Add normal map sample

This adds an example of an SkShader that does normal
mapping. It has a single directional light and an
ambient light.

Committed: https://skia.googlesource.com/skia/+/8e0da72ba890de395c9946ec6639c9e1e7b16027

Review URL: https://codereview.chromium.org/1212813009

1 files changed, 429 insertions, 0 deletions

diff --git a/samplecode/SampleLighting.cpp b/samplecode/SampleLighting.cpp
new file mode 100755
index 0000000000..40e6fbb073
--- /dev/null
+++ b/samplecode/SampleLighting.cpp
@@ -0,0 +1,429 @@
+
+/*
+ * 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 "SampleCode.h"
+#include "Resources.h"
+
+#include "SkCanvas.h"
+#include "SkErrorInternals.h"
+#include "SkGr.h"
+#include "SkReadBuffer.h"
+#include "SkShader.h"
+#include "SkWriteBuffer.h"
+#include "GrFragmentProcessor.h"
+#include "GrCoordTransform.h"
+#include "gl/GrGLProcessor.h"
+#include "gl/builders/GrGLProgramBuilder.h"
+
+///////////////////////////////////////////////////////////////////////////////
+
+struct SkVector3 {
+    SkScalar fX, fY, fZ;
+
+    bool operator==(const SkVector3& other) const {
+        return fX == other.fX && fY == other.fY && fZ == other.fZ;
+    }
+
+    bool operator!=(const SkVector3& other) const {
+        return !(*this == other);
+    }
+};
+
+class LightingShader : public SkShader {
+public:
+    struct Light {
+        SkVector3   fDirection;
+        SkColor     fColor;           // assumed to be linear color
+    };
+
+    LightingShader(const SkBitmap& diffuse, const SkBitmap& normal, const Light& light,
+                   const SkColor ambient) 
+        : fDiffuseMap(diffuse)
+        , fNormalMap(normal)
+        , fLight(light)
+        , fAmbientColor(ambient) {}
+
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(LightingShader);
+
+    void flatten(SkWriteBuffer& buf) const override {
+        buf.writeBitmap(fDiffuseMap);
+        buf.writeBitmap(fNormalMap);
+        buf.writeScalarArray(&fLight.fDirection.fX, 3);
+        buf.writeColor(fLight.fColor);
+        buf.writeColor(fAmbientColor);
+    }
+
+    bool asFragmentProcessor(GrContext*, const SkPaint& paint, const SkMatrix& viewM,
+                             const SkMatrix* localMatrix, GrColor* color,
+                             GrProcessorDataManager*, GrFragmentProcessor** fp) const override;
+
+    SkShader::BitmapType asABitmap(SkBitmap* bitmap, SkMatrix* matrix, 
+                                   SkShader::TileMode* xy) const override {
+        if (bitmap) {
+            *bitmap = fDiffuseMap;
+        }
+        if (matrix) {
+            matrix->reset();
+        }
+        if (xy) {
+            xy[0] = kClamp_TileMode;
+            xy[1] = kClamp_TileMode;
+        }
+        return kDefault_BitmapType;
+    }
+
+#ifndef SK_IGNORE_TO_STRING
+    void toString(SkString* str) const override {
+        str->appendf("LightingShader: ()");
+    }
+#endif
+
+    void setLight(const Light& light) { fLight = light;  }
+
+private:
+    SkBitmap fDiffuseMap;
+    SkBitmap fNormalMap;
+    Light    fLight;
+    SkColor  fAmbientColor;
+};
+
+SkFlattenable* LightingShader::CreateProc(SkReadBuffer& buf) {
+    SkBitmap diffuse;
+    if (!buf.readBitmap(&diffuse)) {
+        return NULL;
+    }
+    diffuse.setImmutable();
+
+    SkBitmap normal;
+    if (!buf.readBitmap(&normal)) {
+        return NULL;
+    }
+    normal.setImmutable();
+
+    Light light;
+    if (!buf.readScalarArray(&light.fDirection.fX, 3)) {
+        return NULL;
+    }
+    light.fColor = buf.readColor();
+
+    SkColor ambient = buf.readColor();
+
+    return SkNEW_ARGS(LightingShader, (diffuse, normal, light, ambient));
+}
+
+////////////////////////////////////////////////////////////////////////////
+
+class LightingFP : public GrFragmentProcessor {
+public:
+    LightingFP(GrTexture* diffuse, GrTexture* normal, const SkMatrix& matrix,
+               SkVector3 lightDir, GrColor lightColor, GrColor ambientColor)
+        : fDeviceTransform(kDevice_GrCoordSet, matrix)
+        , fDiffuseTextureAccess(diffuse)
+        , fNormalTextureAccess(normal)
+        , fLightDir(lightDir)
+        , fLightColor(lightColor)
+        , fAmbientColor(ambientColor) {
+        this->addCoordTransform(&fDeviceTransform);
+        this->addTextureAccess(&fDiffuseTextureAccess);
+        this->addTextureAccess(&fNormalTextureAccess);
+
+        this->initClassID<LightingFP>();
+    }
+
+    class LightingGLFP : public GrGLFragmentProcessor {
+    public:
+        LightingGLFP() : fLightColor(GrColor_ILLEGAL) {
+            fLightDir.fX = 10000.0f;
+        }
+
+        void emitCode(GrGLFPBuilder* builder,
+                      const GrFragmentProcessor& fp,
+                      const char* outputColor,
+                      const char* inputColor,
+                      const TransformedCoordsArray& coords,
+                      const TextureSamplerArray& samplers) override {
+
+            GrGLFragmentBuilder* fpb = builder->getFragmentShaderBuilder();
+
+            // add uniforms
+            const char* lightDirUniName = NULL;
+            fLightDirUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
+                                               kVec3f_GrSLType, kDefault_GrSLPrecision,
+                                               "LightDir", &lightDirUniName);
+
+            const char* lightColorUniName = NULL;
+            fLightColorUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
+                                                 kVec4f_GrSLType, kDefault_GrSLPrecision,
+                                                 "LightColor", &lightColorUniName);
+
+            const char* ambientColorUniName = NULL;
+            fAmbientColorUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
+                                                   kVec4f_GrSLType, kDefault_GrSLPrecision,
+                                                   "AmbientColor", &ambientColorUniName);
+
+            fpb->codeAppend("vec4 diffuseColor = ");
+            fpb->appendTextureLookupAndModulate(inputColor, samplers[0], 
+                                                coords[0].c_str(), coords[0].getType());
+            fpb->codeAppend(";");
+
+            fpb->codeAppend("vec4 normalColor = ");
+            fpb->appendTextureLookup(samplers[1], coords[0].c_str(), coords[0].getType());
+            fpb->codeAppend(";");
+
+            fpb->codeAppend("vec3 normal = normalize(2.0*(normalColor.rgb - vec3(0.5)));");
+            fpb->codeAppendf("vec3 lightDir = normalize(%s);", lightDirUniName);
+            fpb->codeAppend("float NdotL = dot(normal, lightDir);");
+            // diffuse light
+            fpb->codeAppendf("vec3 result = %s.rgb*diffuseColor.rgb*NdotL;", lightColorUniName);
+            // ambient light
+            fpb->codeAppendf("result += %s.rgb;", ambientColorUniName);
+            fpb->codeAppendf("%s = vec4(result.rgb, diffuseColor.a);", outputColor);
+        }
+
+        void setData(const GrGLProgramDataManager& pdman, const GrProcessor& proc) override {
+            const LightingFP& lightingFP = proc.cast<LightingFP>();
+
+            SkVector3 lightDir = lightingFP.lightDir();
+            if (lightDir != fLightDir) {
+                pdman.set3fv(fLightDirUni, 1, &lightDir.fX);
+                fLightDir = lightDir;
+            }
+
+            GrColor lightColor = lightingFP.lightColor();
+            if (lightColor != fLightColor) {
+                GrGLfloat c[4];
+                GrColorToRGBAFloat(lightColor, c);
+                pdman.set4fv(fLightColorUni, 1, c);
+                fLightColor = lightColor;
+            }
+
+            GrColor ambientColor = lightingFP.ambientColor();
+            if (ambientColor != fAmbientColor) {
+                GrGLfloat c[4];
+                GrColorToRGBAFloat(ambientColor, c);
+                pdman.set4fv(fAmbientColorUni, 1, c);
+                fAmbientColor = ambientColor;
+            }
+        }
+
+        static void GenKey(const GrProcessor& proc, const GrGLSLCaps&,
+                           GrProcessorKeyBuilder* b) {
+//            const LightingFP& lightingFP = proc.cast<LightingFP>();
+            // only one shader generated currently
+            b->add32(0x0);
+        }
+
+    private:
+        SkVector3 fLightDir;
+        GrGLProgramDataManager::UniformHandle fLightDirUni;
+
+        GrColor fLightColor;
+        GrGLProgramDataManager::UniformHandle fLightColorUni;
+
+        GrColor fAmbientColor;
+        GrGLProgramDataManager::UniformHandle fAmbientColorUni;
+    };
+
+    GrGLFragmentProcessor* createGLInstance() const override { return SkNEW(LightingGLFP); }
+
+    void getGLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const override {
+        LightingGLFP::GenKey(*this, caps, b);
+    }
+
+    const char* name() const override { return "LightingFP"; }
+
+    void onComputeInvariantOutput(GrInvariantOutput* inout) const override {
+        inout->mulByUnknownFourComponents();
+    }
+
+    SkVector3 lightDir() const { return fLightDir; }
+    GrColor lightColor() const { return fLightColor; }
+    GrColor ambientColor() const { return fAmbientColor; }
+
+private:
+    bool onIsEqual(const GrFragmentProcessor& proc) const override { 
+        const LightingFP& lightingFP = proc.cast<LightingFP>();
+        return fDeviceTransform == lightingFP.fDeviceTransform &&
+               fDiffuseTextureAccess == lightingFP.fDiffuseTextureAccess &&
+               fNormalTextureAccess == lightingFP.fNormalTextureAccess &&
+               fLightDir == lightingFP.fLightDir &&
+               fLightColor == lightingFP.fLightColor &&
+               fAmbientColor == lightingFP.fAmbientColor;
+    }
+
+    GrCoordTransform fDeviceTransform;
+    GrTextureAccess  fDiffuseTextureAccess;
+    GrTextureAccess  fNormalTextureAccess;
+    SkVector3        fLightDir;
+    GrColor          fLightColor;
+    GrColor          fAmbientColor;
+};
+
+bool LightingShader::asFragmentProcessor(GrContext* context, const SkPaint& paint, 
+                                         const SkMatrix& viewM, const SkMatrix* localMatrix, 
+                                         GrColor* color, GrProcessorDataManager*,
+                                         GrFragmentProcessor** fp) const {
+    // we assume diffuse and normal maps have same width and height
+    // TODO: support different sizes
+    SkASSERT(fDiffuseMap.width() == fNormalMap.width() &&
+             fDiffuseMap.height() == fNormalMap.height());
+    SkMatrix matrix;
+    matrix.setIDiv(fDiffuseMap.width(), fDiffuseMap.height());
+
+    SkMatrix lmInverse;
+    if (!this->getLocalMatrix().invert(&lmInverse)) {
+        return false;
+    }
+    if (localMatrix) {
+        SkMatrix inv;
+        if (!localMatrix->invert(&inv)) {
+            return false;
+        }
+        lmInverse.postConcat(inv);
+    }
+    matrix.preConcat(lmInverse);
+
+    // Must set wrap and filter on the sampler before requesting a texture. In two places below
+    // we check the matrix scale factors to determine how to interpret the filter quality setting.
+    // This completely ignores the complexity of the drawVertices case where explicit local coords
+    // are provided by the caller.
+    GrTextureParams::FilterMode textureFilterMode = GrTextureParams::kBilerp_FilterMode;
+    switch (paint.getFilterQuality()) {
+    case kNone_SkFilterQuality:
+        textureFilterMode = GrTextureParams::kNone_FilterMode;
+        break;
+    case kLow_SkFilterQuality:
+        textureFilterMode = GrTextureParams::kBilerp_FilterMode;
+        break;
+    case kMedium_SkFilterQuality:{                          
+        SkMatrix matrix;
+        matrix.setConcat(viewM, this->getLocalMatrix());
+        if (matrix.getMinScale() < SK_Scalar1) {
+            textureFilterMode = GrTextureParams::kMipMap_FilterMode;
+        } else {
+            // Don't trigger MIP level generation unnecessarily.
+            textureFilterMode = GrTextureParams::kBilerp_FilterMode;
+        }
+        break;
+    }
+    case kHigh_SkFilterQuality:
+    default:
+        SkErrorInternals::SetError(kInvalidPaint_SkError,
+            "Sorry, I don't understand the filtering "
+            "mode you asked for.  Falling back to "
+            "MIPMaps.");
+        textureFilterMode = GrTextureParams::kMipMap_FilterMode;
+        break;
+
+    }
+
+    // TODO: support other tile modes
+    GrTextureParams params(kClamp_TileMode, textureFilterMode);
+    SkAutoTUnref<GrTexture> diffuseTexture(GrRefCachedBitmapTexture(context, fDiffuseMap, &params));
+    if (!diffuseTexture) {
+        SkErrorInternals::SetError(kInternalError_SkError,
+            "Couldn't convert bitmap to texture.");
+        return false;
+    }
+
+    SkAutoTUnref<GrTexture> normalTexture(GrRefCachedBitmapTexture(context, fNormalMap, &params));
+    if (!normalTexture) {
+        SkErrorInternals::SetError(kInternalError_SkError,
+            "Couldn't convert bitmap to texture.");
+        return false;
+    }
+
+    GrColor lightColor = GrColorPackRGBA(SkColorGetR(fLight.fColor), SkColorGetG(fLight.fColor),
+                                         SkColorGetB(fLight.fColor), SkColorGetA(fLight.fColor));
+    GrColor ambientColor = GrColorPackRGBA(SkColorGetR(fAmbientColor), SkColorGetG(fAmbientColor),
+                                           SkColorGetB(fAmbientColor), SkColorGetA(fAmbientColor));
+
+    *fp = SkNEW_ARGS(LightingFP, (diffuseTexture, normalTexture, matrix,
+                                  fLight.fDirection, lightColor, ambientColor));
+    *color = GrColorPackA4(paint.getAlpha());
+    return true;
+}
+
+////////////////////////////////////////////////////////////////////////////
+
+class LightingView : public SampleView {
+public:
+    SkAutoTUnref<LightingShader> fShader;
+    SkBitmap                     fDiffuseBitmap;
+    SkBitmap                     fNormalBitmap;
+    SkScalar                     fLightAngle;
+    int                          fColorFactor;
+
+    LightingView() {
+        SkString diffusePath = GetResourcePath("brickwork-texture.jpg");
+        SkImageDecoder::DecodeFile(diffusePath.c_str(), &fDiffuseBitmap);
+        SkString normalPath = GetResourcePath("brickwork_normal-map.jpg");
+        SkImageDecoder::DecodeFile(normalPath.c_str(), &fNormalBitmap);
+
+        fLightAngle = 0.0f;
+        fColorFactor = 0;
+
+        LightingShader::Light light;
+        light.fColor = SkColorSetRGB(0xff, 0xff, 0xff);
+        light.fDirection.fX = SkScalarSin(fLightAngle)*SkScalarSin(SK_ScalarPI*0.25f);
+        light.fDirection.fY = SkScalarCos(fLightAngle)*SkScalarSin(SK_ScalarPI*0.25f);
+        light.fDirection.fZ = SkScalarCos(SK_ScalarPI*0.25f);
+
+        SkColor ambient = SkColorSetRGB(0x1f, 0x1f, 0x1f);
+
+        fShader.reset(SkNEW_ARGS(LightingShader, (fDiffuseBitmap, fNormalBitmap, light, ambient)));
+    }
+
+    virtual ~LightingView() {}
+
+protected:
+    // overrides from SkEventSink
+    bool onQuery(SkEvent* evt) override {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "Lighting");
+            return true;
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+
+    void onDrawContent(SkCanvas* canvas) override {
+        fLightAngle += 0.015f;
+        fColorFactor++;
+
+        LightingShader::Light light;
+        light.fColor = SkColorSetRGB(0xff, 0xff, (fColorFactor >> 1) & 0xff);
+        light.fDirection.fX = SkScalarSin(fLightAngle)*SkScalarSin(SK_ScalarPI*0.25f);
+        light.fDirection.fY = SkScalarCos(fLightAngle)*SkScalarSin(SK_ScalarPI*0.25f);
+        light.fDirection.fZ = SkScalarCos(SK_ScalarPI*0.25f);
+
+        fShader.get()->setLight(light);
+
+        SkPaint paint;
+        paint.setShader(fShader);
+        paint.setColor(SK_ColorBLACK);
+
+        SkRect r = SkRect::MakeWH((SkScalar)fDiffuseBitmap.width(), 
+                                  (SkScalar)fDiffuseBitmap.height());
+        canvas->drawRect(r, paint);
+
+        // so we're constantly updating
+        this->inval(NULL);
+    }
+
+    SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) override {
+        this->inval(NULL);
+        return this->INHERITED::onFindClickHandler(x, y, modi);
+    }
+
+private:
+    typedef SampleView INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new LightingView; }
+static SkViewRegister reg(MyFactory);