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-rw-r--r--gm/patch.cpp114
-rw-r--r--gyp/core.gypi2
-rw-r--r--gyp/gmslides.gypi1
-rw-r--r--include/core/SkPatch.h124
-rw-r--r--src/core/SkPatch.cpp224
5 files changed, 465 insertions, 0 deletions
diff --git a/gm/patch.cpp b/gm/patch.cpp
new file mode 100644
index 0000000000..eb99944c0b
--- /dev/null
+++ b/gm/patch.cpp
@@ -0,0 +1,114 @@
+
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+// This test only works with the GPU backend.
+
+#include "gm.h"
+
+#if SK_SUPPORT_GPU
+
+#include "GrContext.h"
+#include "GrTest.h"
+
+#include "SkPatch.h"
+
+namespace skiagm {
+/**
+ * This GM draws a SkPatch.
+ */
+class SkPatchGM : public GM {
+public:
+ SkPatchGM() {
+ this->setBGColor(0xFFFFFFFF);
+ }
+
+protected:
+ virtual SkString onShortName() SK_OVERRIDE {
+ return SkString("patch_primitive");
+ }
+
+ virtual SkISize onISize() SK_OVERRIDE {
+ return SkISize::Make(800, 800);
+ }
+
+ virtual uint32_t onGetFlags() const SK_OVERRIDE {
+ return kGPUOnly_Flag;
+ }
+
+
+ virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+
+ SkPaint paint;
+ SkColor colors[4] = {
+ SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorCYAN
+ };
+ SkPoint points[] = {
+ {100,100},{130,50},{500,70}, {650,60},
+ {350,125},{490,555},{600,700},
+ {515,595},{140,550},{110,590},
+ {125,400},{70,150}
+
+ };
+
+ SkPatch coons(points, colors);
+
+ SkPatch::VertexData data;
+ coons.getVertexData(&data, 10);
+
+ canvas->drawVertices(SkCanvas::kTriangles_VertexMode,data.fVertexCount,
+ data.fPoints, data.fTexCoords, data.fColors, NULL, data.fIndices,
+ data.fIndexCount, paint);
+
+ //draw control points
+ SkPoint bottom[4];
+ coons.getBottomPoints(bottom);
+ SkPoint top[4];
+ coons.getTopPoints(top);
+ SkPoint left[4];
+ coons.getLeftPoints(left);
+ SkPoint right[4];
+ coons.getRightPoints(right);
+
+ SkPoint corners[4] = { bottom[0], bottom[3], top[0], top[3] };
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 4, bottom, paint);
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 2, bottom+1, paint);
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 4, top, paint);
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 4, left, paint);
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 4, right, paint);
+
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 2, top+1, paint);
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 2, left+1, paint);
+ canvas->drawPoints(SkCanvas::kLines_PointMode, 2, right+1, paint);
+
+ paint.setStrokeWidth(10);
+
+ paint.setColor(SK_ColorRED);
+ canvas->drawPoints(SkCanvas::kPoints_PointMode, 4, corners, paint);
+
+ paint.setColor(SK_ColorBLUE);
+ canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, bottom+1, paint);
+
+ paint.setColor(SK_ColorCYAN);
+ canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, top+1, paint);
+
+ paint.setColor(SK_ColorYELLOW);
+ canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, left+1, paint);
+
+ paint.setColor(SK_ColorGREEN);
+ canvas->drawPoints(SkCanvas::kPoints_PointMode, 2, right+1, paint);
+ }
+
+private:
+ typedef GM INHERITED;
+};
+
+DEF_GM( return SkNEW(SkPatchGM); )
+
+}
+
+#endif
diff --git a/gyp/core.gypi b/gyp/core.gypi
index f7853f91d5..da43a05ff1 100644
--- a/gyp/core.gypi
+++ b/gyp/core.gypi
@@ -122,6 +122,7 @@
'<(skia_src_path)/core/SkPaintOptionsAndroid.cpp',
'<(skia_src_path)/core/SkPaintPriv.cpp',
'<(skia_src_path)/core/SkPaintPriv.h',
+ '<(skia_src_path)/core/SkPatch.cpp',
'<(skia_src_path)/core/SkPath.cpp',
'<(skia_src_path)/core/SkPathEffect.cpp',
'<(skia_src_path)/core/SkPathHeap.cpp',
@@ -278,6 +279,7 @@
'<(skia_include_path)/core/SkOSFile.h',
'<(skia_include_path)/core/SkPackBits.h',
'<(skia_include_path)/core/SkPaint.h',
+ '<(skia_include_path)/core/SkPatch.h',
'<(skia_include_path)/core/SkPath.h',
'<(skia_include_path)/core/SkPathEffect.h',
'<(skia_include_path)/core/SkPathMeasure.h',
diff --git a/gyp/gmslides.gypi b/gyp/gmslides.gypi
index 1ee27fda8c..b9563511a4 100644
--- a/gyp/gmslides.gypi
+++ b/gyp/gmslides.gypi
@@ -122,6 +122,7 @@
'../gm/offsetimagefilter.cpp',
'../gm/optimizations.cpp',
'../gm/ovals.cpp',
+ '../gm/patch.cpp',
'../gm/patheffects.cpp',
'../gm/pathfill.cpp',
'../gm/pathinterior.cpp',
diff --git a/include/core/SkPatch.h b/include/core/SkPatch.h
new file mode 100644
index 0000000000..2354423aba
--- /dev/null
+++ b/include/core/SkPatch.h
@@ -0,0 +1,124 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkPatch_DEFINED
+#define SkPatch_DEFINED
+
+#include "SkColor.h"
+#include "SkPreConfig.h"
+#include "SkPoint.h"
+
+/**
+ * Class that represents a coons patch.
+ */
+class SK_API SkPatch {
+
+public:
+ /**
+ * Structure that holds the vertex data related to the tessellation of a SkPatch. It is passed
+ * as a parameter to the function getVertexData which sets the points, colors and texture
+ * coordinates of the vertices and the indices for them to be drawn as triangles.
+ */
+ struct VertexData {
+ int fVertexCount, fIndexCount;
+ SkPoint* fPoints;
+ SkPoint* fTexCoords;
+ uint32_t* fColors;
+ uint16_t* fIndices;
+
+ VertexData()
+ : fVertexCount(0)
+ , fIndexCount(0)
+ , fPoints(NULL)
+ , fTexCoords(NULL)
+ , fColors(NULL)
+ , fIndices(NULL) { }
+
+ ~VertexData() {
+ SkDELETE_ARRAY(fPoints);
+ SkDELETE_ARRAY(fTexCoords);
+ SkDELETE_ARRAY(fColors);
+ SkDELETE_ARRAY(fIndices);
+ }
+ };
+
+ enum CubicCtrlPts {
+ kTopP0_CubicCtrlPts = 0,
+ kTopP1_CubicCtrlPts = 1,
+ kTopP2_CubicCtrlPts = 2,
+ kTopP3_CubicCtrlPts = 3,
+
+ kRightP0_CubicCtrlPts = 3,
+ kRightP1_CubicCtrlPts = 4,
+ kRightP2_CubicCtrlPts = 5,
+ kRightP3_CubicCtrlPts = 6,
+
+ kBottomP0_CubicCtrlPts = 9,
+ kBottomP1_CubicCtrlPts = 8,
+ kBottomP2_CubicCtrlPts = 7,
+ kBottomP3_CubicCtrlPts = 6,
+
+ kLeftP0_CubicCtrlPts = 0,
+ kLeftP1_CubicCtrlPts = 11,
+ kLeftP2_CubicCtrlPts = 10,
+ kLeftP3_CubicCtrlPts = 9,
+ };
+
+ /**
+ * Points are in the following order:
+ * (top curve)
+ * 0 1 2 3
+ * (left curve) 11 4 (right curve)
+ * 10 5
+ * 9 8 7 6
+ * (bottom curve)
+ * Used pointer to an array to guarantee that this method receives an array of 4 SkColors
+ */
+ SkPatch(SkPoint points[12], SkColor colors[4]);
+
+ /**
+ * Function that evaluates the coons patch interpolation.
+ * data refers to the pointer of the PatchData struct in which the tessellation data is set.
+ * divisions defines the number of steps in which the SkPatch is going to be subdivided per
+ * axis.
+ */
+ bool getVertexData(SkPatch::VertexData* data, int divisions);
+
+ void getTopPoints(SkPoint points[4]) {
+ points[0] = fCtrlPoints[kTopP0_CubicCtrlPts];
+ points[1] = fCtrlPoints[kTopP1_CubicCtrlPts];
+ points[2] = fCtrlPoints[kTopP2_CubicCtrlPts];
+ points[3] = fCtrlPoints[kTopP3_CubicCtrlPts];
+ }
+
+ void getBottomPoints(SkPoint points[4]) {
+ points[0] = fCtrlPoints[kBottomP0_CubicCtrlPts];
+ points[1] = fCtrlPoints[kBottomP1_CubicCtrlPts];
+ points[2] = fCtrlPoints[kBottomP2_CubicCtrlPts];
+ points[3] = fCtrlPoints[kBottomP3_CubicCtrlPts];
+ }
+
+ void getLeftPoints(SkPoint points[4]) {
+ points[0] = fCtrlPoints[kLeftP0_CubicCtrlPts];
+ points[1] = fCtrlPoints[kLeftP1_CubicCtrlPts];
+ points[2] = fCtrlPoints[kLeftP2_CubicCtrlPts];
+ points[3] = fCtrlPoints[kLeftP3_CubicCtrlPts];
+ }
+
+ void getRightPoints(SkPoint points[4]) {
+ points[0] = fCtrlPoints[kRightP0_CubicCtrlPts];
+ points[1] = fCtrlPoints[kRightP1_CubicCtrlPts];
+ points[2] = fCtrlPoints[kRightP2_CubicCtrlPts];
+ points[3] = fCtrlPoints[kRightP3_CubicCtrlPts];
+ }
+
+private:
+ SkPoint fCtrlPoints[12];
+ SkPMColor fCornerColors[4];
+};
+
+#endif
diff --git a/src/core/SkPatch.cpp b/src/core/SkPatch.cpp
new file mode 100644
index 0000000000..acd6cb9b57
--- /dev/null
+++ b/src/core/SkPatch.cpp
@@ -0,0 +1,224 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkPatch.h"
+
+#include "SkGeometry.h"
+#include "SkColorPriv.h"
+
+////////////////////////////////////////////////////////////////////////////////
+
+/**
+ * Evaluator to sample the values of a cubic bezier using forward differences.
+ * Forward differences is a method for evaluating a nth degree polynomial at a uniform step by only
+ * adding precalculated values.
+ * For a linear example we have the function f(t) = m*t+b, then the value of that function at t+h
+ * would be f(t+h) = m*(t+h)+b. If we want to know the uniform step that we must add to the first
+ * evaluation f(t) then we need to substract f(t+h) - f(t) = m*t + m*h + b - m*t + b = mh. After
+ * obtaining this value (mh) we could just add this constant step to our first sampled point
+ * to compute the next one.
+ *
+ * For the cubic case the first difference gives as a result a quadratic polynomial to which we can
+ * apply again forward differences and get linear function to which we can apply again forward
+ * differences to get a constant difference. This is why we keep an array of size 4, the 0th
+ * position keeps the sampled value while the next ones keep the quadratic, linear and constant
+ * difference values.
+ */
+
+class FwDCubicEvaluator {
+
+public:
+ FwDCubicEvaluator() { }
+
+ /**
+ * Receives the 4 control points of the cubic bezier.
+ */
+ FwDCubicEvaluator(SkPoint a, SkPoint b, SkPoint c, SkPoint d) {
+ fPoints[0] = a;
+ fPoints[1] = b;
+ fPoints[2] = c;
+ fPoints[3] = d;
+
+ SkScalar cx[4], cy[4];
+ SkGetCubicCoeff(fPoints, cx, cy);
+ fCoefs[0].set(cx[0], cy[0]);
+ fCoefs[1].set(cx[1], cy[1]);
+ fCoefs[2].set(cx[2], cy[2]);
+ fCoefs[3].set(cx[3], cy[3]);
+
+ this->restart(1);
+ }
+
+ /**
+ * Restarts the forward differences evaluator to the first value of t = 0.
+ */
+ void restart(int divisions) {
+ fDivisions = divisions;
+ SkScalar h = 1.f / fDivisions;
+ fCurrent = 0;
+ fMax = fDivisions + 1;
+ fFwDiff[0] = fCoefs[3];
+ SkScalar h2 = h * h;
+ SkScalar h3 = h2 * h;
+
+ fFwDiff[3].set(6.f * fCoefs[0].x() * h3, 6.f * fCoefs[0].y() * h3); //6ah^3
+ fFwDiff[2].set(fFwDiff[3].x() + 2.f * fCoefs[1].x() * h2, //6ah^3 + 2bh^2
+ fFwDiff[3].y() + 2.f * fCoefs[1].y() * h2);
+ fFwDiff[1].set(fCoefs[0].x() * h3 + fCoefs[1].x() * h2 + fCoefs[2].x() * h,//ah^3 + bh^2 +ch
+ fCoefs[0].y() * h3 + fCoefs[1].y() * h2 + fCoefs[2].y() * h);
+ }
+
+ /**
+ * Check if the evaluator is still within the range of 0<=t<=1
+ */
+ bool done() const {
+ return fCurrent > fMax;
+ }
+
+ /**
+ * Call next to obtain the SkPoint sampled and move to the next one.
+ */
+ SkPoint next() {
+ SkPoint point = fFwDiff[0];
+ fFwDiff[0] += fFwDiff[1];
+ fFwDiff[1] += fFwDiff[2];
+ fFwDiff[2] += fFwDiff[3];
+ fCurrent++;
+ return point;
+ }
+
+ const SkPoint* getCtrlPoints() const {
+ return fPoints;
+ }
+
+private:
+ int fMax, fCurrent, fDivisions;
+ SkPoint fFwDiff[4], fCoefs[4], fPoints[4];
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+SkPatch::SkPatch(SkPoint points[12], SkColor colors[4]) {
+
+ for (int i = 0; i<12; i++) {
+ fCtrlPoints[i] = points[i];
+ }
+
+ fCornerColors[0] = SkPreMultiplyColor(colors[0]);
+ fCornerColors[1] = SkPreMultiplyColor(colors[1]);
+ fCornerColors[2] = SkPreMultiplyColor(colors[2]);
+ fCornerColors[3] = SkPreMultiplyColor(colors[3]);
+}
+
+uint8_t bilinear(SkScalar tx, SkScalar ty, SkScalar c00, SkScalar c10, SkScalar c01, SkScalar c11) {
+ SkScalar a = c00 * (1.f - tx) + c10 * tx;
+ SkScalar b = c01 * (1.f - tx) + c11 * tx;
+ return uint8_t(a * (1.f - ty) + b * ty);
+}
+
+bool SkPatch::getVertexData(SkPatch::VertexData* data, int divisions) {
+
+ if (divisions < 1) {
+ return false;
+ }
+
+ int divX = divisions, divY = divisions;
+
+ data->fVertexCount = (divX + 1) * (divY + 1);
+ data->fIndexCount = divX * divY * 6;
+
+ data->fPoints = SkNEW_ARRAY(SkPoint, data->fVertexCount);
+ data->fColors = SkNEW_ARRAY(uint32_t, data->fVertexCount);
+ data->fTexCoords = SkNEW_ARRAY(SkPoint, data->fVertexCount);
+ data->fIndices = SkNEW_ARRAY(uint16_t, data->fIndexCount);
+
+ FwDCubicEvaluator fBottom(fCtrlPoints[kBottomP0_CubicCtrlPts],
+ fCtrlPoints[kBottomP1_CubicCtrlPts],
+ fCtrlPoints[kBottomP2_CubicCtrlPts],
+ fCtrlPoints[kBottomP3_CubicCtrlPts]),
+ fTop(fCtrlPoints[kTopP0_CubicCtrlPts],
+ fCtrlPoints[kTopP1_CubicCtrlPts],
+ fCtrlPoints[kTopP2_CubicCtrlPts],
+ fCtrlPoints[kTopP2_CubicCtrlPts]),
+ fLeft(fCtrlPoints[kLeftP0_CubicCtrlPts],
+ fCtrlPoints[kLeftP1_CubicCtrlPts],
+ fCtrlPoints[kLeftP2_CubicCtrlPts],
+ fCtrlPoints[kLeftP3_CubicCtrlPts]),
+ fRight(fCtrlPoints[kRightP0_CubicCtrlPts],
+ fCtrlPoints[kRightP1_CubicCtrlPts],
+ fCtrlPoints[kRightP2_CubicCtrlPts],
+ fCtrlPoints[kRightP3_CubicCtrlPts]);
+
+ fBottom.restart(divX);
+ fTop.restart(divX);
+
+ SkScalar u = 0.0f;
+ int stride = divY + 1;
+ for (int x = 0; x <= divX; x++) {
+ SkPoint bottom = fBottom.next(), top = fTop.next();
+ fLeft.restart(divY);
+ fRight.restart(divY);
+ SkScalar v = 0.f;
+ for (int y = 0; y <= divY; y++) {
+ int dataIndex = x * (divX + 1) + y;
+
+ SkPoint left = fLeft.next(), right = fRight.next();
+
+ SkPoint s0 = SkPoint::Make((1.0f - v) * top.x() + v * bottom.x(),
+ (1.0f - v) * top.y() + v * bottom.y());
+ SkPoint s1 = SkPoint::Make((1.0f - u) * left.x() + u * right.x(),
+ (1.0f - u) * left.y() + u * right.y());
+ SkPoint s2 = SkPoint::Make(
+ (1.0f - v) * ((1.0f - u) * fTop.getCtrlPoints()[0].x()
+ + u * fTop.getCtrlPoints()[3].x())
+ + v * ((1.0f - u) * fBottom.getCtrlPoints()[0].x()
+ + u * fBottom.getCtrlPoints()[3].x()),
+ (1.0f - v) * ((1.0f - u) * fTop.getCtrlPoints()[0].y()
+ + u * fTop.getCtrlPoints()[3].y())
+ + v * ((1.0f - u) * fBottom.getCtrlPoints()[0].y()
+ + u * fBottom.getCtrlPoints()[3].y()));
+ data->fPoints[dataIndex] = s0 + s1 - s2;
+
+ uint8_t a = bilinear(u, v,
+ SkScalar(SkColorGetA(fCornerColors[0])),
+ SkScalar(SkColorGetA(fCornerColors[1])),
+ SkScalar(SkColorGetA(fCornerColors[2])),
+ SkScalar(SkColorGetA(fCornerColors[3])));
+ uint8_t r = bilinear(u, v,
+ SkScalar(SkColorGetR(fCornerColors[0])),
+ SkScalar(SkColorGetR(fCornerColors[1])),
+ SkScalar(SkColorGetR(fCornerColors[2])),
+ SkScalar(SkColorGetR(fCornerColors[3])));
+ uint8_t g = bilinear(u, v,
+ SkScalar(SkColorGetG(fCornerColors[0])),
+ SkScalar(SkColorGetG(fCornerColors[1])),
+ SkScalar(SkColorGetG(fCornerColors[2])),
+ SkScalar(SkColorGetG(fCornerColors[3])));
+ uint8_t b = bilinear(u, v,
+ SkScalar(SkColorGetB(fCornerColors[0])),
+ SkScalar(SkColorGetB(fCornerColors[1])),
+ SkScalar(SkColorGetB(fCornerColors[2])),
+ SkScalar(SkColorGetB(fCornerColors[3])));
+ data->fColors[dataIndex] = SkPackARGB32(a,r,g,b);
+
+ data->fTexCoords[dataIndex] = SkPoint::Make(u, v);
+
+ if(x < divX && y < divY) {
+ int i = 6 * (x * divY + y);
+ data->fIndices[i] = x * stride + y;
+ data->fIndices[i + 1] = x * stride + 1 + y;
+ data->fIndices[i + 2] = (x + 1) * stride + 1 + y;
+ data->fIndices[i + 3] = data->fIndices[i];
+ data->fIndices[i + 4] = data->fIndices[i + 2];
+ data->fIndices[i + 5] = (x + 1) * stride + y;
+ }
+ v += 1.f / divY;
+ }
+ u += 1.f / divX;
+ }
+ return true;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-10 08:03:38 +0000