Convert geometry shaders to operate in Skia device space

Defers the transformation to normalized window coordinates until after
the geometry shader. Merges vertex and a geometry shader builders into
a single compilation unit with a common base class.  Updates CCPR
geometry shaders accordingly.

Bug: skia:
Change-Id: If93c90e978b1fdc7120febd05cfb05810fd496b5
Reviewed-on: https://skia-review.googlesource.com/62980
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/glsl/GrGLSLGeometryProcessor.cpp b/src/gpu/glsl/GrGLSLGeometryProcessor.cpp
index cb421ad..8ee9bbd 100644
--- a/src/gpu/glsl/GrGLSLGeometryProcessor.cpp
+++ b/src/gpu/glsl/GrGLSLGeometryProcessor.cpp
@@ -11,15 +11,31 @@
 #include "glsl/GrGLSLFragmentShaderBuilder.h"
 #include "glsl/GrGLSLUniformHandler.h"
 #include "glsl/GrGLSLVarying.h"
-#include "glsl/GrGLSLVertexShaderBuilder.h"
+#include "glsl/GrGLSLVertexGeoBuilder.h"
 
 void GrGLSLGeometryProcessor::emitCode(EmitArgs& args) {
-    GrGLSLVertexBuilder* vBuilder = args.fVertBuilder;
     GrGPArgs gpArgs;
     this->onEmitCode(args, &gpArgs);
-    vBuilder->transformToNormalizedDeviceSpace(gpArgs.fPositionVar, args.fRTAdjustName);
-    if (kFloat2_GrSLType == gpArgs.fPositionVar.getType() ||
-        kHalf2_GrSLType == gpArgs.fPositionVar.getType()) {
+    SkASSERT(kFloat2_GrSLType == gpArgs.fPositionVar.getType() ||
+             kFloat3_GrSLType == gpArgs.fPositionVar.getType());
+
+    GrGLSLVertexBuilder* vBuilder = args.fVertBuilder;
+    if (!args.fGP.willUseGeoShader()) {
+        // Emit the vertex position to the hardware in the normalized window coordinates it expects.
+        vBuilder->emitNormalizedSkPosition(gpArgs.fPositionVar.c_str(), args.fRTAdjustName,
+                                           gpArgs.fPositionVar.getType());
+    } else {
+        // Since we have a geometry shader, leave the vertex position in Skia device space for now.
+        // The geometry Shader will operate in device space, and then convert the final positions to
+        // normalized hardware window coordinates under the hood, once everything else has finished.
+        vBuilder->codeAppendf("sk_Position = float4(%s", gpArgs.fPositionVar.c_str());
+        if (kFloat2_GrSLType == gpArgs.fPositionVar.getType()) {
+            vBuilder->codeAppend(", 0");
+        }
+        vBuilder->codeAppend(", 1);");
+    }
+
+    if (kFloat2_GrSLType == gpArgs.fPositionVar.getType()) {
         args.fVaryingHandler->setNoPerspective();
     }
 }
diff --git a/src/gpu/glsl/GrGLSLGeometryShaderBuilder.cpp b/src/gpu/glsl/GrGLSLGeometryShaderBuilder.cpp
deleted file mode 100644
index d9f34c2..0000000
--- a/src/gpu/glsl/GrGLSLGeometryShaderBuilder.cpp
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * 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 "GrGLSLGeometryShaderBuilder.h"
-#include "GrGLSLProgramBuilder.h"
-#include "GrGLSLVarying.h"
-
-static const char* input_type_name(GrGLSLGeometryBuilder::InputType in) {
-    using InputType = GrGLSLGeometryBuilder::InputType;
-    switch (in) {
-        case InputType::kPoints: return "points";
-        case InputType::kLines: return "lines";
-        case InputType::kLinesAdjacency: return "lines_adjacency";
-        case InputType::kTriangles: return "triangles";
-        case InputType::kTrianglesAdjacency: return "triangles_adjacency";
-    }
-    SK_ABORT("invalid input type");
-    return "unknown_input";
-}
-
-static const char* output_type_name(GrGLSLGeometryBuilder::OutputType out) {
-    using OutputType = GrGLSLGeometryBuilder::OutputType;
-    switch (out) {
-        case OutputType::kPoints: return "points";
-        case OutputType::kLineStrip: return "line_strip";
-        case OutputType::kTriangleStrip: return "triangle_strip";
-    }
-    SK_ABORT("invalid output type");
-    return "unknown_output";
-}
-
-GrGLSLGeometryBuilder::GrGLSLGeometryBuilder(GrGLSLProgramBuilder* program)
-    : INHERITED(program)
-    , fNumInvocations(0) {
-}
-
-void GrGLSLGeometryBuilder::configure(InputType inputType, OutputType outputType, int maxVertices,
-                                      int numInvocations) {
-    SkASSERT(!this->isConfigured());
-    fNumInvocations = numInvocations;
-    this->addLayoutQualifier(input_type_name(inputType), kIn_InterfaceQualifier);
-    this->addLayoutQualifier(SkStringPrintf("invocations = %i", numInvocations).c_str(),
-                             kIn_InterfaceQualifier);
-    this->addLayoutQualifier(output_type_name(outputType), kOut_InterfaceQualifier);
-    this->addLayoutQualifier(SkStringPrintf("max_vertices = %i", maxVertices).c_str(),
-                             kOut_InterfaceQualifier);
-}
-
-void GrGLSLGeometryBuilder::onFinalize() {
-    SkASSERT(this->isConfigured());
-    fProgramBuilder->varyingHandler()->getGeomDecls(&this->inputs(), &this->outputs());
-}
diff --git a/src/gpu/glsl/GrGLSLGeometryShaderBuilder.h b/src/gpu/glsl/GrGLSLGeometryShaderBuilder.h
deleted file mode 100644
index 04be530..0000000
--- a/src/gpu/glsl/GrGLSLGeometryShaderBuilder.h
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef GrGLSLGeometryShaderBuilder_DEFINED
-#define GrGLSLGeometryShaderBuilder_DEFINED
-
-#include "GrGLSLShaderBuilder.h"
-
-class GrGLSLVarying;
-
-class GrGLSLGeometryBuilder : public GrGLSLShaderBuilder {
-public:
-    GrGLSLGeometryBuilder(GrGLSLProgramBuilder* program);
-
-    enum class InputType {
-        kPoints,
-        kLines,
-        kLinesAdjacency,
-        kTriangles,
-        kTrianglesAdjacency
-    };
-
-    enum class OutputType {
-        kPoints,
-        kLineStrip,
-        kTriangleStrip
-    };
-
-    void configure(InputType, OutputType, int maxVertices, int numInvocations = 1);
-    bool isConfigured() const { return fNumInvocations; }
-
-private:
-    void onFinalize() override;
-
-    int fNumInvocations;
-
-    friend class GrGLProgramBuilder;
-
-    typedef GrGLSLShaderBuilder INHERITED;
-};
-
-#endif
diff --git a/src/gpu/glsl/GrGLSLPrimitiveProcessor.cpp b/src/gpu/glsl/GrGLSLPrimitiveProcessor.cpp
index 0cb7e4d..02fa2e7 100644
--- a/src/gpu/glsl/GrGLSLPrimitiveProcessor.cpp
+++ b/src/gpu/glsl/GrGLSLPrimitiveProcessor.cpp
@@ -12,7 +12,7 @@
 #include "glsl/GrGLSLFragmentShaderBuilder.h"
 #include "glsl/GrGLSLProgramBuilder.h"
 #include "glsl/GrGLSLUniformHandler.h"
-#include "glsl/GrGLSLVertexShaderBuilder.h"
+#include "glsl/GrGLSLVertexGeoBuilder.h"
 
 SkMatrix GrGLSLPrimitiveProcessor::GetTransformMatrix(const SkMatrix& localMatrix,
                                                       const GrCoordTransform& coordTransform) {
diff --git a/src/gpu/glsl/GrGLSLProgramBuilder.h b/src/gpu/glsl/GrGLSLProgramBuilder.h
index 0457e71..83a437f 100644
--- a/src/gpu/glsl/GrGLSLProgramBuilder.h
+++ b/src/gpu/glsl/GrGLSLProgramBuilder.h
@@ -13,11 +13,10 @@
 #include "GrProgramDesc.h"
 #include "glsl/GrGLSLFragmentProcessor.h"
 #include "glsl/GrGLSLFragmentShaderBuilder.h"
-#include "glsl/GrGLSLGeometryShaderBuilder.h"
 #include "glsl/GrGLSLPrimitiveProcessor.h"
 #include "glsl/GrGLSLProgramDataManager.h"
 #include "glsl/GrGLSLUniformHandler.h"
-#include "glsl/GrGLSLVertexShaderBuilder.h"
+#include "glsl/GrGLSLVertexGeoBuilder.h"
 #include "glsl/GrGLSLXferProcessor.h"
 
 class GrShaderVar;
diff --git a/src/gpu/glsl/GrGLSLVertexGeoBuilder.cpp b/src/gpu/glsl/GrGLSLVertexGeoBuilder.cpp
new file mode 100644
index 0000000..1cf85f7
--- /dev/null
+++ b/src/gpu/glsl/GrGLSLVertexGeoBuilder.cpp
@@ -0,0 +1,97 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrGLSLVertexGeoBuilder.h"
+
+#include "GrGLSLProgramBuilder.h"
+#include "GrGLSLVarying.h"
+#include "GrTypes.h"
+
+void GrGLSLVertexGeoBuilder::emitNormalizedSkPosition(SkString* out, const char* devPos,
+                                                      const char* rtAdjustName,
+                                                      GrSLType devPosType) {
+    if (this->getProgramBuilder()->desc()->header().fSnapVerticesToPixelCenters) {
+        if (kFloat3_GrSLType == devPosType) {
+            const char* p = devPos;
+            out->appendf("{float2 _posTmp = float2(%s.x/%s.z, %s.y/%s.z);", p, p, p, p);
+        } else {
+            SkASSERT(kFloat2_GrSLType == devPosType);
+            out->appendf("{float2 _posTmp = %s;", devPos);
+        }
+        out->appendf("_posTmp = floor(_posTmp) + half2(0.5, 0.5);"
+                     "sk_Position = float4(_posTmp.x * %s.x + %s.y,"
+                                          "_posTmp.y * %s.z + %s.w, 0, 1);}",
+                     rtAdjustName, rtAdjustName, rtAdjustName, rtAdjustName);
+    } else if (kFloat3_GrSLType == devPosType) {
+        out->appendf("sk_Position = float4(dot(%s.xz, %s.xy), dot(%s.yz, %s.zw), 0, %s.z);",
+                     devPos, rtAdjustName, devPos, rtAdjustName, devPos);
+    } else {
+        SkASSERT(kFloat2_GrSLType == devPosType);
+        out->appendf("sk_Position = float4(%s.x * %s.x + %s.y, %s.y * %s.z + %s.w, 0, 1);",
+                     devPos, rtAdjustName, rtAdjustName, devPos, rtAdjustName, rtAdjustName);
+    }
+}
+
+void GrGLSLVertexBuilder::onFinalize() {
+    // We could have the GrGeometryProcessor do this, but its just easier to have it performed
+    // here. If we ever need to set variable pointsize, then we can reinvestigate.
+    if (this->getProgramBuilder()->desc()->header().fHasPointSize) {
+        this->codeAppend("sk_PointSize = 1.0;");
+    }
+    fProgramBuilder->varyingHandler()->getVertexDecls(&this->inputs(), &this->outputs());
+}
+
+static const char* input_type_name(GrGLSLGeometryBuilder::InputType in) {
+    using InputType = GrGLSLGeometryBuilder::InputType;
+    switch (in) {
+        case InputType::kPoints: return "points";
+        case InputType::kLines: return "lines";
+        case InputType::kLinesAdjacency: return "lines_adjacency";
+        case InputType::kTriangles: return "triangles";
+        case InputType::kTrianglesAdjacency: return "triangles_adjacency";
+    }
+    SK_ABORT("invalid input type");
+    return "unknown_input";
+}
+
+static const char* output_type_name(GrGLSLGeometryBuilder::OutputType out) {
+    using OutputType = GrGLSLGeometryBuilder::OutputType;
+    switch (out) {
+        case OutputType::kPoints: return "points";
+        case OutputType::kLineStrip: return "line_strip";
+        case OutputType::kTriangleStrip: return "triangle_strip";
+    }
+    SK_ABORT("invalid output type");
+    return "unknown_output";
+}
+
+void GrGLSLGeometryBuilder::configure(InputType inputType, OutputType outputType, int maxVertices,
+                                      int numInvocations) {
+    SkASSERT(!this->isConfigured());
+    fNumInvocations = numInvocations;
+    this->addLayoutQualifier(input_type_name(inputType), kIn_InterfaceQualifier);
+    this->addLayoutQualifier(SkStringPrintf("invocations = %i", numInvocations).c_str(),
+                             kIn_InterfaceQualifier);
+    this->addLayoutQualifier(output_type_name(outputType), kOut_InterfaceQualifier);
+    this->addLayoutQualifier(SkStringPrintf("max_vertices = %i", maxVertices).c_str(),
+                             kOut_InterfaceQualifier);
+}
+
+void GrGLSLGeometryBuilder::emitVertex(SkString* out, const char* devPos, const char* rtAdjustName,
+                                       GrSLType devPosType) {
+    this->emitNormalizedSkPosition(out, devPos, rtAdjustName, devPosType);
+    out->append("EmitVertex();");
+}
+
+void GrGLSLGeometryBuilder::endPrimitive() {
+    this->codeAppend("EndPrimitive();");
+}
+
+void GrGLSLGeometryBuilder::onFinalize() {
+    SkASSERT(this->isConfigured());
+    fProgramBuilder->varyingHandler()->getGeomDecls(&this->inputs(), &this->outputs());
+}
diff --git a/src/gpu/glsl/GrGLSLVertexGeoBuilder.h b/src/gpu/glsl/GrGLSLVertexGeoBuilder.h
new file mode 100644
index 0000000..c0a55a0
--- /dev/null
+++ b/src/gpu/glsl/GrGLSLVertexGeoBuilder.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrGLSLVertexGeoBuilder_DEFINED
+#define GrGLSLVertexGeoBuilder_DEFINED
+
+#include "GrGLSLShaderBuilder.h"
+
+/**
+ * Base class for vertex and geometry shader builders. This is the stage that computes input
+ * geometry for the rasterizer.
+ */
+class GrGLSLVertexGeoBuilder : public GrGLSLShaderBuilder {
+protected:
+    GrGLSLVertexGeoBuilder(GrGLSLProgramBuilder* program) : INHERITED(program) {}
+
+    void emitNormalizedSkPosition(const char* devPos, const char* rtAdjustName,
+                                  GrSLType devPosType = GrSLType::kFloat2_GrSLType) {
+        this->emitNormalizedSkPosition(&this->code(), devPos, rtAdjustName, devPosType);
+    }
+
+    void emitNormalizedSkPosition(SkString* out, const char* devPos, const char* rtAdjustName,
+                                  GrSLType devPosType = GrSLType::kFloat2_GrSLType);
+
+    friend class GrGLSLGeometryProcessor;
+
+    typedef GrGLSLShaderBuilder INHERITED;
+};
+
+
+class GrGLSLVertexBuilder : public GrGLSLVertexGeoBuilder {
+public:
+    GrGLSLVertexBuilder(GrGLSLProgramBuilder* program) : INHERITED(program) {}
+
+private:
+    void onFinalize() override;
+
+    friend class GrGLProgramBuilder;
+
+    typedef GrGLSLVertexGeoBuilder INHERITED;
+};
+
+
+class GrGLSLGeometryBuilder : public GrGLSLVertexGeoBuilder {
+public:
+    GrGLSLGeometryBuilder(GrGLSLProgramBuilder* program) : INHERITED(program) {}
+
+    enum class InputType {
+        kPoints,
+        kLines,
+        kLinesAdjacency,
+        kTriangles,
+        kTrianglesAdjacency
+    };
+
+    enum class OutputType {
+        kPoints,
+        kLineStrip,
+        kTriangleStrip
+    };
+
+    void configure(InputType, OutputType, int maxVertices, int numInvocations = 1);
+    bool isConfigured() const { return fNumInvocations; }
+
+    void emitVertex(const char* devPos, const char* rtAdjustName,
+                    GrSLType devPosType = GrSLType::kFloat2_GrSLType) {
+        this->emitVertex(&this->code(), devPos, rtAdjustName, devPosType);
+    }
+    void emitVertex(SkString* out, const char* devPos, const char* rtAdjustName,
+                    GrSLType devPosType = GrSLType::kFloat2_GrSLType);
+
+    void endPrimitive();
+
+private:
+    void onFinalize() override;
+
+    int fNumInvocations = 0;
+
+    friend class GrGLProgramBuilder;
+
+    typedef GrGLSLVertexGeoBuilder INHERITED;
+};
+
+#endif
diff --git a/src/gpu/glsl/GrGLSLVertexShaderBuilder.cpp b/src/gpu/glsl/GrGLSLVertexShaderBuilder.cpp
deleted file mode 100644
index 192417c..0000000
--- a/src/gpu/glsl/GrGLSLVertexShaderBuilder.cpp
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * 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 "GrGLSLVertexShaderBuilder.h"
-#include "glsl/GrGLSLProgramBuilder.h"
-#include "glsl/GrGLSLUniformHandler.h"
-#include "glsl/GrGLSLVarying.h"
-
-GrGLSLVertexBuilder::GrGLSLVertexBuilder(GrGLSLProgramBuilder* program)
-    : INHERITED(program) {
-}
-
-void GrGLSLVertexBuilder::transformToNormalizedDeviceSpace(const GrShaderVar& posVar,
-                                                           const char* rtAdjustName) {
-    // setup RT Uniform
-    if (this->getProgramBuilder()->desc()->header().fSnapVerticesToPixelCenters) {
-        if (kFloat3_GrSLType == posVar.getType()) {
-            const char* p = posVar.c_str();
-            this->codeAppendf("{float2 _posTmp = float2(%s.x/%s.z, %s.y/%s.z);", p, p, p, p);
-        } else {
-            SkASSERT(kFloat2_GrSLType == posVar.getType());
-            this->codeAppendf("{float2 _posTmp = %s;", posVar.c_str());
-        }
-        this->codeAppendf("_posTmp = floor(_posTmp) + half2(0.5, 0.5);"
-                          "sk_Position = float4(_posTmp.x * %s.x + %s.y,"
-                                               "_posTmp.y * %s.z + %s.w, 0, 1);}",
-                          rtAdjustName, rtAdjustName, rtAdjustName, rtAdjustName);
-    } else if (kFloat3_GrSLType == posVar.getType()) {
-        this->codeAppendf("sk_Position = float4(dot(%s.xz, %s.xy), dot(%s.yz, %s.zw), 0, %s.z);",
-                          posVar.c_str(), rtAdjustName,
-                          posVar.c_str(), rtAdjustName,
-                          posVar.c_str());
-    } else {
-        SkASSERT(kFloat2_GrSLType == posVar.getType());
-        this->codeAppendf("sk_Position = float4(%s.x * %s.x + %s.y, %s.y * %s.z + %s.w, 0, 1);",
-                          posVar.c_str(), rtAdjustName, rtAdjustName,
-                          posVar.c_str(), rtAdjustName, rtAdjustName);
-    }
-    // We could have the GrGeometryProcessor do this, but its just easier to have it performed
-    // here. If we ever need to set variable pointsize, then we can reinvestigate.
-    if (this->getProgramBuilder()->desc()->header().fHasPointSize) {
-        this->codeAppend("sk_PointSize = 1.0;");
-    }
-}
-
-void GrGLSLVertexBuilder::onFinalize() {
-    fProgramBuilder->varyingHandler()->getVertexDecls(&this->inputs(), &this->outputs());
-}
diff --git a/src/gpu/glsl/GrGLSLVertexShaderBuilder.h b/src/gpu/glsl/GrGLSLVertexShaderBuilder.h
deleted file mode 100644
index 5d71565..0000000
--- a/src/gpu/glsl/GrGLSLVertexShaderBuilder.h
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef GrGLSLVertexShader_DEFINED
-#define GrGLSLVertexShader_DEFINED
-
-#include "GrGLSLShaderBuilder.h"
-#include "GrGeometryProcessor.h"
-
-class GrGLSLVarying;
-
-// Enough precision to represent 1 / 2048 accurately in printf
-#define GR_SIGNIFICANT_POW2_DECIMAL_DIG 11
-
-class GrGLSLVertexBuilder : public GrGLSLShaderBuilder {
-public:
-    GrGLSLVertexBuilder(GrGLSLProgramBuilder* program);
-
-    void transformToNormalizedDeviceSpace(const GrShaderVar& posVar, const char* rtAdjustName);
-private:
-    void onFinalize() override;
-
-    friend class GrGLProgramBuilder;
-
-    typedef GrGLSLShaderBuilder INHERITED;
-};
-
-#endif