Make GrPaint have a variable sized array of color and coverage stages rather than a fixed size.

src/gpu/SkGpuDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGpuDevice.h"
 
 #include "effects/GrTextureDomainEffect.h"
@@ skipping 20 matching lines @@
     extern bool (*gShouldDrawProc)();
     #define CHECK_SHOULD_DRAW(draw, forceI)                     \
         do {                                                    \
             if (gShouldDrawProc && !gShouldDrawProc()) return;  \
             this->prepareDraw(draw, forceI);                    \
         } while (0)
 #else
     #define CHECK_SHOULD_DRAW(draw, forceI) this->prepareDraw(draw, forceI)
 #endif
 
-// we use the same effect slot on GrPaint for bitmaps and shaders (since drawBitmap, drawSprite,
-// and drawDevice ignore SkShader)
-enum {
-    kShaderEffectIdx = 0,
-    kBitmapEffectIdx = 0,
-    kColorFilterEffectIdx = 1,
-    kXfermodeEffectIdx = 2,
-};
-
 // This constant represents the screen alignment criterion in texels for
 // requiring texture domain clamping to prevent color bleeding when drawing
 // a sub region of a larger source image.
 #define COLOR_BLEED_TOLERANCE SkFloatToScalar(0.001f)
 
 #define DO_DEFERRED_CLEAR()             \
     do {                                \
         if (fNeedClear) {               \
             this->clear(SK_ColorTRANSPARENT); \
         }                               \
@@ skipping 375 matching lines @@
     fContext->setClip(&fClipData);
 
     DO_DEFERRED_CLEAR();
 }
 
 GrRenderTarget* SkGpuDevice::accessRenderTarget() {
     DO_DEFERRED_CLEAR();
     return fRenderTarget;
 }
 
-bool SkGpuDevice::bindDeviceAsTexture(GrPaint* paint) {
-    GrTexture* texture = fRenderTarget->asTexture();
-    if (NULL != texture) {
-        paint->colorStage(kBitmapEffectIdx)->setEffect(
-            GrSimpleTextureEffect::Create(texture, SkMatrix::I()))->unref();
-        return true;
-    }
-    return false;
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 
 SK_COMPILE_ASSERT(SkShader::kNone_BitmapType == 0, shader_type_mismatch);
 SK_COMPILE_ASSERT(SkShader::kDefault_BitmapType == 1, shader_type_mismatch);
 SK_COMPILE_ASSERT(SkShader::kRadial_BitmapType == 2, shader_type_mismatch);
 SK_COMPILE_ASSERT(SkShader::kSweep_BitmapType == 3, shader_type_mismatch);
 SK_COMPILE_ASSERT(SkShader::kTwoPointRadial_BitmapType == 4,
                   shader_type_mismatch);
 SK_COMPILE_ASSERT(SkShader::kTwoPointConical_BitmapType == 5,
                   shader_type_mismatch);
@@ skipping 17 matching lines @@
     grPaint->setDither(skPaint.isDither());
     grPaint->setAntiAlias(skPaint.isAntiAlias());
 
     SkXfermode::Coeff sm;
     SkXfermode::Coeff dm;
 
     SkXfermode* mode = skPaint.getXfermode();
     GrEffectRef* xferEffect = NULL;
     if (SkXfermode::AsNewEffectOrCoeff(mode, dev->context(), &xferEffect, &sm, &dm)) {
         if (NULL != xferEffect) {
-            grPaint->colorStage(kXfermodeEffectIdx)->setEffect(xferEffect)->unref();
+            grPaint->addColorEffect(xferEffect)->unref();
             sm = SkXfermode::kOne_Coeff;
             dm = SkXfermode::kZero_Coeff;
         }
     } else {
         //SkDEBUGCODE(SkDebugf("Unsupported xfer mode.\n");)
 #if 0
         return false;
 #else
         // Fall back to src-over
         sm = SkXfermode::kOne_Coeff;
         dm = SkXfermode::kISA_Coeff;
 #endif
     }
     grPaint->setBlendFunc(sk_blend_to_grblend(sm), sk_blend_to_grblend(dm));
 
     if (justAlpha) {
         uint8_t alpha = skPaint.getAlpha();
         grPaint->setColor(GrColorPackRGBA(alpha, alpha, alpha, alpha));
         // justAlpha is currently set to true only if there is a texture,
         // so constantColor should not also be true.
         GrAssert(!constantColor);
     } else {
         grPaint->setColor(SkColor2GrColor(skPaint.getColor()));
-        GrAssert(!grPaint->isColorStageEnabled(kShaderEffectIdx));
     }
 
     SkColorFilter* colorFilter = skPaint.getColorFilter();
     if (NULL != colorFilter) {
         // if the source color is a constant then apply the filter here once rather than per pixel
         // in a shader.
         if (constantColor) {
             SkColor filtered = colorFilter->filterColor(skPaint.getColor());
             grPaint->setColor(SkColor2GrColor(filtered));
         } else {
             SkAutoTUnref<GrEffectRef> effect(colorFilter->asNewEffect(dev->context()));
             if (NULL != effect.get()) {
-                grPaint->colorStage(kColorFilterEffectIdx)->setEffect(effect);
+                grPaint->addColorEffect(effect);
             } else {
                 // TODO: rewrite this using asNewEffect()
                 SkColor color;
                 SkXfermode::Mode filterMode;
                 if (colorFilter->asColorMode(&color, &filterMode)) {
                     grPaint->setXfermodeColorFilter(filterMode, SkColor2GrColor(color));
                 }
             }
         }
     }
 
     return true;
 }
 
 // This function is similar to skPaint2GrPaintNoShader but also converts
 // skPaint's shader to a GrTexture/GrEffectStage if possible. The texture to
 // be used is set on grPaint and returned in param act. constantColor has the
 // same meaning as in skPaint2GrPaintNoShader.
 inline bool skPaint2GrPaintShader(SkGpuDevice* dev,
                                   const SkPaint& skPaint,
                                   bool constantColor,
                                   GrPaint* grPaint) {
     SkShader* shader = skPaint.getShader();
     if (NULL == shader) {
         return skPaint2GrPaintNoShader(dev, skPaint, false, constantColor, grPaint);
-    } else if (!skPaint2GrPaintNoShader(dev, skPaint, true, false, grPaint)) {
-        return false;
     }
 
+    // setup the shader as the first color effect on the paint
     SkAutoTUnref<GrEffectRef> effect(shader->asNewEffect(dev->context(), skPaint));
     if (NULL != effect.get()) {
-        grPaint->colorStage(kShaderEffectIdx)->setEffect(effect);
-        return true;
+        grPaint->addColorEffect(effect);
+        // Now setup the rest of the paint.
+        return skPaint2GrPaintNoShader(dev, skPaint, true, false, grPaint);
+    } else {
+        // We still don't have SkColorShader::asNewEffect() implemented.
+        SkShader::GradientInfo info;
+        SkColor                color;
+
+        info.fColors = &color;
+        info.fColorOffsets = NULL;
+        info.fColorCount = 1;
+        if (SkShader::kColor_GradientType == shader->asAGradient(&info)) {
+            SkPaint copy(skPaint);
+            copy.setShader(NULL);
+            // modulate the paint alpha by the shader's solid color alpha
+            U8CPU newA = SkMulDiv255Round(SkColorGetA(color), copy.getAlpha());
+            copy.setColor(SkColorSetA(color, newA));
+            return skPaint2GrPaintNoShader(dev, copy, false, constantColor, grPaint);
+        } else {
+            return false;
+        }
     }
-
-    // We still don't have SkColorShader::asNewEffect() implemented.
-    SkShader::GradientInfo info;
-    SkColor                color;
-
-    info.fColors = &color;
-    info.fColorOffsets = NULL;
-    info.fColorCount = 1;
-    if (SkShader::kColor_GradientType == shader->asAGradient(&info)) {
-        SkPaint copy(skPaint);
-        copy.setShader(NULL);
-        // modulate the paint alpha by the shader's solid color alpha
-        U8CPU newA = SkMulDiv255Round(SkColorGetA(color), copy.getAlpha());
-        copy.setColor(SkColorSetA(color, newA));
-        return skPaint2GrPaintNoShader(dev, copy, false, constantColor, grPaint);
-    }
-    return false;
 }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 void SkGpuDevice::clear(SkColor color) {
     SkIRect rect = SkIRect::MakeWH(this->width(), this->height());
     fContext->clear(&rect, SkColor2GrColor(color), fRenderTarget);
     fNeedClear = false;
 }
 
@@ skipping 171 matching lines @@
 ///////////////////////////////////////////////////////////////////////////////
 
 // helpers for applying mask filters
 namespace {
 
 // Draw a mask using the supplied paint. Since the coverage/geometry
 // is already burnt into the mask this boils down to a rect draw.
 // Return true if the mask was successfully drawn.
 bool draw_mask(GrContext* context, const SkRect& maskRect,
                GrPaint* grp, GrTexture* mask) {
-
     GrContext::AutoMatrix am;
     if (!am.setIdentity(context, grp)) {
         return false;
     }
 
-    static const int MASK_IDX = GrPaint::kMaxCoverageStages - 1;
-    // we assume the last mask index is available for use
-    GrAssert(!grp->isCoverageStageEnabled(MASK_IDX));
-
     SkMatrix matrix;
     matrix.setTranslate(-maskRect.fLeft, -maskRect.fTop);
     matrix.postIDiv(mask->width(), mask->height());
 
-    grp->coverageStage(MASK_IDX)->reset();
-    grp->coverageStage(MASK_IDX)->setEffect(GrSimpleTextureEffect::Create(mask, matrix))->unref();
+    grp->addCoverageEffect(GrSimpleTextureEffect::Create(mask, matrix))->unref();
     context->drawRect(*grp, maskRect);
     return true;
 }
 
 bool draw_with_mask_filter(GrContext* context, const SkPath& devPath,
                            SkMaskFilter* filter, const SkRegion& clip, SkBounder* bounder,
                            GrPaint* grp, SkPaint::Style style) {
     SkMask  srcM, dstM;
 
     if (!SkDraw::DrawToMask(devPath, &clip.getBounds(), filter, &context->getMatrix(), &srcM,
@@ skipping 364 matching lines @@
         SkMatrix drawMatrix;
         drawMatrix.setConcat(fContext->getMatrix(), newM);
         SkDraw transformedDraw(draw);
         transformedDraw.fMatrix = &drawMatrix;
 
         this->drawRect(transformedDraw, srcRect, paintWithTexture);
 
         return;
     }
 
-    GrPaint grPaint;
-
-    bool alphaOnly = !(SkBitmap::kA8_Config == bitmap.config());
-    if (!skPaint2GrPaintNoShader(this, paint, alphaOnly, false, &grPaint)) {
-        return;
-    }
     GrTextureParams params;
     params.setBilerp(paint.isFilterBitmap());
 
     if (!this->shouldTileBitmap(bitmap, params, srcRectPtr)) {
         // take the simple case
-        this->internalDrawBitmap(bitmap, srcRect, m, params, &grPaint);
+        this->internalDrawBitmap(bitmap, srcRect, m, params, paint);
     } else {
-        this->drawTiledBitmap(bitmap, srcRect, m, params, &grPaint);
+        this->drawTiledBitmap(bitmap, srcRect, m, params, paint);
     }
 }
 
 // Break 'bitmap' into several tiles to draw it since it has already
 // been determined to be too large to fit in VRAM
 void SkGpuDevice::drawTiledBitmap(const SkBitmap& bitmap,
                                   const SkRect& srcRect,
                                   const SkMatrix& m,
                                   const GrTextureParams& params,
-                                  GrPaint* grPaint) {
+                                  const SkPaint& paint) {
     const int maxTextureSize = fContext->getMaxTextureSize();
 
     int tileSize = determine_tile_size(bitmap, srcRect, maxTextureSize);
 
     // compute clip bounds in local coordinates
     SkRect clipRect;
     {
         const GrRenderTarget* rt = fContext->getRenderTarget();
         clipRect.setWH(SkIntToScalar(rt->width()), SkIntToScalar(rt->height()));
         if (!fContext->getClip()->fClipStack->intersectRectWithClip(&clipRect)) {
@@ skipping 28 matching lines @@
             SkBitmap tmpB;
             SkIRect iTileR;
             tileR.roundOut(&iTileR);
             if (bitmap.extractSubset(&tmpB, iTileR)) {
                 // now offset it to make it "local" to our tmp bitmap
                 tileR.offset(SkIntToScalar(-iTileR.fLeft), SkIntToScalar(-iTileR.fTop));
                 SkMatrix tmpM(m);
                 tmpM.preTranslate(SkIntToScalar(iTileR.fLeft),
                                   SkIntToScalar(iTileR.fTop));
 
-                this->internalDrawBitmap(tmpB, tileR, tmpM, params, grPaint);
+                this->internalDrawBitmap(tmpB, tileR, tmpM, params, paint);
             }
         }
     }
 }
 
 namespace {
 
 bool hasAlignedSamples(const SkRect& srcRect, const SkRect& transformedRect) {
     // detect pixel disalignment
     if (SkScalarAbs(SkScalarRoundToScalar(transformedRect.left()) -
@@ skipping 39 matching lines @@
  *  This is called by drawBitmap(), which has to handle images that may be too
  *  large to be represented by a single texture.
  *
  *  internalDrawBitmap assumes that the specified bitmap will fit in a texture
  *  and that non-texture portion of the GrPaint has already been setup.
  */
 void SkGpuDevice::internalDrawBitmap(const SkBitmap& bitmap,
                                      const SkRect& srcRect,
                                      const SkMatrix& m,
                                      const GrTextureParams& params,
-                                     GrPaint* grPaint) {
+                                     const SkPaint& paint) {
     SkASSERT(bitmap.width() <= fContext->getMaxTextureSize() &&
              bitmap.height() <= fContext->getMaxTextureSize());
 
     GrTexture* texture;
     SkAutoCachedTexture act(this, bitmap, &params, &texture);
     if (NULL == texture) {
         return;
     }
 
     GrRect dstRect(srcRect);
@@ skipping 49 matching lines @@
         }
         textureDomain.setLTRB(left, top, right, bottom);
         effect.reset(GrTextureDomainEffect::Create(texture,
                                                    SkMatrix::I(),
                                                    textureDomain,
                                                    GrTextureDomainEffect::kClamp_WrapMode,
                                                    params.isBilerp()));
     } else {
         effect.reset(GrSimpleTextureEffect::Create(texture, SkMatrix::I(), params));
     }
-    grPaint->colorStage(kBitmapEffectIdx)->setEffect(effect);
-    fContext->drawRectToRect(*grPaint, dstRect, paintRect, &m);
+
+    // Construct a GrPaint by setting the bitmap texture as the first effect and then configuring
+    // the rest from the SkPaint.
+    GrPaint grPaint;
+    grPaint.addColorEffect(effect);
+    bool alphaOnly = !(SkBitmap::kA8_Config == bitmap.config());
+    if (!skPaint2GrPaintNoShader(this, paint, alphaOnly, false, &grPaint)) {
+        return;
+    }
+
+    fContext->drawRectToRect(grPaint, dstRect, paintRect, &m);
 }
 
 static bool filter_texture(SkDevice* device, GrContext* context,
                            GrTexture* texture, SkImageFilter* filter,
                            int w, int h, SkBitmap* result, SkIPoint* offset) {
     GrAssert(filter);
     SkDeviceImageFilterProxy proxy(device);
 
     if (filter->canFilterImageGPU()) {
         // Save the render target and set it to NULL, so we don't accidentally draw to it in the
@@ skipping 11 matching lines @@
     CHECK_SHOULD_DRAW(draw, true);
 
     SkAutoLockPixels alp(bitmap, !bitmap.getTexture());
     if (!bitmap.getTexture() && !bitmap.readyToDraw()) {
         return;
     }
 
     int w = bitmap.width();
     int h = bitmap.height();
 
-    GrPaint grPaint;
-    if(!skPaint2GrPaintNoShader(this, paint, true, false, &grPaint)) {
-        return;
-    }
-
-    GrEffectStage* stage = grPaint.colorStage(kBitmapEffectIdx);
-
     GrTexture* texture;
-    stage->reset();
     // draw sprite uses the default texture params
     SkAutoCachedTexture act(this, bitmap, NULL, &texture);
-    grPaint.colorStage(kBitmapEffectIdx)->setEffect(
-        GrSimpleTextureEffect::Create(texture, SkMatrix::I()))->unref();
 
     SkImageFilter* filter = paint.getImageFilter();
     SkIPoint offset = SkIPoint::Make(0, 0);
     if (NULL != filter) {
         SkBitmap filterBitmap;
         if (filter_texture(this, fContext, texture, filter, w, h, &filterBitmap, &offset)) {
-            grPaint.colorStage(kBitmapEffectIdx)->setEffect(
-                GrSimpleTextureEffect::Create(filterBitmap.getTexture(), SkMatrix::I()))->unref();
-            texture = filterBitmap.getTexture();
+            texture = (GrTexture*) filterBitmap.getTexture();
             w = filterBitmap.width();
             h = filterBitmap.height();
         }
     }
 
+    GrPaint grPaint;
+    grPaint.addColorTextureEffect(texture, SkMatrix::I());
+
+    if(!skPaint2GrPaintNoShader(this, paint, true, false, &grPaint)) {
+        return;
+    }
+
     fContext->drawRectToRect(grPaint,
                              GrRect::MakeXYWH(SkIntToScalar(left),
                                               SkIntToScalar(top),
                                               SkIntToScalar(w),
                                               SkIntToScalar(h)),
                              GrRect::MakeXYWH(SkIntToScalar(offset.fX),
                                               SkIntToScalar(offset.fY),
                                               SK_Scalar1 * w / texture->width(),
                                               SK_Scalar1 * h / texture->height()));
 }
@@ skipping 33 matching lines @@
     // clear of the source device must occur before CHECK_SHOULD_DRAW
     SkGpuDevice* dev = static_cast<SkGpuDevice*>(device);
     if (dev->fNeedClear) {
         // TODO: could check here whether we really need to draw at all
         dev->clear(0x0);
     }
 
     // drawDevice is defined to be in device coords.
     CHECK_SHOULD_DRAW(draw, true);
 
-    GrPaint grPaint;
-    grPaint.colorStage(kBitmapEffectIdx)->reset();
-    if (!dev->bindDeviceAsTexture(&grPaint) ||
-        !skPaint2GrPaintNoShader(this, paint, true, false, &grPaint)) {
+    GrRenderTarget* devRT = device->accessRenderTarget();
+    GrTexture* devTex;
+    if (NULL == (devTex = devRT->asTexture())) {
         return;
     }
 
-    GrTexture* devTex = (*grPaint.getColorStage(kBitmapEffectIdx).getEffect())->texture(0);
-    SkASSERT(NULL != devTex);
-
     const SkBitmap& bm = dev->accessBitmap(false);
     int w = bm.width();
     int h = bm.height();
 
     SkImageFilter* filter = paint.getImageFilter();
+
     if (NULL != filter) {
         SkBitmap filterBitmap;
         SkIPoint offset = SkIPoint::Make(0, 0);
         if (filter_texture(this, fContext, devTex, filter, w, h, &filterBitmap, &offset)) {
-            grPaint.colorStage(kBitmapEffectIdx)->setEffect(
-                GrSimpleTextureEffect::Create(filterBitmap.getTexture(), SkMatrix::I()))->unref();
             devTex = filterBitmap.getTexture();
             w = filterBitmap.width();
             h = filterBitmap.height();
             x += offset.fX;
             y += offset.fY;
         }
     }
 
+    GrPaint grPaint;
+    grPaint.addColorTextureEffect(devTex, SkMatrix::I());
+
+    if (!skPaint2GrPaintNoShader(this, paint, true, false, &grPaint)) {
+        return;
+    }
+
     GrRect dstRect = GrRect::MakeXYWH(SkIntToScalar(x),
                                       SkIntToScalar(y),
                                       SkIntToScalar(w),
                                       SkIntToScalar(h));
 
-    // The device being drawn may not fill up its texture (saveLayer uses
-    // the approximate ).
+    // The device being drawn may not fill up its texture (e.g. saveLayer uses approximate
+    // scratch texture).
     GrRect srcRect = GrRect::MakeWH(SK_Scalar1 * w / devTex->width(),
                                     SK_Scalar1 * h / devTex->height());
 
     fContext->drawRectToRect(grPaint, dstRect, srcRect);
 }
 
 bool SkGpuDevice::canHandleImageFilter(SkImageFilter* filter) {
     return filter->canFilterImageGPU();
 }
 
@@ skipping 252 matching lines @@
                          GrTexture* texture,
                          bool needClear)
     : SkDevice(make_bitmap(context, texture->asRenderTarget())) {
 
     GrAssert(texture && texture->asRenderTarget());
     // This constructor is called from onCreateCompatibleDevice. It has locked the RT in the texture
     // cache. We pass true for the third argument so that it will get unlocked.
     this->initFromRenderTarget(context, texture->asRenderTarget(), true);
     fNeedClear = needClear;
 }