Refactor blending and texture gl state
Change-Id: Ia6b3c8b2afd3dfcee7f3ce401d846b789612054a
diff --git a/libs/hwui/renderstate/Blend.cpp b/libs/hwui/renderstate/Blend.cpp
new file mode 100644
index 0000000..3e7b721
--- /dev/null
+++ b/libs/hwui/renderstate/Blend.cpp
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <renderstate/Blend.h>
+#include "Program.h"
+
+#include "ShadowTessellator.h"
+
+namespace android {
+namespace uirenderer {
+
+/**
+ * Structure mapping Skia xfermodes to OpenGL blending factors.
+ */
+struct Blender {
+ SkXfermode::Mode mode;
+ GLenum src;
+ GLenum dst;
+};
+
+// In this array, the index of each Blender equals the value of the first
+// entry. For instance, gBlends[1] == gBlends[SkXfermode::kSrc_Mode]
+const Blender kBlends[] = {
+ { SkXfermode::kClear_Mode, GL_ZERO, GL_ONE_MINUS_SRC_ALPHA },
+ { SkXfermode::kSrc_Mode, GL_ONE, GL_ZERO },
+ { SkXfermode::kDst_Mode, GL_ZERO, GL_ONE },
+ { SkXfermode::kSrcOver_Mode, GL_ONE, GL_ONE_MINUS_SRC_ALPHA },
+ { SkXfermode::kDstOver_Mode, GL_ONE_MINUS_DST_ALPHA, GL_ONE },
+ { SkXfermode::kSrcIn_Mode, GL_DST_ALPHA, GL_ZERO },
+ { SkXfermode::kDstIn_Mode, GL_ZERO, GL_SRC_ALPHA },
+ { SkXfermode::kSrcOut_Mode, GL_ONE_MINUS_DST_ALPHA, GL_ZERO },
+ { SkXfermode::kDstOut_Mode, GL_ZERO, GL_ONE_MINUS_SRC_ALPHA },
+ { SkXfermode::kSrcATop_Mode, GL_DST_ALPHA, GL_ONE_MINUS_SRC_ALPHA },
+ { SkXfermode::kDstATop_Mode, GL_ONE_MINUS_DST_ALPHA, GL_SRC_ALPHA },
+ { SkXfermode::kXor_Mode, GL_ONE_MINUS_DST_ALPHA, GL_ONE_MINUS_SRC_ALPHA },
+ { SkXfermode::kPlus_Mode, GL_ONE, GL_ONE },
+ { SkXfermode::kModulate_Mode, GL_ZERO, GL_SRC_COLOR },
+ { SkXfermode::kScreen_Mode, GL_ONE, GL_ONE_MINUS_SRC_COLOR }
+};
+
+// This array contains the swapped version of each SkXfermode. For instance
+// this array's SrcOver blending mode is actually DstOver. You can refer to
+// createLayer() for more information on the purpose of this array.
+const Blender kBlendsSwap[] = {
+ { SkXfermode::kClear_Mode, GL_ONE_MINUS_DST_ALPHA, GL_ZERO },
+ { SkXfermode::kSrc_Mode, GL_ZERO, GL_ONE },
+ { SkXfermode::kDst_Mode, GL_ONE, GL_ZERO },
+ { SkXfermode::kSrcOver_Mode, GL_ONE_MINUS_DST_ALPHA, GL_ONE },
+ { SkXfermode::kDstOver_Mode, GL_ONE, GL_ONE_MINUS_SRC_ALPHA },
+ { SkXfermode::kSrcIn_Mode, GL_ZERO, GL_SRC_ALPHA },
+ { SkXfermode::kDstIn_Mode, GL_DST_ALPHA, GL_ZERO },
+ { SkXfermode::kSrcOut_Mode, GL_ZERO, GL_ONE_MINUS_SRC_ALPHA },
+ { SkXfermode::kDstOut_Mode, GL_ONE_MINUS_DST_ALPHA, GL_ZERO },
+ { SkXfermode::kSrcATop_Mode, GL_ONE_MINUS_DST_ALPHA, GL_SRC_ALPHA },
+ { SkXfermode::kDstATop_Mode, GL_DST_ALPHA, GL_ONE_MINUS_SRC_ALPHA },
+ { SkXfermode::kXor_Mode, GL_ONE_MINUS_DST_ALPHA, GL_ONE_MINUS_SRC_ALPHA },
+ { SkXfermode::kPlus_Mode, GL_ONE, GL_ONE },
+ { SkXfermode::kModulate_Mode, GL_DST_COLOR, GL_ZERO },
+ { SkXfermode::kScreen_Mode, GL_ONE_MINUS_DST_COLOR, GL_ONE }
+};
+
+Blend::Blend()
+ : mEnabled(false)
+ , mSrcMode(GL_ZERO)
+ , mDstMode(GL_ZERO) {
+ // gl blending off by default
+}
+
+void Blend::enable(SkXfermode::Mode mode, bool swapSrcDst) {
+ // enable
+ if (!mEnabled) {
+ glEnable(GL_BLEND);
+ mEnabled = true;
+ }
+
+ // select blend mode
+ GLenum sourceMode = swapSrcDst ? kBlendsSwap[mode].src : kBlends[mode].src;
+ GLenum destMode = swapSrcDst ? kBlendsSwap[mode].dst : kBlends[mode].dst;
+
+ if (sourceMode != mSrcMode || destMode != mSrcMode) {
+ glBlendFunc(sourceMode, destMode);
+ mSrcMode = sourceMode;
+ mDstMode = destMode;
+ }
+}
+
+void Blend::disable() {
+ if (mEnabled) {
+ glDisable(GL_BLEND);
+ mEnabled = false;
+ }
+}
+
+void Blend::invalidate() {
+ syncEnabled();
+ mSrcMode = mDstMode = GL_ZERO;
+}
+
+void Blend::syncEnabled() {
+ if (mEnabled) {
+ glEnable(GL_BLEND);
+ } else {
+ glDisable(GL_BLEND);
+ }
+}
+
+} /* namespace uirenderer */
+} /* namespace android */
+