godot/thirdparty/thorvg/src/renderer/sw_engine/tvgSwRasterTexmap.h

/*
 * Copyright (c) 2021 - 2024 the ThorVG project. All rights reserved.

 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:

 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

struct AALine
{ … };

struct AASpans
{ … };

//Careful! Shared resource, No support threading
static float dudx, dvdx;
static float dxdya, dxdyb, dudya, dvdya;
static float xa, xb, ua, va;


//Y Range exception handling
static bool _arrange(const SwImage* image, const SwBBox* region, int& yStart, int& yEnd)
{ … }


static bool _rasterMaskedPolygonImageSegment(SwSurface* surface, const SwImage* image, const SwBBox* region, int yStart, int yEnd, AASpans* aaSpans, uint8_t opacity, uint8_t dirFlag = 0)
{ … }


static void _rasterBlendingPolygonImageSegment(SwSurface* surface, const SwImage* image, const SwBBox* region, int yStart, int yEnd, AASpans* aaSpans, uint8_t opacity)
{ … }


static void _rasterPolygonImageSegment(SwSurface* surface, const SwImage* image, const SwBBox* region, int yStart, int yEnd, AASpans* aaSpans, uint8_t opacity, bool matting)
{ … }


/* This mapping algorithm is based on Mikael Kalms's. */
static void _rasterPolygonImage(SwSurface* surface, const SwImage* image, const SwBBox* region, Polygon& polygon, AASpans* aaSpans, uint8_t opacity)
{ … }


static AASpans* _AASpans(float ymin, float ymax, const SwImage* image, const SwBBox* region)
{ … }


static void _calcIrregularCoverage(AALine* lines, int32_t eidx, int32_t y, int32_t diagonal, int32_t edgeDist, bool reverse)
{ … }


static void _calcVertCoverage(AALine *lines, int32_t eidx, int32_t y, int32_t rewind, bool reverse)
{ … }


static void _calcHorizCoverage(AALine *lines, int32_t eidx, int32_t y, int32_t x, int32_t x2)
{ … }


/*
 * This Anti-Aliasing mechanism is originated from Hermet Park's idea.
 * To understand this AA logic, you can refer this page:
 * https://uigraphics.tistory.com/1
*/
static void _calcAAEdge(AASpans *aaSpans, int32_t eidx)
{ … }


static bool _apply(SwSurface* surface, AASpans* aaSpans)
{ … }


/*
    2 triangles constructs 1 mesh.
    below figure illustrates vert[4] index info.
    If you need better quality, please divide a mesh by more number of triangles.

    0 -- 1
    |  / |
    | /  |
    3 -- 2
*/
static bool _rasterTexmapPolygon(SwSurface* surface, const SwImage* image, const Matrix& transform, const SwBBox* region, uint8_t opacity)
{ … }