--- a/dom/canvas/WebGLTexture.cpp
+++ b/dom/canvas/WebGLTexture.cpp
@@ -1019,17 +1019,17 @@ WebGLTexture::IsTexture() const
 // See this discussion:
 //   https://www.khronos.org/webgl/public-mailing-list/archives/1008/msg00014.html
 void
 WebGLTexture::TexParameter(TexTarget texTarget, GLenum pname, GLint* maybeIntParam,
                            GLfloat* maybeFloatParam)
 {
     MOZ_ASSERT(maybeIntParam || maybeFloatParam);
 
-    GLint   intParam   = maybeIntParam   ? *maybeIntParam   : GLint(*maybeFloatParam);
+    GLint   intParam   = maybeIntParam   ? *maybeIntParam   : GLint(roundf(*maybeFloatParam));
     GLfloat floatParam = maybeFloatParam ? *maybeFloatParam : GLfloat(*maybeIntParam);
 
     bool isPNameValid = false;
     switch (pname) {
     // GLES 2.0.25 p76:
     case LOCAL_GL_TEXTURE_WRAP_S:
     case LOCAL_GL_TEXTURE_WRAP_T:
     case LOCAL_GL_TEXTURE_MIN_FILTER: