update getTexParameter for WebGL 2

Source/core/html/canvas/WebGL2RenderingContextBase.cpp

Index: Source/core/html/canvas/WebGL2RenderingContextBase.cpp
diff --git a/Source/core/html/canvas/WebGL2RenderingContextBase.cpp b/Source/core/html/canvas/WebGL2RenderingContextBase.cpp
index b6f57f87ac8c23137bcad0062f63a038e1dc62b6..0a42d4c07df96becaf4e33cfcb578c352a90ef9f 100644
--- a/Source/core/html/canvas/WebGL2RenderingContextBase.cpp
+++ b/Source/core/html/canvas/WebGL2RenderingContextBase.cpp
@@ -1201,4 +1201,72 @@ DEFINE_TRACE(WebGL2RenderingContextBase)
     WebGLRenderingContextBase::trace(visitor);
 }
 
+WebGLTexture* WebGL2RenderingContextBase::validateTextureBinding(const char* functionName, GLenum target, bool useSixEnumsForCubeMap)
+{
+    switch (target) {
+    case GL_TEXTURE_2D_ARRAY:
+        // FIXME: add 2D Array texture binding point and 3D texture binding point.
+        ASSERT(false);
+        // return m_textureUnits[m_activeTextureUnit].m_texture2DArrayBinding.get();
+    case GL_TEXTURE_3D:
+        ASSERT(false);
+        // return m_textureUnits[m_activeTextureUnit].m_texture3DBinding.get();
+    default:
+        return WebGLRenderingContextBase::validateTextureBinding(functionName, target, useSixEnumsForCubeMap);
+    }
+}
+
+ScriptValue WebGL2RenderingContextBase::getTexParameter(ScriptState* scriptState, GLenum target, GLenum pname)
+{
+    if (isContextLost() || !validateTextureBinding("getTexParameter", target, false))
+        return ScriptValue::createNull(scriptState);
+
+    switch (pname) {
+    case GL_TEXTURE_MAG_FILTER:
+    case GL_TEXTURE_MIN_FILTER:
+    case GL_TEXTURE_WRAP_S:
+    case GL_TEXTURE_WRAP_T:
+    case GL_TEXTURE_WRAP_R:
+    case GL_TEXTURE_COMPARE_FUNC:
+    case GL_TEXTURE_COMPARE_MODE:
+    case GL_TEXTURE_IMMUTABLE_LEVELS:
+        {
+            GLint value = 0;
+            webContext()->getTexParameteriv(target, pname, &value);
+            return WebGLAny(scriptState, static_cast<unsigned>(value));
+        }
+    case GL_TEXTURE_IMMUTABLE_FORMAT:
+        {
+            GLint value = 0;
+            webContext()->getTexParameteriv(target, pname, &value);
+            return WebGLAny(scriptState, static_cast<bool>(value));
+        }
+    case GL_TEXTURE_BASE_LEVEL:
+    case GL_TEXTURE_MAX_LEVEL:
+        {
+            GLfloat value = 0.f;

[Zhenyao Mo, 2015/03/06 18:39:46]

This should be GLint, the function being getTexParameteriv, and no casting
necessary.

[yunchao, 2015/03/09 02:25:25]

Thanks for your review, @zmo. Accroding to OpenGL ES 3.0 (and GLES 3.1) linked
by WebGL spec, these two parameters are obtained by getTexParameterfv (not
getTexParameteriv). See the table 6.9 in
https://www.khronos.org/registry/gles/specs/3.0/es_spec_3.0.3.pdf#nameddest=s....
However, these two parameters are set by texParameter with type 'int' in table
3.20 in the same spec. 

Seems that the type for these two parameters are different in setter
(texParameter) and getter (getTexParameter). In fact, I am a little confused
here. But I suppose the spec is not wrong. I followed the GLES spec. So I choose
getTexParameterfv and cast the type to int to obey WebGL spec. WDYT?

[Zhenyao Mo, 2015/03/09 17:18:44]

Yes, it seems there are some discrepancies in the ES3 spec.  I will clarify them
and get back to you.

+            webContext()->getTexParameterfv(target, pname, &value);
+            return WebGLAny(scriptState, static_cast<int>(value));
+        }
+    case GL_TEXTURE_MAX_LOD:
+    case GL_TEXTURE_MIN_LOD:
+        {
+            GLfloat value = 0.f;
+            webContext()->getTexParameterfv(target, pname, &value);
+            return WebGLAny(scriptState, value);
+        }
+    case GL_TEXTURE_MAX_ANISOTROPY_EXT: // EXT_texture_filter_anisotropic
+        if (extensionEnabled(EXTTextureFilterAnisotropicName)) {
+            GLfloat value = 0.f;
+            webContext()->getTexParameterfv(target, pname, &value);
+            return WebGLAny(scriptState, value);
+        }
+        synthesizeGLError(GL_INVALID_ENUM, "getTexParameter", "invalid parameter name, EXT_texture_filter_anisotropic not enabled");
+        return ScriptValue::createNull(scriptState);
+    default:
+        synthesizeGLError(GL_INVALID_ENUM, "getTexParameter", "invalid parameter name");
+        return ScriptValue::createNull(scriptState);
+    }
+}
+
 } // namespace blink