Move LightingShader to effects

src/effects/SkLightingShader.cpp

Index: src/effects/SkLightingShader.cpp
diff --git a/samplecode/SampleLighting.cpp b/src/effects/SkLightingShader.cpp
old mode 100755
new mode 100644
similarity index 54%
copy from samplecode/SampleLighting.cpp
copy to src/effects/SkLightingShader.cpp
index a002a9320f9843762dae1a492ad84a391ab10d31..507f67387f332ae9e4305031ba8f8ce0b6bff5bb
--- a/samplecode/SampleLighting.cpp
+++ b/src/effects/SkLightingShader.cpp
@@ -5,106 +5,26 @@
  * 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 "SkBitmapProcState.h"
+#include "SkColor.h"
+#include "SkEmptyShader.h"
 #include "SkErrorInternals.h"
-#include "SkGr.h"
-#include "SkPoint3.h"
+#include "SkLightingShader.h"
+#include "SkMathPriv.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"
-
-///////////////////////////////////////////////////////////////////////////////
-
-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));
-}
+#if SK_SUPPORT_GPU
 
-////////////////////////////////////////////////////////////////////////////
+#include "GrCoordTransform.h"
+#include "GrFragmentProcessor.h"
+#include "GrTextureAccess.h"
+#include "gl/GrGLProcessor.h"
+#include "gl/builders/GrGLProgramBuilder.h"
+#include "SkGr.h"
 
 class LightingFP : public GrFragmentProcessor {
 public:
@@ -163,7 +83,7 @@ public:
             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->codeAppend("vec3 normal = normalize(normalColor.rgb - vec3(0.5));");
             fpb->codeAppendf("vec3 lightDir = normalize(%s);", lightDirUniName);

[jvanverth1, 2015/07/23 17:40:14]

From external discussion, and for a future change: it should be safe to assume
the light direction is pre-normalized.

             fpb->codeAppend("float NdotL = dot(normal, lightDir);");
             // diffuse light
@@ -252,10 +172,12 @@ private:
     GrColor          fAmbientColor;
 };
 
-bool LightingShader::asFragmentProcessor(GrContext* context, const SkPaint& paint, 
-                                         const SkMatrix& viewM, const SkMatrix* localMatrix, 
-                                         GrColor* color, GrProcessorDataManager*,
-                                         GrFragmentProcessor** fp) const {
+////////////////////////////////////////////////////////////////////////////
+
+bool SkLightingShader::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() &&
@@ -336,83 +258,246 @@ bool LightingShader::asFragmentProcessor(GrContext* context, const SkPaint& pain
     *color = GrColorPackA4(paint.getAlpha());
     return true;
 }
+#else
+
+bool SkLightingShader::asFragmentProcessor(GrContext* context, const SkPaint& paint, 
+                                           const SkMatrix& viewM, const SkMatrix* localMatrix, 
+                                           GrColor* color, GrProcessorDataManager*,
+                                           GrFragmentProcessor** fp) const {
+    SkDEBUGFAIL("Should not call in GPU-less build");
+    return false;
+}
+
+#endif
 
 ////////////////////////////////////////////////////////////////////////////
 
-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)));
+bool SkLightingShader::isOpaque() const {
+    return fDiffuseMap.isOpaque();
+}
+
+size_t SkLightingShader::contextSize() const {
+    return 2 * sizeof(SkBitmapProcState) + sizeof(LightingShaderContext);
+}
+
+SkLightingShader::LightingShaderContext::LightingShaderContext(const SkLightingShader& shader,
+                                                               const ContextRec& rec,
+                                                               SkBitmapProcState* diffuseState,
+                                                               SkBitmapProcState* normalState)
+    : INHERITED(shader, rec)
+    , fDiffuseState(diffuseState)
+    , fNormalState(normalState)
+{
+    const SkPixmap& pixmap = fDiffuseState->fPixmap;
+    bool isOpaque = pixmap.isOpaque();
+
+    // update fFlags
+    uint32_t flags = 0;
+    if (isOpaque && (255 == this->getPaintAlpha())) {
+        flags |= kOpaqueAlpha_Flag;
+    }
+
+    fFlags = flags;
+}
+
+SkLightingShader::LightingShaderContext::~LightingShaderContext() {
+    // The bitmap proc states have been created outside of the context on memory that will be freed
+    // elsewhere. Call the destructors but leave the freeing of the memory to the caller.
+    fDiffuseState->~SkBitmapProcState();
+    fNormalState->~SkBitmapProcState();
+}
+
+static inline int light(int light, int diff, SkScalar NdotL, int ambient) {
+    int color = int(light * diff * NdotL + 255 * ambient);
+    if (color <= 0) {
+        return 0;
+    } else if (color >= 255*255) {
+        return 255;
+    } else {
+        return SkDiv255Round(color);
     }
+}
+
+// larger is better (fewer times we have to loop), but we shouldn't
+// take up too much stack-space (each could here costs 16 bytes)
+#define TMP_COUNT     16
+
+void SkLightingShader::LightingShaderContext::shadeSpan(int x, int y,
+                                                        SkPMColor result[], int count) {
+    const SkLightingShader& lightShader = static_cast<const SkLightingShader&>(fShader);
+
+    SkPMColor   tmpColor[TMP_COUNT], tmpColor2[TMP_COUNT];
+    SkPMColor   tmpNormal[TMP_COUNT], tmpNormal2[TMP_COUNT];
+
+    SkBitmapProcState::MatrixProc   diffMProc = fDiffuseState->getMatrixProc();
+    SkBitmapProcState::SampleProc32 diffSProc = fDiffuseState->getSampleProc32();
+
+    SkBitmapProcState::MatrixProc   normalMProc = fNormalState->getMatrixProc();
+    SkBitmapProcState::SampleProc32 normalSProc = fNormalState->getSampleProc32();
+
+    SkASSERT(fDiffuseState->fPixmap.addr());
+    SkASSERT(fNormalState->fPixmap.addr());
+
+    SkPoint3 norm;
+    SkScalar NdotL;
+    int r, g, b;
+
+    do {
+        int n = count;
+        if (n > TMP_COUNT) {
+            n = TMP_COUNT;
+        }
+
+        diffMProc(*fDiffuseState, tmpColor, n, x, y);
+        diffSProc(*fDiffuseState, tmpColor, n, tmpColor2);
+
+        normalMProc(*fNormalState, tmpNormal, n, x, y);
+        normalSProc(*fNormalState, tmpNormal, n, tmpNormal2);
+
+        for (int i = 0; i < n; ++i) {
+            SkASSERT(0xFF == SkColorGetA(tmpNormal2[i]));  // opaque -> unpremul
+            norm.set(SkIntToScalar(SkColorGetR(tmpNormal2[i]))-127.0f,
+                     SkIntToScalar(SkColorGetG(tmpNormal2[i]))-127.0f,
+                     SkIntToScalar(SkColorGetB(tmpNormal2[i]))-127.0f);
+            norm.normalize();
+
+            SkColor diffColor = SkUnPreMultiply::PMColorToColor(tmpColor2[i]);
+            NdotL = norm.dot(lightShader.fLight.fDirection);
 
-    virtual ~LightingView() {}
+            // This is all done in linear unpremul color space
+            r = light(SkColorGetR(lightShader.fLight.fColor), SkColorGetR(diffColor), NdotL, 
+                      SkColorGetR(lightShader.fAmbientColor));
+            g = light(SkColorGetG(lightShader.fLight.fColor), SkColorGetG(diffColor), NdotL, 
+                      SkColorGetG(lightShader.fAmbientColor));
+            b = light(SkColorGetB(lightShader.fLight.fColor), SkColorGetB(diffColor), NdotL, 
+                      SkColorGetB(lightShader.fAmbientColor));
 
-protected:
-    // overrides from SkEventSink
-    bool onQuery(SkEvent* evt) override {
-        if (SampleCode::TitleQ(*evt)) {
-            SampleCode::TitleR(evt, "Lighting");
-            return true;
+            result[i] = SkPreMultiplyARGB(SkColorGetA(diffColor), r, g, b);
         }
-        return this->INHERITED::onQuery(evt);
+
+        result += n;
+        x += n;
+        count -= n;
+    } while (count > 0);
+}
+
+////////////////////////////////////////////////////////////////////////////
+
+#ifndef SK_IGNORE_TO_STRING
+void SkLightingShader::toString(SkString* str) const {
+    str->appendf("LightingShader: ()");
+}
+#endif
+
+SkFlattenable* SkLightingShader::CreateProc(SkReadBuffer& buf) {
+    SkBitmap diffuse;
+    if (!buf.readBitmap(&diffuse)) {
+        return NULL;
+    }
+    diffuse.setImmutable();
+
+    SkBitmap normal;
+    if (!buf.readBitmap(&normal)) {
+        return NULL;
     }
+    normal.setImmutable();
 
-    void onDrawContent(SkCanvas* canvas) override {
-        fLightAngle += 0.015f;
-        fColorFactor++;
+    Light light;
+    if (!buf.readScalarArray(&light.fDirection.fX, 3)) {
+        return NULL;
+    }
+    light.fColor = buf.readColor();
 
-        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);
+    SkColor ambient = buf.readColor();
 
-        fShader.get()->setLight(light);
+    // TODO: this would be nice to enable
+    //    return SkCreateLightingShader(diffuse, normal, light, ambient, NULL);
+    return SkNEW_ARGS(SkLightingShader, (diffuse, normal, light, ambient));
+}
 
-        SkPaint paint;
-        paint.setShader(fShader);
-        paint.setColor(SK_ColorBLACK);
+void SkLightingShader::flatten(SkWriteBuffer& buf) const {
+    buf.writeBitmap(fDiffuseMap);
+    buf.writeBitmap(fNormalMap);
+    buf.writeScalarArray(&fLight.fDirection.fX, 3);
+    buf.writeColor(fLight.fColor);
+    buf.writeColor(fAmbientColor);
+}
 
-        SkRect r = SkRect::MakeWH((SkScalar)fDiffuseBitmap.width(), 
-                                  (SkScalar)fDiffuseBitmap.height());
-        canvas->drawRect(r, paint);
+SkShader::Context* SkLightingShader::onCreateContext(const ContextRec& rec, void* storage) const {
 
-        // so we're constantly updating
-        this->inval(NULL);
+    SkMatrix totalInverse;
+    // Do this first, so we know the matrix can be inverted.
+    if (!this->computeTotalInverse(rec, &totalInverse)) {
+        return NULL;
     }
 
-    SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) override {
-        this->inval(NULL);
-        return this->INHERITED::onFindClickHandler(x, y, modi);
+    void* diffuseStateStorage = (char*)storage + sizeof(LightingShaderContext);
+    SkBitmapProcState* diffuseState = SkNEW_PLACEMENT(diffuseStateStorage, SkBitmapProcState);
+    SkASSERT(diffuseState);
+
+    diffuseState->fTileModeX = SkShader::kClamp_TileMode;
+    diffuseState->fTileModeY = SkShader::kClamp_TileMode;
+    diffuseState->fOrigBitmap = fDiffuseMap;
+    if (!diffuseState->chooseProcs(totalInverse, *rec.fPaint)) {
+        diffuseState->~SkBitmapProcState();
+        return NULL;
     }
 
-private:
-    typedef SampleView INHERITED;
-};
+    void* normalStateStorage = (char*)storage + sizeof(LightingShaderContext) + sizeof(SkBitmapProcState);
+    SkBitmapProcState* normalState = SkNEW_PLACEMENT(normalStateStorage, SkBitmapProcState);
+    SkASSERT(normalState);
 
-//////////////////////////////////////////////////////////////////////////////
+    normalState->fTileModeX = SkShader::kClamp_TileMode;
+    normalState->fTileModeY = SkShader::kClamp_TileMode;
+    normalState->fOrigBitmap = fNormalMap;
+    if (!normalState->chooseProcs(totalInverse, *rec.fPaint)) {
+        diffuseState->~SkBitmapProcState();
+        normalState->~SkBitmapProcState();
+        return NULL;
+    }
+
+    return SkNEW_PLACEMENT_ARGS(storage, LightingShaderContext, (*this, rec,
+                                                                 diffuseState, normalState));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+// TODO: it would be nice to be able to call this from SkShader but this
+// would need to reside in core.
+#if 0
+static bool bitmap_is_too_big(const SkBitmap& bm) {
+    // SkBitmapProcShader stores bitmap coordinates in a 16bit buffer, as it
+    // communicates between its matrix-proc and its sampler-proc. Until we can
+    // widen that, we have to reject bitmaps that are larger.
+    //
+    static const int kMaxSize = 65535;
+
+    return bm.width() > kMaxSize || bm.height() > kMaxSize;
+}
+
+SkShader* SkCreateLightingShader(const SkBitmap& diffuse, const SkBitmap& normal,
+                                 const SkLightingShader::Light& light, const SkColor ambient,
+                                 SkTBlitterAllocator* allocator) {
+    SkShader* shader;
+
+    if (diffuse.isNull() || bitmap_is_too_big(diffuse) ||
+        normal.isNull() || bitmap_is_too_big(normal) ||
+        diffuse.width() != normal.width() ||
+        diffuse.height() != normal.height()) {
+        if (!allocator) {
+            shader = SkNEW(SkEmptyShader);
+        } else {
+            shader = allocator->createT<SkEmptyShader>();
+        }
+    } else {
+        if (!allocator) {
+            shader = SkNEW_ARGS(SkLightingShader, (diffuse, normal, light, ambient));
+        } else {
+            shader = allocator->createT<SkLightingShader>(diffuse, normal, light, ambient);
+        }
+    }
+    return shader;
+}
+#endif
 
-static SkView* MyFactory() { return new LightingView; }
-static SkViewRegister reg(MyFactory);
+///////////////////////////////////////////////////////////////////////////////