Refactoring of GPU NormalMap handling out into its own class.

The purpose of this change is to refactor the handling of normal maps out of SkLightingShader, laying the groundwork to eventually allow for multiple normal sources.

What this CL includes:

- Created a new 'NormalMapFP', out of the existing normal map reading behavior in LightingFP.

- Encapsulates this new fragment processor on a new class NormalMapSource.

- Created a NormalSource abstraction that will interface with SkLightingShader.

- Adapted SkLightingShader to use the normals from its NormalSource field ON THE GPU SIDE. No changes done to the CPU side yet.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2043393002

Committed: https://skia.googlesource.com/skia/+/87b0dd00cf9409c5fc990f5d0bb7c0df837f08da
Review-Url: https://codereview.chromium.org/2043393002

1 files changed, 61 insertions, 114 deletions

diff --git a/src/core/SkLightingShader.cpp b/src/core/SkLightingShader.cpp
index aaf29fcf3a..c80f26884a 100644
--- a/src/core/SkLightingShader.cpp
+++ b/src/core/SkLightingShader.cpp
@@ -5,6 +5,7 @@
  * found in the LICENSE file.
  */
 
+#include "SkBitmapProcShader.h"
 #include "SkBitmapProcState.h"
 #include "SkColor.h"
 #include "SkEmptyShader.h"
@@ -42,17 +43,19 @@ public:
 
     /** Create a new lighting shader that uses the provided normal map and
         lights to light the diffuse bitmap.
-        @param diffuse    the diffuse bitmap
-        @param normal     the normal map
-        @param lights     the lights applied to the normal map
-        @param invNormRotation rotation applied to the normal map's normals
-        @param diffLocalM the local matrix for the diffuse coordinates
-        @param normLocalM the local matrix for the normal coordinates
+        @param diffuse           the diffuse bitmap
+        @param normal            the normal map
+        @param lights            the lights applied to the normal map
+        @param invNormRotation   rotation applied to the normal map's normals
+        @param diffLocalM        the local matrix for the diffuse coordinates
+        @param normLocalM        the local matrix for the normal coordinates
+        @param normalSource      the normal source for GPU computations
     */
     SkLightingShaderImpl(const SkBitmap& diffuse, const SkBitmap& normal,
                          const sk_sp<SkLights> lights,
                          const SkVector& invNormRotation,
-                         const SkMatrix* diffLocalM, const SkMatrix* normLocalM)
+                         const SkMatrix* diffLocalM, const SkMatrix* normLocalM,
+                         sk_sp<SkLightingShader::NormalSource> normalSource)
         : INHERITED(diffLocalM)
         , fDiffuseMap(diffuse)
         , fNormalMap(normal)
@@ -67,6 +70,7 @@ public:
         // Pre-cache so future calls to fNormLocalMatrix.getType() are threadsafe.
         (void)fNormLocalMatrix.getType();
 
+        fNormalSource = std::move(normalSource);
     }
 
     bool isOpaque() const override;
@@ -117,6 +121,8 @@ private:
     SkMatrix        fNormLocalMatrix;
     SkVector        fInvNormRotation;
 
+    sk_sp<SkLightingShader::NormalSource> fNormalSource;
+
     friend class SkLightingShader;
 
     typedef SkShader INHERITED;
@@ -139,19 +145,12 @@ private:
 
 class LightingFP : public GrFragmentProcessor {
 public:
-    LightingFP(GrTexture* diffuse, GrTexture* normal, const SkMatrix& diffMatrix,
-               const SkMatrix& normMatrix, const GrTextureParams& diffParams,
-               const GrTextureParams& normParams, sk_sp<SkLights> lights,
-               const SkVector& invNormRotation)
+    LightingFP(GrTexture* diffuse, const SkMatrix& diffMatrix, const GrTextureParams& diffParams,
+               sk_sp<SkLights> lights, sk_sp<GrFragmentProcessor> normalFP)
         : fDiffDeviceTransform(kLocal_GrCoordSet, diffMatrix, diffuse, diffParams.filterMode())
-        , fNormDeviceTransform(kLocal_GrCoordSet, normMatrix, normal, normParams.filterMode())
-        , fDiffuseTextureAccess(diffuse, diffParams)
-        , fNormalTextureAccess(normal, normParams)
-        , fInvNormRotation(invNormRotation) {
+        , fDiffuseTextureAccess(diffuse, diffParams) {
         this->addCoordTransform(&fDiffDeviceTransform);
-        this->addCoordTransform(&fNormDeviceTransform);
         this->addTextureAccess(&fDiffuseTextureAccess);
-        this->addTextureAccess(&fNormalTextureAccess);
 
         // fuse all ambient lights into a single one
         fAmbientColor.set(0.0f, 0.0f, 0.0f);
@@ -165,16 +164,16 @@ public:
             }
         }
 
+        this->registerChildProcessor(std::move(normalFP));
         this->initClassID<LightingFP>();
     }
 
-    class LightingGLFP : public GrGLSLFragmentProcessor {
+    class GLSLLightingFP : public GrGLSLFragmentProcessor {
     public:
-        LightingGLFP() {
+        GLSLLightingFP() {
             fLightDir.fX = 10000.0f;
             fLightColor.fX = 0.0f;
             fAmbientColor.fX = 0.0f;
-            fInvNormRotation.set(0.0f, 0.0f);
         }
 
         void emitCode(EmitArgs& args) override {
@@ -198,33 +197,16 @@ public:
                                                           kVec3f_GrSLType, kDefault_GrSLPrecision,
                                                           "AmbientColor", &ambientColorUniName);
 
-            const char* xformUniName = nullptr;
-            fXformUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
-                                                   kVec2f_GrSLType, kDefault_GrSLPrecision,
-                                                   "Xform", &xformUniName);
-
             fragBuilder->codeAppend("vec4 diffuseColor = ");
             fragBuilder->appendTextureLookupAndModulate(args.fInputColor, args.fTexSamplers[0],
                                                 args.fCoords[0].c_str(),
                                                 args.fCoords[0].getType());
             fragBuilder->codeAppend(";");
 
-            fragBuilder->codeAppend("vec4 normalColor = ");
-            fragBuilder->appendTextureLookup(args.fTexSamplers[1],
-                                     args.fCoords[1].c_str(),
-                                     args.fCoords[1].getType());
-            fragBuilder->codeAppend(";");
-
-            fragBuilder->codeAppend("vec3 normal = normalColor.rgb - vec3(0.5);");
-
-            fragBuilder->codeAppendf(
-                                 "mat3 m = mat3(%s.x, -%s.y, 0.0, %s.y, %s.x, 0.0, 0.0, 0.0, 1.0);",
-                                 xformUniName, xformUniName, xformUniName, xformUniName);
-
-            // TODO: inverse map the light direction vectors in the vertex shader rather than
-            // transforming all the normals here!
-            fragBuilder->codeAppend("normal = normalize(m*normal);");
+            SkString dstNormalName("dstNormal");
+            this->emitChild(0, nullptr, &dstNormalName, args);
 
+            fragBuilder->codeAppendf("vec3 normal = %s.xyz;", dstNormalName.c_str());
             fragBuilder->codeAppendf("float NdotL = clamp(dot(normal, %s), 0.0, 1.0);",
                                      lightDirUniName);
             // diffuse light
@@ -262,12 +244,6 @@ public:
                 pdman.set3fv(fAmbientColorUni, 1, &ambientColor.fX);
                 fAmbientColor = ambientColor;
             }
-
-            const SkVector& invNormRotation = lightingFP.invNormRotation();
-            if (invNormRotation != fInvNormRotation) {
-                pdman.set2fv(fXformUni, 1, &invNormRotation.fX);
-                fInvNormRotation = invNormRotation;
-            }
         }
 
     private:
@@ -279,13 +255,10 @@ public:
 
         SkColor3f fAmbientColor;
         GrGLSLProgramDataManager::UniformHandle fAmbientColorUni;
-
-        SkVector fInvNormRotation;
-        GrGLSLProgramDataManager::UniformHandle fXformUni;
     };
 
     void onGetGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const override {
-        LightingGLFP::GenKey(*this, caps, b);
+        GLSLLightingFP::GenKey(*this, caps, b);
     }
 
     const char* name() const override { return "LightingFP"; }
@@ -297,32 +270,24 @@ public:
     const SkVector3& lightDir() const { return fLightDir; }
     const SkColor3f& lightColor() const { return fLightColor; }
     const SkColor3f& ambientColor() const { return fAmbientColor; }
-    const SkVector& invNormRotation() const { return fInvNormRotation; }
 
 private:
-    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override { return new LightingGLFP; }
+    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override { return new GLSLLightingFP; }
 
     bool onIsEqual(const GrFragmentProcessor& proc) const override {
         const LightingFP& lightingFP = proc.cast<LightingFP>();
         return fDiffDeviceTransform == lightingFP.fDiffDeviceTransform &&
-               fNormDeviceTransform == lightingFP.fNormDeviceTransform &&
                fDiffuseTextureAccess == lightingFP.fDiffuseTextureAccess &&
-               fNormalTextureAccess == lightingFP.fNormalTextureAccess &&
                fLightDir == lightingFP.fLightDir &&
                fLightColor == lightingFP.fLightColor &&
-               fAmbientColor == lightingFP.fAmbientColor &&
-               fInvNormRotation == lightingFP.fInvNormRotation;
+               fAmbientColor == lightingFP.fAmbientColor;
     }
 
     GrCoordTransform fDiffDeviceTransform;
-    GrCoordTransform fNormDeviceTransform;
     GrTextureAccess  fDiffuseTextureAccess;
-    GrTextureAccess  fNormalTextureAccess;
     SkVector3        fLightDir;
     SkColor3f        fLightColor;
     SkColor3f        fAmbientColor;
-
-    SkVector         fInvNormRotation;
 };
 
 ////////////////////////////////////////////////////////////////////////////
@@ -357,56 +322,39 @@ sk_sp<GrFragmentProcessor> SkLightingShaderImpl::asFragmentProcessor(
                                                      SkFilterQuality filterQuality,
                                                      SkSourceGammaTreatment gammaTreatment) const {
     // we assume diffuse and normal maps have same width and height
-    // TODO: support different sizes
+    // TODO: support different sizes, will be addressed when diffuse maps are factored out of
+    //       SkLightingShader in a future CL
     SkASSERT(fDiffuseMap.width() == fNormalMap.width() &&
              fDiffuseMap.height() == fNormalMap.height());
-    SkMatrix diffM, normM;
+    SkMatrix diffM;
 
     if (!make_mat(fDiffuseMap, this->getLocalMatrix(), localMatrix, &diffM)) {
         return nullptr;
     }
 
-    if (!make_mat(fNormalMap, fNormLocalMatrix, localMatrix, &normM)) {
-        return nullptr;
-    }
-
     bool doBicubic;
     GrTextureParams::FilterMode diffFilterMode = GrSkFilterQualityToGrFilterMode(
-                                        SkTMin(filterQuality, kMedium_SkFilterQuality),
-                                        viewM,
-                                        this->getLocalMatrix(),
-                                        &doBicubic);
-    SkASSERT(!doBicubic);
-
-    GrTextureParams::FilterMode normFilterMode = GrSkFilterQualityToGrFilterMode(
-                                        SkTMin(filterQuality, kMedium_SkFilterQuality),
-                                        viewM,
-                                        fNormLocalMatrix,
-                                        &doBicubic);
+                                                    SkTMin(filterQuality, kMedium_SkFilterQuality),
+                                                    viewM,
+                                                    this->getLocalMatrix(),
+                                                    &doBicubic);
     SkASSERT(!doBicubic);
 
     // TODO: support other tile modes
     GrTextureParams diffParams(kClamp_TileMode, diffFilterMode);
-    SkAutoTUnref<GrTexture> diffuseTexture(GrRefCachedBitmapTexture(context,
-                                                                    fDiffuseMap, diffParams,
-                                                                    gammaTreatment));
+    SkAutoTUnref<GrTexture> diffuseTexture(GrRefCachedBitmapTexture(context, fDiffuseMap,
+                                                                    diffParams, gammaTreatment));
     if (!diffuseTexture) {
         SkErrorInternals::SetError(kInternalError_SkError, "Couldn't convert bitmap to texture.");
         return nullptr;
     }
 
-    GrTextureParams normParams(kClamp_TileMode, normFilterMode);
-    SkAutoTUnref<GrTexture> normalTexture(GrRefCachedBitmapTexture(context,
-                                                                   fNormalMap, normParams,
-                                                                   gammaTreatment));
-    if (!normalTexture) {
-        SkErrorInternals::SetError(kInternalError_SkError, "Couldn't convert bitmap to texture.");
-        return nullptr;
-    }
-
+    sk_sp<GrFragmentProcessor> normalFP(
+            fNormalSource->asFragmentProcessor(context, viewM, localMatrix, filterQuality,
+                                               gammaTreatment));
     sk_sp<GrFragmentProcessor> inner (
-        new LightingFP(diffuseTexture, normalTexture, diffM, normM, diffParams, normParams, fLights,
-                       fInvNormRotation));
+            new LightingFP(diffuseTexture, diffM, diffParams, fLights, std::move(normalFP)));
+
     return GrFragmentProcessor::MulOutputByInputAlpha(std::move(inner));
 }
 
@@ -418,14 +366,14 @@ bool SkLightingShaderImpl::isOpaque() const {
     return fDiffuseMap.isOpaque();
 }
 
-SkLightingShaderImpl::LightingShaderContext::LightingShaderContext(const SkLightingShaderImpl& shader,
-                                                                   const ContextRec& rec,
-                                                                   SkBitmapProcState* diffuseState,
-                                                                   SkBitmapProcState* normalState)
+SkLightingShaderImpl::LightingShaderContext::LightingShaderContext(
+                                                                const SkLightingShaderImpl& shader,
+                                                                const ContextRec& rec,
+                                                                SkBitmapProcState* diffuseState,
+                                                                SkBitmapProcState* normalState)
     : INHERITED(shader, rec)
     , fDiffuseState(diffuseState)
-    , fNormalState(normalState)
-{
+    , fNormalState(normalState) {
     const SkPixmap& pixmap = fDiffuseState->fPixmap;
     bool isOpaque = pixmap.isOpaque();
 
@@ -615,8 +563,11 @@ sk_sp<SkFlattenable> SkLightingShaderImpl::CreateProc(SkReadBuffer& buf) {
         invNormRotation = buf.readPoint();
     }
 
+    sk_sp<SkLightingShader::NormalSource> normalSource(
+            buf.readFlattenable<SkLightingShader::NormalSource>());
+
     return sk_make_sp<SkLightingShaderImpl>(diffuse, normal, std::move(lights), invNormRotation,
-                                            &diffLocalM, &normLocalM);
+                                            &diffLocalM, &normLocalM, std::move(normalSource));
 }
 
 void SkLightingShaderImpl::flatten(SkWriteBuffer& buf) const {
@@ -644,6 +595,8 @@ void SkLightingShaderImpl::flatten(SkWriteBuffer& buf) const {
         }
     }
     buf.writePoint(fInvNormRotation);
+
+    buf.writeFlattenable(fNormalSource.get());
 }
 
 bool SkLightingShaderImpl::computeNormTotalInverse(const ContextRec& rec,
@@ -685,7 +638,9 @@ SkShader::Context* SkLightingShaderImpl::onCreateContext(const ContextRec& rec,
         return nullptr;
     }
 
-    void* normalStateStorage = (char*)storage + sizeof(LightingShaderContext) + sizeof(SkBitmapProcState);
+    void* normalStateStorage = (char*)storage +
+                                sizeof(LightingShaderContext) +
+                                sizeof(SkBitmapProcState);
     SkBitmapProcState* normalState = new (normalStateStorage) SkBitmapProcState(fNormalMap,
                                             SkShader::kClamp_TileMode, SkShader::kClamp_TileMode,
                                                                     SkMipMap::DeduceTreatment(rec));
@@ -701,31 +656,23 @@ SkShader::Context* SkLightingShaderImpl::onCreateContext(const ContextRec& rec,
 
 ///////////////////////////////////////////////////////////////////////////////
 
-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;
-}
-
 sk_sp<SkShader> SkLightingShader::Make(const SkBitmap& diffuse, const SkBitmap& normal,
                                        sk_sp<SkLights> lights,
                                        const SkVector& invNormRotation,
                                        const SkMatrix* diffLocalM, const SkMatrix* normLocalM) {
-    if (diffuse.isNull() || bitmap_is_too_big(diffuse) ||
-        normal.isNull() || bitmap_is_too_big(normal) ||
-        diffuse.width() != normal.width() ||
+    if (diffuse.isNull() || SkBitmapProcShader::BitmapIsTooBig(diffuse) ||
+        normal.isNull()  || SkBitmapProcShader::BitmapIsTooBig(normal) ||
+        diffuse.width()  != normal.width() ||
         diffuse.height() != normal.height()) {
         return nullptr;
     }
-
     SkASSERT(SkScalarNearlyEqual(invNormRotation.lengthSqd(), SK_Scalar1));
 
+    sk_sp<SkLightingShader::NormalSource> normalSource =
+            SkLightingShader::NormalMapSource::Make(normal, invNormRotation, normLocalM);
+
     return sk_make_sp<SkLightingShaderImpl>(diffuse, normal, std::move(lights),
-                                            invNormRotation, diffLocalM, normLocalM);
+            invNormRotation, diffLocalM, normLocalM, std::move(normalSource));
 }
 
 ///////////////////////////////////////////////////////////////////////////////