Change general fill rect shader code to match geometry vers
-Matches shader implemented for alligned rects
-Uses multiplication instead of min (used in geom version)
to combine width and height coverages
R=bsalomon@google.com, robertphillips@google.com
Review URL: https://codereview.chromium.org/17035012
git-svn-id: http://skia.googlecode.com/svn/trunk@9626 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrAARectRenderer.cpp b/src/gpu/GrAARectRenderer.cpp
index df4e32a..97fe626 100644
--- a/src/gpu/GrAARectRenderer.cpp
+++ b/src/gpu/GrAARectRenderer.cpp
@@ -78,9 +78,9 @@
"\tfloat coverage = scaleW*clamp((%s.z-abs(%s.x))/spanW, 0.0, 1.0);\n", fsRectName,
fsRectName);
// Compute the coverage for the rect's height and merge with the width
- builder->fsCodeAppendf(
- "\tcoverage = coverage*scaleH*clamp((%s.w-abs(%s.y))/spanH, 0.0, 1.0);\n",
- fsRectName, fsRectName);
+ builder->fsCodeAppendf(
+ "\tcoverage = coverage*scaleH*clamp((%s.w-abs(%s.y))/spanH, 0.0, 1.0);\n",
+ fsRectName, fsRectName);
SkString modulate;
GrGLSLModulatef<4>(&modulate, inputColor, "coverage");
@@ -184,26 +184,34 @@
builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[1]);
builder->vsCodeAppendf("\t%s = %s;\n", vsWidthHeightName, attr1Name->c_str());
- // TODO: compute these scale factors in the VS
- // These scale factors adjust the coverage for < 1 pixel wide/high rects
- builder->fsCodeAppendf("\tfloat wScale = max(1.0, 2.0/(0.5+%s.x));\n",
- fsWidthHeightName);
- builder->fsCodeAppendf("\tfloat hScale = max(1.0, 2.0/(0.5+%s.y));\n",
- fsWidthHeightName);
+ // TODO: compute all these offsets, spans, and scales in the VS
+ builder->fsCodeAppendf("\tfloat insetW = min(1.0, %s.x) - 0.5;\n", fsWidthHeightName);
+ builder->fsCodeAppendf("\tfloat insetH = min(1.0, %s.y) - 0.5;\n", fsWidthHeightName);
+ builder->fsCodeAppend("\tfloat outset = 0.5;\n");
+ // For rects > 1 pixel wide and tall the span's are noops (i.e., 1.0). For rects
+ // < 1 pixel wide or tall they serve to normalize the < 1 ramp to a 0 .. 1 range.
+ builder->fsCodeAppend("\tfloat spanW = insetW + outset;\n");
+ builder->fsCodeAppend("\tfloat spanH = insetH + outset;\n");
+ // For rects < 1 pixel wide or tall, these scale factors are used to cap the maximum
+ // value of coverage that is used. In other words it is the coverage that is
+ // used in the interior of the rect after the ramp.
+ builder->fsCodeAppend("\tfloat scaleW = min(1.0, 2.0*insetW/spanW);\n");
+ builder->fsCodeAppend("\tfloat scaleH = min(1.0, 2.0*insetH/spanH);\n");
// Compute the coverage for the rect's width
builder->fsCodeAppendf("\tvec2 offset = %s.xy - %s.xy;\n",
builder->fragmentPosition(), fsRectEdgeName);
builder->fsCodeAppendf("\tfloat perpDot = abs(offset.x * %s.w - offset.y * %s.z);\n",
fsRectEdgeName, fsRectEdgeName);
- builder->fsCodeAppendf("\tfloat coverage = clamp(wScale*(%s.x-perpDot), 0.0, 1.0);\n",
- fsWidthHeightName);
+ builder->fsCodeAppendf(
+ "\tfloat coverage = scaleW*clamp((%s.x-perpDot)/spanW, 0.0, 1.0);\n",
+ fsWidthHeightName);
// Compute the coverage for the rect's height and merge with the width
builder->fsCodeAppendf("\tperpDot = abs(dot(offset, %s.zw));\n",
fsRectEdgeName);
builder->fsCodeAppendf(
- "\tcoverage = min(coverage, clamp(hScale*(%s.y-perpDot), 0.0, 1.0));\n",
+ "\tcoverage = coverage*scaleH*clamp((%s.y-perpDot)/spanH, 0.0, 1.0);\n",
fsWidthHeightName);
SkString modulate;