1 files changed, 58 insertions, 0 deletions
diff --git a/src/quick/scenegraph/shaders/hiqsubpixeldistancefieldtext.frag b/src/quick/scenegraph/shaders/hiqsubpixeldistancefieldtext.frag
new file mode 100644
index 0000000000..9b65e5f79b
--- /dev/null
+++ b/src/quick/scenegraph/shaders/hiqsubpixeldistancefieldtext.frag
@@ -0,0 +1,58 @@
+varying highp vec2 sampleCoord;
+varying highp vec3 sampleFarLeft;
+varying highp vec3 sampleNearLeft;
+varying highp vec3 sampleNearRight;
+varying highp vec3 sampleFarRight;
+
+uniform sampler2D _qt_texture;
+uniform lowp vec4 color;
+uniform mediump float alphaMin;
+uniform mediump float alphaMax;
+
+void main()
+{
+    highp vec4 n;
+    n.x = texture2DProj(_qt_texture, sampleFarLeft).a;
+    n.y = texture2DProj(_qt_texture, sampleNearLeft).a;
+    highp float c = texture2D(_qt_texture, sampleCoord).a;
+    n.z = texture2DProj(_qt_texture, sampleNearRight).a;
+    n.w = texture2DProj(_qt_texture, sampleFarRight).a;
+#if 0
+    // Blurrier, faster.
+    n = smoothstep(alphaMin, alphaMax, n);
+    c = smoothstep(alphaMin, alphaMax, c);
+#else
+    // Sharper, slower.
+    highp vec2 d = min(abs(n.yw - n.xz) * 2., 0.67);
+    highp vec2 lo = mix(vec2(alphaMin), vec2(0.5), d);
+    highp vec2 hi = mix(vec2(alphaMax), vec2(0.5), d);
+    n = smoothstep(lo.xxyy, hi.xxyy, n);
+    c = smoothstep(lo.x + lo.y, hi.x + hi.y, 2. * c);
+#endif
+    gl_FragColor = vec4(0.333 * (n.xyz + n.yzw + c), c) * color.w;
+}
+
+/*
+#extension GL_OES_standard_derivatives: enable
+
+varying highp vec2 sampleCoord;
+
+uniform sampler2D _qt_texture;
+uniform lowp vec4 color;
+uniform highp float alphaMin;
+uniform highp float alphaMax;
+
+void main()
+{
+    highp vec2 delta = dFdx(sampleCoord);
+    highp vec4 n;
+    n.x = texture2D(_qt_texture, sampleCoord - 0.667 * delta).a;
+    n.y = texture2D(_qt_texture, sampleCoord - 0.333 * delta).a;
+    highp float c = texture2D(_qt_texture, sampleCoord).a;
+    n.z = texture2D(_qt_texture, sampleCoord + 0.333 * delta).a;
+    n.w = texture2D(_qt_texture, sampleCoord + 0.667 * delta).a;
+    n = smoothstep(alphaMin, alphaMax, n);
+    c = smoothstep(alphaMin, alphaMax, c);
+    gl_FragColor = vec4(0.333 * (n.xyz + n.yzw + c), c) * color.w;
+};
+*/
+\ No newline at end of file