Expand backend allocation API to allow an initialization color (only for GL to start)

Change-Id: I8e676e80f85f14c81c3cec8d766d0fdc7e25f426
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/214445
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrContextPriv.cpp b/src/gpu/GrContextPriv.cpp
index 09b5327..ab4b2f0 100644
--- a/src/gpu/GrContextPriv.cpp
+++ b/src/gpu/GrContextPriv.cpp
@@ -764,3 +764,48 @@
     fContext->drawingManager()->testingOnly_removeOnFlushCallbackObject(cb);
 }
 #endif
+
+//////////////////////////////////////////////////////////////////////////////
+GrBackendTexture GrContextPriv::createBackendTexture(int width, int height,
+                                                     GrBackendFormat backendFormat,
+                                                     const SkColor4f& color,
+                                                     GrMipMapped mipMapped,
+                                                     GrRenderable renderable) {
+    if (!fContext->asDirectContext()) {
+        return GrBackendTexture();
+    }
+
+    if (this->abandoned()) {
+        return GrBackendTexture();
+    }
+
+    if (!backendFormat.isValid()) {
+        return GrBackendTexture();
+    }
+
+    GrGpu* gpu = fContext->fGpu.get();
+
+    return gpu->createBackendTexture(width, height, backendFormat,
+                                     mipMapped, renderable, nullptr, 0, color);
+}
+
+GrBackendTexture GrContextPriv::createBackendTexture(int width, int height,
+                                                     SkColorType colorType,
+                                                     const SkColor4f& color,
+                                                     GrMipMapped mipMapped,
+                                                     GrRenderable renderable) {
+    if (!fContext->asDirectContext()) {
+        return GrBackendTexture();
+    }
+
+    if (this->abandoned()) {
+        return GrBackendTexture();
+    }
+
+    GrBackendFormat format = fContext->caps()->getBackendFormatFromColorType(colorType);
+    if (!format.isValid()) {
+        return GrBackendTexture();
+    }
+
+    return this->createBackendTexture(width, height, format, color, mipMapped, renderable);
+}
diff --git a/src/gpu/GrContextPriv.h b/src/gpu/GrContextPriv.h
index 86af1f3..5dbb038 100644
--- a/src/gpu/GrContextPriv.h
+++ b/src/gpu/GrContextPriv.h
@@ -292,6 +292,20 @@
     void testingOnly_flushAndRemoveOnFlushCallbackObject(GrOnFlushCallbackObject*);
 #endif
 
+    // If possible, create a backend texture initialized to a particular color. The client should
+    // ensure that the returned backend texture is valid.
+    GrBackendTexture createBackendTexture(int width, int height,
+                                          GrBackendFormat, const SkColor4f& color,
+                                          GrMipMapped, GrRenderable);
+
+    // If possible, create a backend texture initialized to a particular color. The client should
+    // ensure that the returned backend texture is valid.
+    // If successful, the created backend texture will be compatible with the provided
+    // SkColorType.
+    GrBackendTexture createBackendTexture(int width, int height,
+                                          SkColorType, const SkColor4f& color,
+                                          GrMipMapped, GrRenderable);
+
 private:
     explicit GrContextPriv(GrContext* context) : fContext(context) {}
     GrContextPriv(const GrContextPriv&); // unimpl
diff --git a/src/gpu/GrDataUtils.cpp b/src/gpu/GrDataUtils.cpp
new file mode 100644
index 0000000..40d69e0
--- /dev/null
+++ b/src/gpu/GrDataUtils.cpp
@@ -0,0 +1,287 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrDataUtils.h"
+
+#include "include/private/GrColor.h"
+
+static const int kNumModifierTables = 8;
+static const int kNumPixelIndices = 4;
+
+// The index of each row in this table is the ETC1 table codeword
+// The index of each column in this table is the ETC1 pixel index value
+static const int kModifierTables[kNumModifierTables][kNumPixelIndices] = {
+    /* 0 */ { 2,    8,  -2,   -8 },
+    /* 1 */ { 5,   17,  -5,  -17 },
+    /* 2 */ { 9,   29,  -9,  -29 },
+    /* 3 */ { 13,  42, -13,  -42 },
+    /* 4 */ { 18,  60, -18,  -60 },
+    /* 5 */ { 24,  80, -24,  -80 },
+    /* 6 */ { 33, 106, -33, -106 },
+    /* 7 */ { 47, 183, -47, -183 }
+};
+
+static inline int convert_5To8(int b) {
+    int c = b & 0x1f;
+    return (c << 3) | (c >> 2);
+}
+
+// Evaluate one of the entries in 'kModifierTables' to see how close it can get (r8,g8,b8) to
+// the original color (rOrig, gOrib, bOrig).
+static int test_table_entry(int rOrig, int gOrig, int bOrig,
+                            int r8, int g8, int b8,
+                            int table, int offset) {
+    SkASSERT(0 <= table && table < 8);
+    SkASSERT(0 <= offset && offset < 4);
+
+    r8 = SkTPin<uint8_t>(r8 + kModifierTables[table][offset], 0, 255);
+    g8 = SkTPin<uint8_t>(g8 + kModifierTables[table][offset], 0, 255);
+    b8 = SkTPin<uint8_t>(b8 + kModifierTables[table][offset], 0, 255);
+
+    return SkTAbs(rOrig - r8) + SkTAbs(gOrig - g8) + SkTAbs(bOrig - b8);
+}
+
+// Create an ETC1 compressed block that is filled with 'col'
+static void create_etc1_block(SkColor col, ETC1Block* block) {
+    block->fHigh = 0;
+    block->fLow = 0;
+
+    int rOrig = SkColorGetR(col);
+    int gOrig = SkColorGetG(col);
+    int bOrig = SkColorGetB(col);
+
+    int r5 = SkMulDiv255Round(31, rOrig);
+    int g5 = SkMulDiv255Round(31, gOrig);
+    int b5 = SkMulDiv255Round(31, bOrig);
+
+    int r8 = convert_5To8(r5);
+    int g8 = convert_5To8(g5);
+    int b8 = convert_5To8(b5);
+
+    // We always encode solid color textures as 555 + zero diffs
+    block->fHigh |= (r5 << 27) | (g5 << 19) | (b5 << 11) | 0x2;
+
+    int bestTableIndex = 0, bestPixelIndex = 0;
+    int bestSoFar = 1024;
+    for (int tableIndex = 0; tableIndex < kNumModifierTables; ++tableIndex) {
+        for (int pixelIndex = 0; pixelIndex < kNumPixelIndices; ++pixelIndex) {
+            int score = test_table_entry(rOrig, gOrig, bOrig, r8, g8, b8,
+                                         tableIndex, pixelIndex);
+
+            if (bestSoFar > score) {
+                bestSoFar = score;
+                bestTableIndex = tableIndex;
+                bestPixelIndex = pixelIndex;
+            }
+        }
+    }
+
+    block->fHigh |= (bestTableIndex << 5) | (bestTableIndex << 2);
+
+    for (int i = 0; i < 16; ++i) {
+        block->fLow |= bestPixelIndex << 2*i;
+    }
+}
+
+int GrNumETC1Blocks(int w, int h) {
+    if (w < 4) {
+        w = 1;
+    } else {
+       SkASSERT((w & 3) == 0);
+       w >>= 2;
+    }
+
+    if (h < 4) {
+        h = 1;
+    } else {
+       SkASSERT((h & 3) == 0);
+       h >>= 2;
+    }
+
+    return w * h;
+}
+
+void GrFillInETC1WithColor(const SkColor4f& colorf, ETC1Block* blocks, int numBlocks) {
+    SkColor color = colorf.toSkColor();
+
+    ETC1Block block;
+    create_etc1_block(color, &block);
+
+    for (int i = 0; i < numBlocks; ++i) {
+        blocks[i] = block;
+    }
+}
+
+bool GrFillBufferWithColor(GrPixelConfig config, int width, int height,
+                           const SkColor4f& colorf, void* dest) {
+    SkASSERT(kRGB_ETC1_GrPixelConfig != config);
+
+    GrColor color = colorf.toBytes_RGBA();
+
+    uint8_t r = GrColorUnpackR(color);
+    uint8_t g = GrColorUnpackG(color);
+    uint8_t b = GrColorUnpackB(color);
+    uint8_t a = GrColorUnpackA(color);
+
+    // TODO: use sk_memset32, sk_memset16, and SkOpts::rect_memset16/32/64
+    switch (config) {
+        case kAlpha_8_GrPixelConfig:                            // fall through
+        case kAlpha_8_as_Alpha_GrPixelConfig:                   // fall through
+        case kAlpha_8_as_Red_GrPixelConfig: {
+            memset(dest, a, width * height);
+            break;
+        }
+        case kGray_8_GrPixelConfig:                             // fall through
+        case kGray_8_as_Lum_GrPixelConfig:                      // fall through
+        case kGray_8_as_Red_GrPixelConfig: {
+            uint8_t gray8 = SkComputeLuminance(r, g, b);
+            memset(dest, gray8, width * height);
+            break;
+        }
+        case kRGB_565_GrPixelConfig: {
+            uint16_t* dest16 = (uint16_t*) dest;
+            uint16_t rgb565 = SkPack888ToRGB16(r, g, b);
+            for (int i = 0; i < width * height; ++i) {
+                dest16[i] = rgb565;
+            }
+            break;
+        }
+        case kRGBA_4444_GrPixelConfig: {
+            uint16_t* dest16 = (uint16_t*) dest;
+            uint8_t r4 = (r >> 4) & 0xF;
+            uint8_t g4 = (g >> 4) & 0xF;
+            uint8_t b4 = (b >> 4) & 0xF;
+            uint8_t a4 = (a >> 4) & 0xF;
+
+            uint16_t rgba4444 = r4 << SK_R4444_SHIFT | g4 << SK_G4444_SHIFT |
+                                b4 << SK_B4444_SHIFT | a4 << SK_A4444_SHIFT;
+
+            for (int i = 0; i < width * height; ++i) {
+                dest16[i] = rgba4444;
+            }
+            break;
+        }
+        case kRGBA_8888_GrPixelConfig: {
+            GrColor* destColor = (GrColor *) dest;
+            for (int i = 0; i < width * height; ++i) {
+                destColor[i] = color;
+            }
+            break;
+        }
+        case kRGB_888_GrPixelConfig: {
+            uint8_t* dest8 = (uint8_t*) dest;
+            for (int i = 0; i < width * height; ++i, dest8 += 3) {
+                dest8[0] = r;
+                dest8[1] = g;
+                dest8[2] = b;
+            }
+            break;
+        }
+        case kRGB_888X_GrPixelConfig: {
+            GrColor opaque = GrColorPackRGBA(r, g, b, 0xFF);
+
+            GrColor* destColor = (GrColor *) dest;
+            for (int i = 0; i < width * height; ++i) {
+                destColor[i] = opaque;
+            }
+            break;
+        }
+        case kRG_88_GrPixelConfig: {
+            uint8_t* dest8 = (uint8_t*) dest;
+            for (int i = 0; i < width * height; ++i, dest8 += 2) {
+                dest8[0] = r;
+                dest8[1] = g;
+            }
+            break;
+        }
+        case kBGRA_8888_GrPixelConfig: {
+            GrColor swizzled = GrColorPackRGBA(b, g, r, a);
+
+            GrColor* destColor = (GrColor *) dest;
+            for (int i = 0; i < width * height; ++i) {
+                destColor[i] = swizzled;
+            }
+            break;
+        }
+        case kSRGBA_8888_GrPixelConfig: {
+            // TODO: ask Brian O. what to do here
+            GrColor* destColor = (GrColor *) dest;
+            for (int i = 0; i < width * height; ++i) {
+                destColor[i] = color;
+            }
+            break;
+        }
+        case kSBGRA_8888_GrPixelConfig: {
+            // TODO: ask Brian O. what to do here
+            GrColor swizzled = GrColorPackRGBA(b, g, r, a);
+
+            GrColor* destColor = (GrColor *) dest;
+            for (int i = 0; i < width * height; ++i) {
+                destColor[i] = swizzled;
+            }
+            break;
+        }
+        case kRGBA_1010102_GrPixelConfig: {
+            uint32_t r10 = SkScalarRoundToInt(colorf.fR * 1023.0f);
+            uint32_t g10 = SkScalarRoundToInt(colorf.fG * 1023.0f);
+            uint32_t b10 = SkScalarRoundToInt(colorf.fB * 1023.0f);
+            uint8_t  a2  = SkScalarRoundToInt(colorf.fA * 3.0f);
+
+            uint32_t rgba1010102 = a2 << 30 | b10 << 20 | g10 << 10 | r10;
+
+            uint32_t* destColor = (uint32_t *) dest;
+            for (int i = 0; i < width * height; ++i) {
+                destColor[i] = rgba1010102;
+            }
+            break;
+        }
+        case kRGBA_float_GrPixelConfig: {
+            SkColor4f* destColor = (SkColor4f*) dest;
+            for (int i = 0; i < width * height; ++i) {
+                destColor[i] = colorf;
+            }
+            break;
+        }
+        case kRG_float_GrPixelConfig: {
+            float* destFloat = (float*) dest;
+            for (int i = 0; i < width * height; ++i, destFloat += 2) {
+                destFloat[0] = colorf.fR;
+                destFloat[1] = colorf.fG;
+            }
+            break;
+        }
+        case kAlpha_half_as_Red_GrPixelConfig:                  // fall through
+        case kAlpha_half_GrPixelConfig: {
+            SkHalf* destHalf = (SkHalf*) dest;
+            SkHalf alphaHalf = SkFloatToHalf(colorf.fA);
+            for (int i = 0; i < width * height; ++i) {
+                destHalf[i] = alphaHalf;
+            }
+            break;
+        }
+        case kRGBA_half_GrPixelConfig:                          // fall through
+        case kRGBA_half_Clamped_GrPixelConfig: {
+            SkHalf* destHalf = (SkHalf*) dest;
+            SkHalf rHalf = SkFloatToHalf(colorf.fR);
+            SkHalf gHalf = SkFloatToHalf(colorf.fG);
+            SkHalf bHalf = SkFloatToHalf(colorf.fB);
+            SkHalf aHalf = SkFloatToHalf(colorf.fA);
+            for (int i = 0; i < width * height; ++i, destHalf += 4) {
+                destHalf[0] = rHalf;
+                destHalf[1] = gHalf;
+                destHalf[2] = bHalf;
+                destHalf[3] = aHalf;
+            }
+            break;
+        }
+        default:
+            return false;
+            break;
+    }
+
+    return true;
+}
diff --git a/src/gpu/GrDataUtils.h b/src/gpu/GrDataUtils.h
new file mode 100644
index 0000000..a700a74
--- /dev/null
+++ b/src/gpu/GrDataUtils.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrDataUtils_DEFINED
+#define GrDataUtils_DEFINED
+
+#include "include/core/SkColor.h"
+#include "include/private/GrTypesPriv.h"
+
+// Fill in the width x height 'dest' with the munged version of 'color' that matches 'config'
+bool GrFillBufferWithColor(GrPixelConfig config, int width, int height,
+                           const SkColor4f& color, void* dest);
+
+struct ETC1Block {
+    uint32_t fHigh;
+    uint32_t fLow;
+};
+
+int GrNumETC1Blocks(int w, int h);
+
+// Fill in 'blocks' with ETC1 blocks derived from 'color'
+void GrFillInETC1WithColor(const SkColor4f& color, ETC1Block* blocks, int numBlocks);
+
+#endif
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index 86aa109..630644a 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -403,10 +403,14 @@
     /**
      * Creates a texture directly in the backend API without wrapping it in a GrTexture.
      * Must be matched with a call to deleteBackendTexture().
+     * Right now, the color is ignored if pixel data is provided.
+     * In the future, if neither a color nor pixels are provided then the backend texture
+     * will be uninitialized.
      */
     virtual GrBackendTexture createBackendTexture(int w, int h, const GrBackendFormat&,
                                                   GrMipMapped, GrRenderable,
-                                                  const void* pixels, size_t rowBytes) = 0;
+                                                  const void* pixels, size_t rowBytes,
+                                                  const SkColor4f& = SkColors::kTransparent) = 0;
 
     /**
      * Frees a texture created by createBackendTexture(). If ownership of the backend
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index 07adb70..de653bc 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -21,6 +21,7 @@
 #include "src/core/SkTraceEvent.h"
 #include "src/gpu/GrContextPriv.h"
 #include "src/gpu/GrCpuBuffer.h"
+#include "src/gpu/GrDataUtils.h"
 #include "src/gpu/GrFixedClip.h"
 #include "src/gpu/GrGpuResourcePriv.h"
 #include "src/gpu/GrMesh.h"
@@ -4057,7 +4058,8 @@
                                                const GrBackendFormat& format,
                                                GrMipMapped mipMapped,
                                                GrRenderable renderable,
-                                               const void* pixels, size_t rowBytes) {
+                                               const void* pixels, size_t rowBytes,
+                                               const SkColor4f& colorf) {
     this->handleDirtyContext();
 
     const GrGLenum* glFormat = format.getGLFormat();
@@ -4123,6 +4125,13 @@
         SkASSERT(GrRenderable::kNo == renderable);
         SkASSERT(0 == rowBytes);
 
+        int numBlocks = GrNumETC1Blocks(w, h);
+        SkAutoTMalloc<ETC1Block> defaultStorage(numBlocks);
+        if (!pixels) {
+            GrFillInETC1WithColor(colorf, defaultStorage.get(), numBlocks);
+            pixels = defaultStorage.get();
+        }
+
         for (int i = 0; i < mipLevelCount; ++i) {
             // TODO: this isn't correct when pixels for additional mip levels are passed in
             texels.get()[i] = { pixels, 0 };
@@ -4140,8 +4149,11 @@
         size_t baseLayerSize = bpp * w * h;
         SkAutoMalloc defaultStorage(baseLayerSize);
         if (!pixels) {
-            // Fill in the texture with all zeros so we don't have random garbage
-            memset(defaultStorage.get(), 0, baseLayerSize);
+            if (!GrFillBufferWithColor(config, w, h, colorf, defaultStorage.get())) {
+                GL_CALL(DeleteTextures(1, &(info.fID)));
+                return GrBackendTexture();
+            }
+
             pixels = defaultStorage.get();
             rowBytes = trimRowBytes;
         }
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index feb7597..869a3f2 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -138,7 +138,8 @@
                                                                 int height) override;
     GrBackendTexture createBackendTexture(int w, int h, const GrBackendFormat&,
                                           GrMipMapped, GrRenderable,
-                                          const void* pixels, size_t rowBytes) override;
+                                          const void* pixels, size_t rowBytes,
+                                          const SkColor4f& color = SkColors::kTransparent) override;
     void deleteBackendTexture(const GrBackendTexture&) override;
 
 #if GR_TEST_UTILS
diff --git a/src/gpu/mock/GrMockGpu.cpp b/src/gpu/mock/GrMockGpu.cpp
index 5102ef6..3c67b63 100644
--- a/src/gpu/mock/GrMockGpu.cpp
+++ b/src/gpu/mock/GrMockGpu.cpp
@@ -201,7 +201,8 @@
                                                  GrMipMapped mipMapped,
                                                  GrRenderable /* renderable */,
                                                  const void* /* pixels */,
-                                                 size_t /* rowBytes */) {
+                                                 size_t /* rowBytes */,
+                                                 const SkColor4f& /* color */) {
 
     const GrPixelConfig* pixelConfig = format.getMockFormat();
     if (!pixelConfig) {
diff --git a/src/gpu/mock/GrMockGpu.h b/src/gpu/mock/GrMockGpu.h
index 97c06cf..cf49972 100644
--- a/src/gpu/mock/GrMockGpu.h
+++ b/src/gpu/mock/GrMockGpu.h
@@ -123,7 +123,8 @@
                                                                 int height) override;
     GrBackendTexture createBackendTexture(int w, int h, const GrBackendFormat&,
                                           GrMipMapped, GrRenderable,
-                                          const void* pixels, size_t rowBytes) override;
+                                          const void* pixels, size_t rowBytes,
+                                          const SkColor4f& color = SkColors::kTransparent) override;
     void deleteBackendTexture(const GrBackendTexture&) override;
 
 #if GR_TEST_UTILS
diff --git a/src/gpu/mtl/GrMtlGpu.h b/src/gpu/mtl/GrMtlGpu.h
index 6a8c082..14a47b3 100644
--- a/src/gpu/mtl/GrMtlGpu.h
+++ b/src/gpu/mtl/GrMtlGpu.h
@@ -62,7 +62,9 @@
 
     GrBackendTexture createBackendTexture(int w, int h, const GrBackendFormat&,
                                           GrMipMapped, GrRenderable,
-                                          const void* pixels, size_t rowBytes) override;
+                                          const void* pixels, size_t rowBytes,
+                                          const SkColor4f& color = SkColors::kTransparent) override;
+
     void deleteBackendTexture(const GrBackendTexture&) override;
 
 #if GR_TEST_UTILS
diff --git a/src/gpu/mtl/GrMtlGpu.mm b/src/gpu/mtl/GrMtlGpu.mm
index 5506f9c..8fae4b6 100644
--- a/src/gpu/mtl/GrMtlGpu.mm
+++ b/src/gpu/mtl/GrMtlGpu.mm
@@ -770,7 +770,8 @@
                                                 const GrBackendFormat& format,
                                                 GrMipMapped mipMapped,
                                                 GrRenderable renderable,
-                                                const void* pixels, size_t rowBytes) {
+                                                const void* pixels, size_t rowBytes,
+                                                const SkColor4f& color) {
     if (w > this->caps()->maxTextureSize() || h > this->caps()->maxTextureSize()) {
         return GrBackendTexture();
     }
diff --git a/src/gpu/vk/GrVkGpu.cpp b/src/gpu/vk/GrVkGpu.cpp
index 5cdbc70..7d5a9d5 100644
--- a/src/gpu/vk/GrVkGpu.cpp
+++ b/src/gpu/vk/GrVkGpu.cpp
@@ -1894,7 +1894,8 @@
                                                const GrBackendFormat& format,
                                                GrMipMapped mipMapped,
                                                GrRenderable renderable,
-                                               const void* srcData, size_t rowBytes) {
+                                               const void* srcData, size_t rowBytes,
+                                               const SkColor4f& color) {
     this->handleDirtyContext();
 
 
diff --git a/src/gpu/vk/GrVkGpu.h b/src/gpu/vk/GrVkGpu.h
index 9b24df1..1caa2f0 100644
--- a/src/gpu/vk/GrVkGpu.h
+++ b/src/gpu/vk/GrVkGpu.h
@@ -82,7 +82,8 @@
 
     GrBackendTexture createBackendTexture(int w, int h, const GrBackendFormat&,
                                           GrMipMapped, GrRenderable,
-                                          const void* pixels, size_t rowBytes) override;
+                                          const void* pixels, size_t rowBytes,
+                                          const SkColor4f& color = SkColors::kTransparent) override;
     void deleteBackendTexture(const GrBackendTexture&) override;
 #if GR_TEST_UTILS
     bool isTestingOnlyBackendTexture(const GrBackendTexture&) const override;