static int
checkOverlayAcceptability(XVisualInfo * vi, unsigned int mode)
{
int value;
/* Must support OpenGL. */
glXGetConfig(__glutDisplay, vi, GLX_USE_GL, &value);
if (!value)
return 1;
/* Must be color index. */
glXGetConfig(__glutDisplay, vi, GLX_RGBA, &value);
if (value)
return 1;
/* Must match single/double buffering request. */
glXGetConfig(__glutDisplay, vi, GLX_DOUBLEBUFFER, &value);
if (GLUT_WIND_IS_DOUBLE(mode) != (value != 0))
return 1;
/* Must match mono/stereo request. */
glXGetConfig(__glutDisplay, vi, GLX_STEREO, &value);
if (GLUT_WIND_IS_STEREO(mode) != (value != 0))
return 1;
/* Alpha and accumulation buffers incompatible with color
index. */
if (GLUT_WIND_HAS_ALPHA(mode) || GLUT_WIND_HAS_ACCUM(mode))
return 1;
/* Look for depth buffer if requested. */
glXGetConfig(__glutDisplay, vi, GLX_DEPTH_SIZE, &value);
if (GLUT_WIND_HAS_DEPTH(mode) && (value <= 0))
return 1;
/* Look for stencil buffer if requested. */
glXGetConfig(__glutDisplay, vi, GLX_STENCIL_SIZE, &value);
if (GLUT_WIND_HAS_STENCIL(mode) && (value <= 0))
return 1;
#if defined(GLX_VERSION_1_1) && defined(GLX_SGIS_multisample)
/* XXX Multisampled overlay color index?? Pretty unlikely. */
/* Look for multisampling if requested. */
if (__glutIsSupportedByGLX("GLX_SGIS_multisample"))
glXGetConfig(__glutDisplay, vi, GLX_SAMPLES_SGIS, &value);
else
value = 0;
if (GLUT_WIND_IS_MULTISAMPLE(mode) && (value <= 0))
return 1;
#endif
return 0;
}
XVisualInfo *
__glutDetermineVisual(
unsigned int displayMode,
Bool * treatAsSingle,
XVisualInfo * (getVisualInfo) (unsigned int))
{
XVisualInfo *vis;
/* Should not be looking at display mode mask if
__glutDisplayString is non-NULL. */
assert(!__glutDisplayString);
*treatAsSingle = GLUT_WIND_IS_SINGLE(displayMode);
vis = getVisualInfo(displayMode);
if (!vis) {
/* Fallback cases when can't get exactly what was asked
for... */
if (GLUT_WIND_IS_SINGLE(displayMode)) {
/* If we can't find a single buffered visual, try looking
for a double buffered visual. We can treat a double
buffered visual as a single buffer visual by changing
the draw buffer to GL_FRONT and treating any swap
buffers as no-ops. */
displayMode |= GLUT_DOUBLE;
vis = getVisualInfo(displayMode);
*treatAsSingle = True;
}
if (!vis && GLUT_WIND_IS_MULTISAMPLE(displayMode)) {
/* If we can't seem to get multisampling (ie, not Reality
Engine class graphics!), go without multisampling. It
is up to the application to query how many multisamples
were allocated (0 equals no multisampling) if the
application is going to use multisampling for more than
just antialiasing. */
displayMode &= ~GLUT_MULTISAMPLE;
vis = getVisualInfo(displayMode);
}
}
return vis;
}
static XVisualInfo *
getVisualInfoRGB(unsigned int mode)
{
#if POKA
int list[32];
int n = 0;
/* Should not be looking at display mode mask if
__glutDisplayString is non-NULL. */
assert(!__glutDisplayString);
/* XXX Would a caching mechanism to minize the calls to
glXChooseVisual? You'd have to reference count
XVisualInfo* pointers. Would also have to properly
interact with glutInitDisplayString. */
list[n++] = GLX_RGBA;
list[n++] = GLX_RED_SIZE;
list[n++] = 1;
list[n++] = GLX_GREEN_SIZE;
list[n++] = 1;
list[n++] = GLX_BLUE_SIZE;
list[n++] = 1;
if (GLUT_WIND_HAS_ALPHA(mode)) {
list[n++] = GLX_ALPHA_SIZE;
list[n++] = 1;
}
if (GLUT_WIND_IS_DOUBLE(mode)) {
list[n++] = GLX_DOUBLEBUFFER;
}
if (GLUT_WIND_IS_STEREO(mode)) {
list[n++] = GLX_STEREO;
}
if (GLUT_WIND_HAS_DEPTH(mode)) {
list[n++] = GLX_DEPTH_SIZE;
list[n++] = 1;
}
if (GLUT_WIND_HAS_STENCIL(mode)) {
list[n++] = GLX_STENCIL_SIZE;
list[n++] = 1;
}
if (GLUT_WIND_HAS_ACCUM(mode)) {
list[n++] = GLX_ACCUM_RED_SIZE;
list[n++] = 1;
list[n++] = GLX_ACCUM_GREEN_SIZE;
list[n++] = 1;
list[n++] = GLX_ACCUM_BLUE_SIZE;
list[n++] = 1;
if (GLUT_WIND_HAS_ALPHA(mode)) {
list[n++] = GLX_ACCUM_ALPHA_SIZE;
list[n++] = 1;
}
}
#if defined(GLX_VERSION_1_1) && (defined(GLX_SGIS_multisample) || defined(GLX_ARB_multisample))
if (GLUT_WIND_IS_MULTISAMPLE(mode)) {
if (!__glutIsSupportedByGLX("GLX_SGIS_multisample") &&
!__glutIsSupportedByGLX("GLX_ARB_multisample"))
return NULL;
#if defined(GLX_ARB_multisample)
list[n++] = GLX_SAMPLES_ARB;
#elif defined(GLX_SGIS_multisample)
list[n++] = GLX_SAMPLES_SGIS;
#endif
/* XXX Is 4 a reasonable minimum acceptable number of
samples? */
list[n++] = 4;
}
#endif
list[n] = (int) None; /* terminate list */
return glXChooseVisual(__glutDisplay,
__glutScreen, list);
#else /* POKA */
return
glXChooseVisual(mode);
#endif
}
static XVisualInfo *
getVisualInfoRGB(unsigned int mode)
{
int list[32];
int n = 0;
/* Should not be looking at display mode mask if
__glutDisplayString is non-NULL. */
assert(!__glutDisplayString);
/* XXX Would a caching mechanism to minize the calls to
glXChooseVisual? You'd have to reference count
XVisualInfo* pointers. Would also have to properly
interact with glutInitDisplayString. */
list[n++] = GLX_RGBA;
list[n++] = GLX_RED_SIZE;
list[n++] = 1;
list[n++] = GLX_GREEN_SIZE;
list[n++] = 1;
list[n++] = GLX_BLUE_SIZE;
list[n++] = 1;
if (GLUT_WIND_HAS_ALPHA(mode)) {
list[n++] = GLX_ALPHA_SIZE;
list[n++] = 1;
}
if (GLUT_WIND_IS_DOUBLE(mode)) {
list[n++] = GLX_DOUBLEBUFFER;
}
if (GLUT_WIND_IS_STEREO(mode)) {
list[n++] = GLX_STEREO;
}
if (GLUT_WIND_HAS_DEPTH(mode)) {
list[n++] = GLX_DEPTH_SIZE;
list[n++] = 1;
}
if (GLUT_WIND_HAS_STENCIL(mode)) {
list[n++] = GLX_STENCIL_SIZE;
list[n++] = 1;
}
if (GLUT_WIND_HAS_ACCUM(mode)) {
list[n++] = GLX_ACCUM_RED_SIZE;
list[n++] = 1;
list[n++] = GLX_ACCUM_GREEN_SIZE;
list[n++] = 1;
list[n++] = GLX_ACCUM_BLUE_SIZE;
list[n++] = 1;
if (GLUT_WIND_HAS_ALPHA(mode)) {
list[n++] = GLX_ACCUM_ALPHA_SIZE;
list[n++] = 1;
}
}
/* GLX_SAMPLES_SGIS has the same value as GLX_SAMPLES_ARB. */
# ifndef GLX_SAMPLES_ARB
# define GLX_SAMPLES_ARB 100001
# endif
if (GLUT_WIND_IS_MULTISAMPLE(mode)) {
if (
#ifdef _WIN32
!has_WGL_ARB_multisample
#else
!__glutIsSupportedByGLX("GLX_SGIS_multisample") &&
!__glutIsSupportedByGLX("GLX_ARB_multisample")
#endif
) {
return NULL;
}
/* Accept either the SGIS or ARB GLX multisample extensions. */
list[n++] = GLX_SAMPLES_ARB;
list[n++] = 2;
}
list[n] = (int) None; /* terminate list */
return glXChooseVisual(__glutDisplay,
__glutScreen, list);
}
static XVisualInfo *
getVisualInfoRGB(unsigned int mode)
{
int list[32];
int n = 0;
/* XXX Would a caching mechanism to minize the calls to
glXChooseVisual? You'd have to reference count
XVisualInfo* pointers. */
list[n++] = GLX_RGBA;
list[n++] = GLX_RED_SIZE;
list[n++] = 1;
list[n++] = GLX_GREEN_SIZE;
list[n++] = 1;
list[n++] = GLX_BLUE_SIZE;
list[n++] = 1;
if (GLUT_WIND_HAS_ALPHA(mode)) {
list[n++] = GLX_ALPHA_SIZE;
list[n++] = 1;
}
if (GLUT_WIND_IS_DOUBLE(mode)) {
list[n++] = GLX_DOUBLEBUFFER;
}
if (GLUT_WIND_IS_STEREO(mode)) {
list[n++] = GLX_STEREO;
}
if (GLUT_WIND_HAS_DEPTH(mode)) {
list[n++] = GLX_DEPTH_SIZE;
list[n++] = 1;
}
if (GLUT_WIND_HAS_STENCIL(mode)) {
list[n++] = GLX_STENCIL_SIZE;
list[n++] = 1;
}
if (GLUT_WIND_HAS_ACCUM(mode)) {
list[n++] = GLX_ACCUM_RED_SIZE;
list[n++] = 1;
list[n++] = GLX_ACCUM_GREEN_SIZE;
list[n++] = 1;
list[n++] = GLX_ACCUM_BLUE_SIZE;
list[n++] = 1;
if (GLUT_WIND_HAS_ALPHA(mode)) {
list[n++] = GLX_ACCUM_ALPHA_SIZE;
list[n++] = 1;
}
}
#if defined(GLX_VERSION_1_1) && defined(GLX_SGIS_multisample)
if (GLUT_WIND_IS_MULTISAMPLE(mode)) {
if (!__glutIsSupportedByGLX("GLX_SGIS_multisample"))
return NULL;
list[n++] = GLX_SAMPLES_SGIS;
/* XXX Is 4 a reasonable minimum acceptable number of
samples? */
list[n++] = 4;
}
#endif
list[n] = (int) None; /* terminate list */
return glXChooseVisual(__glutDisplay,
__glutScreen, list);
}