Add GPUInfo.TexWrapBorderColor to query for BorderColor support.

Fixes #56

render.go

@@ -210,6 +210,13 @@ type GPUInfo struct {
 	// 4x4 matrix is 16 floating-point values) that can be used inside a GLSL
 	// fragment shader, or -1 if not available. Generally at least 64.
 	GLSLMaxFragmentInputs int
+
+	// Whether or not the graphics hardware supports the use of the
+	// BorderColor TexWrap mode. If the hardware doesn't support it the
+	// renderer falls back to the Clamp TexWrap mode in it's place.
+	//
+	// OpenGL ES 2 does not support BorderColor.
+	TexWrapBorderColor bool
 }
 
 // Renderer is capable of loading meshes, textures, and shaders. A renderer can

texwrap.go

@@ -36,6 +36,16 @@ const (
 
 	// BorderColor represents the extra area of the texture by the border color
 	// specified on the Texture object.
+	//
+	// Not all renderers support BorderColor (See GPUInfo.TexWrapBorderColor
+	// for more information). To check for support:
+	//
+	//  if gpuInfo.TexWrapBorderColor {
+	//      // Have BorderColor support.
+	//  }
+	//
+	// Renderers fall back to the Clamp TexWrap mode in the event that you
+	// try and use BorderColor and the GPU does not support it.
 	BorderColor
 
 	// Mirror represents the extra area of the texture by mirroring itself into