X-Plane Graphics

These routines allow you to use OpenGL with X-Plane.

XPLMTextureID

enum

XPLM Texture IDs name well-known textures in the sim for you to use. This allows you to recycle textures from X-Plane, saving VRAM.

Warning: do not use these enums. The only remaining use they have is to access the legacy compatibility v10 UI texture; if you need this, get it via the Widgets library.

Name	Value	Description
xplm_Tex_GeneralInterface	0	The bitmap that contains window outlines, button outlines, fonts, etc.
xplm_Tex_AircraftPaint	1	The exterior paint for the user's aircraft (daytime).
xplm_Tex_AircraftLiteMap	2	The exterior light map for the user's aircraft.
xplm_Tex_Radar_Pilot	3	The weather radar instrument texture as controlled by the pilot-side radar controls
xplm_Tex_Radar_Copilot	4	The weather radar instrument texture as controlled by the copilot-side radar controls
xplm_Tex_SVT_Pilot	5	The SVT instrument texture as seen by pilot-side instruments
xplm_Tex_SVT_Copilot	6	The SVT instrument texture as seen by copilot-side instruments

XPLMSetGraphicsState

function

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.

XPLM_API void       XPLMSetGraphicsState(
                         int                  inEnableFog,
                         int                  inNumberTexUnits,
                         int                  inEnableLighting,
                         int                  inEnableAlphaTesting,
                         int                  inEnableAlphaBlending,
                         int                  inEnableDepthTesting,
                         int                  inEnableDepthWriting
                    );

XPLMBindTexture2d

function

XPLMBindTexture2d changes what texture is bound to the 2d texturing target. This routine caches the current 2d texture across all texturing units in the sim and plug-ins, preventing extraneous binding. For example, consider several plug-ins running in series; if they all use the 'general interface' bitmap to do UI, calling this function will skip the rebinding of the general interface texture on all but the first plug-in, which can provide better frame rates on some graphics cards.

inTextureID is the ID of the texture object to bind; inTextureUnit is a zero-based texture unit (e.g. 0 for the first one), up to a maximum of 4 units. (This number may increase in future versions of X-Plane.)

Use this routine instead of glBindTexture(GL_TEXTURE_2D, ....);

XPLM_API void       XPLMBindTexture2d(
                         int                  inTextureNum,
                         int                  inTextureUnit
                    );

XPLMGenerateTextureNumbers

function

Use this routine instead of glGenTextures to generate new texture object IDs. This routine historically ensured that plugins don't use texure IDs that X-Plane is reserving for its own use.

XPLM_API void       XPLMGenerateTextureNumbers(
                         int *                outTextureIDs,
                         int                  inCount
                    );

XPLMGetTexture

function

XPLMGetTexture returns the OpenGL texture ID of an X-Plane texture based on a generic identifying code. For example, you can get the texture for X-Plane's weather radar.

XPLM_API int        XPLMGetTexture(
                         XPLMTextureID        inTexture
                    );

XPLMDrawTranslucentDarkBox

function

This routine draws a translucent dark box, partially obscuring parts of the screen but making text easy to read. This is the same graphics primitive used by X-Plane to show text files.

XPLM_API void       XPLMDrawTranslucentDarkBox(
                         int                  inLeft,
                         int                  inTop,
                         int                  inRight,
                         int                  inBottom
                    );