Copy distance field shader changes to OpenGL runtime

Also fixes the OpenGL runtime to use alpha channel for the glyph texture
when using ES2.

Task-number: QT3DS-3343
Change-Id: Ia37c341802e504da21ebeaff6f3f1f5b50bd1bfe
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Antti Määttä <antti.maatta@qt.io>
 

1 files changed, 2 insertions, 30 deletions

diff --git a/src/Runtime/res/effectlib/distancefieldtext_core.vert b/src/Runtime/res/effectlib/distancefieldtext_core.vert
index ce6a165c..2dc198f4 100644
--- a/src/Runtime/res/effectlib/distancefieldtext_core.vert
+++ b/src/Runtime/res/effectlib/distancefieldtext_core.vert
@@ -3,41 +3,13 @@ in vec2 tCoord;
 
 out vec2 sampleCoord;
 
-out vec2 alphas;
-
 uniform mat4 mvp;
 uniform int textureWidth;
 uniform int textureHeight;
 uniform float fontScale;
 
-float thresholdFunc(float scale)
-{
-    float base = 0.5;
-    float baseDev = 0.065;
-    float devScaleMin = 0.15;
-    float devScaleMax = 0.3;
-    return base - ((clamp(scale, devScaleMin, devScaleMax) - devScaleMin)
-                   / (devScaleMax - devScaleMin) * -baseDev + baseDev);
-}
-
-float spreadFunc(float scale)
-{
-    return 0.06 / scale;
-}
-
-vec2 alphaRange(float scale)
-{
-    float base = thresholdFunc(scale);
-    float range = spreadFunc(scale);
-    float alphaMin = max(0.0, base - range);
-    float alphaMax = min(base + range, 1.0);
-    return vec2(alphaMin, alphaMax);
-}
-
 void main()
 {
-     float scale = fontScale * sqrt(abs(determinant(mvp)));
-     alphas = alphaRange(scale);
-     sampleCoord = tCoord * vec2(1.0 / float(textureWidth), 1.0 / float(textureHeight));
-     gl_Position = mvp * vec4(vCoord, 1.0);
+    sampleCoord = tCoord * vec2(1.0 / float(textureWidth), 1.0 / float(textureHeight));
+    gl_Position = mvp * vec4(vCoord, 1.0);
 }