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..289482c380421344c745ae8142fcdd90117bd7f4 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);

[Zhenyao Mo, 2015/03/11 17:31:40]

Thinking more, maybe it's better to return nullptr here instead of ASSERTING and
crash the renderer.

[yunchao, 2015/04/21 11:14:46]

Done.

+        // return m_textureUnits[m_activeTextureUnit].m_texture2DArrayBinding.get();
+    case GL_TEXTURE_3D:
+        ASSERT(false);

[Zhenyao Mo, 2015/03/11 17:31:40]

Same here.

[yunchao, 2015/04/21 11:14:46]

Done.

+        // 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:
+        {
+            GLint value = 0;
+            webContext()->getTexParameteriv(target, pname, &value);
+            return WebGLAny(scriptState, 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

[Zhenyao Mo, 2015/03/11 17:31:40]

Actually I am not sure about extension situation.  kbr can advise on it.  Will
WebGL2 just carry over WebGL1 extensions? If yes, probably you want to do the
same as validateTextureBinding(), i.e., only handle the WebGL 2 specific enums
here, and delegate the rest to the WebGLRenderingContextBase::getTexParameter().
 This way, in the future when we add an extension, we don't have to add the
handing in multiple RenderingContext.

[yunchao, 2015/04/21 11:14:46]

Done.

+        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");

[Zhenyao Mo, 2015/03/11 17:31:40]

This is not needed.  It can just fall through to the default.

[yunchao, 2015/04/21 11:14:46]

Acknowledged.

+        return ScriptValue::createNull(scriptState);
+    default:
+        synthesizeGLError(GL_INVALID_ENUM, "getTexParameter", "invalid parameter name");
+        return ScriptValue::createNull(scriptState);
+    }
+}
+
 } // namespace blink