Default geometry processor

src/gpu/GrDefaultGeoProcFactory.cpp

+/*
+ * 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 "GrDefaultGeoProcFactory.h"
+
+#include "gl/builders/GrGLProgramBuilder.h"
+#include "gl/GrGLGeometryProcessor.h"
+#include "GrDrawState.h"
+#include "GrTBackendProcessorFactory.h"
+
+/*
+ * The default Geometry Processor simply takes position and multiplies it by the uniform view
+ * matrix. It also leaves coverage untouched.  Behind the scenes, we may add per vertex color or
+ * local coords.
+ */
+class DefaultGeoProc : public GrGeometryProcessor {
+public:
+    static GrGeometryProcessor* Create() {
+        GR_CREATE_STATIC_PROCESSOR(gDefaultGeoProc, DefaultGeoProc, ());
+        return SkRef(gDefaultGeoProc);
+    }
+
+    static const char* Name() { return "DefaultGeometryProcessor"; }
+
+    virtual const GrBackendGeometryProcessorFactory& getFactory() const SK_OVERRIDE {
+        return GrTBackendGeometryProcessorFactory<DefaultGeoProc>::getInstance();
+    }
+
+    class GLProcessor : public GrGLGeometryProcessor {
+    public:
+        GLProcessor(const GrBackendProcessorFactory& factory, const GrProcessor&)
+            : INHERITED (factory) {}
+
+        virtual void emitCode(const EmitArgs& args) SK_OVERRIDE {
+            GrGLVertexBuilder* vs = args.fPB->getVertexShaderBuilder();
+
+            // setup position varying
+            vs->codeAppendf("%s = %s * vec3(%s, 1);", vs->glPosition(), vs->uViewM(),
+                            vs->inPosition());
+
+            // output coverage in FS(pass through)
+            GrGLGPFragmentBuilder* fs = args.fPB->getFragmentShaderBuilder();
+            fs->codeAppendf("%s = %s;", args.fOutput, GrGLSLExpr4(args.fInput).c_str());
+        }
+
+        static inline void GenKey(const GrProcessor&, const GrGLCaps&, GrProcessorKeyBuilder*) {}
+
+        virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) SK_OVERRIDE {}
+
+    private:
+        typedef GrGLGeometryProcessor INHERITED;
+    };
+
+private:
+    DefaultGeoProc() {}
+
+    virtual bool onIsEqual(const GrGeometryProcessor& other) const SK_OVERRIDE {
+        return true;
+    }
+
+    virtual void onComputeInvariantOutput(InvariantOutput* inout) const SK_OVERRIDE {
+        inout->mulByUnknownAlpha();
+    }
+
+    GR_DECLARE_GEOMETRY_PROCESSOR_TEST;
+
+    typedef GrFragmentProcessor INHERITED;
+};
+
+GR_DEFINE_GEOMETRY_PROCESSOR_TEST(DefaultGeoProc);
+
+GrGeometryProcessor* DefaultGeoProc::TestCreate(SkRandom* random,
+                                                GrContext*,
+                                                const GrDrawTargetCaps& caps,
+                                                GrTexture*[]) {
+    return DefaultGeoProc::Create();
+}
+
+// We use these arrays to customize our default GP.  We only need 4 because we omit coverage if
+// coverage is not requested in the flags to the create function.
+GrVertexAttrib kDefaultPositionGeoProc[] = {
+    { kVec2f_GrVertexAttribType, 0,                kPosition_GrVertexAttribBinding },
+    { kVec4ub_GrVertexAttribType, sizeof(SkPoint), kCoverage_GrVertexAttribBinding },
+};
+
+GrVertexAttrib kDefaultPosColorGeoProc[] = {
+    { kVec2f_GrVertexAttribType, 0,                                  kPosition_GrVertexAttribBinding },
+    { kVec4ub_GrVertexAttribType, sizeof(SkPoint),                   kColor_GrVertexAttribBinding },
+    { kVec4ub_GrVertexAttribType, sizeof(SkPoint) + sizeof(GrColor), kCoverage_GrVertexAttribBinding },
+};
+
+GrVertexAttrib kDefaultPosUVGeoProc[] = {
+    { kVec2f_GrVertexAttribType, 0,                    kPosition_GrVertexAttribBinding },
+    { kVec2f_GrVertexAttribType, sizeof(SkPoint),      kLocalCoord_GrVertexAttribBinding },
+    { kVec4ub_GrVertexAttribType, 2 * sizeof(SkPoint), kCoverage_GrVertexAttribBinding },
+};
+
+GrVertexAttrib kDefaultPosColUVGeoProc[] = {
+    { kVec2f_GrVertexAttribType, 0,                                      kPosition_GrVertexAttribBinding },
+    { kVec4ub_GrVertexAttribType, sizeof(SkPoint),                       kColor_GrVertexAttribBinding },
+    { kVec2f_GrVertexAttribType, sizeof(SkPoint) + sizeof(GrColor),      kLocalCoord_GrVertexAttribBinding },
+    { kVec4ub_GrVertexAttribType, 2 * sizeof(SkPoint) + sizeof(GrColor), kCoverage_GrVertexAttribBinding },
+};
+
+static size_t get_size(GrDefaultGeoProcFactory::GPType flag) {
+    switch (flag) {
+        case GrDefaultGeoProcFactory::kPosition_GPType:
+            return GrVertexAttribTypeSize(kVec2f_GrVertexAttribType);
+        case GrDefaultGeoProcFactory::kColor_GPType:
+            return GrVertexAttribTypeSize(kVec4ub_GrVertexAttribType);
+        case GrDefaultGeoProcFactory::kLocalCoord_GPType:
+            return GrVertexAttribTypeSize(kVec2f_GrVertexAttribType);
+        case GrDefaultGeoProcFactory::kCoverage_GPType:
+            return GrVertexAttribTypeSize(kVec4ub_GrVertexAttribType);
+        default:
+            SkFAIL("Should never get here");
+            return 0;
+    }
+}
+
+const GrGeometryProcessor*
+GrDefaultGeoProcFactory::CreateAndSetAttribs(GrDrawState* ds, uint32_t gpTypeFlags) {
+    SkASSERT(ds);
+    // always atleast position in the GP
+    size_t size = get_size(kPosition_GPType);
+    int count = 1;
+
+    bool hasColor = SkToBool(gpTypeFlags & kColor_GPType);
+    bool hasLocalCoord = SkToBool(gpTypeFlags & kLocalCoord_GPType);
+    bool hasCoverage = SkToBool(gpTypeFlags & kCoverage_GPType);
+
+    if (hasColor) {
+        size += get_size(kColor_GPType);
+        count++;
+        if (hasLocalCoord) {
+            size += get_size(kLocalCoord_GPType);
+            count++;
+            if (hasCoverage) {
+                size += get_size(kCoverage_GPType);
+                count++;
+                ds->setVertexAttribs<kDefaultPosColUVGeoProc>(count, size);
+            } else {
+                ds->setVertexAttribs<kDefaultPosColUVGeoProc>(count, size);
+
+            }
+        } else {
+            if (hasCoverage) {
+                size += get_size(kCoverage_GPType);
+                count++;
+                ds->setVertexAttribs<kDefaultPosColorGeoProc>(count, size);
+            } else {
+                ds->setVertexAttribs<kDefaultPosColorGeoProc>(count, size);
+            }
+        }
+    } else if (hasLocalCoord) {
+        size += get_size(kLocalCoord_GPType);
+        count++;
+        if (hasCoverage) {
+            size += get_size(kCoverage_GPType);
+            count++;
+            ds->setVertexAttribs<kDefaultPosUVGeoProc>(count, size);
+        } else {
+            ds->setVertexAttribs<kDefaultPosUVGeoProc>(count, size);
+        }
+    } else if (hasCoverage) {
+        size += get_size(kCoverage_GPType);
+        count++;
+        ds->setVertexAttribs<kDefaultPositionGeoProc>(count, size);
+    } else {
+        // Just position
+        ds->setVertexAttribs<kDefaultPositionGeoProc>(count, size);
+    }
+    return DefaultGeoProc::Create();
+}
+
+const GrGeometryProcessor* GrDefaultGeoProcFactory::Create() {
+    return DefaultGeoProc::Create();
+}