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Merge branch 'dtrebilco-master'
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@floooh
floooh committed Oct 23, 2023
2 parents 89cdc55 + 1db0431 commit e123956
Showing 1 changed file with 145 additions and 48 deletions.
193 changes: 145 additions & 48 deletions sokol_app.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5968,6 +5968,99 @@ _SOKOL_PRIVATE void _sapp_gl_init_fbconfig(_sapp_gl_fbconfig* fbconfig) {
fbconfig->samples = -1;
}

typedef struct {
int least_missing;
int least_color_diff;
int least_extra_diff;
bool best_match;
} _sapp_gl_fbselect;

_SOKOL_PRIVATE void _sapp_gl_init_fbselect(_sapp_gl_fbselect* fbselect) {
_sapp_clear(fbselect, sizeof(_sapp_gl_fbselect));
fbselect->least_missing = 1000000;
fbselect->least_color_diff = 10000000;
fbselect->least_extra_diff = 10000000;
fbselect->best_match = false;
}

// NOTE: this is used only in the WGL code path
_SOKOL_PRIVATE bool _sapp_gl_select_fbconfig(_sapp_gl_fbselect* fbselect, const _sapp_gl_fbconfig* desired, const _sapp_gl_fbconfig* current) {
int missing = 0;
if (desired->doublebuffer != current->doublebuffer) {
return false;
}

if ((desired->alpha_bits > 0) && (current->alpha_bits == 0)) {
missing++;
}
if ((desired->depth_bits > 0) && (current->depth_bits == 0)) {
missing++;
}
if ((desired->stencil_bits > 0) && (current->stencil_bits == 0)) {
missing++;
}
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++;
}

/* These polynomials make many small channel size differences matter
less than one large channel size difference
Calculate color channel size difference value
*/
int color_diff = 0;
if (desired->red_bits != -1) {
color_diff += (desired->red_bits - current->red_bits) * (desired->red_bits - current->red_bits);
}
if (desired->green_bits != -1) {
color_diff += (desired->green_bits - current->green_bits) * (desired->green_bits - current->green_bits);
}
if (desired->blue_bits != -1) {
color_diff += (desired->blue_bits - current->blue_bits) * (desired->blue_bits - current->blue_bits);
}

/* Calculate non-color channel size difference value */
int extra_diff = 0;
if (desired->alpha_bits != -1) {
extra_diff += (desired->alpha_bits - current->alpha_bits) * (desired->alpha_bits - current->alpha_bits);
}
if (desired->depth_bits != -1) {
extra_diff += (desired->depth_bits - current->depth_bits) * (desired->depth_bits - current->depth_bits);
}
if (desired->stencil_bits != -1) {
extra_diff += (desired->stencil_bits - current->stencil_bits) * (desired->stencil_bits - current->stencil_bits);
}
if (desired->samples != -1) {
extra_diff += (desired->samples - current->samples) * (desired->samples - current->samples);
}

/* 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
*/
bool new_closest = false;
if (missing < fbselect->least_missing) {
new_closest = true;
} else if (missing == fbselect->least_missing) {
if ((color_diff < fbselect->least_color_diff) ||
((color_diff == fbselect->least_color_diff) && (extra_diff < fbselect->least_extra_diff)))
{
new_closest = true;
}
}
if (new_closest) {
fbselect->least_missing = missing;
fbselect->least_color_diff = color_diff;
fbselect->least_extra_diff = extra_diff;
fbselect->best_match = (missing | color_diff | extra_diff) == 0;
}
return new_closest;
}

// NOTE: this is used only in the GLX code path
_SOKOL_PRIVATE const _sapp_gl_fbconfig* _sapp_gl_choose_fbconfig(const _sapp_gl_fbconfig* desired, const _sapp_gl_fbconfig* alternatives, int count) {
int missing, least_missing = 1000000;
int color_diff, least_color_diff = 10000000;
Expand Down Expand Up @@ -6655,22 +6748,21 @@ _SOKOL_PRIVATE void _sapp_wgl_attribiv(int pixel_format, int num_attribs, const
_SOKOL_PRIVATE int _sapp_wgl_find_pixel_format(void) {
SOKOL_ASSERT(_sapp.win32.dc);
SOKOL_ASSERT(_sapp.wgl.arb_pixel_format);
const _sapp_gl_fbconfig* closest;

#define _sapp_wgl_num_query_tags (12)
const int query_tags[_sapp_wgl_num_query_tags] = {
WGL_SUPPORT_OPENGL_ARB,
WGL_DRAW_TO_WINDOW_ARB,
WGL_PIXEL_TYPE_ARB,
WGL_ACCELERATION_ARB,
WGL_DOUBLE_BUFFER_ARB,
WGL_RED_BITS_ARB,
WGL_GREEN_BITS_ARB,
WGL_BLUE_BITS_ARB,
WGL_ALPHA_BITS_ARB,
WGL_DEPTH_BITS_ARB,
WGL_STENCIL_BITS_ARB,
WGL_SAMPLES_ARB,
WGL_SUPPORT_OPENGL_ARB,
WGL_DRAW_TO_WINDOW_ARB,
WGL_PIXEL_TYPE_ARB,
WGL_ACCELERATION_ARB,
WGL_DOUBLE_BUFFER_ARB,
WGL_RED_BITS_ARB,
WGL_GREEN_BITS_ARB,
WGL_BLUE_BITS_ARB,
WGL_ALPHA_BITS_ARB,
WGL_DEPTH_BITS_ARB,
WGL_STENCIL_BITS_ARB,
WGL_SAMPLES_ARB,
};
const int result_support_opengl_index = 0;
const int result_draw_to_window_index = 1;
Expand All @@ -6694,54 +6786,59 @@ _SOKOL_PRIVATE int _sapp_wgl_find_pixel_format(void) {
}

int native_count = _sapp_wgl_attrib(1, WGL_NUMBER_PIXEL_FORMATS_ARB);
_sapp_gl_fbconfig* usable_configs = (_sapp_gl_fbconfig*) _sapp_malloc_clear((size_t)native_count * sizeof(_sapp_gl_fbconfig));
SOKOL_ASSERT(usable_configs);
int usable_count = 0;

_sapp_gl_fbconfig desired;
_sapp_gl_init_fbconfig(&desired);
desired.red_bits = 8;
desired.green_bits = 8;
desired.blue_bits = 8;
desired.alpha_bits = 8;
desired.depth_bits = 24;
desired.stencil_bits = 8;
desired.doublebuffer = true;
desired.samples = (_sapp.sample_count > 1) ? _sapp.sample_count : 0;

int pixel_format = 0;
_sapp_gl_fbconfig u;
_sapp_gl_init_fbconfig(&u);

_sapp_gl_fbselect fbselect;
_sapp_gl_init_fbselect(&fbselect);
for (int i = 0; i < native_count; i++) {
const int n = i + 1;
_sapp_gl_fbconfig* u = usable_configs + usable_count;
_sapp_gl_init_fbconfig(u);
_sapp_wgl_attribiv(n, query_count, query_tags, query_results);

if (query_results[result_support_opengl_index] == 0
|| query_results[result_draw_to_window_index] == 0
|| query_results[result_pixel_type_index] != WGL_TYPE_RGBA_ARB
|| query_results[result_acceleration_index] == WGL_NO_ACCELERATION_ARB)
|| query_results[result_draw_to_window_index] == 0
|| query_results[result_pixel_type_index] != WGL_TYPE_RGBA_ARB
|| query_results[result_acceleration_index] == WGL_NO_ACCELERATION_ARB)
{
continue;
}
u->red_bits = query_results[result_red_bits_index];
u->green_bits = query_results[result_green_bits_index];
u->blue_bits = query_results[result_blue_bits_index];
u->alpha_bits = query_results[result_alpha_bits_index];
u->depth_bits = query_results[result_depth_bits_index];
u->stencil_bits = query_results[result_stencil_bits_index];

u.red_bits = query_results[result_red_bits_index];
u.green_bits = query_results[result_green_bits_index];
u.blue_bits = query_results[result_blue_bits_index];
u.alpha_bits = query_results[result_alpha_bits_index];
u.depth_bits = query_results[result_depth_bits_index];
u.stencil_bits = query_results[result_stencil_bits_index];
if (query_results[result_double_buffer_index]) {
u->doublebuffer = true;
u.doublebuffer = true;
}

u->samples = query_results[result_samples_index]; // NOTE: If arb_multisample is not supported - just takes the default 0
u.samples = query_results[result_samples_index]; // NOTE: If arb_multisample is not supported - just takes the default 0

u->handle = (uintptr_t)n;
usable_count++;
}
SOKOL_ASSERT(usable_count > 0);
_sapp_gl_fbconfig desired;
_sapp_gl_init_fbconfig(&desired);
desired.red_bits = 8;
desired.green_bits = 8;
desired.blue_bits = 8;
desired.alpha_bits = 8;
desired.depth_bits = 24;
desired.stencil_bits = 8;
desired.doublebuffer = true;
desired.samples = _sapp.sample_count > 1 ? _sapp.sample_count : 0;
closest = _sapp_gl_choose_fbconfig(&desired, usable_configs, usable_count);
int pixel_format = 0;
if (closest) {
pixel_format = (int) closest->handle;
// Test if this pixel format is better than the previous one
if (_sapp_gl_select_fbconfig(&fbselect, &desired, &u)) {
pixel_format = (uintptr_t)n;

// Early exit if matching as good as possible
if (fbselect.best_match) {
break;
}
}
}
_sapp_free(usable_configs);

return pixel_format;
}

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