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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 #include "renderstate/Scissor.h"
     17 
     18 #include "Rect.h"
     19 
     20 #include <utils/Log.h>
     21 
     22 namespace android {
     23 namespace uirenderer {
     24 
     25 Scissor::Scissor()
     26         : mEnabled(false), mScissorX(0), mScissorY(0), mScissorWidth(0), mScissorHeight(0) {}
     27 
     28 bool Scissor::setEnabled(bool enabled) {
     29     if (mEnabled != enabled) {
     30         if (enabled) {
     31             glEnable(GL_SCISSOR_TEST);
     32         } else {
     33             glDisable(GL_SCISSOR_TEST);
     34         }
     35         mEnabled = enabled;
     36         return true;
     37     }
     38     return false;
     39 }
     40 
     41 bool Scissor::set(GLint x, GLint y, GLint width, GLint height) {
     42     if (mEnabled &&
     43         (x != mScissorX || y != mScissorY || width != mScissorWidth || height != mScissorHeight)) {
     44         if (x < 0) {
     45             width += x;
     46             x = 0;
     47         }
     48         if (y < 0) {
     49             height += y;
     50             y = 0;
     51         }
     52         if (width < 0) {
     53             width = 0;
     54         }
     55         if (height < 0) {
     56             height = 0;
     57         }
     58         glScissor(x, y, width, height);
     59 
     60         mScissorX = x;
     61         mScissorY = y;
     62         mScissorWidth = width;
     63         mScissorHeight = height;
     64 
     65         return true;
     66     }
     67     return false;
     68 }
     69 
     70 void Scissor::set(int viewportHeight, const Rect& clip) {
     71     // transform to Y-flipped GL space, and prevent negatives
     72     GLint x = std::max(0, (int)clip.left);
     73     GLint y = std::max(0, viewportHeight - (int)clip.bottom);
     74     GLint width = std::max(0, ((int)clip.right) - x);
     75     GLint height = std::max(0, (viewportHeight - (int)clip.top) - y);
     76 
     77     if (x != mScissorX || y != mScissorY || width != mScissorWidth || height != mScissorHeight) {
     78         glScissor(x, y, width, height);
     79 
     80         mScissorX = x;
     81         mScissorY = y;
     82         mScissorWidth = width;
     83         mScissorHeight = height;
     84     }
     85 }
     86 
     87 void Scissor::reset() {
     88     mScissorX = mScissorY = mScissorWidth = mScissorHeight = 0;
     89 }
     90 
     91 void Scissor::invalidate() {
     92     mEnabled = glIsEnabled(GL_SCISSOR_TEST);
     93     setEnabled(true);
     94     reset();
     95 }
     96 
     97 void Scissor::dump() {
     98     ALOGD("Scissor: enabled %d, %d %d %d %d", mEnabled, mScissorX, mScissorY, mScissorWidth,
     99           mScissorHeight);
    100 }
    101 
    102 } /* namespace uirenderer */
    103 } /* namespace android */
    104