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