Add functions to support NV_path_rendering in OpenGL ES

src/gpu/gl/GrGLCaps.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLCaps.h"
 #include "GrGLContext.h"
@@ skipping 293 matching lines @@
     }
 
     fHWAALineSupport = (kGL_GrGLStandard == standard);
 
     GR_GL_GetIntegerv(gli, GR_GL_MAX_TEXTURE_SIZE, &fMaxTextureSize);
     GR_GL_GetIntegerv(gli, GR_GL_MAX_RENDERBUFFER_SIZE, &fMaxRenderTargetSize);
     // Our render targets are always created with textures as the color
     // attachment, hence this min:
     fMaxRenderTargetSize = SkTMin(fMaxTextureSize, fMaxRenderTargetSize);
 
-    fPathRenderingSupport = ctxInfo.hasExtension("GL_NV_path_rendering") &&
-        ctxInfo.hasExtension("GL_EXT_direct_state_access");
+    fPathRenderingSupport = ctxInfo.hasExtension("GL_NV_path_rendering");
+
+    if (fPathRenderingSupport) {
+        if (kGL_GrGLStandard == standard) {
+            // We need one of the two possible texturing methods: using fixed function pipeline
+            // (PathTexGen, texcoords, ...)  or using the newer NVPR API additions that support
+            // setting individual fragment inputs with ProgramPathFragmentInputGen. The API
+            // additions are detected by checking the existence of the function. Eventually we may
+            // choose to remove the fixed function codepath.
+            // Set fMaxFixedFunctionTextureCoords = 0 here if you want to force
+            // ProgramPathFragmentInputGen usage on desktop.
+            fPathRenderingSupport = ctxInfo.hasExtension("GL_EXT_direct_state_access") &&
+                (fMaxFixedFunctionTextureCoords > 0 ||
+                 ((ctxInfo.version() >= GR_GL_VER(4,3) ||
+                   ctxInfo.hasExtension("GL_ARB_program_interface_query")) &&
+                  NULL != gli->fFunctions.fProgramPathFragmentInputGen));
+        } else {
+            // Note: path rendering is not yet implemented for GLES.
+            fPathRenderingSupport = ctxInfo.version() >= GR_GL_VER(3,1) && false;
+        }
+    }
 
     fGpuTracingSupport = ctxInfo.hasExtension("GL_EXT_debug_marker");
 
     fDstReadInShaderSupport = kNone_FBFetchType != fFBFetchType;
 
     // Disable scratch texture reuse on Mali and Adreno devices
     fReuseScratchTextures = kARM_GrGLVendor != ctxInfo.vendor() &&
                             kQualcomm_GrGLVendor != ctxInfo.vendor();
 
     // Enable supported shader-related caps
@@ skipping 465 matching lines @@
     r.appendf("Two Format Limit: %s\n", (fTwoFormatLimit ? "YES": "NO"));
     r.appendf("Fragment coord conventions support: %s\n",
              (fFragCoordsConventionSupport ? "YES": "NO"));
     r.appendf("Vertex array object support: %s\n", (fVertexArrayObjectSupport ? "YES": "NO"));
     r.appendf("Use non-VBO for dynamic data: %s\n",
              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
     r.appendf("Full screen clear is free: %s\n", (fFullClearIsFree ? "YES" : "NO"));
     r.appendf("Drops tile on zero divide: %s\n", (fDropsTileOnZeroDivide ? "YES" : "NO"));
     return r;
 }