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Diffstat (limited to 'src/runtime/shaders/distancefieldtext.vert')
| -rw-r--r-- | src/runtime/shaders/distancefieldtext.vert | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/src/runtime/shaders/distancefieldtext.vert b/src/runtime/shaders/distancefieldtext.vert index fa96ff7..306d109 100644 --- a/src/runtime/shaders/distancefieldtext.vert +++ b/src/runtime/shaders/distancefieldtext.vert @@ -1,3 +1,9 @@ +#ifdef GL_OES_standard_derivatives +# extension GL_OES_standard_derivatives : enable +#else +# define use_fallback +#endif + uniform highp mat4 mvp; uniform highp float fontScale; uniform int textureWidth; @@ -7,6 +13,8 @@ attribute highp vec4 vCoord; attribute highp vec2 tCoord; varying highp vec2 sampleCoord; + +#ifdef use_fallback varying highp vec2 alphas; highp float thresholdFunc(highp float scale) @@ -53,11 +61,15 @@ highp float determinant(highp mat4 m) det -= m[3][0] * determinantOfSubmatrix(m, 0, 1, 2, 1, 2, 3); return det; } +#endif void main() { - highp float scale = fontScale * sqrt(abs(determinant(mvp))); +#ifdef use_fallback + highp float scale = fontScale * pow(abs(determinant(mvp)), 1.0 / 3.0); alphas = alphaRange(scale); +#endif + sampleCoord = tCoord * vec2(1.0 / float(textureWidth), 1.0 / float(textureHeight)); gl_Position = mvp * vCoord; } |