implement instanced drawing

engine/shader.cpp

@@ -124,7 +124,10 @@ void Shader::u_float(kShaderUniform id, float f)
 {
     glUniform1f(m_umap[id], f);
 }
-
+GLint ui::Shader::GetAttribLocation(const char* name)
+{
+    return glGetAttribLocation(prog, name);
+}
 bool ShaderManager::create(kShader id, const char* vertex, const char* fragment)
 {
     return m_shaders[id].create(vertex, fragment);