Store mipmap levels in deferred texture image

src/image/SkImage_Gpu.cpp

Index: src/image/SkImage_Gpu.cpp
diff --git a/src/image/SkImage_Gpu.cpp b/src/image/SkImage_Gpu.cpp
index fa911827489ad82a4482c9f50c94f9bc275f0ac2..0f4fff0a976e05c372be5a92e4a754ad179e9d78 100644
--- a/src/image/SkImage_Gpu.cpp
+++ b/src/image/SkImage_Gpu.cpp
@@ -16,6 +16,7 @@
 #include "SkGrPixelRef.h"
 #include "SkGrPriv.h"
 #include "SkImage_Gpu.h"
+#include "SkMipMap.h"
 #include "SkPixelRef.h"
 
 SkImage_Gpu::SkImage_Gpu(int w, int h, uint32_t uniqueID, SkAlphaType at, GrTexture* tex,
@@ -362,7 +363,7 @@ private:
 };
 
 size_t SkImage::getDeferredTextureImageData(const GrContextThreadSafeProxy& proxy,
-                                            const DeferredTextureImageUsageParams[],
+                                            const DeferredTextureImageUsageParams params[],
                                             int paramCnt, void* buffer) const {
     const bool fillMode = SkToBool(buffer);
     if (fillMode && !SkIsAlign8(reinterpret_cast<intptr_t>(buffer))) {
@@ -405,7 +406,27 @@ size_t SkImage::getDeferredTextureImageData(const GrContextThreadSafeProxy& prox
             SkASSERT(!pixmap.ctable());
         }
     }
+    bool shouldUseMipMaps = false;
     int mipMapLevelCount = 1;
+    for (int currentParamIndex = paramCnt; currentParamIndex > 0; currentParamIndex--) {
+        SkScalar minScaleFactor = params[currentParamIndex].fMatrix.getMinScale();
+        if ((params[currentParamIndex].fQuality == kMedium_SkFilterQuality ||
+            params[currentParamIndex].fQuality == kHigh_SkFilterQuality) &&
+            minScaleFactor != -1.f && minScaleFactor < 1.f) {

[bsalomon, 2016/06/03 14:43:33]

Do we not use mip maps when the matrix has perspective?

[cblume, 2016/06/03 17:03:40]

Hrmmm I think any time perspective is involved it is likely being used in a
regular 3d sense, which means mipmaps would be fitting imho. I'll add that.

+            shouldUseMipMaps = true;
+            mipMapLevelCount = SkMipMap::ComputeLevelCount(width(), height());
+            break;
+        }
+    }
+    SkAlphaType at = this->isOpaque() ? kOpaque_SkAlphaType : kPremul_SkAlphaType;
+    if (shouldUseMipMaps) {
+        for (int currentMipMapLevelIndex = mipMapLevelCount; currentMipMapLevelIndex > 0;
+             currentMipMapLevelIndex--) {
+            SkSize mipSize = SkMipMap::ComputeLevelSize(width(), height(), currentMipMapLevelIndex);
+            SkImageInfo mipInfo = SkImageInfo::MakeN32(mipSize.fWidth, mipSize.fHeight, at);
+            pixelSize += SkAlign8(SkAutoPixmapStorage::AllocSize(mipInfo, nullptr));
+        }
+    }
     size_t size = 0;
     size_t dtiSize = SkAlign8(sizeof(DeferredTextureImage));
     size += dtiSize;
@@ -439,6 +460,27 @@ size_t SkImage::getDeferredTextureImageData(const GrContextThreadSafeProxy& prox
     dti->fData.fMipMapLevelCount = mipMapLevelCount;
     dti->fData.fMipMapLevelData[0].fPixelData = pixels;
     dti->fData.fMipMapLevelData[0].fRowBytes = rowBytes;
+
+    // Fill in the mipmap levels if they exist
+    intptr_t mipLevelPtr = bufferAsInt + pixelOffset;
+    if (shouldUseMipMaps) {
+        SkAutoTDelete<SkMipMap> mipmaps(SkMipMap::Build(pixmap, nullptr));
+        for (int currentMipMapLevelIndex = 1; currentMipMapLevelIndex < mipMapLevelCount;
+             currentMipMapLevelIndex++) {
+            SkSize prevMipSize = SkMipMap::ComputeLevelSize(width(), height(), currentMipMapLevelIndex);
+            SkImageInfo prevMipInfo = SkImageInfo::MakeN32(prevMipSize.fWidth, prevMipSize.fHeight, at);
+            mipLevelPtr += SkAlign8(SkAutoPixmapStorage::AllocSize(prevMipInfo, nullptr));
+
+            SkMipMap::Level currentMipMapLevel;
+            mipmaps->getLevel(currentMipMapLevelIndex, &currentMipMapLevel);
+            memcpy(reinterpret_cast<void*>(mipLevelPtr), currentMipMapLevel.fPixmap.addr(),

[bsalomon, 2016/06/03 14:43:33]

It's too bad we have to memcpy here. Should we extend the mip builder to allow
building in client provided memory?

[cblume, 2016/06/03 17:03:40]

I agree @ memcpy. I would love to add a CL that modifies SkMipMap allowing
user-specified memory. I'll do that in a follow-up CL then have a second
follow-up CL which modifies this call site.

+                   currentMipMapLevel.fPixmap.getSafeSize());
+            dti->fData.fMipMapLevelData[currentMipMapLevelIndex].fPixelData =
+                reinterpret_cast<void*>(mipLevelPtr);
+            dti->fData.fMipMapLevelData[currentMipMapLevelIndex].fRowBytes =
+                currentMipMapLevel.fPixmap.rowBytes();
+        }
+    }
     return size;
 }
 
@@ -457,11 +499,23 @@ sk_sp<SkImage> SkImage::MakeFromDeferredTextureImageData(GrContext* context, con
         SkASSERT(dti->fData.fColorTableData);
         colorTable.reset(new SkColorTable(dti->fData.fColorTableData, dti->fData.fColorTableCnt));
     }
-    SkASSERT(dti->fData.fMipMapLevelCount == 1);
-    SkPixmap pixmap;
-    pixmap.reset(dti->fData.fInfo, dti->fData.fMipMapLevelData[0].fPixelData,
-                 dti->fData.fMipMapLevelData[0].fRowBytes, colorTable.get());
-    return SkImage::MakeTextureFromPixmap(context, pixmap, budgeted);
+    int mipLevelCount = dti->fData.fMipMapLevelCount;
+    SkASSERT(mipLevelCount >= 1);
+    if (mipLevelCount == 1) {
+        SkPixmap pixmap;
+        pixmap.reset(dti->fData.fInfo, dti->fData.fMipMapLevelData[0].fPixelData,
+                     dti->fData.fMipMapLevelData[0].fRowBytes, colorTable.get());
+        return SkImage::MakeTextureFromPixmap(context, pixmap, budgeted);
+    } else {
+        SkAutoTDeleteArray<GrMipLevel> texels(new GrMipLevel[mipLevelCount]);
+        for (int i = 0; i < mipLevelCount; i++) {
+            texels[i].fPixels = dti->fData.fMipMapLevelData[i].fPixelData;
+            texels[i].fRowBytes = dti->fData.fMipMapLevelData[i].fRowBytes;
+        }
+
+        return SkImage::MakeTextureFromMipMap(context, dti->fData.fInfo, texels.get(),
+                                              mipLevelCount, SkBudgeted::kYes);
+    }
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////