Add compressed texture capabilities for GPU devices

src/gpu/gl/GrGLCaps.cpp

Index: src/gpu/gl/GrGLCaps.cpp
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index f577e9d740398dc5ca53fec9379b2e7266f544db..6523e032335f30925587a34e51a6cbe868283f50 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -369,6 +369,8 @@ bool GrGLCaps::init(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
 
     this->initConfigRenderableTable(ctxInfo);
 
+    this->initCompressedTextureSupport(ctxInfo);
+
     return true;
 }
 
@@ -458,6 +460,38 @@ void GrGLCaps::initConfigRenderableTable(const GrGLContextInfo& ctxInfo) {
     }
 }
 
+void GrGLCaps::initCompressedTextureSupport(const GrGLContextInfo &ctxInfo) {
+    GrGLStandard standard = ctxInfo.standard();
+    GrGLVersion version = ctxInfo.version();
+
+    // glCompressedTexImage2D is available on all OpenGL ES devices...
+    // however, it is only available on standard OpenGL after version 1.3
+    if (kGL_GrGLStandard == standard && version < GR_GL_VER(1, 3)) {
+        return;
+    }
+
+    // Check for ETC1
+    bool hasETC1 = false;
+
+    // First check version for support
+    if (kGL_GrGLStandard == standard) {
+        hasETC1 =
+            version >= GR_GL_VER(4, 3) ||
+            ctxInfo.hasExtension("GL_ARB_ES3_compatibility");
+    } else {
+        hasETC1 =
+            version >= GR_GL_VER(3, 0) ||
+            ctxInfo.hasExtension("GL_OES_compressed_ETC1_RGB8_texture") ||
+            // ETC2 is a superset of ETC1, so we can just check for that, too.
+            (ctxInfo.hasExtension("GL_OES_compressed_ETC2_RGB8_texture") &&
+             ctxInfo.hasExtension("GL_OES_compressed_ETC2_RGBA8_texture"));
+    }
+    fCompressedFormatSupport[kETC1_GrCompressedFormat] = hasETC1;
+
+    fCompressedFormatSupport[kETC2_GrCompressedFormat] = false;
+    fCompressedFormatSupport[kDXT1_GrCompressedFormat] = false;
+}
+
 bool GrGLCaps::readPixelsSupported(const GrGLInterface* intf,
                                    GrGLenum format,
                                    GrGLenum type) const {