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skia2/gm/runtimeshader.cpp
Kevin Lubick 677a12f38d [includes] Fix up transitive dependencies on SkBitmap 
Change-Id: Ie1ba66881743eee01d36f7c7032307fbdca1e671
Bug: 242216
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/518496
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
2022-03-09 18:25:17 +00:00

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/*
* Copyright 2019 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm/gm.h"
#include "include/core/SkBitmap.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkData.h"
#include "include/core/SkPaint.h"
#include "include/core/SkRRect.h"
#include "include/core/SkSize.h"
#include "include/core/SkString.h"
#include "include/core/SkSurface.h"
#include "include/effects/SkGradientShader.h"
#include "include/effects/SkImageFilters.h"
#include "include/effects/SkRuntimeEffect.h"
#include "include/utils/SkRandom.h"
#include "src/core/SkColorSpacePriv.h"
#include "tools/Resources.h"
enum RT_Flags {
kAnimate_RTFlag = 0x1,
kBench_RTFlag = 0x2,
kColorFilter_RTFlag = 0x4,
};
class RuntimeShaderGM : public skiagm::GM {
public:
RuntimeShaderGM(const char* name, SkISize size, const char* sksl, uint32_t flags = 0)
: fName(name), fSize(size), fFlags(flags), fSkSL(sksl) {}
void onOnceBeforeDraw() override {
auto [effect, error] = (fFlags & kColorFilter_RTFlag)
? SkRuntimeEffect::MakeForColorFilter(fSkSL)
: SkRuntimeEffect::MakeForShader(fSkSL);
if (!effect) {
SkDebugf("RuntimeShader error: %s\n", error.c_str());
}
fEffect = std::move(effect);
}
bool runAsBench() const override { return SkToBool(fFlags & kBench_RTFlag); }
SkString onShortName() override { return fName; }
SkISize onISize() override { return fSize; }
bool onAnimate(double nanos) override {
fSecs = nanos / (1000 * 1000 * 1000);
return SkToBool(fFlags & kAnimate_RTFlag);
}
protected:
SkString fName;
SkISize fSize;
uint32_t fFlags;
float fSecs = 0.0f;
SkString fSkSL;
sk_sp<SkRuntimeEffect> fEffect;
};
class SimpleRT : public RuntimeShaderGM {
public:
SimpleRT() : RuntimeShaderGM("runtime_shader", {512, 256}, R"(
uniform half4 gColor;
half4 main(float2 p) {
return half4(p*(1.0/255), gColor.b, 1);
}
)", kBench_RTFlag) {}
void onDraw(SkCanvas* canvas) override {
SkRuntimeShaderBuilder builder(fEffect);
SkMatrix localM;
localM.setRotate(90, 128, 128);
builder.uniform("gColor") = SkColor4f{1, 0, 0, 1};
SkPaint p;
p.setShader(builder.makeShader(&localM));
canvas->drawRect({0, 0, 256, 256}, p);
}
};
DEF_GM(return new SimpleRT;)
static sk_sp<SkShader> make_shader(sk_sp<SkImage> img, SkISize size) {
SkMatrix scale = SkMatrix::Scale(size.width() / (float)img->width(),
size.height() / (float)img->height());
return img->makeShader(SkSamplingOptions(), scale);
}
static sk_sp<SkShader> make_threshold(SkISize size) {
auto info = SkImageInfo::Make(size.width(), size.height(), kAlpha_8_SkColorType,
kPremul_SkAlphaType);
auto surf = SkSurface::MakeRaster(info);
auto canvas = surf->getCanvas();
const SkScalar rad = 50;
SkColor colors[] = {SK_ColorBLACK, 0};
SkPaint paint;
paint.setAntiAlias(true);
paint.setShader(SkGradientShader::MakeRadial({0,0}, rad, colors, nullptr, 2, SkTileMode::kClamp));
SkPaint layerPaint;
const SkScalar sigma = 16.0f;
layerPaint.setImageFilter(SkImageFilters::Blur(sigma, sigma, nullptr));
canvas->saveLayer(nullptr, &layerPaint);
SkRandom rand;
for (int i = 0; i < 25; ++i) {
SkScalar x = rand.nextF() * size.width();
SkScalar y = rand.nextF() * size.height();
canvas->save();
canvas->translate(x, y);
canvas->drawCircle(0, 0, rad, paint);
canvas->restore();
}
canvas->restore(); // apply the blur
return surf->makeImageSnapshot()->makeShader(SkSamplingOptions());
}
class ThresholdRT : public RuntimeShaderGM {
public:
ThresholdRT() : RuntimeShaderGM("threshold_rt", {256, 256}, R"(
uniform shader before_map;
uniform shader after_map;
uniform shader threshold_map;
uniform float cutoff;
uniform float slope;
float smooth_cutoff(float x) {
x = x * slope + (0.5 - slope * cutoff);
return clamp(x, 0, 1);
}
half4 main(float2 xy) {
half4 before = before_map.eval(xy);
half4 after = after_map.eval(xy);
float m = smooth_cutoff(threshold_map.eval(xy).a);
return mix(before, after, m);
}
)", kAnimate_RTFlag | kBench_RTFlag) {}
sk_sp<SkShader> fBefore, fAfter, fThreshold;
void onOnceBeforeDraw() override {
const SkISize size = {256, 256};
fThreshold = make_threshold(size);
fBefore = make_shader(GetResourceAsImage("images/mandrill_256.png"), size);
fAfter = make_shader(GetResourceAsImage("images/dog.jpg"), size);
this->RuntimeShaderGM::onOnceBeforeDraw();
}
void onDraw(SkCanvas* canvas) override {
SkRuntimeShaderBuilder builder(fEffect);
builder.uniform("cutoff") = sin(fSecs) * 0.55f + 0.5f;
builder.uniform("slope") = 10.0f;
builder.child("before_map") = fBefore;
builder.child("after_map") = fAfter;
builder.child("threshold_map") = fThreshold;
SkPaint paint;
paint.setShader(builder.makeShader());
canvas->drawRect({0, 0, 256, 256}, paint);
auto draw = [&](SkScalar x, SkScalar y, sk_sp<SkShader> shader) {
paint.setShader(shader);
canvas->save();
canvas->translate(x, y);
canvas->drawRect({0, 0, 256, 256}, paint);
canvas->restore();
};
draw(256, 0, fThreshold);
draw( 0, 256, fBefore);
draw(256, 256, fAfter);
}
};
DEF_GM(return new ThresholdRT;)
class SpiralRT : public RuntimeShaderGM {
public:
SpiralRT() : RuntimeShaderGM("spiral_rt", {512, 512}, R"(
uniform float rad_scale;
uniform float2 in_center;
layout(color) uniform float4 in_colors0;
layout(color) uniform float4 in_colors1;
half4 main(float2 p) {
float2 pp = p - in_center;
float radius = length(pp);
radius = sqrt(radius);
float angle = atan(pp.y / pp.x);
float t = (angle + 3.1415926/2) / (3.1415926);
t += radius * rad_scale;
t = fract(t);
return in_colors0 * (1-t) + in_colors1 * t;
}
)", kAnimate_RTFlag | kBench_RTFlag) {}
void onDraw(SkCanvas* canvas) override {
SkRuntimeShaderBuilder builder(fEffect);
builder.uniform("rad_scale") = std::sin(fSecs * 0.5f + 2.0f) / 5;
builder.uniform("in_center") = SkV2{256, 256};
builder.uniform("in_colors0") = SkColors::kRed;
builder.uniform("in_colors1") = SkColors::kGreen;
SkPaint paint;
paint.setShader(builder.makeShader());
canvas->drawRect({0, 0, 512, 512}, paint);
}
};
DEF_GM(return new SpiralRT;)
// Test case for sampling with both unmodified input coordinates, and explicit coordinates.
// The first version of skbug.com/11869 suffered a bug where all samples of a child were treated
// as pass-through if *at least one* used the unmodified coordinates. This was detected & tracked
// in b/181092919. This GM is similar, and demonstrates the bug before the fix was applied.
class UnsharpRT : public RuntimeShaderGM {
public:
UnsharpRT() : RuntimeShaderGM("unsharp_rt", {512, 256}, R"(
uniform shader child;
half4 main(float2 xy) {
half4 c = child.eval(xy) * 5;
c -= child.eval(xy + float2( 1, 0));
c -= child.eval(xy + float2(-1, 0));
c -= child.eval(xy + float2( 0, 1));
c -= child.eval(xy + float2( 0, -1));
return c;
}
)") {}
sk_sp<SkImage> fMandrill;
void onOnceBeforeDraw() override {
fMandrill = GetResourceAsImage("images/mandrill_256.png");
this->RuntimeShaderGM::onOnceBeforeDraw();
}
void onDraw(SkCanvas* canvas) override {
// First we draw the unmodified image
canvas->drawImage(fMandrill, 0, 0);
// Now draw the image with our unsharp mask applied
SkRuntimeShaderBuilder builder(fEffect);
const SkSamplingOptions sampling(SkFilterMode::kNearest);
builder.child("child") = fMandrill->makeShader(sampling);
SkPaint paint;
paint.setShader(builder.makeShader());
canvas->translate(256, 0);
canvas->drawRect({ 0, 0, 256, 256 }, paint);
}
};
DEF_GM(return new UnsharpRT;)
class ColorCubeRT : public RuntimeShaderGM {
public:
ColorCubeRT() : RuntimeShaderGM("color_cube_rt", {512, 512}, R"(
uniform shader child;
uniform shader color_cube;
uniform float rg_scale;
uniform float rg_bias;
uniform float b_scale;
uniform float inv_size;
half4 main(float2 xy) {
float4 c = unpremul(child.eval(xy));
// Map to cube coords:
float3 cubeCoords = float3(c.rg * rg_scale + rg_bias, c.b * b_scale);
// Compute slice coordinate
float2 coords1 = float2((floor(cubeCoords.b) + cubeCoords.r) * inv_size, cubeCoords.g);
float2 coords2 = float2(( ceil(cubeCoords.b) + cubeCoords.r) * inv_size, cubeCoords.g);
// Two bilinear fetches, plus a manual lerp for the third axis:
half4 color = mix(color_cube.eval(coords1), color_cube.eval(coords2),
fract(cubeCoords.b));
// Premul again
color.rgb *= color.a;
return color;
}
)") {}
sk_sp<SkImage> fMandrill, fMandrillSepia, fIdentityCube, fSepiaCube;
void onOnceBeforeDraw() override {
fMandrill = GetResourceAsImage("images/mandrill_256.png");
fMandrillSepia = GetResourceAsImage("images/mandrill_sepia.png");
fIdentityCube = GetResourceAsImage("images/lut_identity.png");
fSepiaCube = GetResourceAsImage("images/lut_sepia.png");
this->RuntimeShaderGM::onOnceBeforeDraw();
}
void onDraw(SkCanvas* canvas) override {
SkRuntimeShaderBuilder builder(fEffect);
// First we draw the unmodified image, and a copy that was sepia-toned in Photoshop:
canvas->drawImage(fMandrill, 0, 0);
canvas->drawImage(fMandrillSepia, 0, 256);
// LUT dimensions should be (kSize^2, kSize)
constexpr float kSize = 16.0f;
const SkSamplingOptions sampling(SkFilterMode::kLinear);
builder.uniform("rg_scale") = (kSize - 1) / kSize;
builder.uniform("rg_bias") = 0.5f / kSize;
builder.uniform("b_scale") = kSize - 1;
builder.uniform("inv_size") = 1.0f / kSize;
builder.child("child") = fMandrill->makeShader(sampling);
SkPaint paint;
// TODO: Should we add SkImage::makeNormalizedShader() to handle this automatically?
SkMatrix normalize = SkMatrix::Scale(1.0f / (kSize * kSize), 1.0f / kSize);
// Now draw the image with an identity color cube - it should look like the original
builder.child("color_cube") = fIdentityCube->makeShader(sampling, normalize);
paint.setShader(builder.makeShader());
canvas->translate(256, 0);
canvas->drawRect({ 0, 0, 256, 256 }, paint);
// ... and with a sepia-tone color cube. This should match the sepia-toned image.
builder.child("color_cube") = fSepiaCube->makeShader(sampling, normalize);
paint.setShader(builder.makeShader());
canvas->translate(0, 256);
canvas->drawRect({ 0, 0, 256, 256 }, paint);
}
};
DEF_GM(return new ColorCubeRT;)
// Same as above, but demonstrating how to implement this as a runtime color filter (that samples
// a shader child for the LUT).
class ColorCubeColorFilterRT : public RuntimeShaderGM {
public:
ColorCubeColorFilterRT() : RuntimeShaderGM("color_cube_cf_rt", {512, 512}, R"(
uniform shader color_cube;
uniform float rg_scale;
uniform float rg_bias;
uniform float b_scale;
uniform float inv_size;
half4 main(half4 inColor) {
float4 c = unpremul(inColor);
// Map to cube coords:
float3 cubeCoords = float3(c.rg * rg_scale + rg_bias, c.b * b_scale);
// Compute slice coordinate
float2 coords1 = float2((floor(cubeCoords.b) + cubeCoords.r) * inv_size, cubeCoords.g);
float2 coords2 = float2(( ceil(cubeCoords.b) + cubeCoords.r) * inv_size, cubeCoords.g);
// Two bilinear fetches, plus a manual lerp for the third axis:
half4 color = mix(color_cube.eval(coords1), color_cube.eval(coords2),
fract(cubeCoords.b));
// Premul again
color.rgb *= color.a;
return color;
}
)", kColorFilter_RTFlag) {}
sk_sp<SkImage> fMandrill, fMandrillSepia, fIdentityCube, fSepiaCube;
void onOnceBeforeDraw() override {
fMandrill = GetResourceAsImage("images/mandrill_256.png");
fMandrillSepia = GetResourceAsImage("images/mandrill_sepia.png");
fIdentityCube = GetResourceAsImage("images/lut_identity.png");
fSepiaCube = GetResourceAsImage("images/lut_sepia.png");
this->RuntimeShaderGM::onOnceBeforeDraw();
}
void onDraw(SkCanvas* canvas) override {
// First we draw the unmodified image, and a copy that was sepia-toned in Photoshop:
canvas->drawImage(fMandrill, 0, 0);
canvas->drawImage(fMandrillSepia, 0, 256);
// LUT dimensions should be (kSize^2, kSize)
constexpr float kSize = 16.0f;
const SkSamplingOptions sampling(SkFilterMode::kLinear);
float uniforms[] = {
(kSize - 1) / kSize, // rg_scale
0.5f / kSize, // rg_bias
kSize - 1, // b_scale
1.0f / kSize, // inv_size
};
SkPaint paint;
// TODO: Should we add SkImage::makeNormalizedShader() to handle this automatically?
SkMatrix normalize = SkMatrix::Scale(1.0f / (kSize * kSize), 1.0f / kSize);
// Now draw the image with an identity color cube - it should look like the original
SkRuntimeEffect::ChildPtr children[] = {fIdentityCube->makeShader(sampling, normalize)};
paint.setColorFilter(fEffect->makeColorFilter(
SkData::MakeWithCopy(uniforms, sizeof(uniforms)), SkMakeSpan(children)));
canvas->drawImage(fMandrill, 256, 0, sampling, &paint);
// ... and with a sepia-tone color cube. This should match the sepia-toned image.
children[0] = fSepiaCube->makeShader(sampling, normalize);
paint.setColorFilter(fEffect->makeColorFilter(
SkData::MakeWithCopy(uniforms, sizeof(uniforms)), SkMakeSpan(children)));
canvas->drawImage(fMandrill, 256, 256, sampling, &paint);
}
};
DEF_GM(return new ColorCubeColorFilterRT;)
class DefaultColorRT : public RuntimeShaderGM {
public:
DefaultColorRT() : RuntimeShaderGM("default_color_rt", {512, 256}, R"(
uniform shader child;
half4 main(float2 xy) {
return child.eval(xy);
}
)") {}
sk_sp<SkImage> fMandrill;
void onOnceBeforeDraw() override {
fMandrill = GetResourceAsImage("images/mandrill_256.png");
this->RuntimeShaderGM::onOnceBeforeDraw();
}
void onDraw(SkCanvas* canvas) override {
SkRuntimeShaderBuilder builder(fEffect);
// First, we leave the child as null, so sampling it returns the default (paint) color
SkPaint paint;
paint.setColor4f({ 0.25f, 0.75f, 0.75f, 1.0f });
paint.setShader(builder.makeShader());
canvas->drawRect({ 0, 0, 256, 256 }, paint);
// Now we bind an image shader as the child. This (by convention) scales by the paint alpha
builder.child("child") = fMandrill->makeShader(SkSamplingOptions());
paint.setColor4f({ 1.0f, 1.0f, 1.0f, 0.5f });
paint.setShader(builder.makeShader());
canvas->translate(256, 0);
canvas->drawRect({ 0, 0, 256, 256 }, paint);
}
};
DEF_GM(return new DefaultColorRT;)
// Emits coverage for a rounded rectangle whose corners are superellipses defined by the boundary:
//
// x^n + y^n == 1
//
// Where x and y are normalized, clamped coordinates ranging from 0..1 inside the nearest corner's
// bounding box.
//
// See: https://en.wikipedia.org/wiki/Superellipse
class ClipSuperRRect : public RuntimeShaderGM {
public:
ClipSuperRRect(const char* name, float power) : RuntimeShaderGM(name, {500, 500}, R"(
uniform float power_minus1;
uniform float2 stretch_factor;
uniform float2x2 derivatives;
half4 main(float2 xy) {
xy = max(abs(xy) + stretch_factor, 0);
float2 exp_minus1 = pow(xy, power_minus1.xx); // If power == 3.5: xy * xy * sqrt(xy)
float f = dot(exp_minus1, xy) - 1; // f = x^n + y^n - 1
float2 grad = exp_minus1 * derivatives;
float fwidth = abs(grad.x) + abs(grad.y) + 1e-12; // 1e-12 to avoid a divide by zero.
return half4(saturate(.5 - f/fwidth)); // Approx coverage by riding the gradient to f=0.
}
)"), fPower(power) {}
void drawSuperRRect(SkCanvas* canvas, const SkRect& superRRect, float radX, float radY,
SkColor color) {
SkPaint paint;
paint.setColor(color);
if (fPower == 2) {
// Draw a normal round rect for the sake of testing.
SkRRect rrect = SkRRect::MakeRectXY(superRRect, radX, radY);
paint.setAntiAlias(true);
canvas->drawRRect(rrect, paint);
return;
}
SkRuntimeShaderBuilder builder(fEffect);
builder.uniform("power_minus1") = fPower - 1;
// Size the corners such that the "apex" of our "super" rounded corner is in the same
// location that the apex of a circular rounded corner would be with the given radii. We
// define the apex as the point on the rounded corner that is 45 degrees between the
// horizontal and vertical edges.
float scale = (1 - SK_ScalarRoot2Over2) / (1 - exp2f(-1/fPower));
float cornerWidth = radX * scale;
float cornerHeight = radY * scale;
cornerWidth = std::min(cornerWidth, superRRect.width() * .5f);
cornerHeight = std::min(cornerHeight, superRRect.height() * .5f);
// The stretch factor controls how long the flat edge should be between rounded corners.
builder.uniform("stretch_factor") = SkV2{1 - superRRect.width()*.5f / cornerWidth,
1 - superRRect.height()*.5f / cornerHeight};
// Calculate a 2x2 "derivatives" matrix that the shader will use to find the gradient.
//
// f = s^n + t^n - 1 [s,t are "super" rounded corner coords in normalized 0..1 space]
//
// gradient = [df/dx df/dy] = [ns^(n-1) nt^(n-1)] * |ds/dx ds/dy|
// |dt/dx dt/dy|
//
// = [s^(n-1) t^(n-1)] * |n 0| * |ds/dx ds/dy|
// |0 n| |dt/dx dt/dy|
//
// = [s^(n-1) t^(n-1)] * |2n/cornerWidth 0| * mat2x2(canvasMatrix)^-1
// |0 2n/cornerHeight|
//
// = [s^(n-1) t^(n-1)] * "derivatives"
//
const SkMatrix& M = canvas->getTotalMatrix();
float a=M.getScaleX(), b=M.getSkewX(), c=M.getSkewY(), d=M.getScaleY();
float determinant = a*d - b*c;
float dx = fPower / (cornerWidth * determinant);
float dy = fPower / (cornerHeight * determinant);
builder.uniform("derivatives") = SkV4{d*dx, -c*dy, -b*dx, a*dy};
// This matrix will be inverted by the effect system, giving a matrix that converts local
// coordinates to (almost) coner coordinates. To get the rest of the way to the nearest
// corner's space, the shader will have to take the absolute value, add the stretch_factor,
// then clamp above zero.
SkMatrix cornerToLocal;
cornerToLocal.setScaleTranslate(cornerWidth, cornerHeight, superRRect.centerX(),
superRRect.centerY());
canvas->clipShader(builder.makeShader(&cornerToLocal));
// Bloat the outer edges of the rect we will draw so it contains all the antialiased pixels.
// Bloat by a full pixel instead of half in case Skia is in a mode that draws this rect with
// unexpected AA of its own.
float inverseDet = 1 / fabsf(determinant);
float bloatX = (fabsf(d) + fabsf(c)) * inverseDet;
float bloatY = (fabsf(b) + fabsf(a)) * inverseDet;
canvas->drawRect(superRRect.makeOutset(bloatX, bloatY), paint);
}
void onDraw(SkCanvas* canvas) override {
SkRandom rand(2);
canvas->save();
canvas->translate(canvas->imageInfo().width() / 2.f, canvas->imageInfo().height() / 2.f);
canvas->save();
canvas->rotate(21);
this->drawSuperRRect(canvas, SkRect::MakeXYWH(-5, 25, 175, 100), 50, 30,
rand.nextU() | 0xff808080);
canvas->restore();
canvas->save();
canvas->rotate(94);
this->drawSuperRRect(canvas, SkRect::MakeXYWH(95, 75, 125, 100), 30, 30,
rand.nextU() | 0xff808080);
canvas->restore();
canvas->save();
canvas->rotate(132);
this->drawSuperRRect(canvas, SkRect::MakeXYWH(0, 75, 150, 100), 40, 30,
rand.nextU() | 0xff808080);
canvas->restore();
canvas->save();
canvas->rotate(282);
this->drawSuperRRect(canvas, SkRect::MakeXYWH(15, -20, 100, 100), 20, 20,
rand.nextU() | 0xff808080);
canvas->restore();
canvas->save();
canvas->rotate(0);
this->drawSuperRRect(canvas, SkRect::MakeXYWH(140, -50, 90, 110), 25, 25,
rand.nextU() | 0xff808080);
canvas->restore();
canvas->save();
canvas->rotate(-35);
this->drawSuperRRect(canvas, SkRect::MakeXYWH(160, -60, 60, 90), 18, 18,
rand.nextU() | 0xff808080);
canvas->restore();
canvas->save();
canvas->rotate(65);
this->drawSuperRRect(canvas, SkRect::MakeXYWH(220, -120, 60, 90), 18, 18,
rand.nextU() | 0xff808080);
canvas->restore();
canvas->save();
canvas->rotate(265);
this->drawSuperRRect(canvas, SkRect::MakeXYWH(150, -129, 80, 160), 24, 39,
rand.nextU() | 0xff808080);
canvas->restore();
canvas->restore();
}
private:
const float fPower;
};
DEF_GM(return new ClipSuperRRect("clip_super_rrect_pow2", 2);)
// DEF_GM(return new ClipSuperRRect("clip_super_rrect_pow3", 3);)
DEF_GM(return new ClipSuperRRect("clip_super_rrect_pow3.5", 3.5);)
// DEF_GM(return new ClipSuperRRect("clip_super_rrect_pow4", 4);)
// DEF_GM(return new ClipSuperRRect("clip_super_rrect_pow4.5", 4.5);)
// DEF_GM(return new ClipSuperRRect("clip_super_rrect_pow5", 5);)
class LinearGradientRT : public RuntimeShaderGM {
public:
LinearGradientRT() : RuntimeShaderGM("linear_gradient_rt", {256 + 10, 128 + 15}, R"(
layout(color) uniform vec4 in_colors0;
layout(color) uniform vec4 in_colors1;
vec4 main(vec2 p) {
float t = p.x / 256;
if (p.y < 32) {
return mix(in_colors0, in_colors1, t);
} else {
vec3 linColor0 = toLinearSrgb(in_colors0.rgb);
vec3 linColor1 = toLinearSrgb(in_colors1.rgb);
vec3 linColor = mix(linColor0, linColor1, t);
return fromLinearSrgb(linColor).rgb1;
}
}
)") {}
void onDraw(SkCanvas* canvas) override {
// Colors chosen to use values other than 0 and 1 - so that it's obvious if the conversion
// intrinsics are doing anything. (Most transfer functions map 0 -> 0 and 1 -> 1).
SkRuntimeShaderBuilder builder(fEffect);
builder.uniform("in_colors0") = SkColor4f{0.75f, 0.25f, 0.0f, 1.0f};
builder.uniform("in_colors1") = SkColor4f{0.0f, 0.75f, 0.25f, 1.0f};
SkPaint paint;
paint.setShader(builder.makeShader());
canvas->save();
canvas->clear(SK_ColorWHITE);
canvas->translate(5, 5);
// We draw everything twice. First to a surface with no color management, where the
// intrinsics should do nothing (eg, the top bar should look the same in the top and bottom
// halves). Then to an sRGB surface, where they should produce linearly interpolated
// gradients (the bottom half of the second bar should be brighter than the top half).
for (auto cs : {static_cast<SkColorSpace*>(nullptr), sk_srgb_singleton()}) {
SkImageInfo info = SkImageInfo::Make(
256, 64, kN32_SkColorType, kPremul_SkAlphaType, sk_ref_sp(cs));
auto surface = canvas->makeSurface(info);
if (!surface) {
surface = SkSurface::MakeRaster(info);
}
surface->getCanvas()->drawRect({0, 0, 256, 64}, paint);
canvas->drawImage(surface->makeImageSnapshot(), 0, 0);
canvas->translate(0, 64 + 5);
}
canvas->restore();
}
};
DEF_GM(return new LinearGradientRT;)
DEF_SIMPLE_GM(child_sampling_rt, canvas, 256,256) {
static constexpr char scale[] =
"uniform shader child;"
"half4 main(float2 xy) {"
" return child.eval(xy*0.1);"
"}";
SkPaint p;
p.setColor(SK_ColorRED);
p.setAntiAlias(true);
p.setStyle(SkPaint::kStroke_Style);
p.setStrokeWidth(1);
auto surf = SkSurface::MakeRasterN32Premul(100,100);
surf->getCanvas()->drawLine(0, 0, 100, 100, p);
auto shader = surf->makeImageSnapshot()->makeShader(SkSamplingOptions(SkFilterMode::kLinear));
SkRuntimeShaderBuilder builder(SkRuntimeEffect::MakeForShader(SkString(scale)).effect);
builder.child("child") = shader;
p.setShader(builder.makeShader());
canvas->drawPaint(p);
}
static sk_sp<SkShader> normal_map_shader() {
// Produces a hemispherical normal:
static const char* kSrc = R"(
half4 main(vec2 p) {
p = (p / 256) * 2 - 1;
float p2 = dot(p, p);
vec3 v = (p2 > 1) ? vec3(0, 0, 1) : vec3(p, sqrt(1 - p2));
return (v * 0.5 + 0.5).xyz1;
}
)";
auto effect = SkRuntimeEffect::MakeForShader(SkString(kSrc)).effect;
return effect->makeShader(nullptr, {});
}
static sk_sp<SkImage> normal_map_image() {
// Above, baked into an image:
auto info = SkImageInfo::Make(256, 256, kN32_SkColorType, kPremul_SkAlphaType);
auto surface = SkSurface::MakeRaster(info);
SkPaint p;
p.setShader(normal_map_shader());
surface->getCanvas()->drawPaint(p);
return surface->makeImageSnapshot();
}
static sk_sp<SkShader> normal_map_image_shader() {
return normal_map_image()->makeShader(SkSamplingOptions{});
}
static sk_sp<SkShader> normal_map_raw_image_shader() {
return normal_map_image()->makeRawShader(SkSamplingOptions{});
}
static sk_sp<SkImage> normal_map_unpremul_image() {
auto image = normal_map_image();
SkPixmap pm;
SkAssertResult(image->peekPixels(&pm));
SkBitmap bmp;
bmp.allocPixels(image->imageInfo().makeAlphaType(kUnpremul_SkAlphaType));
// Copy all pixels over, but set alpha to 0
for (int y = 0; y < pm.height(); y++) {
for (int x = 0; x < pm.width(); x++) {
*bmp.getAddr32(x, y) = *pm.addr32(x, y) & 0x00FFFFFF;
}
}
return bmp.asImage();
}
static sk_sp<SkShader> normal_map_unpremul_image_shader() {
return normal_map_unpremul_image()->makeShader(SkSamplingOptions{});
}
static sk_sp<SkShader> normal_map_raw_unpremul_image_shader() {
return normal_map_unpremul_image()->makeRawShader(SkSamplingOptions{});
}
static sk_sp<SkShader> lit_shader(sk_sp<SkShader> normals) {
// Simple N-dot-L against a fixed, directional light:
static const char* kSrc = R"(
uniform shader normals;
half4 main(vec2 p) {
vec3 n = normalize(normals.eval(p).xyz * 2 - 1);
vec3 l = normalize(vec3(1, -1, 1));
return saturate(dot(n, l)).xxx1;
}
)";
auto effect = SkRuntimeEffect::MakeForShader(SkString(kSrc)).effect;
return effect->makeShader(nullptr, &normals, 1);
}
static sk_sp<SkShader> lit_shader_linear(sk_sp<SkShader> normals) {
// Simple N-dot-L against a fixed, directional light, done in linear space:
static const char* kSrc = R"(
uniform shader normals;
half4 main(vec2 p) {
vec3 n = normalize(normals.eval(p).xyz * 2 - 1);
vec3 l = normalize(vec3(1, -1, 1));
return fromLinearSrgb(saturate(dot(n, l)).xxx).xxx1;
}
)";
auto effect = SkRuntimeEffect::MakeForShader(SkString(kSrc)).effect;
return effect->makeShader(nullptr, &normals, 1);
}
DEF_SIMPLE_GM(paint_alpha_normals_rt, canvas, 512,512) {
// Various draws, with non-opaque paint alpha. This demonstrates several issues around how
// paint alpha is applied differently on CPU (globally, after all shaders) and GPU (per shader,
// inconsistently). See: skbug.com/11942
//
// When this works, it will be a demo of applying paint alpha to fade out a complex effect.
auto draw_shader = [=](int x, int y, sk_sp<SkShader> shader) {
SkPaint p;
p.setAlpha(164);
p.setShader(shader);
canvas->save();
canvas->translate(x, y);
canvas->clipRect({0, 0, 256, 256});
canvas->drawPaint(p);
canvas->restore();
};
draw_shader(0, 0, normal_map_shader());
draw_shader(0, 256, normal_map_image_shader());
draw_shader(256, 0, lit_shader(normal_map_shader()));
draw_shader(256, 256, lit_shader(normal_map_image_shader()));
}
DEF_SIMPLE_GM(raw_image_shader_normals_rt, canvas, 768, 512) {
// Demonstrates the utility of SkImage::makeRawShader, for non-color child shaders.
// First, make an offscreen surface, so we can control the destination color space:
auto surfInfo = SkImageInfo::Make(512, 512,
kN32_SkColorType,
kPremul_SkAlphaType,
SkColorSpace::MakeSRGB()->makeColorSpin());
auto surface = canvas->makeSurface(surfInfo);
if (!surface) {
surface = SkSurface::MakeRaster(surfInfo);
}
auto draw_shader = [](int x, int y, sk_sp<SkShader> shader, SkCanvas* canvas) {
SkPaint p;
p.setShader(shader);
canvas->save();
canvas->translate(x, y);
canvas->clipRect({0, 0, 256, 256});
canvas->drawPaint(p);
canvas->restore();
};
sk_sp<SkShader> colorNormals = normal_map_image_shader(),
rawNormals = normal_map_raw_image_shader();
// Draw our normal map as colors (will be color-rotated), and raw (untransformed)
draw_shader(0, 0, colorNormals, surface->getCanvas());
draw_shader(0, 256, rawNormals, surface->getCanvas());
// Now draw our lighting shader using the normal and raw versions of the normals as children.
// The top image will have the normals rotated (incorrectly), so the lighting is very dark.
draw_shader(256, 0, lit_shader(colorNormals), surface->getCanvas());
draw_shader(256, 256, lit_shader(rawNormals), surface->getCanvas());
// Now draw the offscreen surface back to our original canvas. If we do this naively, the image
// will be un-transformed back to the canvas' color space. That will have the effect of undoing
// the color spin on the upper-left, and APPLYING a color-spin on the bottom left. To preserve
// the intent of this GM (and make it draw consistently whether or not the original surface has
// a color space attached), we reinterpret the offscreen image as being in sRGB:
canvas->drawImage(
surface->makeImageSnapshot()->reinterpretColorSpace(SkColorSpace::MakeSRGB()), 0, 0);
// Finally, to demonstrate that raw unpremul image shaders don't premul, draw lighting two more
// times, with an unpremul normal map (containing ZERO in the alpha channel). THe top will
// premultiply the normals, resulting in totally dark lighting. The bottom will retain the RGB
// encoded normals, even with zero alpha:
draw_shader(512, 0, lit_shader(normal_map_unpremul_image_shader()), canvas);
draw_shader(512, 256, lit_shader(normal_map_raw_unpremul_image_shader()), canvas);
}
DEF_SIMPLE_GM(lit_shader_linear_rt, canvas, 512, 256) {
// First, make an offscreen surface, so we can control the destination color space:
auto surfInfo = SkImageInfo::Make(512, 256,
kN32_SkColorType,
kPremul_SkAlphaType,
SkColorSpace::MakeSRGB());
auto surface = canvas->makeSurface(surfInfo);
if (!surface) {
surface = SkSurface::MakeRaster(surfInfo);
}
auto draw_shader = [](int x, int y, sk_sp<SkShader> shader, SkCanvas* canvas) {
SkPaint p;
p.setShader(shader);
canvas->save();
canvas->translate(x, y);
canvas->clipRect({0, 0, 256, 256});
canvas->drawPaint(p);
canvas->restore();
};
// We draw two lit spheres - one does math in the working space (so gamma-encoded). The second
// works in linear space, then converts to sRGB. This produces (more accurate) sharp falloff:
draw_shader(0, 0, lit_shader(normal_map_shader()), surface->getCanvas());
draw_shader(256, 0, lit_shader_linear(normal_map_shader()), surface->getCanvas());
// Now draw the offscreen surface back to our original canvas:
canvas->drawImage(surface->makeImageSnapshot(), 0, 0);
}
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