Turned on SkSL->GLSL compiler

src/sksl/SkSLMain.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "stdio.h"
 #include <fstream>
 #include "SkSLCompiler.h"
 
+bool endsWith(const std::string& s, const std::string& ending) {
+    if (s.length() >= ending.length()) {
+        return (0 == s.compare(s.length() - ending.length(), ending.length(), ending));
+    }
+    return false;
+}
+
+static SkSL::GLCaps default_caps() {
+    return { 
+             400, 
+             SkSL::GLCaps::kGL_Standard,
+             false, // isCoreProfile
+             false, // usesPrecisionModifiers;
+             false, // mustDeclareFragmentShaderOutput
+             true   // canUseMinAndAbsTogether
+           };
+}
+
 /**
  * Very simple standalone executable to facilitate testing.
  */
 int main(int argc, const char** argv) {
     if (argc != 3) {
         printf("usage: skslc <input> <output>\n");
         exit(1);
     }
     SkSL::Program::Kind kind;
     size_t len = strlen(argv[1]);
     if (len > 5 && !strcmp(argv[1] + strlen(argv[1]) - 5, ".vert")) {
         kind = SkSL::Program::kVertex_Kind;
     } else if (len > 5 && !strcmp(argv[1] + strlen(argv[1]) - 5, ".frag")) {
         kind = SkSL::Program::kFragment_Kind;
     } else {
         printf("input filename must end in '.vert' or '.frag'\n");
         exit(1);
     }
 
     std::ifstream in(argv[1]);
     std::string text((std::istreambuf_iterator<char>(in)),
                      std::istreambuf_iterator<char>());
     if (in.rdstate()) {
         printf("error reading '%s'\n", argv[1]);
         exit(2);
     }
-    std::ofstream out(argv[2], std::ofstream::binary);
-    SkSL::Compiler compiler;
-    if (!compiler.toSPIRV(kind, text, out)) {
-        printf("%s", compiler.errorText().c_str());
-        exit(3);
-    }
-    if (out.rdstate()) {
-        printf("error writing '%s'\n", argv[2]);
-        exit(4);
+    std::string name(argv[2]);
+    if (endsWith(name, ".spirv")) {
+        std::ofstream out(argv[2], std::ofstream::binary);
+        SkSL::Compiler compiler;
+        if (!compiler.toSPIRV(kind, text, out)) {
+            printf("%s", compiler.errorText().c_str());
+            exit(3);
+        }
+        if (out.rdstate()) {
+            printf("error writing '%s'\n", argv[2]);
+            exit(4);
+        }
+    } else if (endsWith(name, ".glsl")) {
+        std::ofstream out(argv[2], std::ofstream::binary);
+        SkSL::Compiler compiler;
+        if (!compiler.toGLSL(kind, text, default_caps(), out)) {
+            printf("%s", compiler.errorText().c_str());
+            exit(3);
+        }
+        if (out.rdstate()) {
+            printf("error writing '%s'\n", argv[2]);
+            exit(4);
+        }
+    } else {
+        printf("expected output filename to end with '.spirv' or '.glsl'");
     }
 }