Force input coverage to be only a byte in gpu shaders.

tests/GLProgramsTest.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 // This is a GPU-backend specific test. It relies on static intializers to work
 
@@ skipping 170 matching lines @@
 
     // local coords
     setup_random_ff_attribute(kLocalCoord_GrVertexAttribBinding, kVec2f_GrVertexAttribType,
                               random, &attribIndex, &runningStride);
 
     // color
     setup_random_ff_attribute(kColor_GrVertexAttribBinding, kVec4f_GrVertexAttribType,
                               random, &attribIndex, &runningStride);
 
     // coverage
-    setup_random_ff_attribute(kCoverage_GrVertexAttribBinding, kVec4f_GrVertexAttribType,
+    setup_random_ff_attribute(kCoverage_GrVertexAttribBinding, kUByte_GrVertexAttribType,
                               random, &attribIndex, &runningStride);
 
     // Update the geometry processor attributes
     const GrGeometryProcessor::VertexAttribArray& v = gp->getVertexAttribs();
     int numGPAttribs = v.count();
     SkASSERT(numGPAttribs <= GrGeometryProcessor::kMaxVertexAttribs &&
              GrGeometryProcessor::kMaxVertexAttribs == 2);
 
     // we actually can't overflow if kMaxVertexAttribs == 2, but GCC 4.8 wants more proof
     int maxIndex = SK_ARRAY_COUNT(kGenericVertexAttribs);
@@ skipping 304 matching lines @@
             if (type == GrContextFactory::kANGLE_GLContextType) {
                 maxStages = 3;
             }
 #endif
             REPORTER_ASSERT(reporter, gpu->programUnitTest(maxStages));
         }
     }
 }
 
 #endif