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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)
     27     , mScissorX(0)
     28     , mScissorY(0)
     29     , mScissorWidth(0)
     30     , mScissorHeight(0) {
     31 }
     32 
     33 bool Scissor::setEnabled(bool enabled) {
     34     if (mEnabled != enabled) {
     35         if (enabled) {
     36             glEnable(GL_SCISSOR_TEST);
     37         } else {
     38             glDisable(GL_SCISSOR_TEST);
     39         }
     40         mEnabled = enabled;
     41         return true;
     42     }
     43     return false;
     44 }
     45 
     46 bool Scissor::set(GLint x, GLint y, GLint width, GLint height) {
     47     if (mEnabled && (x != mScissorX || y != mScissorY
     48             || width != mScissorWidth || height != mScissorHeight)) {
     49 
     50         if (x < 0) {
     51             width += x;
     52             x = 0;
     53         }
     54         if (y < 0) {
     55             height += y;
     56             y = 0;
     57         }
     58         if (width < 0) {
     59             width = 0;
     60         }
     61         if (height < 0) {
     62             height = 0;
     63         }
     64         glScissor(x, y, width, height);
     65 
     66         mScissorX = x;
     67         mScissorY = y;
     68         mScissorWidth = width;
     69         mScissorHeight = height;
     70 
     71         return true;
     72     }
     73     return false;
     74 }
     75 
     76 void Scissor::set(int viewportHeight, const Rect& clip) {
     77     // transform to Y-flipped GL space, and prevent negatives
     78     GLint x = std::max(0, (int)clip.left);
     79     GLint y = std::max(0, viewportHeight - (int)clip.bottom);
     80     GLint width = std::max(0, ((int)clip.right) - x);
     81     GLint height = std::max(0, (viewportHeight - (int)clip.top) - y);
     82 
     83     if (x != mScissorX
     84             || y != mScissorY
     85             || width != mScissorWidth
     86             || height != mScissorHeight) {
     87         glScissor(x, y, width, height);
     88 
     89         mScissorX = x;
     90         mScissorY = y;
     91         mScissorWidth = width;
     92         mScissorHeight = height;
     93     }
     94 }
     95 
     96 void Scissor::reset() {
     97     mScissorX = mScissorY = mScissorWidth = mScissorHeight = 0;
     98 }
     99 
    100 void Scissor::invalidate() {
    101     mEnabled = glIsEnabled(GL_SCISSOR_TEST);
    102     setEnabled(true);
    103     reset();
    104 }
    105 
    106 void Scissor::dump() {
    107     ALOGD("Scissor: enabled %d, %d %d %d %d",
    108             mEnabled, mScissorX, mScissorY, mScissorWidth, mScissorHeight);
    109 }
    110 
    111 } /* namespace uirenderer */
    112 } /* namespace android */
    113 
    114