[Reland] Relocate shaders to own dir

Consolidate all shader impls under src/shaders/.

(reland of https://skia-review.googlesource.com/c/17927/)

Change-Id: I7918bdc1aafe842ed194412ba95b9ae53a2ec1d7
Reviewed-on: https://skia-review.googlesource.com/18146
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>

1 files changed, 488 insertions, 0 deletions

diff --git a/src/shaders/SkLightingShader.cpp b/src/shaders/SkLightingShader.cpp
new file mode 100644
index 0000000000..cdfa528e1e
--- /dev/null
+++ b/src/shaders/SkLightingShader.cpp
@@ -0,0 +1,488 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkArenaAlloc.h"
+#include "SkBitmapProcShader.h"
+#include "SkBitmapProcState.h"
+#include "SkColor.h"
+#include "SkColorSpaceXformer.h"
+#include "SkEmptyShader.h"
+#include "SkLightingShader.h"
+#include "SkMathPriv.h"
+#include "SkNormalSource.h"
+#include "SkPoint3.h"
+#include "SkReadBuffer.h"
+#include "SkShaderBase.h"
+#include "SkWriteBuffer.h"
+
+////////////////////////////////////////////////////////////////////////////
+
+/*
+   SkLightingShader TODOs:
+        support different light types
+        support multiple lights
+        fix non-opaque diffuse textures
+
+    To Test:
+        A8 diffuse textures
+        down & upsampled draws
+*/
+
+
+
+/** \class SkLightingShaderImpl
+    This subclass of shader applies lighting.
+*/
+class SkLightingShaderImpl : public SkShaderBase {
+public:
+    /** Create a new lighting shader that uses the provided normal map and
+        lights to light the diffuse bitmap.
+        @param diffuseShader     the shader that provides the diffuse colors
+        @param normalSource      the source of normals for lighting computation
+        @param lights            the lights applied to the geometry
+    */
+    SkLightingShaderImpl(sk_sp<SkShader> diffuseShader,
+                         sk_sp<SkNormalSource> normalSource,
+                         sk_sp<SkLights> lights)
+        : fDiffuseShader(std::move(diffuseShader))
+        , fNormalSource(std::move(normalSource))
+        , fLights(std::move(lights)) {}
+
+    bool isOpaque() const override;
+
+#if SK_SUPPORT_GPU
+    sk_sp<GrFragmentProcessor> asFragmentProcessor(const AsFPArgs&) const override;
+#endif
+
+    class LightingShaderContext : public Context {
+    public:
+        // The context takes ownership of the context and provider. It will call their destructors
+        // and then indirectly free their memory by calling free() on heapAllocated
+        LightingShaderContext(const SkLightingShaderImpl&, const ContextRec&,
+                              SkShaderBase::Context* diffuseContext, SkNormalSource::Provider*,
+                              void* heapAllocated);
+
+        void shadeSpan(int x, int y, SkPMColor[], int count) override;
+
+        uint32_t getFlags() const override { return fFlags; }
+
+    private:
+        SkShaderBase::Context*    fDiffuseContext;
+        SkNormalSource::Provider* fNormalProvider;
+        SkColor                   fPaintColor;
+        uint32_t                  fFlags;
+
+        typedef Context INHERITED;
+    };
+
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLightingShaderImpl)
+
+protected:
+    void flatten(SkWriteBuffer&) const override;
+    Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const override;
+    sk_sp<SkShader> onMakeColorSpace(SkColorSpaceXformer* xformer) const override;
+
+private:
+    sk_sp<SkShader> fDiffuseShader;
+    sk_sp<SkNormalSource> fNormalSource;
+    sk_sp<SkLights> fLights;
+
+    friend class SkLightingShader;
+
+    typedef SkShaderBase INHERITED;
+};
+
+////////////////////////////////////////////////////////////////////////////
+
+#if SK_SUPPORT_GPU
+
+#include "GrCoordTransform.h"
+#include "GrFragmentProcessor.h"
+#include "glsl/GrGLSLFragmentProcessor.h"
+#include "glsl/GrGLSLFragmentShaderBuilder.h"
+#include "glsl/GrGLSLProgramDataManager.h"
+#include "glsl/GrGLSLUniformHandler.h"
+#include "SkGr.h"
+
+// This FP expects a premul'd color input for its diffuse color. Premul'ing of the paint's color is
+// handled by the asFragmentProcessor() factory, but shaders providing diffuse color must output it
+// premul'd.
+class LightingFP : public GrFragmentProcessor {
+public:
+    LightingFP(sk_sp<GrFragmentProcessor> normalFP, sk_sp<SkLights> lights)
+            : INHERITED(kPreservesOpaqueInput_OptimizationFlag) {
+        // fuse all ambient lights into a single one
+        fAmbientColor = lights->ambientLightColor();
+        for (int i = 0; i < lights->numLights(); ++i) {
+            if (SkLights::Light::kDirectional_LightType == lights->light(i).type()) {
+                fDirectionalLights.push_back(lights->light(i));
+                // TODO get the handle to the shadow map if there is one
+            } else {
+                SkDEBUGFAIL("Unimplemented Light Type passed to LightingFP");
+            }
+        }
+
+        this->registerChildProcessor(std::move(normalFP));
+        this->initClassID<LightingFP>();
+    }
+
+    class GLSLLightingFP : public GrGLSLFragmentProcessor {
+    public:
+        GLSLLightingFP() {
+            fAmbientColor.fX = 0.0f;
+        }
+
+        void emitCode(EmitArgs& args) override {
+
+            GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
+            GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
+            const LightingFP& lightingFP = args.fFp.cast<LightingFP>();
+
+            const char *lightDirsUniName = nullptr;
+            const char *lightColorsUniName = nullptr;
+            if (lightingFP.fDirectionalLights.count() != 0) {
+                fLightDirsUni = uniformHandler->addUniformArray(
+                        kFragment_GrShaderFlag,
+                        kVec3f_GrSLType,
+                        kDefault_GrSLPrecision,
+                        "LightDir",
+                        lightingFP.fDirectionalLights.count(),
+                        &lightDirsUniName);
+                fLightColorsUni = uniformHandler->addUniformArray(
+                        kFragment_GrShaderFlag,
+                        kVec3f_GrSLType,
+                        kDefault_GrSLPrecision,
+                        "LightColor",
+                        lightingFP.fDirectionalLights.count(),
+                        &lightColorsUniName);
+            }
+
+            const char* ambientColorUniName = nullptr;
+            fAmbientColorUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
+                                                          kVec3f_GrSLType, kDefault_GrSLPrecision,
+                                                          "AmbientColor", &ambientColorUniName);
+
+            fragBuilder->codeAppendf("vec4 diffuseColor = %s;", args.fInputColor);
+
+            SkString dstNormalName("dstNormal");
+            this->emitChild(0, &dstNormalName, args);
+
+            fragBuilder->codeAppendf("vec3 normal = %s.xyz;", dstNormalName.c_str());
+
+            fragBuilder->codeAppend( "vec3 result = vec3(0.0);");
+
+            // diffuse light
+            if (lightingFP.fDirectionalLights.count() != 0) {
+                fragBuilder->codeAppendf("for (int i = 0; i < %d; i++) {",
+                                         lightingFP.fDirectionalLights.count());
+                // TODO: modulate the contribution from each light based on the shadow map
+                fragBuilder->codeAppendf("    float NdotL = clamp(dot(normal, %s[i]), 0.0, 1.0);",
+                                         lightDirsUniName);
+                fragBuilder->codeAppendf("    result += %s[i]*diffuseColor.rgb*NdotL;",
+                                         lightColorsUniName);
+                fragBuilder->codeAppend("}");
+            }
+
+            // ambient light
+            fragBuilder->codeAppendf("result += %s * diffuseColor.rgb;", ambientColorUniName);
+
+            // Clamping to alpha (equivalent to an unpremul'd clamp to 1.0)
+            fragBuilder->codeAppendf("%s = vec4(clamp(result.rgb, 0.0, diffuseColor.a), "
+                                               "diffuseColor.a);", args.fOutputColor);
+        }
+
+        static void GenKey(const GrProcessor& proc, const GrShaderCaps&, GrProcessorKeyBuilder* b) {
+            const LightingFP& lightingFP = proc.cast<LightingFP>();
+            b->add32(lightingFP.fDirectionalLights.count());
+        }
+
+    protected:
+        void onSetData(const GrGLSLProgramDataManager& pdman,
+                       const GrFragmentProcessor& proc) override {
+            const LightingFP& lightingFP = proc.cast<LightingFP>();
+
+            const SkTArray<SkLights::Light>& directionalLights = lightingFP.directionalLights();
+            if (directionalLights != fDirectionalLights) {
+                SkTArray<SkColor3f> lightDirs(directionalLights.count());
+                SkTArray<SkVector3> lightColors(directionalLights.count());
+                for (const SkLights::Light& light : directionalLights) {
+                    lightDirs.push_back(light.dir());
+                    lightColors.push_back(light.color());
+                }
+
+                pdman.set3fv(fLightDirsUni, directionalLights.count(), &(lightDirs[0].fX));
+                pdman.set3fv(fLightColorsUni, directionalLights.count(), &(lightColors[0].fX));
+
+                fDirectionalLights = directionalLights;
+            }
+
+            const SkColor3f& ambientColor = lightingFP.ambientColor();
+            if (ambientColor != fAmbientColor) {
+                pdman.set3fv(fAmbientColorUni, 1, &ambientColor.fX);
+                fAmbientColor = ambientColor;
+            }
+        }
+
+    private:
+        SkTArray<SkLights::Light> fDirectionalLights;
+        GrGLSLProgramDataManager::UniformHandle fLightDirsUni;
+        GrGLSLProgramDataManager::UniformHandle fLightColorsUni;
+
+        SkColor3f fAmbientColor;
+        GrGLSLProgramDataManager::UniformHandle fAmbientColorUni;
+    };
+
+    void onGetGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const override {
+        GLSLLightingFP::GenKey(*this, caps, b);
+    }
+
+    const char* name() const override { return "LightingFP"; }
+
+    const SkTArray<SkLights::Light>& directionalLights() const { return fDirectionalLights; }
+    const SkColor3f& ambientColor() const { return fAmbientColor; }
+
+private:
+    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override { return new GLSLLightingFP; }
+
+    bool onIsEqual(const GrFragmentProcessor& proc) const override {
+        const LightingFP& lightingFP = proc.cast<LightingFP>();
+        return fDirectionalLights == lightingFP.fDirectionalLights &&
+               fAmbientColor == lightingFP.fAmbientColor;
+    }
+
+    SkTArray<SkLights::Light> fDirectionalLights;
+    SkColor3f                 fAmbientColor;
+
+    typedef GrFragmentProcessor INHERITED;
+};
+
+////////////////////////////////////////////////////////////////////////////
+
+sk_sp<GrFragmentProcessor> SkLightingShaderImpl::asFragmentProcessor(const AsFPArgs& args) const {
+    sk_sp<GrFragmentProcessor> normalFP(fNormalSource->asFragmentProcessor(args));
+    if (!normalFP) {
+        return nullptr;
+    }
+
+    if (fDiffuseShader) {
+        sk_sp<GrFragmentProcessor> fpPipeline[] = {
+            as_SB(fDiffuseShader)->asFragmentProcessor(args),
+            sk_make_sp<LightingFP>(std::move(normalFP), fLights)
+        };
+        if(!fpPipeline[0]) {
+            return nullptr;
+        }
+
+        sk_sp<GrFragmentProcessor> innerLightFP = GrFragmentProcessor::RunInSeries(fpPipeline, 2);
+        // FP is wrapped because paint's alpha needs to be applied to output
+        return GrFragmentProcessor::MulOutputByInputAlpha(std::move(innerLightFP));
+    } else {
+        // FP is wrapped because paint comes in unpremul'd to fragment shader, but LightingFP
+        // expects premul'd color.
+        return GrFragmentProcessor::PremulInput(sk_make_sp<LightingFP>(std::move(normalFP),
+                                                                       fLights));
+    }
+}
+
+#endif
+
+////////////////////////////////////////////////////////////////////////////
+
+bool SkLightingShaderImpl::isOpaque() const {
+    return (fDiffuseShader ? fDiffuseShader->isOpaque() : false);
+}
+
+SkLightingShaderImpl::LightingShaderContext::LightingShaderContext(
+        const SkLightingShaderImpl& shader, const ContextRec& rec,
+        SkShaderBase::Context* diffuseContext, SkNormalSource::Provider* normalProvider,
+        void* heapAllocated)
+    : INHERITED(shader, rec)
+    , fDiffuseContext(diffuseContext)
+    , fNormalProvider(normalProvider) {
+    bool isOpaque = shader.isOpaque();
+
+    // update fFlags
+    uint32_t flags = 0;
+    if (isOpaque && (255 == this->getPaintAlpha())) {
+        flags |= kOpaqueAlpha_Flag;
+    }
+
+    fPaintColor = rec.fPaint->getColor();
+    fFlags = flags;
+}
+
+static inline SkPMColor convert(SkColor3f color, U8CPU a) {
+    if (color.fX <= 0.0f) {
+        color.fX = 0.0f;
+    } else if (color.fX >= 255.0f) {
+        color.fX = 255.0f;
+    }
+
+    if (color.fY <= 0.0f) {
+        color.fY = 0.0f;
+    } else if (color.fY >= 255.0f) {
+        color.fY = 255.0f;
+    }
+
+    if (color.fZ <= 0.0f) {
+        color.fZ = 0.0f;
+    } else if (color.fZ >= 255.0f) {
+        color.fZ = 255.0f;
+    }
+
+    return SkPreMultiplyARGB(a, (int) color.fX,  (int) color.fY, (int) color.fZ);
+}
+
+// larger is better (fewer times we have to loop), but we shouldn't
+// take up too much stack-space (each one here costs 16 bytes)
+#define BUFFER_MAX 16
+void SkLightingShaderImpl::LightingShaderContext::shadeSpan(int x, int y,
+                                                            SkPMColor result[], int count) {
+    const SkLightingShaderImpl& lightShader = static_cast<const SkLightingShaderImpl&>(fShader);
+
+    SkPMColor diffuse[BUFFER_MAX];
+    SkPoint3 normals[BUFFER_MAX];
+
+    SkColor diffColor = fPaintColor;
+
+    do {
+        int n = SkTMin(count, BUFFER_MAX);
+
+        fNormalProvider->fillScanLine(x, y, normals, n);
+
+        if (fDiffuseContext) {
+            fDiffuseContext->shadeSpan(x, y, diffuse, n);
+        }
+
+        for (int i = 0; i < n; ++i) {
+            if (fDiffuseContext) {
+                diffColor = SkUnPreMultiply::PMColorToColor(diffuse[i]);
+            }
+
+            SkColor3f accum = SkColor3f::Make(0.0f, 0.0f, 0.0f);
+
+            // Adding ambient light
+            accum.fX += lightShader.fLights->ambientLightColor().fX * SkColorGetR(diffColor);
+            accum.fY += lightShader.fLights->ambientLightColor().fY * SkColorGetG(diffColor);
+            accum.fZ += lightShader.fLights->ambientLightColor().fZ * SkColorGetB(diffColor);
+
+            // This is all done in linear unpremul color space (each component 0..255.0f though)
+            for (int l = 0; l < lightShader.fLights->numLights(); ++l) {
+                const SkLights::Light& light = lightShader.fLights->light(l);
+
+                SkScalar illuminanceScalingFactor = 1.0f;
+
+                if (SkLights::Light::kDirectional_LightType == light.type()) {
+                    illuminanceScalingFactor = normals[i].dot(light.dir());
+                    if (illuminanceScalingFactor < 0.0f) {
+                        illuminanceScalingFactor = 0.0f;
+                    }
+                }
+
+                accum.fX += light.color().fX * SkColorGetR(diffColor) * illuminanceScalingFactor;
+                accum.fY += light.color().fY * SkColorGetG(diffColor) * illuminanceScalingFactor;
+                accum.fZ += light.color().fZ * SkColorGetB(diffColor) * illuminanceScalingFactor;
+            }
+
+            // convert() premultiplies the accumulate color with alpha
+            result[i] = convert(accum, SkColorGetA(diffColor));
+        }
+
+        result += n;
+        x += n;
+        count -= n;
+    } while (count > 0);
+}
+
+////////////////////////////////////////////////////////////////////////////
+
+#ifndef SK_IGNORE_TO_STRING
+void SkLightingShaderImpl::toString(SkString* str) const {
+    str->appendf("LightingShader: ()");
+}
+#endif
+
+sk_sp<SkFlattenable> SkLightingShaderImpl::CreateProc(SkReadBuffer& buf) {
+
+    // Discarding SkShader flattenable params
+    bool hasLocalMatrix = buf.readBool();
+    SkAssertResult(!hasLocalMatrix);
+
+    sk_sp<SkLights> lights = SkLights::MakeFromBuffer(buf);
+
+    sk_sp<SkNormalSource> normalSource(buf.readFlattenable<SkNormalSource>());
+
+    bool hasDiffuse = buf.readBool();
+    sk_sp<SkShader> diffuseShader = nullptr;
+    if (hasDiffuse) {
+        diffuseShader = buf.readFlattenable<SkShaderBase>();
+    }
+
+    return sk_make_sp<SkLightingShaderImpl>(std::move(diffuseShader), std::move(normalSource),
+                                            std::move(lights));
+}
+
+void SkLightingShaderImpl::flatten(SkWriteBuffer& buf) const {
+    this->INHERITED::flatten(buf);
+
+    fLights->flatten(buf);
+
+    buf.writeFlattenable(fNormalSource.get());
+    buf.writeBool(fDiffuseShader);
+    if (fDiffuseShader) {
+        buf.writeFlattenable(fDiffuseShader.get());
+    }
+}
+
+SkShaderBase::Context* SkLightingShaderImpl::onMakeContext(
+    const ContextRec& rec, SkArenaAlloc* alloc) const
+{
+    SkShaderBase::Context *diffuseContext = nullptr;
+    if (fDiffuseShader) {
+        diffuseContext = as_SB(fDiffuseShader)->makeContext(rec, alloc);
+        if (!diffuseContext) {
+            return nullptr;
+        }
+    }
+
+    SkNormalSource::Provider* normalProvider = fNormalSource->asProvider(rec, alloc);
+    if (!normalProvider) {
+        return nullptr;
+    }
+
+    return alloc->make<LightingShaderContext>(*this, rec, diffuseContext, normalProvider, nullptr);
+}
+
+sk_sp<SkShader> SkLightingShaderImpl::onMakeColorSpace(SkColorSpaceXformer* xformer) const {
+    sk_sp<SkShader> xformedDiffuseShader =
+            fDiffuseShader ? xformer->apply(fDiffuseShader.get()) : nullptr;
+    return SkLightingShader::Make(std::move(xformedDiffuseShader), fNormalSource,
+                                  fLights->makeColorSpace(xformer));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+sk_sp<SkShader> SkLightingShader::Make(sk_sp<SkShader> diffuseShader,
+                                       sk_sp<SkNormalSource> normalSource,
+                                       sk_sp<SkLights> lights) {
+    SkASSERT(lights);
+    if (!normalSource) {
+        normalSource = SkNormalSource::MakeFlat();
+    }
+
+    return sk_make_sp<SkLightingShaderImpl>(std::move(diffuseShader), std::move(normalSource),
+                                            std::move(lights));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkLightingShader)
+    SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkLightingShaderImpl)
+SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END
+
+///////////////////////////////////////////////////////////////////////////////