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      1 /*
      2  * Copyright 2011 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 
      9 
     10 #ifndef GrGLIRect_DEFINED
     11 #define GrGLIRect_DEFINED
     12 
     13 #include "gl/GrGLInterface.h"
     14 #include "GrGLUtil.h"
     15 
     16 /**
     17  * Helper struct for dealing with the fact that Ganesh and GL use different
     18  * window coordinate systems (top-down vs bottom-up)
     19  */
     20 struct GrGLIRect {
     21     GrGLint   fLeft;
     22     GrGLint   fBottom;
     23     GrGLsizei fWidth;
     24     GrGLsizei fHeight;
     25 
     26     /**
     27      *  cast-safe way to treat the rect as an array of (4) ints.
     28      */
     29     const int* asInts() const {
     30         return &fLeft;
     31 
     32         GR_STATIC_ASSERT(0 == offsetof(GrGLIRect, fLeft));
     33         GR_STATIC_ASSERT(4 == offsetof(GrGLIRect, fBottom));
     34         GR_STATIC_ASSERT(8 == offsetof(GrGLIRect, fWidth));
     35         GR_STATIC_ASSERT(12 == offsetof(GrGLIRect, fHeight));
     36         GR_STATIC_ASSERT(16 == sizeof(GrGLIRect)); // For an array of GrGLIRect.
     37     }
     38     int* asInts() { return &fLeft; }
     39 
     40     void pushToGLViewport(const GrGLInterface* gl) const {
     41         GR_GL_CALL(gl, Viewport(fLeft, fBottom, fWidth, fHeight));
     42     }
     43 
     44     void pushToGLScissor(const GrGLInterface* gl) const {
     45         GR_GL_CALL(gl, Scissor(fLeft, fBottom, fWidth, fHeight));
     46     }
     47 
     48     void setFromGLViewport(const GrGLInterface* gl) {
     49         GR_STATIC_ASSERT(sizeof(GrGLIRect) == 4*sizeof(GrGLint));
     50         GR_GL_GetIntegerv(gl, GR_GL_VIEWPORT, (GrGLint*) this);
     51     }
     52 
     53     // sometimes we have a SkIRect from the client that we
     54     // want to simultaneously make relative to GL's viewport
     55     // and (optionally) convert from top-down to bottom-up.
     56     void setRelativeTo(const GrGLIRect& glViewport, const SkIRect& devRect, GrSurfaceOrigin org) {
     57         this->setRelativeTo(glViewport, devRect.x(), devRect.y(), devRect.width(), devRect.height(),
     58                             org);
     59     }
     60 
     61     void setRelativeTo(const GrGLIRect& glRect,
     62                        int leftOffset,
     63                        int topOffset,
     64                        int width,
     65                        int height,
     66                        GrSurfaceOrigin origin) {
     67         fLeft = glRect.fLeft + leftOffset;
     68         fWidth = width;
     69         if (kBottomLeft_GrSurfaceOrigin == origin) {
     70             fBottom = glRect.fBottom + (glRect.fHeight - topOffset - height);
     71         } else {
     72             fBottom = glRect.fBottom + topOffset;
     73         }
     74         fHeight = height;
     75 
     76         SkASSERT(fWidth >= 0);
     77         SkASSERT(fHeight >= 0);
     78     }
     79 
     80     bool contains(const GrGLIRect& glRect) const {
     81         return fLeft <= glRect.fLeft &&
     82                fBottom <= glRect.fBottom &&
     83                fLeft + fWidth >=  glRect.fLeft + glRect.fWidth &&
     84                fBottom + fHeight >=  glRect.fBottom + glRect.fHeight;
     85     }
     86 
     87     void invalidate() {fLeft = fWidth = fBottom = fHeight = -1;}
     88 
     89     bool operator ==(const GrGLIRect& glRect) const {
     90         return 0 == memcmp(this, &glRect, sizeof(GrGLIRect));
     91     }
     92 
     93     bool operator !=(const GrGLIRect& glRect) const {return !(*this == glRect);}
     94 };
     95 
     96 #endif
     97