Modified: trunk/Source/WebCore/ChangeLog (137393 => 137394)
--- trunk/Source/WebCore/ChangeLog 2012-12-12 01:15:00 UTC (rev 137393)
+++ trunk/Source/WebCore/ChangeLog 2012-12-12 01:18:12 UTC (rev 137394)
@@ -1,3 +1,19 @@
+2012-12-11 No'am Rosenthal <[email protected]>
+
+ [Texmap] Slightly improve readability of the antialias shader
+ https://bugs.webkit.org/show_bug.cgi?id=104708
+
+ Reviewed by Martin Robinson.
+
+ Modify the antialiasing shader to include separate function that perform
+ discrete operations, rather than one big function that repeats the same
+ operations.
+
+ No new tests, readability fix.
+
+ * platform/graphics/texmap/TextureMapperShaderManager.cpp:
+ (WebCore::getShaderSpec):
+
2012-12-11 Tim Horton <[email protected]>
-webkit-svg-shadow radius changes don't cause children's boundaries to be recomputed
Modified: trunk/Source/WebCore/platform/graphics/texmap/TextureMapperShaderManager.cpp (137393 => 137394)
--- trunk/Source/WebCore/platform/graphics/texmap/TextureMapperShaderManager.cpp 2012-12-12 01:15:00 UTC (rev 137393)
+++ trunk/Source/WebCore/platform/graphics/texmap/TextureMapperShaderManager.cpp 2012-12-12 01:18:12 UTC (rev 137394)
@@ -188,36 +188,54 @@
varying highp vec2 v_sourceTexCoord;
uniform lowp float u_opacity;
uniform vec3 u_expandedQuadEdgesInScreenSpace[8];
- void main()
- {
- vec4 sampledColor = texture2D(s_sampler, clamp(v_sourceTexCoord, 0.0, 1.0));
- vec3 pos = vec3(gl_FragCoord.xy, 1);
// The data passed in u_expandedQuadEdgesInScreenSpace is merely the
// pre-scaled coeffecients of the line equations describing the four edges
// of the expanded quad in screen space and the rectangular bounding box
// of the expanded quad.
//
+ float normalizedDistance(vec3 edgeCoefficient)
+ {
// We are doing a simple distance calculation here according to the formula:
// (A*p.x + B*p.y + C) / sqrt(A^2 + B^2) = distance from line to p
// Note that A, B and C have already been scaled by 1 / sqrt(A^2 + B^2).
- float a0 = clamp(dot(u_expandedQuadEdgesInScreenSpace[0], pos), 0.0, 1.0);
- float a1 = clamp(dot(u_expandedQuadEdgesInScreenSpace[1], pos), 0.0, 1.0);
- float a2 = clamp(dot(u_expandedQuadEdgesInScreenSpace[2], pos), 0.0, 1.0);
- float a3 = clamp(dot(u_expandedQuadEdgesInScreenSpace[3], pos), 0.0, 1.0);
- float a4 = clamp(dot(u_expandedQuadEdgesInScreenSpace[4], pos), 0.0, 1.0);
- float a5 = clamp(dot(u_expandedQuadEdgesInScreenSpace[5], pos), 0.0, 1.0);
- float a6 = clamp(dot(u_expandedQuadEdgesInScreenSpace[6], pos), 0.0, 1.0);
- float a7 = clamp(dot(u_expandedQuadEdgesInScreenSpace[7], pos), 0.0, 1.0);
+ return clamp(dot(edgeCoefficient, vec3(gl_FragCoord.xy, 1.)), 0., 1.);
+ }
+ float antialiasQuad(vec3 coefficient1, vec3 coefficient2, vec3 coefficient3, vec3 coefficient4)
+ {
// Now we want to reduce the alpha value of the fragment if it is close to the
// edges of the expanded quad (or rectangular bounding box -- which seems to be
// important for backfacing quads). Note that we are combining the contribution
// from the (top || bottom) and (left || right) edge by simply multiplying. This follows
// the approach described at: http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter22.html,
// in this case without using Gaussian weights.
- gl_FragColor = sampledColor * u_opacity * min(min(a0, a2) * min(a1, a3), min(a4, a6) * min(a5, a7));
+ return min(normalizedDistance(coefficient1), normalizedDistance(coefficient2))
+ * min(normalizedDistance(coefficient3), normalizedDistance(coefficient4));
}
+
+ float antialias()
+ {
+ float antialiasValueForQuad =
+ antialiasQuad(u_expandedQuadEdgesInScreenSpace[0],
+ u_expandedQuadEdgesInScreenSpace[1],
+ u_expandedQuadEdgesInScreenSpace[2],
+ u_expandedQuadEdgesInScreenSpace[3]);
+
+ float antialiasValueForBoundingRect =
+ antialiasQuad(u_expandedQuadEdgesInScreenSpace[4],
+ u_expandedQuadEdgesInScreenSpace[5],
+ u_expandedQuadEdgesInScreenSpace[6],
+ u_expandedQuadEdgesInScreenSpace[7]);
+
+ return min(antialiasValueForQuad, antialiasValueForBoundingRect);
+ }
+
+ void main()
+ {
+ vec4 sampledColor = texture2D(s_sampler, clamp(v_sourceTexCoord, 0.0, 1.0));
+ gl_FragColor = sampledColor * u_opacity * antialias();
+ }
);
static const char* fragmentRectSimple =
