Add functions to support NV_path_rendering in OpenGL ES

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 4a62c5acaab1ce370545f9b11d991153260d0e3f..c462fd8b7cd6e2206dfef420955556e3fc7b10e1 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -311,8 +311,22 @@ bool GrGLCaps::init(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
     // 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) {
+            // 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));

[bsalomon, 2014/07/02 13:25:33]

Can you explain in a comment why you're looking for presence of a specific
function here? I'm guessing that it is to distinguish between newer and older
versions of the NV_PR extension. Otherwise, this lgtm.

[Kimmo Kinnunen, 2014/07/03 05:43:20]

Added following:
// 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.

+        } 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");