Default geometry processor

src/gpu/GrOvalRenderer.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrOvalRenderer.h"
 
 #include "gl/builders/GrGLProgramBuilder.h"
@@ skipping 82 matching lines @@
         : INHERITED (factory) {}
 
         virtual void emitCode(const EmitArgs& args) SK_OVERRIDE {
             const CircleEdgeEffect& circleEffect = args.fGP.cast<CircleEdgeEffect>();
             GrGLVertToFrag v(kVec4f_GrSLType);
             args.fPB->addVarying("CircleEdge", &v);
 
             GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();;
             vsBuilder->codeAppendf("%s = %s;", v.vsOut(), circleEffect.inCircleEdge().c_str());
 
+            // setup position varying
+            vsBuilder->codeAppendf("vec3 pos3 = %s * vec3(%s, 1);", args.fGP.uViewM(),
+                                   args.fGP.inPosition());
+            vsBuilder->transformPositionToDeviceSpace("pos3");

[bsalomon, 2014/11/07 14:44:03]

This name is a bit confusing. I'd expect it to take a local coordinate to Skia's
non-normalized device space. But it actually converts from Skia device space to
GL normalized device space.

Can't we just make the builder auto convert gl_Position as the last line of the
shader without being asked to? For the most part processors only have to think
in terms of Skia's coordinate systems, it'd be nice to do that here too.

+
             GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
             fsBuilder->codeAppendf("float d = length(%s.xy);", v.fsIn());
             fsBuilder->codeAppendf("float edgeAlpha = clamp(%s.z - d, 0.0, 1.0);", v.fsIn());
             if (circleEffect.isStroked()) {
                 fsBuilder->codeAppendf("float innerAlpha = clamp(d - %s.w, 0.0, 1.0);",
                                        v.fsIn());
                 fsBuilder->codeAppend("edgeAlpha *= innerAlpha;");
             }
 
             fsBuilder->codeAppendf("%s = %s;\n", args.fOutput,
@@ skipping 99 matching lines @@
 
             GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
             vsBuilder->codeAppendf("%s = %s;", ellipseOffsets.vsOut(),
                                    ellipseEffect.inEllipseOffset().c_str());
 
             GrGLVertToFrag ellipseRadii(kVec4f_GrSLType);
             args.fPB->addVarying("EllipseRadii", &ellipseRadii);
             vsBuilder->codeAppendf("%s = %s;", ellipseRadii.vsOut(),
                                    ellipseEffect.inEllipseRadii().c_str());
 
+            // setup position varying
+            vsBuilder->codeAppendf("vec3 pos3 = %s * vec3(%s, 1);", args.fGP.uViewM(),
+                                   args.fGP.inPosition());
+            vsBuilder->transformPositionToDeviceSpace("pos3");
+
             // for outer curve
             GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
             fsBuilder->codeAppendf("vec2 scaledOffset = %s*%s.xy;", ellipseOffsets.fsIn(),
                                    ellipseRadii.fsIn());
             fsBuilder->codeAppend("float test = dot(scaledOffset, scaledOffset) - 1.0;");
             fsBuilder->codeAppendf("vec2 grad = 2.0*scaledOffset*%s.xy;", ellipseRadii.fsIn());
             fsBuilder->codeAppend("float grad_dot = dot(grad, grad);");
 
             // avoid calling inversesqrt on zero.
             fsBuilder->codeAppend("grad_dot = max(grad_dot, 1.0e-4);");
@@ skipping 126 matching lines @@
 
             GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
             vsBuilder->codeAppendf("%s = %s;", offsets0.vsOut(),
                                    ellipseEffect.inEllipseOffsets0().c_str());
 
             GrGLVertToFrag offsets1(kVec2f_GrSLType);
             args.fPB->addVarying("EllipseOffsets1", &offsets1);
             vsBuilder->codeAppendf("%s = %s;", offsets1.vsOut(),
                                    ellipseEffect.inEllipseOffsets1().c_str());
 
+            // setup position varying
+            vsBuilder->codeAppendf("vec3 pos3 = %s * vec3(%s, 1);", args.fGP.uViewM(),
+                                   args.fGP.inPosition());
+            vsBuilder->transformPositionToDeviceSpace("pos3");
+
             GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
             SkAssertResult(fsBuilder->enableFeature(
                     GrGLFragmentShaderBuilder::kStandardDerivatives_GLSLFeature));
             // for outer curve
             fsBuilder->codeAppendf("vec2 scaledOffset = %s.xy;", offsets0.fsIn());
             fsBuilder->codeAppend("float test = dot(scaledOffset, scaledOffset) - 1.0;");
             fsBuilder->codeAppendf("vec2 duvdx = dFdx(%s);", offsets0.fsIn());
             fsBuilder->codeAppendf("vec2 duvdy = dFdy(%s);", offsets0.fsIn());
             fsBuilder->codeAppendf("vec2 grad = vec2(2.0*%s.x*duvdx.x + 2.0*%s.y*duvdx.y,"
                                    "                 2.0*%s.x*duvdy.x + 2.0*%s.y*duvdy.y);",
@@ skipping 861 matching lines @@
         // drop out the middle quad if we're stroked
         int indexCnt = isStrokeOnly ? SK_ARRAY_COUNT(gRRectIndices) - 6 :
                                       SK_ARRAY_COUNT(gRRectIndices);
         target->setIndexSourceToBuffer(indexBuffer);
         target->drawIndexedInstances(kTriangles_GrPrimitiveType, 1, 16, indexCnt, &bounds);
     }
 
     target->resetIndexSource();
     return true;
 }