Add convex polygon rendering effect and GM to test it.
BUG=skia:2051
R=robertphillips@google.com, jvanverth@google.com
Author: bsalomon@google.com
Review URL: https://codereview.chromium.org/149683004
git-svn-id: http://skia.googlecode.com/svn/trunk@13242 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/effects/GrConvexPolyEffect.cpp b/src/gpu/effects/GrConvexPolyEffect.cpp
new file mode 100644
index 0000000..d780e28
--- /dev/null
+++ b/src/gpu/effects/GrConvexPolyEffect.cpp
@@ -0,0 +1,185 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrConvexPolyEffect.h"
+
+#include "gl/GrGLEffect.h"
+#include "gl/GrGLSL.h"
+#include "gl/GrGLVertexEffect.h"
+#include "GrTBackendEffectFactory.h"
+
+#include "SkPath.h"
+
+class GrGLConvexPolyEffect : public GrGLEffect {
+public:
+ GrGLConvexPolyEffect(const GrBackendEffectFactory&, const GrDrawEffect&);
+
+ virtual void emitCode(GrGLShaderBuilder* builder,
+ const GrDrawEffect& drawEffect,
+ EffectKey key,
+ const char* outputColor,
+ const char* inputColor,
+ const TransformedCoordsArray&,
+ const TextureSamplerArray&) SK_OVERRIDE;
+
+ static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&);
+
+ virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE;
+
+private:
+ GrGLUniformManager::UniformHandle fEdgeUniform;
+ SkScalar fPrevEdges[3 * GrConvexPolyEffect::kMaxEdges];
+ typedef GrGLEffect INHERITED;
+};
+
+GrGLConvexPolyEffect::GrGLConvexPolyEffect(const GrBackendEffectFactory& factory,
+ const GrDrawEffect& drawEffect)
+ : INHERITED (factory) {
+ fPrevEdges[0] = SK_ScalarNaN;
+}
+
+void GrGLConvexPolyEffect::emitCode(GrGLShaderBuilder* builder,
+ const GrDrawEffect& drawEffect,
+ EffectKey key,
+ const char* outputColor,
+ const char* inputColor,
+ const TransformedCoordsArray&,
+ const TextureSamplerArray& samplers) {
+ const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>();
+
+ const char *edgeArrayName;
+ fEdgeUniform = builder->addUniformArray(GrGLShaderBuilder::kFragment_Visibility,
+ kVec3f_GrSLType,
+ "edges",
+ cpe.getEdgeCount(),
+ &edgeArrayName);
+ builder->fsCodeAppend("\t\tfloat alpha = 1.0;\n");
+ builder->fsCodeAppend("\t\tfloat edge;\n");
+ const char* fragmentPos = builder->fragmentPosition();
+ for (int i = 0; i < cpe.getEdgeCount(); ++i) {
+ builder->fsCodeAppendf("\t\tedge = dot(%s[%d], vec3(%s.x, %s.y, 1));\n",
+ edgeArrayName, i, fragmentPos, fragmentPos);
+ switch (cpe.getEdgeType()) {
+ case GrConvexPolyEffect::kFillAA_EdgeType:
+ builder->fsCodeAppend("\t\tedge = clamp(edge, 0.0, 1.0);\n");
+ builder->fsCodeAppend("\t\talpha *= edge;\n");
+ break;
+ case GrConvexPolyEffect::kFillNoAA_EdgeType:
+ builder->fsCodeAppend("\t\tedge = edge >= 0.5 ? 1.0 : 0.0;\n");
+ builder->fsCodeAppend("\t\talpha *= edge;\n");
+ break;
+ }
+ }
+
+ builder->fsCodeAppendf("\t%s = %s;\n", outputColor,
+ (GrGLSLExpr4(inputColor) * GrGLSLExpr1("alpha")).c_str());
+}
+
+void GrGLConvexPolyEffect::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) {
+ const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>();
+ size_t byteSize = 3 * cpe.getEdgeCount() * sizeof(SkScalar);
+ if (0 != memcmp(fPrevEdges, cpe.getEdges(), byteSize)) {
+ uman.set3fv(fEdgeUniform, cpe.getEdgeCount(), cpe.getEdges());
+ memcpy(fPrevEdges, cpe.getEdges(), byteSize);
+ }
+}
+
+GrGLEffect::EffectKey GrGLConvexPolyEffect::GenKey(const GrDrawEffect& drawEffect,
+ const GrGLCaps&) {
+ const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>();
+ GR_STATIC_ASSERT(GrConvexPolyEffect::kEdgeTypeCnt <= 4);
+ return (cpe.getEdgeCount() << 2) | cpe.getEdgeType();
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
+GrEffectRef* GrConvexPolyEffect::Create(EdgeType type, const SkPath& path) {
+ if (path.getSegmentMasks() != SkPath::kLine_SegmentMask ||
+ !path.isConvex() ||
+ path.isInverseFillType()) {
+ return NULL;
+ }
+
+ if (path.countPoints() > kMaxEdges) {
+ return NULL;
+ }
+
+ SkPoint pts[kMaxEdges];
+ SkScalar edges[3 * kMaxEdges];
+
+ SkPath::Direction dir;
+ SkAssertResult(path.cheapComputeDirection(&dir));
+
+ int count = path.getPoints(pts, kMaxEdges);
+ int n = 0;
+ for (int lastPt = count - 1, i = 0; i < count; lastPt = i++) {
+ if (pts[lastPt] != pts[i]) {
+ SkVector v = pts[i] - pts[lastPt];
+ v.normalize();
+ if (SkPath::kCCW_Direction == dir) {
+ edges[3 * n] = v.fY;
+ edges[3 * n + 1] = -v.fX;
+ } else {
+ edges[3 * n] = -v.fY;
+ edges[3 * n + 1] = v.fX;
+ }
+ edges[3 * n + 2] = -(edges[3 * n] * pts[i].fX + edges[3 * n + 1] * pts[i].fY);
+ ++n;
+ }
+ }
+ return Create(type, n, edges);
+}
+
+GrConvexPolyEffect::~GrConvexPolyEffect() {}
+
+void GrConvexPolyEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
+ *validFlags = 0;
+}
+
+const GrBackendEffectFactory& GrConvexPolyEffect::getFactory() const {
+ return GrTBackendEffectFactory<GrConvexPolyEffect>::getInstance();
+}
+
+GrConvexPolyEffect::GrConvexPolyEffect(EdgeType edgeType, int n, const SkScalar edges[])
+ : fEdgeType(edgeType)
+ , fEdgeCount(n) {
+ // Factory function should have already ensured this.
+ SkASSERT(n <= kMaxEdges);
+ memcpy(fEdges, edges, 3 * n * sizeof(SkScalar));
+ // Outset the edges by 0.5 so that a pixel with center on an edge is 50% covered in the AA case
+ // and 100% covered in the non-AA case.
+ for (int i = 0; i < n; ++i) {
+ fEdges[3 * i + 2] += SK_ScalarHalf;
+ }
+ this->setWillReadFragmentPosition();
+}
+
+bool GrConvexPolyEffect::onIsEqual(const GrEffect& other) const {
+ const GrConvexPolyEffect& cpe = CastEffect<GrConvexPolyEffect>(other);
+ // ignore the fact that 0 == -0 and just use memcmp.
+ return (cpe.fEdgeType == fEdgeType && cpe.fEdgeCount == fEdgeCount &&
+ 0 == memcmp(cpe.fEdges, fEdges, 3 * fEdgeCount * sizeof(SkScalar)));
+}
+
+//////////////////////////////////////////////////////////////////////////////
+
+GR_DEFINE_EFFECT_TEST(GrConvexPolyEffect);
+
+GrEffectRef* GrConvexPolyEffect::TestCreate(SkRandom* random,
+ GrContext*,
+ const GrDrawTargetCaps& caps,
+ GrTexture*[]) {
+ EdgeType edgeType = static_cast<EdgeType>(random->nextULessThan(kEdgeTypeCnt));
+ int count = random->nextULessThan(kMaxEdges + 1);
+ SkScalar edges[kMaxEdges * 3];
+ for (int i = 0; i < 3 * count; ++i) {
+ edges[i] = random->nextSScalar1();
+ }
+
+ return GrConvexPolyEffect::Create(edgeType, count, edges);
+}
+