Infer sampler precision from pixel config

src/gpu/gl/GrGLProgramDesc.cpp

Index: src/gpu/gl/GrGLProgramDesc.cpp
diff --git a/src/gpu/gl/GrGLProgramDesc.cpp b/src/gpu/gl/GrGLProgramDesc.cpp
index 68020a92d5977accaa513eabb52944a6ffffdec9..dde0a3e619cf8b634784f9634a82d2bb0cd5a731 100644
--- a/src/gpu/gl/GrGLProgramDesc.cpp
+++ b/src/gpu/gl/GrGLProgramDesc.cpp
@@ -17,24 +17,27 @@
 #include "glsl/GrGLSLFragmentShaderBuilder.h"
 #include "glsl/GrGLSLCaps.h"
 
-static uint8_t texture_target_key(GrGLenum target) {
-    switch (target) {
-        case GR_GL_TEXTURE_2D:
-            return 0;
-        case GR_GL_TEXTURE_EXTERNAL:
-            return 1;
-        case GR_GL_TEXTURE_RECTANGLE:
-            return 2;
-        default:
-            SkFAIL("Unexpected texture target.");
-            return 0;
-    }
+static uint8_t sampler_type_key_4_bits(GrSLType samplerType) {
+    static constexpr int kFirstSamplerType = kSampler2D_GrSLType;
+    static constexpr int kLastSamplerType = kSampler2DRect_GrSLType;
+
+    SkASSERT(samplerType >= kFirstSamplerType && samplerType <= kLastSamplerType);
+    return samplerType - kFirstSamplerType;
+
+    GR_STATIC_ASSERT(kLastSamplerType - kFirstSamplerType < (1 << 4));
+}
+
+static uint8_t precision_key_nonzero_2_bits(GrShaderType shaderType, GrSLPrecision precision,
+                                            const GrShaderCaps& caps) {
+    return 1 + caps.effectiveFloatPrecision(shaderType, precision);
+
+    GR_STATIC_ASSERT(1 + kLast_GrSLPrecision < (1 << 2));
 }
 
 static void add_texture_key(GrProcessorKeyBuilder* b, const GrProcessor& proc,
                             const GrGLSLCaps& caps) {
     int numTextures = proc.numTextures();
-    // Need two bytes per key (swizzle and target).
+    // Need two bytes per key (swizzle, sampler type, and precision).
     int word32Count = (proc.numTextures() + 1) / 2;
     if (0 == word32Count) {
         return;
@@ -44,7 +47,18 @@ static void add_texture_key(GrProcessorKeyBuilder* b, const GrProcessor& proc,
         const GrTextureAccess& access = proc.textureAccess(i);
         GrGLTexture* texture = static_cast<GrGLTexture*>(access.getTexture());
         k16[i] = SkToU16(caps.configTextureSwizzle(texture->config()).asKey() |
-                         (texture_target_key(texture->target()) << 8));
+                         (sampler_type_key_4_bits(texture->samplerType()) << 8));
+        if (caps.usesPrecisionModifiers()) {
+            GrSLPrecision p = GrPixelConfigPrecision(texture->config());
+            if (access.getVisibility() & kFragment_GrShaderFlag) {
+                k16[i] |= precision_key_nonzero_2_bits(kFragment_GrShaderType, p, caps) << 12;
+            }
+            if (access.getVisibility() & (kVertex_GrShaderFlag | kGeometry_GrShaderFlag)) {
+                SkASSERT(precision_key_nonzero_2_bits(kVertex_GrShaderType, p, caps) ==
+                         precision_key_nonzero_2_bits(kGeometry_GrShaderType, p, caps));
+                k16[i] |= precision_key_nonzero_2_bits(kVertex_GrShaderType, p, caps) << 14;
+            }
+        }
     }
     // zero the last 16 bits if the number of textures is odd.
     if (numTextures & 0x1) {