QVector<int> qglx_buildSpec(const QPlatformWindowFormat &format, int drawableBit)
{
QVector<int> spec(48);
int i = 0;
spec[i++] = GLX_LEVEL;
spec[i++] = 0;
spec[i++] = GLX_DRAWABLE_TYPE; spec[i++] = drawableBit;
if (format.rgba()) {
spec[i++] = GLX_RENDER_TYPE; spec[i++] = GLX_RGBA_BIT;
spec[i++] = GLX_RED_SIZE; spec[i++] = (format.redBufferSize() == -1) ? 1 : format.redBufferSize();
spec[i++] = GLX_GREEN_SIZE; spec[i++] = (format.greenBufferSize() == -1) ? 1 : format.greenBufferSize();
spec[i++] = GLX_BLUE_SIZE; spec[i++] = (format.blueBufferSize() == -1) ? 1 : format.blueBufferSize();
if (format.alpha()) {
spec[i++] = GLX_ALPHA_SIZE; spec[i++] = (format.alphaBufferSize() == -1) ? 1 : format.alphaBufferSize();
}
if (format.accum()) {
spec[i++] = GLX_ACCUM_RED_SIZE; spec[i++] = (format.accumBufferSize() == -1) ? 1 : format.accumBufferSize();
spec[i++] = GLX_ACCUM_GREEN_SIZE; spec[i++] = (format.accumBufferSize() == -1) ? 1 : format.accumBufferSize();
spec[i++] = GLX_ACCUM_BLUE_SIZE; spec[i++] = (format.accumBufferSize() == -1) ? 1 : format.accumBufferSize();
if (format.alpha()) {
spec[i++] = GLX_ACCUM_ALPHA_SIZE; spec[i++] = (format.accumBufferSize() == -1) ? 1 : format.accumBufferSize();
}
}
} else {
spec[i++] = GLX_RENDER_TYPE; spec[i++] = GLX_COLOR_INDEX_BIT; //I'm really not sure if this works....
spec[i++] = GLX_BUFFER_SIZE; spec[i++] = 8;
}
spec[i++] = GLX_DOUBLEBUFFER; spec[i++] = format.doubleBuffer() ? True : False;
spec[i++] = GLX_STEREO; spec[i++] = format.stereo() ? True : False;
if (format.depth()) {
spec[i++] = GLX_DEPTH_SIZE; spec[i++] = (format.depthBufferSize() == -1) ? 1 : format.depthBufferSize();
}
if (format.stencil()) {
spec[i++] = GLX_STENCIL_SIZE; spec[i++] = (format.stencilBufferSize() == -1) ? 1 : format.stencilBufferSize();
}
if (format.sampleBuffers()) {
spec[i++] = GLX_SAMPLE_BUFFERS_ARB;
spec[i++] = 1;
spec[i++] = GLX_SAMPLES_ARB;
spec[i++] = format.samples() == -1 ? 4 : format.samples();
}
spec[i++] = XNone;
return spec;
}
GLXFBConfig qglx_findConfig(Display *display, int screen , const QPlatformWindowFormat &format, int drawableBit)
{
bool reduced = true;
GLXFBConfig chosenConfig = 0;
QPlatformWindowFormat reducedFormat = format;
while (!chosenConfig && reduced) {
QVector<int> spec = qglx_buildSpec(reducedFormat, drawableBit);
int confcount = 0;
GLXFBConfig *configs;
configs = glXChooseFBConfig(display, screen,spec.constData(),&confcount);
if (confcount)
{
for (int i = 0; i < confcount; i++) {
chosenConfig = configs[i];
// Make sure we try to get an ARGB visual if the format asked for an alpha:
if (reducedFormat.alpha()) {
int alphaSize;
glXGetFBConfigAttrib(display,configs[i],GLX_ALPHA_SIZE,&alphaSize);
if (alphaSize > 0)
break;
} else {
break; // Just choose the first in the list if there's no alpha requested
}
}
XFree(configs);
}
reducedFormat = qglx_reducePlatformWindowFormat(reducedFormat,&reduced);
}
if (!chosenConfig)
qWarning("Warning: no suitable glx confiuration found");
return chosenConfig;
}
QT_BEGIN_NAMESPACE
QGLFormat QGLFormat::fromPlatformWindowFormat(const QPlatformWindowFormat &format)
{
QGLFormat retFormat;
retFormat.setAccum(format.accum());
if (format.accumBufferSize() >= 0)
retFormat.setAccumBufferSize(format.accumBufferSize());
retFormat.setAlpha(format.alpha());
if (format.alphaBufferSize() >= 0)
retFormat.setAlphaBufferSize(format.alphaBufferSize());
if (format.blueBufferSize() >= 0)
retFormat.setBlueBufferSize(format.blueBufferSize());
retFormat.setDepth(format.depth());
if (format.depthBufferSize() >= 0)
retFormat.setDepthBufferSize(format.depthBufferSize());
retFormat.setDirectRendering(format.directRendering());
retFormat.setDoubleBuffer(format.doubleBuffer());
if (format.greenBufferSize() >= 0)
retFormat.setGreenBufferSize(format.greenBufferSize());
if (format.redBufferSize() >= 0)
retFormat.setRedBufferSize(format.redBufferSize());
retFormat.setRgba(format.rgba());
retFormat.setSampleBuffers(format.sampleBuffers());
retFormat.setSamples(format.sampleBuffers());
retFormat.setStencil(format.stencil());
if (format.stencilBufferSize() >= 0)
retFormat.setStencilBufferSize(format.stencilBufferSize());
retFormat.setStereo(format.stereo());
retFormat.setSwapInterval(format.swapInterval());
return retFormat;
}
QPlatformWindowFormat qglx_reducePlatformWindowFormat(const QPlatformWindowFormat &format, bool *reduced)
{
QPlatformWindowFormat retFormat = format;
*reduced = true;
if (retFormat.sampleBuffers()) {
retFormat.setSampleBuffers(false);
} else if (retFormat.stereo()) {
retFormat.setStereo(false);
} else if (retFormat.accum()) {
retFormat.setAccum(false);
}else if (retFormat.stencil()) {
retFormat.setStencil(false);
}else if (retFormat.alpha()) {
retFormat.setAlpha(false);
}else if (retFormat.depth()) {
retFormat.setDepth(false);
}else if (retFormat.doubleBuffer()) {
retFormat.setDoubleBuffer(false);
}else{
*reduced = false;
}
return retFormat;
}
QT_BEGIN_NAMESPACE
QVector<EGLint> q_createConfigAttributesFromFormat(const QPlatformWindowFormat &format)
{
int redSize = format.redBufferSize();
int greenSize = format.greenBufferSize();
int blueSize = format.blueBufferSize();
int alphaSize = format.alphaBufferSize();
int depthSize = format.depthBufferSize();
int stencilSize = format.stencilBufferSize();
int sampleCount = format.samples();
// QPlatformWindowFormat uses a magic value of -1 to indicate "don't care", even when a buffer of that
// type has been requested. So we must check QPlatformWindowFormat's booleans too if size is -1:
if (format.alpha() && alphaSize <= 0)
alphaSize = 1;
if (format.depth() && depthSize <= 0)
depthSize = 1;
if (format.stencil() && stencilSize <= 0)
stencilSize = 1;
if (format.sampleBuffers() && sampleCount <= 0)
sampleCount = 1;
// We want to make sure 16-bit configs are chosen over 32-bit configs as they will provide
// the best performance. The EGL config selection algorithm is a bit stange in this regard:
// The selection criteria for EGL_BUFFER_SIZE is "AtLeast", so we can't use it to discard
// 32-bit configs completely from the selection. So it then comes to the sorting algorithm.
// The red/green/blue sizes have a sort priority of 3, so they are sorted by first. The sort
// order is special and described as "by larger _total_ number of color bits.". So EGL will
// put 32-bit configs in the list before the 16-bit configs. However, the spec also goes on
// to say "If the requested number of bits in attrib_list for a particular component is 0,
// then the number of bits for that component is not considered". This part of the spec also
// seems to imply that setting the red/green/blue bits to zero means none of the components
// are considered and EGL disregards the entire sorting rule. It then looks to the next
// highest priority rule, which is EGL_BUFFER_SIZE. Despite the selection criteria being
// "AtLeast" for EGL_BUFFER_SIZE, it's sort order is "smaller" meaning 16-bit configs are
// put in the list before 32-bit configs. So, to make sure 16-bit is preffered over 32-bit,
// we must set the red/green/blue sizes to zero. This has an unfortunate consequence that
// if the application sets the red/green/blue size to 5/6/5 on the QPlatformWindowFormat,
// they will probably get a 32-bit config, even when there's an RGB565 config available.
// Now normalize the values so -1 becomes 0
redSize = redSize > 0 ? redSize : 0;
greenSize = greenSize > 0 ? greenSize : 0;
blueSize = blueSize > 0 ? blueSize : 0;
alphaSize = alphaSize > 0 ? alphaSize : 0;
depthSize = depthSize > 0 ? depthSize : 0;
stencilSize = stencilSize > 0 ? stencilSize : 0;
sampleCount = sampleCount > 0 ? sampleCount : 0;
QVector<EGLint> configAttributes;
configAttributes.append(EGL_RED_SIZE);
configAttributes.append(redSize);
configAttributes.append(EGL_GREEN_SIZE);
configAttributes.append(greenSize);
configAttributes.append(EGL_BLUE_SIZE);
configAttributes.append(blueSize);
configAttributes.append(EGL_ALPHA_SIZE);
configAttributes.append(alphaSize);
configAttributes.append(EGL_DEPTH_SIZE);
configAttributes.append(depthSize);
configAttributes.append(EGL_STENCIL_SIZE);
configAttributes.append(stencilSize);
configAttributes.append(EGL_SAMPLES);
configAttributes.append(sampleCount);
configAttributes.append(EGL_SAMPLE_BUFFERS);
configAttributes.append(sampleCount? 1:0);
return configAttributes;
}