Function XPLMSetGraphicsState 

pub unsafe extern "C" fn XPLMSetGraphicsState(
    inEnableFog: c_int,
    inNumberTexUnits: c_int,
    inEnableLighting: c_int,
    inEnableAlphaTesting: c_int,
    inEnableAlphaBlending: c_int,
    inEnableDepthTesting: c_int,
    inEnableDepthWriting: c_int,
)

XPLMSetGraphicsState

XPLMSetGraphicsState changes OpenGL’s fixed function pipeline state. You are not responsible for restoring any state that is accessed via XPLMSetGraphicsState, but you are responsible for not accessing this state directly.

• inEnableFog - enables or disables fog, equivalent to: glEnable(GL_FOG);
• inNumberTexUnits - enables or disables a number of multitexturing units. If the number is 0, 2d texturing is disabled entirely, as in glDisable(GL_TEXTURE_2D); Otherwise, 2d texturing is enabled, and a number of multitexturing units are enabled sequentially, starting with unit 0, e.g. glActiveTextureARB(GL_TEXTURE0_ARB); glEnable (GL_TEXTURE_2D);
• inEnableLighting - enables or disables OpenGL lighting, e.g. glEnable(GL_LIGHTING); glEnable(GL_LIGHT0);
• inEnableAlphaTesting - enables or disables the alpha test per pixel, e.g. glEnable(GL_ALPHA_TEST);
• inEnableAlphaBlending - enables or disables alpha blending per pixel, e.g. glEnable(GL_BLEND);
• inEnableDepthTesting - enables per pixel depth testing, as in glEnable(GL_DEPTH_TEST);
• inEnableDepthWriting - enables writing back of depth information to the depth buffer, as in glDepthMask(GL_TRUE);

The purpose of this function is to change OpenGL state while keeping X-Plane aware of the state changes; this keeps X-Plane from getting surprised by OGL state changes, and prevents X-Plane and plug-ins from having to set all state before all draws; XPLMSetGraphicsState internally skips calls to change state that is already properly enabled.

X-Plane does not have a ‘default’ OGL state for plug-ins with respect to the above state vector; plug-ins should totally set OGL state using this API before drawing. Use XPLMSetGraphicsState instead of any of the above OpenGL calls.

WARNING: Any routine that performs drawing (e.g. XPLMDrawString or widget code) may change X-Plane’s state. Always set state before drawing after unknown code has executed.

Deprecation Warnings: X-Plane’s lighting and fog environment is significantly more complex than the fixed function pipeline can express; do not assume that lighting and fog state is a good approximation for 3-d drawing. Prefer to use XPLMInstancing to draw objects. All calls to XPLMSetGraphicsState should have no fog or lighting.