TextureTools: don't require more than 8 texture units in distanceFiel…

…d(). ES2 contexts on iOS don't have more than that. It's weird, because ES3 contexts have 16.
mosra · Jul 19, 2018 · 2e4beb3 · 2e4beb3
1 parent 4edb080
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Showing 3 changed files with 10 additions and 2 deletions.
diff --git a/doc/changelog.dox b/doc/changelog.dox
@@ -122,6 +122,12 @@ See also:
     @ref Shaders::VertexColor::Color4 attribute specifiers for more convenient
     distinction between three- and four-component vertex color attribute.
 
+@subsubsection changelog-latest-changes-texturetools TextureTools library
+
+-   Fixed @ref TextureTools::distanceField() to not require more than 8 texture
+    units, which is the limit on all iOS ES2 contexts, independently on the
+    device (ES3 contexts have 16).
+
 @subsubsection changelog-latest-changes-trade Trade library
 
 -   @ref Trade::PhongMaterialData now contains well-defined color values

diff --git a/src/Magnum/TextureTools/DistanceField.cpp b/src/Magnum/TextureTools/DistanceField.cpp
@@ -75,7 +75,9 @@ class DistanceFieldShader: public GL::AbstractShaderProgram {
         }
 
     private:
-        enum: Int { TextureUnit = 8 };
+        /* ES2 on iOS (apparently independent on the device) has only 8 texture
+           units, so be careful to not step over that. ES3 has 16. */
+        enum: Int { TextureUnit = 7 };
 
         Int radiusUniform{0},
             scalingUniform{1},

diff --git a/src/Magnum/TextureTools/DistanceFieldShader.frag b/src/Magnum/TextureTools/DistanceFieldShader.frag
@@ -46,7 +46,7 @@ uniform mediump vec2 scaling;
 #endif
 
 #ifdef EXPLICIT_TEXTURE_LAYER
-layout(binding = 8) uniform sampler2D textureData;
+layout(binding = 7) uniform sampler2D textureData;
 #else
 uniform lowp sampler2D textureData;
 #endif