Move gpu conic calculations to GrPathUtils
BUG=
R=bsalomon@google.com, jvanverth@google.com
Author: egdaniel@google.com
Review URL: https://chromiumcodereview.appspot.com/22865023
git-svn-id: http://skia.googlecode.com/svn/trunk/src@10832 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/GrAAHairLinePathRenderer.cpp b/gpu/GrAAHairLinePathRenderer.cpp
index 2b5f3cc..f8c47d8 100644
--- a/gpu/GrAAHairLinePathRenderer.cpp
+++ b/gpu/GrAAHairLinePathRenderer.cpp
@@ -600,72 +600,29 @@
}
}
-// Input:
-// Three control points: p[0], p[1], p[2] and weight: w
-// Output:
-// Let:
-// l = (2*w * (y1 - y0), 2*w * (x0 - x1), 2*w * (x1*y0 - x0*y1))
-// m = (2*w * (y2 - y1), 2*w * (x1 - x2), 2*w * (x2*y1 - x1*y2))
-// k = (y2 - y0, x0 - x2, (x2 - x0)*y0 - (y2 - y0)*x0 )
-void calc_conic_klm(const SkPoint p[3], const SkScalar weight,
- SkScalar k[3], SkScalar l[3], SkScalar m[3]) {
- const SkScalar w2 = 2 * weight;
- l[0] = w2 * (p[1].fY - p[0].fY);
- l[1] = w2 * (p[0].fX - p[1].fX);
- l[2] = w2 * (p[1].fX * p[0].fY - p[0].fX * p[1].fY);
-
- m[0] = w2 * (p[2].fY - p[1].fY);
- m[1] = w2 * (p[1].fX - p[2].fX);
- m[2] = w2 * (p[2].fX * p[1].fY - p[1].fX * p[2].fY);
-
- k[0] = p[2].fY - p[0].fY;
- k[1] = p[0].fX - p[2].fX;
- k[2] = (p[2].fX - p[0].fX) * p[0].fY - (p[2].fY - p[0].fY) * p[0].fX;
-
- // scale the max absolute value of coeffs to 10
- SkScalar scale = 0.0f;
- for (int i = 0; i < 3; ++i) {
- scale = SkMaxScalar(scale, SkScalarAbs(k[i]));
- scale = SkMaxScalar(scale, SkScalarAbs(l[i]));
- scale = SkMaxScalar(scale, SkScalarAbs(m[i]));
- }
- SkASSERT(scale > 0);
- scale /= 10.0f;
- k[0] /= scale;
- k[1] /= scale;
- k[2] /= scale;
- l[0] /= scale;
- l[1] /= scale;
- l[2] /= scale;
- m[0] /= scale;
- m[1] /= scale;
- m[2] /= scale;
-}
-
// Equations based off of Loop-Blinn Quadratic GPU Rendering
// Input Parametric:
// P(t) = (P0*(1-t)^2 + 2*w*P1*t*(1-t) + P2*t^2) / (1-t)^2 + 2*w*t*(1-t) + t^2)
// Output Implicit:
// f(x, y, w) = f(P) = K^2 - LM
// K = dot(k, P), L = dot(l, P), M = dot(m, P)
-// k, l, m are calculated in function calc_conic_klm
-void set_conic_coeffs(const SkPoint p[3], BezierVertex verts[kVertsPerQuad], const float weight) {
- SkScalar k[3];
- SkScalar l[3];
- SkScalar m[3];
+// k, l, m are calculated in function GrPathUtils::getConicKLM
+void set_conic_coeffs(const SkPoint p[3], BezierVertex verts[kVertsPerQuad],
+ const SkScalar weight) {
+ SkScalar klm[9];
- calc_conic_klm(p, weight, k, l, m);
+ GrPathUtils::getConicKLM(p, weight, klm);
for (int i = 0; i < kVertsPerQuad; ++i) {
const SkPoint pnt = verts[i].fPos;
- verts[i].fConic.fK = pnt.fX * k[0] + pnt.fY * k[1] + k[2];
- verts[i].fConic.fL = pnt.fX * l[0] + pnt.fY * l[1] + l[2];
- verts[i].fConic.fM = pnt.fX * m[0] + pnt.fY * m[1] + m[2];
+ verts[i].fConic.fK = pnt.fX * klm[0] + pnt.fY * klm[1] + klm[2];
+ verts[i].fConic.fL = pnt.fX * klm[3] + pnt.fY * klm[4] + klm[5];
+ verts[i].fConic.fM = pnt.fX * klm[6] + pnt.fY * klm[7] + klm[8];
}
}
void add_conics(const SkPoint p[3],
- float weight,
+ const SkScalar weight,
const SkMatrix* toDevice,
const SkMatrix* toSrc,
BezierVertex** vert,
diff --git a/gpu/GrPathUtils.cpp b/gpu/GrPathUtils.cpp
index ca87833..e354e41 100644
--- a/gpu/GrPathUtils.cpp
+++ b/gpu/GrPathUtils.cpp
@@ -275,6 +275,39 @@
}
}
+////////////////////////////////////////////////////////////////////////////////
+
+// k = (y2 - y0, x0 - x2, (x2 - x0)*y0 - (y2 - y0)*x0 )
+// l = (2*w * (y1 - y0), 2*w * (x0 - x1), 2*w * (x1*y0 - x0*y1))
+// m = (2*w * (y2 - y1), 2*w * (x1 - x2), 2*w * (x2*y1 - x1*y2))
+void GrPathUtils::getConicKLM(const SkPoint p[3], const SkScalar weight, SkScalar klm[9]) {
+ const SkScalar w2 = 2.f * weight;
+ klm[0] = p[2].fY - p[0].fY;
+ klm[1] = p[0].fX - p[2].fX;
+ klm[2] = (p[2].fX - p[0].fX) * p[0].fY - (p[2].fY - p[0].fY) * p[0].fX;
+
+ klm[3] = w2 * (p[1].fY - p[0].fY);
+ klm[4] = w2 * (p[0].fX - p[1].fX);
+ klm[5] = w2 * (p[1].fX * p[0].fY - p[0].fX * p[1].fY);
+
+ klm[6] = w2 * (p[2].fY - p[1].fY);
+ klm[7] = w2 * (p[1].fX - p[2].fX);
+ klm[8] = w2 * (p[2].fX * p[1].fY - p[1].fX * p[2].fY);
+
+ // scale the max absolute value of coeffs to 10
+ SkScalar scale = 0.f;
+ for (int i = 0; i < 9; ++i) {
+ scale = SkMaxScalar(scale, SkScalarAbs(klm[i]));
+ }
+ SkASSERT(scale > 0.f);
+ scale = 10.f / scale;
+ for (int i = 0; i < 9; ++i) {
+ klm[i] *= scale;
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
namespace {
// a is the first control point of the cubic.
diff --git a/gpu/GrPathUtils.h b/gpu/GrPathUtils.h
index dc4ecd9..71f6e0b 100644
--- a/gpu/GrPathUtils.h
+++ b/gpu/GrPathUtils.h
@@ -97,6 +97,15 @@
float fM[6];
};
+ // Input is 3 control points and a weight for a bezier conic. Calculates the
+ // three linear functionals (K,L,M) that represent the implicit equation of the
+ // conic, K^2 - LM.
+ //
+ // Output:
+ // K = (klm[0], klm[1], klm[2])
+ // L = (klm[3], klm[4], klm[5])
+ // M = (klm[6], klm[7], klm[8])
+ void getConicKLM(const SkPoint p[3], const SkScalar weight, SkScalar klm[9]);
// Converts a cubic into a sequence of quads. If working in device space
// use tolScale = 1, otherwise set based on stretchiness of the matrix. The
