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move rgb<->hsl sksl to common spot

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We'll want to reuse these for other HSL effects, e.g. matrix filter.
Any preference where they go?  New header?

Change-Id: I64534d9801b8bdecf0ef22b3517f8232de998170
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/370712
Reviewed-by: Brian Osman <brianosman@google.com>
This commit is contained in:
Mike Klein 2021-02-16 10:35:10 -06:00
parent e0d9b86421
commit 2bb5ef3e9f
2 changed files with 37 additions and 31 deletions
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33
src/core/SkRuntimeEffectPriv.h
View File

@ -14,4 +14,37 @@
*/
void SkRuntimeEffect_SetInlineThreshold(int threshold);
// This is mostly from skvm's rgb->hsl code, with some GPU-related finesse pulled from
// GrHighContrastFilterEffect.fp, see next comment.
constexpr char kRGB_to_HSL_sksl[] =
"half3 rgb_to_hsl(half3 c) {"
"half mx = max(max(c.r,c.g),c.b),"
" mn = min(min(c.r,c.g),c.b),"
" d = mx-mn, "
" invd = 1.0 / d, "
" g_lt_b = c.g < c.b ? 6.0 : 0.0;"
// We'd prefer to write these tests like `mx == c.r`, but on some GPUs max(x,y) is
// not always equal to either x or y. So we use long form, c.r >= c.g && c.r >= c.b.
"half h = (1/6.0) * (mx == mn ? 0.0 :"
" /*mx==c.r*/ c.r >= c.g && c.r >= c.b ? invd * (c.g - c.b) + g_lt_b :"
" /*mx==c.g*/ c.g >= c.b ? invd * (c.b - c.r) + 2.0 "
" /*mx==c.b*/ : invd * (c.r - c.g) + 4.0);"
"half sum = mx+mn,"
" l = sum * 0.5,"
" s = mx == mn ? 0.0"
" : d / (l > 0.5 ? 2.0 - sum : sum);"
"return half3(h,s,l);"
"}";
//This is straight out of GrHSLToRGBFilterEffect.fp.
constexpr char kHSL_to_RGB_sksl[] =
"half3 hsl_to_rgb(half3 hsl) {"
"half C = (1 - abs(2 * hsl.z - 1)) * hsl.y;"
"half3 p = hsl.xxx + half3(0, 2/3.0, 1/3.0);"
"half3 q = saturate(abs(fract(p) * 6 - 3) - 1);"
"return (q - 0.5) * C + hsl.z;"
"}";
#endif

35
src/effects/SkHighContrastFilter.cpp
View File

@ -9,6 +9,7 @@
#include "include/effects/SkHighContrastFilter.h"
#include "include/effects/SkRuntimeEffect.h"
#include "include/private/SkTPin.h"
#include "src/core/SkRuntimeEffectPriv.h"
sk_sp<SkColorFilter> SkHighContrastFilter::Make(const SkHighContrastConfig& userConfig) {
if (!userConfig.isValid()) {
@ -26,39 +27,11 @@ sk_sp<SkColorFilter> SkHighContrastFilter::Make(const SkHighContrastConfig& user
SkString code{
"uniform shader input;"
"uniform half M;"
//This is straight out of GrHSLToRGBFilterEffect.fp.
"half3 hsl_to_rgb(half3 hsl) {"
"half C = (1 - abs(2 * hsl.z - 1)) * hsl.y;"
"half3 p = hsl.xxx + half3(0, 2/3.0, 1/3.0);"
"half3 q = saturate(abs(fract(p) * 6 - 3) - 1);"
"return (q - 0.5) * C + hsl.z;"
"}"
// This is mostly from skvm's rgb->hsl code, with some GPU-related finesse pulled from
// GrHighContrastFilterEffect.fp, see next comment.
"half3 rgb_to_hsl(half3 c) {"
"half mx = max(max(c.r,c.g),c.b),"
" mn = min(min(c.r,c.g),c.b),"
" d = mx-mn, "
" invd = 1.0 / d, "
" g_lt_b = c.g < c.b ? 6.0 : 0.0;"
// We'd prefer to write these tests like `mx == c.r`, but on some GPUs max(x,y) is
// not always equal to either x or y. So we use long form, c.r >= c.g && c.r >= c.b.
"half h = (1/6.0) * (mx == mn ? 0.0 :"
" /*mx==c.r*/ c.r >= c.g && c.r >= c.b ? invd * (c.g - c.b) + g_lt_b :"
" /*mx==c.g*/ c.g >= c.b ? invd * (c.b - c.r) + 2.0 "
" /*mx==c.b*/ : invd * (c.r - c.g) + 4.0);"
"half sum = mx+mn,"
" l = sum * 0.5,"
" s = mx == mn ? 0.0"
" : d / (l > 0.5 ? 2.0 - sum : sum);"
"return half3(h,s,l);"
"}"
};
code += kRGB_to_HSL_sksl;
code += kHSL_to_RGB_sksl;
code += "half4 main() {";
if (true) {
code += "half4 c = sample(input);"; // c is linear unpremul RGBA in the dst gamut.