1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/include/gpu/GrCoordTransform.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,119 @@
1.4 +/*
1.5 + * Copyright 2013 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef GrCoordTransform_DEFINED
1.12 +#define GrCoordTransform_DEFINED
1.13 +
1.14 +#include "GrEffect.h"
1.15 +#include "SkMatrix.h"
1.16 +#include "GrTexture.h"
1.17 +#include "GrTypes.h"
1.18 +
1.19 +/**
1.20 + * Coordinates available to GrEffect subclasses for requesting transformations. Transformed
1.21 + * coordinates are made available in the the portion of fragment shader emitted by the effect.
1.22 + */
1.23 +enum GrCoordSet {
1.24 + /**
1.25 + * The user-space coordinates that map to the fragment being rendered. These coords account for
1.26 + * any change of coordinate system done on the CPU by GrContext before rendering, and also are
1.27 + * correct for draws that take explicit local coords rather than inferring them from the
1.28 + * primitive's positions (e.g. drawVertices). These are usually the coords a GrEffect wants.
1.29 + */
1.30 + kLocal_GrCoordSet,
1.31 +
1.32 + /**
1.33 + * The actual vertex position. Note that GrContext may not draw using the original view matrix
1.34 + * specified by the caller, as it may have transformed vertices into another space. These are
1.35 + * usually not the coordinates a GrEffect wants.
1.36 + */
1.37 + kPosition_GrCoordSet
1.38 +};
1.39 +
1.40 +/**
1.41 + * A class representing a linear transformation from one of the built-in coordinate sets (local or
1.42 + * position). GrEffects just define these transformations, and the framework does the rest of the
1.43 + * work to make the transformed coordinates available in their fragment shader.
1.44 + */
1.45 +class GrCoordTransform : public SkNoncopyable {
1.46 +public:
1.47 + GrCoordTransform() { SkDEBUGCODE(fInEffect = false); }
1.48 +
1.49 + /**
1.50 + * Create a transformation that maps [0, 1] to a texture's boundaries.
1.51 + */
1.52 + GrCoordTransform(GrCoordSet sourceCoords, const GrTexture* texture) {
1.53 + SkDEBUGCODE(fInEffect = false);
1.54 + this->reset(sourceCoords, texture);
1.55 + }
1.56 +
1.57 + /**
1.58 + * Create a transformation from a matrix. The optional texture parameter is used to infer if the
1.59 + * framework should internally do a y reversal to account for it being upside down by Skia's
1.60 + * coord convention.
1.61 + */
1.62 + GrCoordTransform(GrCoordSet sourceCoords, const SkMatrix& m, const GrTexture* texture = NULL) {
1.63 + SkDEBUGCODE(fInEffect = false);
1.64 + this->reset(sourceCoords, m, texture);
1.65 + }
1.66 +
1.67 + void reset(GrCoordSet sourceCoords, const GrTexture* texture) {
1.68 + SkASSERT(!fInEffect);
1.69 + SkASSERT(NULL != texture);
1.70 + this->reset(sourceCoords, GrEffect::MakeDivByTextureWHMatrix(texture), texture);
1.71 + }
1.72 +
1.73 + void reset(GrCoordSet sourceCoords, const SkMatrix& m, const GrTexture* texture = NULL) {
1.74 + SkASSERT(!fInEffect);
1.75 + fSourceCoords = sourceCoords;
1.76 + fMatrix = m;
1.77 + fReverseY = NULL != texture && kBottomLeft_GrSurfaceOrigin == texture->origin();
1.78 + }
1.79 +
1.80 + GrCoordTransform& operator= (const GrCoordTransform& other) {
1.81 + SkASSERT(!fInEffect);
1.82 + fSourceCoords = other.fSourceCoords;
1.83 + fMatrix = other.fMatrix;
1.84 + fReverseY = other.fReverseY;
1.85 + return *this;
1.86 + }
1.87 +
1.88 + /**
1.89 + * Access the matrix for editing. Note, this must be done before adding the transform to an
1.90 + * effect, since effects are immutable.
1.91 + */
1.92 + SkMatrix* accessMatrix() {
1.93 + SkASSERT(!fInEffect);
1.94 + return &fMatrix;
1.95 + }
1.96 +
1.97 + bool operator== (const GrCoordTransform& other) const {
1.98 + return fSourceCoords == other.fSourceCoords &&
1.99 + fMatrix.cheapEqualTo(other.fMatrix) &&
1.100 + fReverseY == other.fReverseY;
1.101 + }
1.102 +
1.103 + GrCoordSet sourceCoords() const { return fSourceCoords; }
1.104 + const SkMatrix& getMatrix() const { return fMatrix; }
1.105 + bool reverseY() const { return fReverseY; }
1.106 +
1.107 +private:
1.108 + GrCoordSet fSourceCoords;
1.109 + SkMatrix fMatrix;
1.110 + bool fReverseY;
1.111 +
1.112 + typedef SkNoncopyable INHERITED;
1.113 +
1.114 +#ifdef SK_DEBUG
1.115 +public:
1.116 + void setInEffect() const { fInEffect = true; }
1.117 +private:
1.118 + mutable bool fInEffect;
1.119 +#endif
1.120 +};
1.121 +
1.122 +#endif
