Add API to enable mipmaps on Bitmap

Bug #7353771

This API can be used when scaling large images down to a small size
to get nicer looking results.

Change-Id: If09087eed36077eee5355f6047a3ca67747d7d9e

4 files changed, 25 insertions, 3 deletions

diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index 2b50091..62e62bc 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -49,7 +49,7 @@ namespace uirenderer {
 
 #define ALPHA_THRESHOLD 0
 
-#define FILTER(paint) (paint && paint->isFilterBitmap() ? GL_LINEAR : GL_NEAREST)
+#define FILTER(paint) (!paint || paint->isFilterBitmap() ? GL_LINEAR : GL_NEAREST)
 
 ///////////////////////////////////////////////////////////////////////////////
 // Globals
diff --git a/libs/hwui/Texture.h b/libs/hwui/Texture.h
index 03e2172..8d88bdc 100644
--- a/libs/hwui/Texture.h
+++ b/libs/hwui/Texture.h
@@ -36,6 +36,8 @@ struct Texture {
         minFilter = GL_NEAREST;
         magFilter = GL_NEAREST;
 
+        mipMap = false;
+
         firstFilter = true;
         firstWrap = true;
 
@@ -83,6 +85,8 @@ struct Texture {
                 glBindTexture(renderTarget, id);
             }
 
+            if (mipMap && min == GL_LINEAR) min = GL_LINEAR_MIPMAP_LINEAR;
+
             glTexParameteri(renderTarget, GL_TEXTURE_MIN_FILTER, min);
             glTexParameteri(renderTarget, GL_TEXTURE_MAG_FILTER, mag);
         }
@@ -116,7 +120,12 @@ struct Texture {
      * Optional, size of the original bitmap.
      */
     uint32_t bitmapSize;
+    /**
+     * Indicates whether this texture will use trilinear filtering.
+     */
+    bool mipMap;
 
+private:
     /**
      * Last wrap modes set on this texture. Defaults to GL_CLAMP_TO_EDGE.
      */
@@ -129,7 +138,6 @@ struct Texture {
     GLenum minFilter;
     GLenum magFilter;
 
-private:
     bool firstFilter;
     bool firstWrap;
 }; // struct Texture
diff --git a/libs/hwui/TextureCache.cpp b/libs/hwui/TextureCache.cpp
index 4d16bb4..431367a 100644
--- a/libs/hwui/TextureCache.cpp
+++ b/libs/hwui/TextureCache.cpp
@@ -22,6 +22,7 @@
 
 #include <utils/threads.h>
 
+#include "Caches.h"
 #include "TextureCache.h"
 #include "Properties.h"
 
@@ -73,6 +74,8 @@ void TextureCache::init() {
     INIT_LOGD("    Maximum texture dimension is %d pixels", mMaxTextureSize);
 
     mDebugEnabled = readDebugLevel() & kDebugCaches;
+
+    mHasNPot = Caches::getInstance().extensions.hasNPot();
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -216,8 +219,11 @@ void TextureCache::generateTexture(SkBitmap* bitmap, Texture* texture, bool rege
         return;
     }
 
+    // If the texture had mipmap enabled but not anymore,
+    // force a glTexImage2D to discard the mipmap levels
     const bool resize = !regenerate || bitmap->width() != int(texture->width) ||
-            bitmap->height() != int(texture->height);
+            bitmap->height() != int(texture->height) ||
+            (regenerate && mHasNPot && texture->mipMap && !bitmap->hasHardwareMipMap());
 
     if (!regenerate) {
         glGenTextures(1, &texture->id);
@@ -261,6 +267,13 @@ void TextureCache::generateTexture(SkBitmap* bitmap, Texture* texture, bool rege
         break;
     }
 
+    if (mHasNPot) {
+        texture->mipMap = bitmap->hasHardwareMipMap();
+        if (texture->mipMap) {
+            glGenerateMipmap(GL_TEXTURE_2D);
+        }
+    }
+
     if (!regenerate) {
         texture->setFilter(GL_NEAREST);
         texture->setWrap(GL_CLAMP_TO_EDGE);
diff --git a/libs/hwui/TextureCache.h b/libs/hwui/TextureCache.h
index 31a2e3d..8e19092 100644
--- a/libs/hwui/TextureCache.h
+++ b/libs/hwui/TextureCache.h
@@ -138,6 +138,7 @@ private:
 
     float mFlushRate;
 
+    bool mHasNPot;
     bool mDebugEnabled;
 
     Vector<SkBitmap*> mGarbage;