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1/*
2 * Copyright 2018 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 "src/gpu/mtl/GrMtlVaryingHandler.h"
9
10#include "include/private/GrMtlTypesPriv.h"
11
12#if !__has_feature(objc_arc)
13#error This file must be compiled with Arc. Use -fobjc-arc flag
14#endif
15
16GR_NORETAIN_BEGIN
17
18static void finalize_helper(GrMtlVaryingHandler::VarArray& vars) {
19    int locationIndex = 0;
20    int componentCount = 0;
21    for (GrShaderVar& var : vars.items()) {
22        // Metal only allows scalars (including bool and char) and vectors as varyings
23        SkASSERT(GrSLTypeVecLength(var.getType()) != -1);
24        componentCount += GrSLTypeVecLength(var.getType());
25
26        SkString location;
27        location.appendf("location = %d", locationIndex);
28        var.addLayoutQualifier(location.c_str());
29        ++locationIndex;
30    }
31    // The max number of inputs is 60 for iOS and 32 for macOS. The max number of components is 60
32    // for iOS and 128 for macOS. To be conservative, we are going to assert that we have less than
33    // 32 varyings and less than 60 components across all varyings. If we hit this assert, we can
34    // implement a function in GrMtlCaps to be less conservative.
35    SkASSERT(locationIndex <= 32);
36    SkASSERT(componentCount <= 60);
37}
38
39void GrMtlVaryingHandler::onFinalize() {
40    finalize_helper(fVertexInputs);
41    finalize_helper(fVertexOutputs);
42    finalize_helper(fGeomInputs);
43    finalize_helper(fGeomOutputs);
44    finalize_helper(fFragInputs);
45    finalize_helper(fFragOutputs);
46}
47
48GR_NORETAIN_END
49