Infer sampler precision from pixel config

src/gpu/vk/GrVkCaps.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrVkCaps.h"
 
 #include "GrVkUtil.h"
@@ skipping 136 matching lines @@
 
     // GrShaderCaps
 
     glslCaps->fShaderDerivativeSupport = true;
     glslCaps->fGeometryShaderSupport = SkToBool(featureFlags & kGeometryShader_GrVkFeatureFlag);
 
     glslCaps->fDualSourceBlendingSupport = SkToBool(featureFlags & kDualSrcBlend_GrVkFeatureFlag);
 
     glslCaps->fIntegerSupport = true;
 
+    // Assume the minimum precisions mandated by the SPIR-V spec.
+    glslCaps->fShaderPrecisionVaries = true;
+    for (int s = 0; s < kGrShaderTypeCount; ++s) {
+        auto& highp = glslCaps->fFloatPrecisions[s][kHigh_GrSLPrecision];
+        highp.fLogRangeLow = highp.fLogRangeHigh = 127;
+        highp.fBits = 23;
+
+        auto& mediump = glslCaps->fFloatPrecisions[s][kMedium_GrSLPrecision];
+        mediump.fLogRangeLow = mediump.fLogRangeHigh = 14;
+        mediump.fBits = 10;
+
+        glslCaps->fFloatPrecisions[s][kLow_GrSLPrecision] = mediump;
+    }
+    glslCaps->initEffectiveFloatPrecisionTable();
+
     glslCaps->fMaxVertexSamplers =
     glslCaps->fMaxGeometrySamplers =
     glslCaps->fMaxFragmentSamplers = SkTMin(properties.limits.maxPerStageDescriptorSampledImages,
                                             properties.limits.maxPerStageDescriptorSamplers);
     glslCaps->fMaxCombinedSamplers = SkTMin(properties.limits.maxDescriptorSetSampledImages,
                                             properties.limits.maxDescriptorSetSamplers);
 }
 
 bool stencil_format_supported(const GrVkInterface* interface,
                               VkPhysicalDevice physDev,
@@ skipping 55 matching lines @@
 
 void GrVkCaps::ConfigInfo::init(const GrVkInterface* interface,
                                 VkPhysicalDevice physDev,
                                 VkFormat format) {
     VkFormatProperties props;
     memset(&props, 0, sizeof(VkFormatProperties));
     GR_VK_CALL(interface, GetPhysicalDeviceFormatProperties(physDev, format, &props));
     InitConfigFlags(props.linearTilingFeatures, &fLinearFlags);
     InitConfigFlags(props.optimalTilingFeatures, &fOptimalFlags);
 }