fix [3127755] Launcher is missing anti-aliasing

Enable limited forms of mipmaping when possible.

Change-Id: I39ad90becaa4048844fdbbbcb187333e7d59fc6a

Author: pixelflinger

libs/rs/rsContext.cpp

@@ -572,6 +572,7 @@ void Context::setSurface(uint32_t w, uint32_t h, ANativeWindow *sur)
             glGetIntegerv(GL_MAX_FRAGMENT_UNIFORM_VECTORS, &mGL.mMaxFragmentUniformVectors);
 
             mGL.OES_texture_npot = NULL != strstr((const char *)mGL.mExtensions, "GL_OES_texture_npot");
+            mGL.GL_IMG_texture_npot = NULL != strstr((const char *)mGL.mExtensions, "GL_IMG_texture_npot");
         }
 
     }

libs/rs/rsContext.h

@@ -166,6 +166,7 @@ class Context
     mutable const ObjectBase * mObjHead;
 
     bool ext_OES_texture_npot() const {return mGL.OES_texture_npot;}
+    bool ext_GL_IMG_texture_npot() const {return mGL.GL_IMG_texture_npot;}
 
 protected:
     Device *mDev;
@@ -202,6 +203,7 @@ class Context
         int32_t mMaxVertexTextureUnits;
 
         bool OES_texture_npot;
+        bool GL_IMG_texture_npot;
     } mGL;
 
     uint32_t mWidth;

libs/rs/rsSampler.cpp

@@ -70,7 +70,11 @@ void Sampler::setupGL(const Context *rsc, bool npot)
     }
 
     if ((mMinFilter == RS_SAMPLER_LINEAR_MIP_LINEAR) && forceNonMip) {
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        if (rsc->ext_GL_IMG_texture_npot()) {
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
+        } else {
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        }
     } else {
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, trans[mMinFilter]);
     }