1/*
2 * Copyright 2014 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#include "GrPrimitiveProcessor.h"
9
10#include "GrCoordTransform.h"
11
12/**
13 * The key for an individual coord transform is made up of a matrix type, a precision, and a bit
14 * that indicates the source of the input coords.
15 */
16enum {
17    kMatrixTypeKeyBits   = 1,
18    kMatrixTypeKeyMask   = (1 << kMatrixTypeKeyBits) - 1,
19
20    kPrecisionBits       = 2,
21    kPrecisionShift      = kMatrixTypeKeyBits,
22
23    kPositionCoords_Flag = (1 << (kPrecisionShift + kPrecisionBits)),
24
25    kTransformKeyBits    = kMatrixTypeKeyBits + kPrecisionBits + 2,
26};
27
28GR_STATIC_ASSERT(kHigh_GrSLPrecision < (1 << kPrecisionBits));
29
30/**
31 * We specialize the vertex code for each of these matrix types.
32 */
33enum MatrixType {
34    kNoPersp_MatrixType  = 0,
35    kGeneral_MatrixType  = 1,
36};
37
38uint32_t
39GrPrimitiveProcessor::getTransformKey(const SkTArray<const GrCoordTransform*, true>& coords,
40                                      int numCoords) const {
41    uint32_t totalKey = 0;
42    for (int t = 0; t < numCoords; ++t) {
43        uint32_t key = 0;
44        const GrCoordTransform* coordTransform = coords[t];
45        if (coordTransform->getMatrix().hasPerspective()) {
46            key |= kGeneral_MatrixType;
47        } else {
48            key |= kNoPersp_MatrixType;
49        }
50
51        if (!this->hasExplicitLocalCoords()) {
52            key |= kPositionCoords_Flag;
53        }
54
55        GR_STATIC_ASSERT(kGrSLPrecisionCount <= (1 << kPrecisionBits));
56        key |= (coordTransform->precision() << kPrecisionShift);
57
58        key <<= kTransformKeyBits * t;
59
60        SkASSERT(0 == (totalKey & key)); // keys for each transform ought not to overlap
61        totalKey |= key;
62    }
63    return totalKey;
64}
65