[impeller] aa line disappear when scaled down #165994
Description
reproduction
- AiksTest.ScaleExperimentAntialiasLines
- Set the line width to 2, the scale to 0.2
--- a/engine/src/flutter/impeller/entity/shaders/line.frag
+++ b/engine/src/flutter/impeller/entity/shaders/line.frag
@@ -41,6 +40,7 @@ float CalculateLine() {
void main() {
float line = CalculateLine();
- frag_color = vec4(frag_info.color.xyz, line);
+ // frag_color = vec4(frag_info.color.xyz, line);
+ frag_color = vec4(mix(vec3(1.0, 0.0, 0.0), frag_info.color.xyz, line), 1.0);
frag_color = IPPremultiply(frag_color);
}
observed results
In this image red is where the fragment shader is returning zero, the actual line is lime green but is isn't visible at all.
expected results
I expect the line to be lime green, not red.