From 7bf96a0a6f4824f2d15ec95249b8ff038fe02239 Mon Sep 17 00:00:00 2001
From: John Reck <jreck@google.com>
Date: Wed, 28 Jun 2017 11:08:07 -0700
Subject: [PATCH] Selectively disable filtering if estimated safe

If the output matches the source rect then use
GL_NEAREST instead of GL_FILTER. This is a more
pixel-exact capture.

Bug: 38242146
Test: CtsUiRendering & CtsViewTestCases:.PixelCopyTest passes on fugu
Change-Id: I9f57a4124374568f83d45fdc8f83cc767ded888a
---
 libs/hwui/GlopBuilder.cpp    | 6 ++++--
 libs/hwui/GlopBuilder.h      | 3 ++-
 libs/hwui/OpenGLReadback.cpp | 8 +++++++-
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/libs/hwui/GlopBuilder.cpp b/libs/hwui/GlopBuilder.cpp
index 931a55a70fd89..248e92f7c97b9 100644
--- a/libs/hwui/GlopBuilder.cpp
+++ b/libs/hwui/GlopBuilder.cpp
@@ -456,11 +456,13 @@ GlopBuilder& GlopBuilder::setFillTextureLayer(GlLayer& layer, float alpha) {
     return *this;
 }
 
-GlopBuilder& GlopBuilder::setFillExternalTexture(Texture& texture, Matrix4& textureTransform) {
+GlopBuilder& GlopBuilder::setFillExternalTexture(Texture& texture, Matrix4& textureTransform,
+        bool requiresFilter) {
     TRIGGER_STAGE(kFillStage);
     REQUIRE_STAGES(kMeshStage | kRoundRectClipStage);
 
-    mOutGlop->fill.texture = { &texture, GL_LINEAR, GL_CLAMP_TO_EDGE, &textureTransform };
+    GLenum filter = requiresFilter ? GL_LINEAR : GL_NEAREST;
+    mOutGlop->fill.texture = { &texture, filter, GL_CLAMP_TO_EDGE, &textureTransform };
 
     setFill(SK_ColorWHITE, 1.0f, SkBlendMode::kSrc, Blend::ModeOrderSwap::NoSwap,
             nullptr, nullptr);
diff --git a/libs/hwui/GlopBuilder.h b/libs/hwui/GlopBuilder.h
index 87b1568ed72bb..6d11da19e1383 100644
--- a/libs/hwui/GlopBuilder.h
+++ b/libs/hwui/GlopBuilder.h
@@ -75,7 +75,8 @@ public:
     GlopBuilder& setFillTextureLayer(GlLayer& layer, float alpha);
     // TODO: setFillLayer normally forces its own wrap & filter mode,
     // which isn't always correct.
-    GlopBuilder& setFillExternalTexture(Texture& texture, Matrix4& textureTransform);
+    GlopBuilder& setFillExternalTexture(Texture& texture, Matrix4& textureTransform,
+            bool requiresFilter);
 
     GlopBuilder& setTransform(const Matrix4& canvas, const int transformFlags);
 
diff --git a/libs/hwui/OpenGLReadback.cpp b/libs/hwui/OpenGLReadback.cpp
index c460c0d2dfd47..51927d5a2c617 100644
--- a/libs/hwui/OpenGLReadback.cpp
+++ b/libs/hwui/OpenGLReadback.cpp
@@ -191,6 +191,7 @@ inline CopyResult copyTextureInto(Caches& caches, RenderState& renderState,
             GL_TEXTURE_2D, texture, 0);
 
     {
+        bool requiresFilter;
         // Draw & readback
         renderState.setViewport(destWidth, destHeight);
         renderState.scissor().setEnabled(false);
@@ -208,12 +209,17 @@ inline CopyResult copyTextureInto(Caches& caches, RenderState& renderState,
             croppedTexTransform.scale(srcRect.getWidth() / sourceTexture.width(),
                     srcRect.getHeight() / sourceTexture.height(), 1);
             croppedTexTransform.multiply(sFlipV);
+            requiresFilter = srcRect.getWidth() != (float) destWidth
+                    || srcRect.getHeight() != (float) destHeight;
+        } else {
+            requiresFilter = sourceTexture.width() != (uint32_t) destWidth
+                    || sourceTexture.height() != (uint32_t) destHeight;
         }
         Glop glop;
         GlopBuilder(renderState, caches, &glop)
                 .setRoundRectClipState(nullptr)
                 .setMeshTexturedUnitQuad(nullptr)
-                .setFillExternalTexture(sourceTexture, croppedTexTransform)
+                .setFillExternalTexture(sourceTexture, croppedTexTransform, requiresFilter)
                 .setTransform(Matrix4::identity(), TransformFlags::None)
                 .setModelViewMapUnitToRect(Rect(destWidth, destHeight))
                 .build();