130 lines
4.6 KiB
C++
130 lines
4.6 KiB
C++
// Copyright (c) Wojciech Figat. All rights reserved.
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#pragma once
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#include "Engine/Core/Collections/Array.h"
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#include "Engine/Core/Math/Math.h"
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#include <ThirdParty/freetype/ftoutln.h>
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#include <ThirdParty/msdfgen/msdfgen.h>
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class MSDFGenerator
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{
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using Point2 = msdfgen::Point2;
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using Shape = msdfgen::Shape;
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using Contour = msdfgen::Contour;
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using EdgeHolder = msdfgen::EdgeHolder;
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static Point2 ftPoint2(const FT_Vector& vector, double scale)
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{
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return Point2(scale * vector.x, scale * vector.y);
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}
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struct FtContext
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{
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double scale;
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Point2 position;
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Shape* shape;
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Contour* contour;
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};
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static int ftMoveTo(const FT_Vector* to, void* user)
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{
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FtContext* context = reinterpret_cast<FtContext*>(user);
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if (!(context->contour && context->contour->edges.empty()))
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context->contour = &context->shape->addContour();
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context->position = ftPoint2(*to, context->scale);
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return 0;
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}
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static int ftLineTo(const FT_Vector* to, void* user)
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{
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FtContext* context = reinterpret_cast<FtContext*>(user);
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Point2 endpoint = ftPoint2(*to, context->scale);
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if (endpoint != context->position)
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{
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context->contour->addEdge(EdgeHolder(context->position, endpoint));
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context->position = endpoint;
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}
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return 0;
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}
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static int ftConicTo(const FT_Vector* control, const FT_Vector* to, void* user)
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{
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FtContext* context = reinterpret_cast<FtContext*>(user);
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Point2 endpoint = ftPoint2(*to, context->scale);
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if (endpoint != context->position)
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{
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context->contour->addEdge(EdgeHolder(context->position, ftPoint2(*control, context->scale), endpoint));
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context->position = endpoint;
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}
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return 0;
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}
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static int ftCubicTo(const FT_Vector* control1, const FT_Vector* control2, const FT_Vector* to, void* user)
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{
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FtContext* context = reinterpret_cast<FtContext*>(user);
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Point2 endpoint = ftPoint2(*to, context->scale);
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if (endpoint != context->position || msdfgen::crossProduct(ftPoint2(*control1, context->scale) - endpoint, ftPoint2(*control2, context->scale) - endpoint))
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{
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context->contour->addEdge(EdgeHolder(context->position, ftPoint2(*control1, context->scale), ftPoint2(*control2, context->scale), endpoint));
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context->position = endpoint;
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}
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return 0;
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}
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public:
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static void GenerateMSDF(FT_GlyphSlot glyph, Array<byte>& output, int32& outputWidth, int32& outputHeight, int16& top, int16& left)
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{
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Shape shape;
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shape.contours.clear();
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shape.inverseYAxis = true;
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FtContext context = { };
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context.scale = 1.0 / 64.0;
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context.shape = &shape;
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FT_Outline_Funcs ftFunctions;
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ftFunctions.move_to = &ftMoveTo;
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ftFunctions.line_to = &ftLineTo;
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ftFunctions.conic_to = &ftConicTo;
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ftFunctions.cubic_to = &ftCubicTo;
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ftFunctions.shift = 0;
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ftFunctions.delta = 0;
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FT_Outline_Decompose(&glyph->outline, &ftFunctions, &context);
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shape.normalize();
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edgeColoringSimple(shape, 3.0);
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// Todo: make this configurable
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// Also hard-coded in material: MSDFFontMaterial
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const double pxRange = 4.0;
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msdfgen::Shape::Bounds bounds = shape.getBounds();
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int32 width = static_cast<int32>(Math::CeilToInt(bounds.r - bounds.l + pxRange));
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int32 height = static_cast<int32>(Math::CeilToInt(bounds.t - bounds.b + pxRange));
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msdfgen::Bitmap<float, 4> msdf(width, height);
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msdfgen::SDFTransformation t(
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msdfgen::Projection(1.0, msdfgen::Vector2(-bounds.l + pxRange / 2.0, -bounds.b + pxRange / 2.0)), msdfgen::Range(pxRange)
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);
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generateMTSDF(msdf, shape, t);
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output.Resize(width * height * 4);
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const msdfgen::BitmapConstRef<float, 4>& bitmap = msdf;
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for (int y = 0; y < height; ++y)
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{
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for (int x = 0; x < width; ++x)
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{
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output[(y * width + x) * 4] = msdfgen::pixelFloatToByte(bitmap(x, y)[0]);
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output[(y * width + x) * 4 + 1] = msdfgen::pixelFloatToByte(bitmap(x, y)[1]);
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output[(y * width + x) * 4 + 2] = msdfgen::pixelFloatToByte(bitmap(x, y)[2]);
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output[(y * width + x) * 4 + 3] = msdfgen::pixelFloatToByte(bitmap(x, y)[3]);
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}
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}
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outputWidth = width;
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outputHeight = height;
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top = static_cast<int16>(Math::CeilToInt(bounds.t + pxRange / 2.0));
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left = static_cast<int16>(Math::FloorToInt(bounds.l + pxRange / 2.0));
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}
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};
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