Reworked gradient shader to no longer explicitly set gl_FragColor or return prematurely.
This should fix failing linux buildbot, and should play nicer with programs that don't use the gl_FragColor global, or that have multiple stages.
Also disabled debug printing from revision 4445.
Review URL: https://codereview.appspot.com/6345063
git-svn-id: http://skia.googlecode.com/svn/trunk@4454 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/effects/GrGradientEffects.cpp b/src/gpu/effects/GrGradientEffects.cpp
index f9fd4d2..c62de45 100644
--- a/src/gpu/effects/GrGradientEffects.cpp
+++ b/src/gpu/effects/GrGradientEffects.cpp
@@ -475,6 +475,10 @@
p3.c_str(), p5.c_str());
}
+ // output will default to transparent black (we simply won't write anything
+ // else to it if invalid, instead of discarding or returning prematurely)
+ code->appendf("\t%s = vec4(0.0,0.0,0.0,0.0);\n", outputColor);
+
// c = (x^2)+(y^2) - params[4]
code->appendf("\tfloat %s = dot(%s, %s) - %s;\n", cName.c_str(),
state->fSampleCoords.c_str(), state->fSampleCoords.c_str(),
@@ -491,43 +495,58 @@
code->appendf("\tfloat %s = %s * %s - %s;\n", dName.c_str(),
bVar.c_str(), bVar.c_str(), ac4Name.c_str());
- // if discriminant is < 0, set to transparent black and return
- code->appendf("\tif (%s < 0.0) {\n\t\tgl_FragColor = vec4(0.0,0.0,0.0,"
- "0.0);\n\t\treturn;\n\t}\n", dName.c_str());
+ // only proceed if discriminant is >= 0
+ code->appendf("\tif (%s >= 0.0) {\n", dName.c_str());
// intermediate value we'll use to compute the roots
// q = -0.5 * (b +/- sqrt(d))
- code->appendf("\tfloat %s = -0.5 * (%s + (%s < 0.0 ? -1.0 : 1.0)"
+ code->appendf("\t\tfloat %s = -0.5 * (%s + (%s < 0.0 ? -1.0 : 1.0)"
" * sqrt(%s));\n", qName.c_str(), bVar.c_str(),
bVar.c_str(), dName.c_str());
// compute both roots
// r0 = q * params[1]
- code->appendf("\tfloat %s = %s * %s;\n", r0Name.c_str(), qName.c_str(),
- p1.c_str());
+ code->appendf("\t\tfloat %s = %s * %s;\n", r0Name.c_str(),
+ qName.c_str(), p1.c_str());
// r1 = c / q
- code->appendf("\tfloat %s = %s / %s;\n", r1Name.c_str(), cName.c_str(),
- qName.c_str());
+ code->appendf("\t\tfloat %s = %s / %s;\n", r1Name.c_str(),
+ cName.c_str(), qName.c_str());
// Note: If there are two roots that both generate radius(t) > 0, the
// Canvas spec says to choose the larger t.
// so we'll look at the larger one first:
- code->appendf("\tfloat %s = max(%s, %s);\n", tName.c_str(),
+ code->appendf("\t\tfloat %s = max(%s, %s);\n", tName.c_str(),
r0Name.c_str(), r1Name.c_str());
- // if r(t) for the larger root is <= 0, try the other one
- code->appendf("\tif (%s * %s + %s <= 0.0) {\n", tName.c_str(),
+ // if r(t) > 0, then we're done; t will be our x coordinate
+ code->appendf("\t\tif (%s * %s + %s > 0.0) {\n", tName.c_str(),
p5.c_str(), p3.c_str());
- code->appendf("\t\t%s = min(%s, %s);\n", tName.c_str(),
+
+ // y coord is 0.5 (texture is effectively 1D)
+ code->appendf("\t\t");
+ state->fSampleCoords.printf("vec2(%s, 0.5)", tName.c_str());
+ state->emitDefaultFetch(outputColor, samplerName);
+
+ // otherwise, if r(t) for the larger root was <= 0, try the other root
+ code->appendf("\t\t} else {\n");
+ code->appendf("\t\t\t%s = min(%s, %s);\n", tName.c_str(),
r0Name.c_str(), r1Name.c_str());
- // if r(t) for the smaller root is also <= 0, set the fragment to
- // transparent black and return
- code->appendf("\t\tif (%s * %s + %s <= 0.0) {\n\t\t\tgl_FragColor = "
- "vec4(0.0,0.0,0.0,0.0);\n\t\t\treturn;\n\t\t}\n",
+ // if r(t) > 0 for the smaller root, then t will be our x coordinate
+ code->appendf("\t\t\tif (%s * %s + %s > 0.0) {\n",
tName.c_str(), p5.c_str(), p3.c_str());
-
+
+ // y coord is 0.5 (texture is effectively 1D)
+ code->appendf("\t\t\t");
+ state->fSampleCoords.printf("vec2(%s, 0.5)", tName.c_str());
+ state->emitDefaultFetch(outputColor, samplerName);
+
+ // end if (r(t) > 0) for smaller root
+ code->appendf("\t\t\t}\n");
+ // end if (r(t) > 0), else, for larger root
+ code->appendf("\t\t}\n");
+ // end if (discriminant >= 0)
code->appendf("\t}\n");
} else {
@@ -535,18 +554,15 @@
code->appendf("\tfloat %s = -(%s / %s);\n", tName.c_str(),
cName.c_str(), bVar.c_str());
- // set the fragment to transparent black and return if r(t) is <= 0
- code->appendf("\tif (%s * %s + %s <= 0.0) {\n\t\tgl_FragColor = vec4("
- "0.0,0.0,0.0,0.0);\n\t\treturn;\n\t}\n", tName.c_str(),
+ // if r(t) > 0, then t will be the x coordinate
+ code->appendf("\tif (%s * %s + %s > 0.0) {\n", tName.c_str(),
p5.c_str(), p3.c_str());
+ code->appendf("\t");
+ state->fSampleCoords.printf("vec2(%s, 0.5)", tName.c_str());
+ state->emitDefaultFetch(outputColor, samplerName);
+ code->appendf("\t}\n");
}
state->fComplexCoord = true;
-
- // x coord is: t
- // y coord is 0.5 (texture is effectively 1D)
- state->fSampleCoords.printf("\tvec2(%s, 0.5)", tName.c_str());
-
- state->emitDefaultFetch(outputColor, samplerName);
}
void GrGLConical2Gradient::initUniforms(const GrGLInterface* gl, int programID) {