Reland "Fix precision caps and rrect/ellipse effect precisions"

This is a reland of e42180022720f2fcfd3c634cad855506a7940591
Original change's description:
> Fix precision caps and rrect/ellipse effect precisions
>
> Replaces all the complex precision caps with a single flag that says
> whether "float" == fp32. Updates the ellipse and rrect effects to
> use float coords, and use the scale workaround when float != fp32.
>
> Bug: skia:7190
> Change-Id: Ieccff9f38acd05e5cec78fe90d01a5da901a9307
> Reviewed-on: https://skia-review.googlesource.com/70961
> Commit-Queue: Chris Dalton <csmartdalton@google.com>
> Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

TBR=bsalomon@google.com

Bug: skia:7190
Change-Id: I7ced37a64164b83d86f6a957c35e10ce9085aba0
Reviewed-on: https://skia-review.googlesource.com/72760
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>

1 files changed, 16 insertions, 17 deletions

diff --git a/src/gpu/effects/GrEllipseEffect.cpp b/src/gpu/effects/GrEllipseEffect.cpp
index 4a0f37665c..6b1a8cc59f 100644
--- a/src/gpu/effects/GrEllipseEffect.cpp
+++ b/src/gpu/effects/GrEllipseEffect.cpp
@@ -28,34 +28,33 @@ public:
         (void)center;
         auto radii = _outer.radii();
         (void)radii;
-        prevRadii = half2(-1.0);
-        useScale = sk_Caps.floatPrecisionVaries;
+        prevRadii = float2(-1.0);
+        useScale = !sk_Caps.floatIs32Bits;
         fEllipseVar = args.fUniformHandler->addUniform(kFragment_GrShaderFlag, kFloat4_GrSLType,
                                                        kDefault_GrSLPrecision, "ellipse");
         if (useScale) {
-            fScaleVar = args.fUniformHandler->addUniform(kFragment_GrShaderFlag, kHalf2_GrSLType,
+            fScaleVar = args.fUniformHandler->addUniform(kFragment_GrShaderFlag, kFloat2_GrSLType,
                                                          kDefault_GrSLPrecision, "scale");
         }
         fragBuilder->codeAppendf(
-                "half2 prevCenter;\nhalf2 prevRadii = half2(%f, %f);\nbool useScale = %s;\nhalf2 d "
-                "= half2(sk_FragCoord.xy - %s.xy);\n@if (useScale) {\n    d *= %s.y;\n}\nhalf2 Z = "
-                "d * half2(%s.zw);\nhalf implicit = dot(Z, d) - 1.0;\nhalf grad_dot = 4.0 * dot(Z, "
-                "Z);\ngrad_dot = half(max(float(grad_dot), 0.0001));\nhalf approx_dist = "
-                "float(implicit) * inversesqrt(float(grad_dot));\n@if (useScale) {\n    "
-                "approx_dist *= %s.x;\n}\nhalf alpha;\n@switch (%d) {\n    case 0:\n        alpha "
-                "= half(float(approx_dist) > 0.0 ? 0.0 : 1.",
+                "float2 prevCenter;\nfloat2 prevRadii = float2(%f, %f);\nbool useScale = "
+                "%s;\nfloat2 d = sk_FragCoord.xy - %s.xy;\n@if (useScale) {\n    d *= "
+                "%s.y;\n}\nfloat2 Z = d * %s.zw;\nfloat implicit = dot(Z, d) - 1.0;\nfloat "
+                "grad_dot = 4.0 * dot(Z, Z);\ngrad_dot = max(grad_dot, 0.0001);\nfloat approx_dist "
+                "= implicit * inversesqrt(grad_dot);\n@if (useScale) {\n    approx_dist *= "
+                "%s.x;\n}\nhalf alpha;\n@switch (%d) {\n    case 0:\n        alpha = "
+                "half(approx_dist > 0.0 ? 0.0 : 1.0);\n        break;\n    case 1:\n      ",
                 prevRadii.fX, prevRadii.fY, (useScale ? "true" : "false"),
                 args.fUniformHandler->getUniformCStr(fEllipseVar),
-                fScaleVar.isValid() ? args.fUniformHandler->getUniformCStr(fScaleVar) : "half2(0)",
+                fScaleVar.isValid() ? args.fUniformHandler->getUniformCStr(fScaleVar) : "float2(0)",
                 args.fUniformHandler->getUniformCStr(fEllipseVar),
-                fScaleVar.isValid() ? args.fUniformHandler->getUniformCStr(fScaleVar) : "half2(0)",
+                fScaleVar.isValid() ? args.fUniformHandler->getUniformCStr(fScaleVar) : "float2(0)",
                 (int)_outer.edgeType());
         fragBuilder->codeAppendf(
-                "0);\n        break;\n    case 1:\n        alpha = half(clamp(0.5 - "
-                "float(approx_dist), 0.0, 1.0));\n        break;\n    case 2:\n        alpha = "
-                "half(float(approx_dist) > 0.0 ? 1.0 : 0.0);\n        break;\n    case 3:\n        "
-                "alpha = half(clamp(0.5 + float(approx_dist), 0.0, 1.0));\n        break;\n    "
-                "default:\n        discard;\n}\n%s = %s * alpha;\n",
+                "  alpha = half(clamp(0.5 - approx_dist, 0.0, 1.0));\n        break;\n    case "
+                "2:\n        alpha = half(approx_dist > 0.0 ? 1.0 : 0.0);\n        break;\n    "
+                "case 3:\n        alpha = half(clamp(0.5 + approx_dist, 0.0, 1.0));\n        "
+                "break;\n    default:\n        discard;\n}\n%s = %s * alpha;\n",
                 args.fOutputColor, args.fInputColor ? args.fInputColor : "half4(1)");
     }