drawLine wrong when thickness !=1

[NgVThangBz]

• axmol version:2.3.1
• devices test on:All devices
• developing environments
  • NDK version: r23c
  • Xcode version: 14.2+
  • Visual Studio:
    • VS version: 2022 (17.9+)
    • MSVC version: 19.39+
    • Windows SDK version: 10.0.22621.0+
  • cmake version:
    Steps to Reproduce:

just simple check:
mydraw->drawLine(Vec2(200,200), Vec2(400,200), Color4B::RED,1);
mydraw->drawLine(Vec2(200,300), Vec2(400,300), Color4B::RED,2);
and result:

It seems like the thickness needs to be divided by a factor

It seems to be related to _contentScaleFactor

[rh101]

If the thickness is being scaled, then isn't the existing behavior correct?

For example, if you draw a line of thickness 1, and the contentScaleFactor is 2, then the line drawn should be be 2 pixels thick. Isn't that the purpose of the content scale factor, or am I misunderstanding it?

If you have a content scale factor that is not equal to 1, yet you require the lines to not be affected by it, then wouldn't the following work?

mydraw->drawLine(Vec2(200, 200), Vec2(400, 200), Color4B::RED, 1 / AX_CONTENT_SCALE_FACTOR());

[NgVThangBz]

i tested, even when _contentScaleFactor = 1, the error still occurs,
line with thickness = 0.9 is bigger than line with thickness = 1
i think drawing thickness = 1 is fine now, we just need to recalculate drawing thickness != 1 to match the size

However, I have an app with contentScaleFactor = 10, and lines with thickness!= are drawn much larger

[rh101]

i tested, even when _contentScaleFactor = 1, the error still occurs, line with thickness = 0.9 is bigger than line with thickness = 1 i think drawing thickness = 1 is fine now, we just need to recalculate drawing thickness != 1 to match the size

However, I have an app with contentScaleFactor = 10, and lines with thickness!= are drawn much larger

OK, in that case it may be a bug. @aismann would the one who is familiar with the DrawNode implementation.

[NgVThangBz]

sorry for the misinformation, but it seems _contentScaleFactor doesn't affect drawNode

[aismann]

@NgVThangBz
Can you try this snippet:

mydraw->properties.setDrawOrder(true);  // drawing all with polygons
float _scaleFactor = Director::getInstance()->getContentScaleFactor() * 2;
mydraw->drawLine(Vec2(200,200), Vec2(400,200), Color4B::RED, 1.0f / _scaleFactor);
mydraw->drawLine(Vec2(200,300), Vec2(400,300), Color4B::RED, 2.0f / _scaleFactor);

A faster way is using a defined thickness array:

mydraw->properties.setDrawOrder(true);  // drawing all with polygons
float myScaleFactor = AX_CONTENT_SCALE_FACTOR();
float thickness[10];  /// max thickness is 9
for (int i = 0; i < 10; i++)
{
    thickness[i] = (float) i / (myScaleFactor * 2);
}
mydraw->drawLine(Vec2(200,200), Vec2(400,200), Color4B::RED, thickness[1]);
mydraw->drawLine(Vec2(200,300), Vec2(400,300), Color4B::RED, thickness[2]);

[NgVThangBz]

@aismann
Yes, I was able to handle it in my code,
however I wish Axmol could handle it too so that newbies can easily use DrawNode

[aismann]

@aismann Yes, I was able to handle it in my code, ...

@NgVThangBz
Using mydraw->properties.setDrawOrder(true); and your own thickness (scale) is working for you, right?

[aismann]

I will add a new property:
drawNode->properties.drawAllWithPolygons(false/true) // false is the default

The problem is:
The performance will be slower if each draw call have scale the same thickness again.

At the moment I add Wiki entry: