virtual void onDraw(SkCanvas* canvas) { SkDevice* device = canvas->getDevice(); GrRenderTarget* target = (GrRenderTarget*) device->accessRenderTarget(); GrContext* ctx = GetGr(); if (ctx && target) { SkPMColor gTextureData[(2 * S) * (2 * S)]; static const int stride = 2 * S; static const SkPMColor gray = SkPackARGB32(0x40, 0x40, 0x40, 0x40); static const SkPMColor white = SkPackARGB32(0xff, 0xff, 0xff, 0xff); static const SkPMColor red = SkPackARGB32(0x80, 0x80, 0x00, 0x00); static const SkPMColor blue = SkPackARGB32(0x80, 0x00, 0x00, 0x80); static const SkPMColor green = SkPackARGB32(0x80, 0x00, 0x80, 0x00); static const SkPMColor black = SkPackARGB32(0x00, 0x00, 0x00, 0x00); for (int i = 0; i < 2; ++i) { int offset = 0; // fill upper-left for (int y = 0; y < S; ++y) { for (int x = 0; x < S; ++x) { gTextureData[offset + y * stride + x] = gray; } } // fill upper-right offset = S; for (int y = 0; y < S; ++y) { for (int x = 0; x < S; ++x) { gTextureData[offset + y * stride + x] = white; } } // fill lower left offset = S * stride; for (int y = 0; y < S; ++y) { for (int x = 0; x < S; ++x) { gTextureData[offset + y * stride + x] = black; } } // fill lower right offset = S * stride + S; for (int y = 0; y < S; ++y) { for (int x = 0; x < S; ++x) { gTextureData[offset + y * stride + x] = gray; } } GrTextureDesc desc; desc.fAALevel = kNone_GrAALevel; // use RT flag bit because in GL it makes the texture be bottom-up desc.fFlags = i ? kRenderTarget_GrTextureFlagBit : kNone_GrTextureFlags; desc.fConfig = kSkia8888_PM_GrPixelConfig; desc.fWidth = 2 * S; desc.fHeight = 2 * S; GrTexture* texture = ctx->createUncachedTexture(desc, gTextureData, 0); if (!texture) { return; } GrAutoUnref au(texture); ctx->setClip(GrRect::MakeWH(2*S, 2*S)); ctx->setRenderTarget(target); GrPaint paint; paint.reset(); paint.fColor = 0xffffffff; paint.fSrcBlendCoeff = kOne_BlendCoeff; paint.fDstBlendCoeff = kISA_BlendCoeff; GrMatrix vm; if (i) { vm.setRotate(90 * SK_Scalar1, S * SK_Scalar1, S * SK_Scalar1); } else { vm.reset(); } ctx->setMatrix(vm); GrMatrix tm; tm = vm; tm.postIDiv(2*S, 2*S); paint.textureSampler(0)->setMatrix(tm); paint.setTexture(0, texture); ctx->drawRect(paint, GrRect::MakeWH(2*S, 2*S)); // now update the lower right of the texture in first pass // or upper right in second pass offset = 0; for (int y = 0; y < S; ++y) { for (int x = 0; x < S; ++x) { gTextureData[offset + y * stride + x] = ((x + y) % 2) ? (i ? green : red) : blue; } } texture->writePixels(S, (i ? 0 : S), S, S, texture->config(), gTextureData, 4 * stride); ctx->drawRect(paint, GrRect::MakeWH(2*S, 2*S)); } } }