge_type) { return wireframe(edge_type, 1.0, 1); }
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float wireframe() { return wireframe("polygons", 1.0, 1); }
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float draw_string(string str, float s, float t, int wrap_s, int wrap_t, int jitter) {
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// Glyphs from http://font.gohu.org/ (8x14 version, most common ascii characters only)
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int glyph_pixel(int c_, int x_, int y) {
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int c = c_ - 33; // nudge to origin
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int x = x_ - 1;
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if (c < 0 || x < 0 || y < 0 ) return 0;
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if (c > 93 || x > 6 || y > 13) return 0;
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int i = 98 * c + 7 * y + x;
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return ((getchar("0@P01248@00120000P49B0000000000000:DXlW2UoDX@10008@h;IR4n@R<Y?48000PYDF"
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"PP011J:U1000<T8QQQDAR4a50000@P012000000000000222448@P024@010028P0148@PP011100000"
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"ABELDU410000000048@l7124000000000000000H`01100000000n10000000000000000006<0000@P"
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"P011224488@00000`CXHY:=:D8?0000004<DT01248@000000l4:444444h700000`C8@Ph02D8?0000"
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"008HX89b?8@P000000n58`7@P05b300000`CP0O25:D8?00000POPP0112248000000l4:D8?Q25b300"
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"000`CX@Ql1244700000000H`0000<H00000000`P1000H`0110000044444@014@0000000n100PO000"
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"0000004@014@@@@@0000h948@@@@00120000`G`l5;F\\Lf0n100000l4:DXOQ25:400000hCX@Qn4:D"
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"X?000000?Q248@P0Ql000000N49DX@Q25i100000hGP01N48@PO00000PO124hAP012000000l4:@PLQ"
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"25b3000008DX@Qn5:DX@000000748@P0124L00000001248@P25b3000008DT456D8AT@00000P01248"
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"@P01n10000017G=IbP1364000008dXAU:U:E\\H000000?Q25:DX@Ql000000n4:DX?1248000000`CX"
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"@Q2U:E4GP0000P?Q25jCR8Q2100000l4:@0?P05b300000l71248@P01200000P@Q25:DX@Ql0000002"
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"5:D89BT`P1000004<HbT9[:BT800000P@QT8QQ49Q210000013:B4548@P000000h7888888@PO00000"
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"7248@P01248`10P0148P0148P0148000h01248@P0124>000015A000000000000000000000000h?00"
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"04@010000000000000000l0bGX@aL10000124XcX@Q25j300000000?Q248@8?000008@Pl5:DX@aL10"
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"000000`CX@o24`70000`AP01N48@P0100000000l5:DX@aL12T70124XcX@Q25:40000@P0P348@P01>"
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"00000240HP01248@P0a101248@T47B4940000HP01248@P01L00000000oBV<IbT910000000hCX@Q25"
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":400000000?Q25:D8?00000000j<:DX@Qn48@00000`GX@Q25c58@P0000P>S248@P000000000l48P7"
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"@Pn0000048@`31248@030000000P@Q25:D<G0000000025:T49<H000000004<HbTE5920000000P@QT"
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"`@BX@0000000025:DX@aL12T70000h744444h70000PS01248>P0124`1001248@P01248@P0007@P01"
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"24`@P01R30000000S9S10000000", i / 6) - 48) >> (i % 6)) & 1;
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}
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int modp(int a, int b) {
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int x = a % b;
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return x < 0 ? x + b : x;
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}
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int len = strlen(str);
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int jit = jitter ? hash(str) : 0;
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int pix_w = len * 8;
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int pix_h = 14;
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int x = int(floor(s));
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int y = int(floor(t));
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if (wrap_s) x = modp(x + ( jitter & 15), pix_w + pix_h);
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if (wrap_t) y = modp(y + ((jitter >> 16) & 15), pix_h + pix_h);
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return float(glyph_pixel(getchar(str, x / 8), x - (x / 8) * 8, y));
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}
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#endif /* OSLUTIL_H */
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