skia2/gm/daa.cpp
Mike Klein 1edcea99ab add more test cases to DAA gm
These explicitly hit the double up edge screw case we use all the time,
with a couple variations in number of draws and in the winding.

Bug: skia:6886
Change-Id: I0a22d9a48254fe80c874dcfc46e2af6eb1c21f17
Reviewed-on: https://skia-review.googlesource.com/c/190667
Commit-Queue: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
2019-02-08 17:37:50 +00:00

131 lines
3.8 KiB
C++

/*
* Copyright 2018 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm.h"
#include "SkFont.h"
#include "SkPath.h"
// This GM shows off a flaw in delta-based rasterizers (DAA, CCPR, etc.).
// See also the bottom of dashing4 and skia:6886.
static const int K = 49;
DEF_SIMPLE_GM(daa, canvas, K+350, 5*K) {
SkPaint paint;
paint.setAntiAlias(true);
{
paint.setColor(SK_ColorBLACK);
canvas->drawString("Should be a green square with no red showing through.",
K*1.5f, K*0.5f, SkFont(), paint);
paint.setColor(SK_ColorRED);
canvas->drawRect({0,0,K,K}, paint);
SkPath path;
SkPoint tri1[] = {{0,0},{K,K},{0,K},{0,0}};
SkPoint tri2[] = {{0,0},{K,K},{K,0},{0,0}};
path.addPoly(tri1, SK_ARRAY_COUNT(tri1), false);
path.addPoly(tri2, SK_ARRAY_COUNT(tri2), false);
paint.setColor(SK_ColorGREEN);
canvas->drawPath(path, paint);
}
canvas->translate(0,K);
{
paint.setColor(SK_ColorBLACK);
canvas->drawString("Adjacent rects, two draws. Blue then green, no red?",
K*1.5f, K*0.5f, SkFont(), paint);
paint.setColor(SK_ColorRED);
canvas->drawRect({0,0,K,K}, paint);
{
SkPath path;
SkPoint rect1[] = {{0,0},{0,K},{K*0.5f,K},{K*0.5f,0}};
path.addPoly(rect1, SK_ARRAY_COUNT(rect1), false);
paint.setColor(SK_ColorBLUE);
canvas->drawPath(path, paint);
}
{
SkPath path;
SkPoint rect2[] = {{K*0.5f,0},{K*0.5f,K},{K,K},{K,0}};
path.addPoly(rect2, SK_ARRAY_COUNT(rect2), false);
paint.setColor(SK_ColorGREEN);
canvas->drawPath(path, paint);
}
}
canvas->translate(0,K);
{
paint.setColor(SK_ColorBLACK);
canvas->drawString("Adjacent rects, wound together. All green?",
K*1.5f, K*0.5f, SkFont(), paint);
paint.setColor(SK_ColorRED);
canvas->drawRect({0,0,K,K}, paint);
{
SkPath path;
SkPoint rect1[] = {{0,0},{0,K},{K*0.5f,K},{K*0.5f,0}};
SkPoint rect2[] = {{K*0.5f,0},{K*0.5f,K},{K,K},{K,0}};
path.addPoly(rect1, SK_ARRAY_COUNT(rect1), false);
path.addPoly(rect2, SK_ARRAY_COUNT(rect2), false);
paint.setColor(SK_ColorGREEN);
canvas->drawPath(path, paint);
}
}
canvas->translate(0,K);
{
paint.setColor(SK_ColorBLACK);
canvas->drawString("Adjacent rects, wound opposite. All green?",
K*1.5f, K*0.5f, SkFont(), paint);
paint.setColor(SK_ColorRED);
canvas->drawRect({0,0,K,K}, paint);
{
SkPath path;
SkPoint rect1[] = {{0,0},{0,K},{K*0.5f,K},{K*0.5f,0}};
SkPoint rect2[] = {{K*0.5f,0},{K,0},{K,K},{K*0.5f,K}};
path.addPoly(rect1, SK_ARRAY_COUNT(rect1), false);
path.addPoly(rect2, SK_ARRAY_COUNT(rect2), false);
paint.setColor(SK_ColorGREEN);
canvas->drawPath(path, paint);
}
}
canvas->translate(0,K);
{
paint.setColor(SK_ColorBLACK);
canvas->drawString("One poly, wound opposite. All green?",
K*1.5f, K*0.5f, SkFont(), paint);
paint.setColor(SK_ColorRED);
canvas->drawRect({0,0,K,K}, paint);
{
SkPath path;
SkPoint poly[] = {{K*0.5f,0},{0,0},{0,K},{K*0.5f,K},{K*0.5f,0},{K,0},{K,K},{K*0.5f,K}};
path.addPoly(poly, SK_ARRAY_COUNT(poly), false);
paint.setColor(SK_ColorGREEN);
canvas->drawPath(path, paint);
}
}
}