Wayland: Apply the same framebuffer selection optimisation

Not as much of a win, since EGL only causes approx 1K getpid() calls of
which this optimization eliminates only half
This commit is contained in:
Kovid Goyal
2020-06-09 21:59:25 +05:30
parent 9a97f0bced
commit 8a178ebe55
4 changed files with 38 additions and 234 deletions

168
glfw/context.c vendored
View File

@@ -173,174 +173,6 @@ bool _glfwIsValidContextConfig(const _GLFWctxconfig* ctxconfig)
return true;
}
// Chooses the framebuffer config that best matches the desired one
//
const _GLFWfbconfig* _glfwChooseFBConfig(const _GLFWfbconfig* desired,
const _GLFWfbconfig* alternatives,
unsigned int count)
{
unsigned int i;
unsigned int missing, leastMissing = UINT_MAX;
unsigned int colorDiff, leastColorDiff = UINT_MAX;
unsigned int extraDiff, leastExtraDiff = UINT_MAX;
const _GLFWfbconfig* current;
const _GLFWfbconfig* closest = NULL;
for (i = 0; i < count; i++)
{
current = alternatives + i;
if (desired->stereo > 0 && current->stereo == 0)
{
// Stereo is a hard constraint
continue;
}
if (desired->doublebuffer != current->doublebuffer)
{
// Double buffering is a hard constraint
continue;
}
// Count number of missing buffers
{
missing = 0;
if (desired->alphaBits > 0 && current->alphaBits == 0)
missing++;
if (desired->depthBits > 0 && current->depthBits == 0)
missing++;
if (desired->stencilBits > 0 && current->stencilBits == 0)
missing++;
if (desired->auxBuffers > 0 &&
current->auxBuffers < desired->auxBuffers)
{
missing += desired->auxBuffers - current->auxBuffers;
}
if (desired->samples > 0 && current->samples == 0)
{
// Technically, several multisampling buffers could be
// involved, but that's a lower level implementation detail and
// not important to us here, so we count them as one
missing++;
}
if (desired->transparent != current->transparent)
missing++;
}
// These polynomials make many small channel size differences matter
// less than one large channel size difference
// Calculate color channel size difference value
{
colorDiff = 0;
if (desired->redBits != GLFW_DONT_CARE)
{
colorDiff += (desired->redBits - current->redBits) *
(desired->redBits - current->redBits);
}
if (desired->greenBits != GLFW_DONT_CARE)
{
colorDiff += (desired->greenBits - current->greenBits) *
(desired->greenBits - current->greenBits);
}
if (desired->blueBits != GLFW_DONT_CARE)
{
colorDiff += (desired->blueBits - current->blueBits) *
(desired->blueBits - current->blueBits);
}
}
// Calculate non-color channel size difference value
{
extraDiff = 0;
if (desired->alphaBits != GLFW_DONT_CARE)
{
extraDiff += (desired->alphaBits - current->alphaBits) *
(desired->alphaBits - current->alphaBits);
}
if (desired->depthBits != GLFW_DONT_CARE)
{
extraDiff += (desired->depthBits - current->depthBits) *
(desired->depthBits - current->depthBits);
}
if (desired->stencilBits != GLFW_DONT_CARE)
{
extraDiff += (desired->stencilBits - current->stencilBits) *
(desired->stencilBits - current->stencilBits);
}
if (desired->accumRedBits != GLFW_DONT_CARE)
{
extraDiff += (desired->accumRedBits - current->accumRedBits) *
(desired->accumRedBits - current->accumRedBits);
}
if (desired->accumGreenBits != GLFW_DONT_CARE)
{
extraDiff += (desired->accumGreenBits - current->accumGreenBits) *
(desired->accumGreenBits - current->accumGreenBits);
}
if (desired->accumBlueBits != GLFW_DONT_CARE)
{
extraDiff += (desired->accumBlueBits - current->accumBlueBits) *
(desired->accumBlueBits - current->accumBlueBits);
}
if (desired->accumAlphaBits != GLFW_DONT_CARE)
{
extraDiff += (desired->accumAlphaBits - current->accumAlphaBits) *
(desired->accumAlphaBits - current->accumAlphaBits);
}
if (desired->samples != GLFW_DONT_CARE)
{
extraDiff += (desired->samples - current->samples) *
(desired->samples - current->samples);
}
if (desired->sRGB && !current->sRGB)
extraDiff++;
}
// Figure out if the current one is better than the best one found so far
// Least number of missing buffers is the most important heuristic,
// then color buffer size match and lastly size match for other buffers
if (missing < leastMissing)
closest = current;
else if (missing == leastMissing)
{
if ((colorDiff < leastColorDiff) ||
(colorDiff == leastColorDiff && extraDiff < leastExtraDiff))
{
closest = current;
}
}
if (current == closest)
{
leastMissing = missing;
leastColorDiff = colorDiff;
leastExtraDiff = extraDiff;
}
}
return closest;
}
// Retrieves the attributes of the current context
//
bool _glfwRefreshContextAttribs(_GLFWwindow* window,