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Merge "Bowing my head in shame, going back to gamma interpolated gradients"

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This commit is contained in:
TreeHugger Robot
2017-03-16 21:15:12 +00:00
committed by Android (Google) Code Review
parent 2257285aef 6183c97e5f
commit f596ba9375
4 changed files with 41 additions and 40 deletions
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13
libs/hwui/FloatColor.h
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@@ -38,13 +38,14 @@ struct FloatColor {
}
// "color" is a gamma-encoded sRGB color
// After calling this method, the color is stored as a linear color. The color
// is not pre-multiplied.
void setUnPreMultipliedSRGB(uint32_t color) {
// After calling this method, the color is stored as a un-premultiplied linear color
// if linear blending is enabled. Otherwise, the color is stored as a un-premultiplied
// gamma-encoded sRGB color
void setUnPreMultiplied(uint32_t color) {
a = ((color >> 24) & 0xff) / 255.0f;
r = EOCF_sRGB(((color >> 16) & 0xff) / 255.0f);
g = EOCF_sRGB(((color >> 8) & 0xff) / 255.0f);
b = EOCF_sRGB(((color ) & 0xff) / 255.0f);
r = EOCF(((color >> 16) & 0xff) / 255.0f);
g = EOCF(((color >> 8) & 0xff) / 255.0f);
b = EOCF(((color ) & 0xff) / 255.0f);
}
bool isNotBlack() {

23
libs/hwui/GradientCache.cpp
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@@ -189,9 +189,9 @@ void GradientCache::mixBytes(const FloatColor& start, const FloatColor& end,
float amount, uint8_t*& dst) const {
float oppAmount = 1.0f - amount;
float a = start.a * oppAmount + end.a * amount;
*dst++ = uint8_t(a * OECF_sRGB((start.r * oppAmount + end.r * amount)) * 255.0f);
*dst++ = uint8_t(a * OECF_sRGB((start.g * oppAmount + end.g * amount)) * 255.0f);
*dst++ = uint8_t(a * OECF_sRGB((start.b * oppAmount + end.b * amount)) * 255.0f);
*dst++ = uint8_t(a * OECF(start.r * oppAmount + end.r * amount) * 255.0f);
*dst++ = uint8_t(a * OECF(start.g * oppAmount + end.g * amount) * 255.0f);
*dst++ = uint8_t(a * OECF(start.b * oppAmount + end.b * amount) * 255.0f);
*dst++ = uint8_t(a * 255.0f);
}
@@ -201,17 +201,14 @@ void GradientCache::mixFloats(const FloatColor& start, const FloatColor& end,
float a = start.a * oppAmount + end.a * amount;
float* d = (float*) dst;
#ifdef ANDROID_ENABLE_LINEAR_BLENDING
// We want to stay linear
*d++ = a * (start.r * oppAmount + end.r * amount);
*d++ = a * (start.g * oppAmount + end.g * amount);
*d++ = a * (start.b * oppAmount + end.b * amount);
#else
// What we're doing to the alpha channel here is technically incorrect
// but reproduces Android's old behavior when the alpha was pre-multiplied
// with gamma-encoded colors
a = EOCF_sRGB(a);
*d++ = a * OECF_sRGB(start.r * oppAmount + end.r * amount);
*d++ = a * OECF_sRGB(start.g * oppAmount + end.g * amount);
*d++ = a * OECF_sRGB(start.b * oppAmount + end.b * amount);
*d++ = a * OECF(start.r * oppAmount + end.r * amount);
*d++ = a * OECF(start.g * oppAmount + end.g * amount);
*d++ = a * OECF(start.b * oppAmount + end.b * amount);
#endif
*d++ = a;
dst += 4 * sizeof(float);
@@ -232,10 +229,10 @@ void GradientCache::generateTexture(uint32_t* colors, float* positions,
ChannelMixer mix = gMixers[mUseFloatTexture];
FloatColor start;
start.setUnPreMultipliedSRGB(colors[0]);
start.setUnPreMultiplied(colors[0]);
FloatColor end;
end.setUnPreMultipliedSRGB(colors[1]);
end.setUnPreMultiplied(colors[1]);
int currentPos = 1;
float startPos = positions[0];
@@ -250,7 +247,7 @@ void GradientCache::generateTexture(uint32_t* colors, float* positions,
currentPos++;
end.setUnPreMultipliedSRGB(colors[currentPos]);
end.setUnPreMultiplied(colors[currentPos]);
distance = positions[currentPos] - startPos;
}

41
libs/hwui/ProgramCache.cpp
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@@ -202,23 +202,26 @@ const char* gFS_Gradient_Functions = R"__SHADER__(
)__SHADER__";
const char* gFS_Gradient_Preamble[2] = {
// Linear framebuffer
"\nvec4 dither(const vec4 color) {\n"
" return color + (triangleNoise(gl_FragCoord.xy * screenSize.xy) / 255.0);\n"
"}\n"
"\nvec4 gammaMix(const vec4 a, const vec4 b, float v) {\n"
" vec4 c = mix(a, b, v);\n"
" c.a = EOTF_sRGB(c.a);\n" // This is technically incorrect but preserves compatibility
" return vec4(OETF_sRGB(c.rgb) * c.a, c.a);\n"
"}\n",
R"__SHADER__(
vec4 dither(const vec4 color) {
return color + (triangleNoise(gl_FragCoord.xy * screenSize.xy) / 255.0);
}
vec4 gradientMix(const vec4 a, const vec4 b, float v) {
vec4 c = mix(a, b, v);
return vec4(c.rgb * c.a, c.a);
}
)__SHADER__",
// sRGB framebuffer
"\nvec4 dither(const vec4 color) {\n"
" vec3 dithered = sqrt(color.rgb) + (triangleNoise(gl_FragCoord.xy * screenSize.xy) / 255.0);\n"
" return vec4(dithered * dithered, color.a);\n"
"}\n"
"\nvec4 gammaMix(const vec4 a, const vec4 b, float v) {\n"
" vec4 c = mix(a, b, v);\n"
" return vec4(c.rgb * c.a, c.a);\n"
"}\n"
R"__SHADER__(
vec4 dither(const vec4 color) {
vec3 dithered = sqrt(color.rgb) + (triangleNoise(gl_FragCoord.xy * screenSize.xy) / 255.0);
return vec4(dithered * dithered, color.a);
}
vec4 gradientMixMix(const vec4 a, const vec4 b, float v) {
vec4 c = mix(a, b, v);
return vec4(c.rgb * c.a, c.a);
}
)__SHADER__",
};
// Uses luminance coefficients from Rec.709 to choose the appropriate gamma
@@ -272,19 +275,19 @@ const char* gFS_Main_FetchGradient[6] = {
// Linear
" vec4 gradientColor = texture2D(gradientSampler, linear);\n",
" vec4 gradientColor = gammaMix(startColor, endColor, clamp(linear, 0.0, 1.0));\n",
" vec4 gradientColor = gradientMix(startColor, endColor, clamp(linear, 0.0, 1.0));\n",
// Circular
" vec4 gradientColor = texture2D(gradientSampler, vec2(length(circular), 0.5));\n",
" vec4 gradientColor = gammaMix(startColor, endColor, clamp(length(circular), 0.0, 1.0));\n",
" vec4 gradientColor = gradientMix(startColor, endColor, clamp(length(circular), 0.0, 1.0));\n",
// Sweep
" highp float index = atan(sweep.y, sweep.x) * 0.15915494309; // inv(2 * PI)\n"
" vec4 gradientColor = texture2D(gradientSampler, vec2(index - floor(index), 0.5));\n",
" highp float index = atan(sweep.y, sweep.x) * 0.15915494309; // inv(2 * PI)\n"
" vec4 gradientColor = gammaMix(startColor, endColor, clamp(index - floor(index), 0.0, 1.0));\n"
" vec4 gradientColor = gradientMix(startColor, endColor, clamp(index - floor(index), 0.0, 1.0));\n"
};
const char* gFS_Main_FetchBitmap =
" vec4 bitmapColor = OETF(texture2D(bitmapSampler, outBitmapTexCoords));\n";

4
libs/hwui/SkiaShader.cpp
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@@ -173,8 +173,8 @@ bool tryStoreGradient(Caches& caches, const SkShader& shader, const Matrix4 mode
outData->gradientSampler = 0;
outData->gradientTexture = nullptr;
outData->startColor.setUnPreMultipliedSRGB(gradInfo.fColors[0]);
outData->endColor.setUnPreMultipliedSRGB(gradInfo.fColors[1]);
outData->startColor.setUnPreMultiplied(gradInfo.fColors[0]);
outData->endColor.setUnPreMultiplied(gradInfo.fColors[1]);
}
return true;