| /* |
| * Copyright 2014 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "GrCoordTransform.h" |
| #include "GrCaps.h" |
| #include "GrContext.h" |
| #include "GrGpu.h" |
| |
| void GrCoordTransform::reset(const SkMatrix& m, const GrTexture* texture, |
| GrSamplerParams::FilterMode filter) { |
| SkASSERT(texture); |
| SkASSERT(!fInProcessor); |
| |
| fMatrix = m; |
| fReverseY = kBottomLeft_GrSurfaceOrigin == texture->origin(); |
| |
| // Always start at kDefault. Then if precisions differ we see if the precision needs to be |
| // increased. Our rule is that we want at least 4 subpixel values in the representation for |
| // coords between 0 to 1 when bi- or tri-lerping and 1 value when nearest filtering. Note that |
| // this still might not be enough when drawing with repeat or mirror-repeat modes but that case |
| // can be arbitrarily bad. |
| int subPixelThresh = filter > GrSamplerParams::kNone_FilterMode ? 4 : 1; |
| fPrecision = kDefault_GrSLPrecision; |
| if (texture->getContext()) { |
| const GrShaderCaps* caps = texture->getContext()->caps()->shaderCaps(); |
| if (caps->floatPrecisionVaries()) { |
| int maxD = SkTMax(texture->width(), texture->height()); |
| const GrShaderCaps::PrecisionInfo* info; |
| info = &caps->getFloatShaderPrecisionInfo(kFragment_GrShaderType, fPrecision); |
| do { |
| SkASSERT(info->supported()); |
| // Make sure there is at least 2 bits of subpixel precision in the range of |
| // texture coords from 0.5 to 1.0. |
| if ((2 << info->fBits) / maxD > subPixelThresh) { |
| break; |
| } |
| if (kHigh_GrSLPrecision == fPrecision) { |
| break; |
| } |
| GrSLPrecision nextP = static_cast<GrSLPrecision>(fPrecision + 1); |
| info = &caps->getFloatShaderPrecisionInfo(kFragment_GrShaderType, nextP); |
| if (!info->supported()) { |
| break; |
| } |
| fPrecision = nextP; |
| } while (true); |
| } |
| } |
| } |
| |
| void GrCoordTransform::reset(const SkMatrix& m, GrSLPrecision precision) { |
| SkASSERT(!fInProcessor); |
| fMatrix = m; |
| fReverseY = false; |
| fPrecision = precision; |
| } |