static void get_pixel_formats_to_try(HDC dc, const SkWGLExtensions& extensions,
bool doubleBuffered, int msaaSampleCount, bool deepColor,
int formatsToTry[2]) {
auto appendAttr = [](SkTDArray<int>& attrs, int attr, int value) {
attrs.push(attr);
attrs.push(value);
};
SkTDArray<int> iAttrs;
appendAttr(iAttrs, SK_WGL_DRAW_TO_WINDOW, TRUE);
appendAttr(iAttrs, SK_WGL_DOUBLE_BUFFER, (doubleBuffered ? TRUE : FALSE));
appendAttr(iAttrs, SK_WGL_ACCELERATION, SK_WGL_FULL_ACCELERATION);
appendAttr(iAttrs, SK_WGL_SUPPORT_OPENGL, TRUE);
if (deepColor) {
appendAttr(iAttrs, SK_WGL_RED_BITS, 10);
appendAttr(iAttrs, SK_WGL_GREEN_BITS, 10);
appendAttr(iAttrs, SK_WGL_BLUE_BITS, 10);
appendAttr(iAttrs, SK_WGL_ALPHA_BITS, 2);
} else {
appendAttr(iAttrs, SK_WGL_COLOR_BITS, 24);
appendAttr(iAttrs, SK_WGL_ALPHA_BITS, 8);
}
appendAttr(iAttrs, SK_WGL_STENCIL_BITS, 8);
float fAttrs[] = {0, 0};
// Get a MSAA format if requested and possible.
if (msaaSampleCount > 0 &&
extensions.hasExtension(dc, "WGL_ARB_multisample")) {
SkTDArray<int> msaaIAttrs = iAttrs;
appendAttr(msaaIAttrs, SK_WGL_SAMPLE_BUFFERS, TRUE);
appendAttr(msaaIAttrs, SK_WGL_SAMPLES, msaaSampleCount);
appendAttr(msaaIAttrs, 0, 0);
unsigned int num;
int formats[64];
extensions.choosePixelFormat(dc, msaaIAttrs.begin(), fAttrs, 64, formats, &num);
num = SkTMin(num, 64U);
formatsToTry[0] = extensions.selectFormat(formats, num, dc, msaaSampleCount);
}
// Get a non-MSAA format
int* format = -1 == formatsToTry[0] ? &formatsToTry[0] : &formatsToTry[1];
unsigned int num;
appendAttr(iAttrs, 0, 0);
extensions.choosePixelFormat(dc, iAttrs.begin(), fAttrs, 1, format, &num);
}
HGLRC SkCreateWGLContext(HDC dc, int msaaSampleCount, bool preferCoreProfile) {
SkWGLExtensions extensions;
if (!extensions.hasExtension(dc, "WGL_ARB_pixel_format")) {
return NULL;
}
HDC prevDC = wglGetCurrentDC();
HGLRC prevGLRC = wglGetCurrentContext();
PIXELFORMATDESCRIPTOR pfd;
int format = 0;
static const int iAttrs[] = {
SK_WGL_DRAW_TO_WINDOW, TRUE,
SK_WGL_DOUBLE_BUFFER, TRUE,
SK_WGL_ACCELERATION, SK_WGL_FULL_ACCELERATION,
SK_WGL_SUPPORT_OPENGL, TRUE,
SK_WGL_COLOR_BITS, 24,
SK_WGL_ALPHA_BITS, 8,
SK_WGL_STENCIL_BITS, 8,
0, 0
};
float fAttrs[] = {0, 0};
if (msaaSampleCount > 0 &&
extensions.hasExtension(dc, "WGL_ARB_multisample")) {
static const int kIAttrsCount = SK_ARRAY_COUNT(iAttrs);
int msaaIAttrs[kIAttrsCount + 6];
memcpy(msaaIAttrs, iAttrs, sizeof(int) * kIAttrsCount);
SkASSERT(0 == msaaIAttrs[kIAttrsCount - 2] &&
0 == msaaIAttrs[kIAttrsCount - 1]);
msaaIAttrs[kIAttrsCount - 2] = SK_WGL_SAMPLE_BUFFERS;
msaaIAttrs[kIAttrsCount - 1] = TRUE;
msaaIAttrs[kIAttrsCount + 0] = SK_WGL_SAMPLES;
msaaIAttrs[kIAttrsCount + 1] = msaaSampleCount;
if (extensions.hasExtension(dc, "WGL_NV_multisample_coverage")) {
msaaIAttrs[kIAttrsCount + 2] = SK_WGL_COLOR_SAMPLES;
// We want the fewest number of color samples possible.
// Passing 0 gives only the formats where all samples are color
// samples.
msaaIAttrs[kIAttrsCount + 3] = 1;
msaaIAttrs[kIAttrsCount + 4] = 0;
msaaIAttrs[kIAttrsCount + 5] = 0;
} else {
msaaIAttrs[kIAttrsCount + 2] = 0;
msaaIAttrs[kIAttrsCount + 3] = 0;
}
unsigned int num;
int formats[64];
extensions.choosePixelFormat(dc, msaaIAttrs, fAttrs, 64, formats, &num);
num = min(num,64);
int formatToTry = extensions.selectFormat(formats,
num,
dc,
msaaSampleCount);
DescribePixelFormat(dc, formatToTry, sizeof(pfd), &pfd);
if (SetPixelFormat(dc, formatToTry, &pfd)) {
format = formatToTry;
}
}
if (0 == format) {
// Either MSAA wasn't requested or creation failed
unsigned int num;
extensions.choosePixelFormat(dc, iAttrs, fAttrs, 1, &format, &num);
DescribePixelFormat(dc, format, sizeof(pfd), &pfd);
SkDEBUGCODE(BOOL set =) SetPixelFormat(dc, format, &pfd);
SkASSERT(TRUE == set);
}
