commit 3722d3195be5ddba7f3d44095565628dbe65452b
author Chris Dalton <csmartdalton@google.com> Wed Jun 23 17:52:09 2021 -0600
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Thu Jun 24 16:04:19 2021 +0000
tree fcf17adb729e6538de6ab51bcfe5db2abc5d35b1
parent c5a65cb22d362f917777db09f1eac15ab29fa018

Remove all instances of incorrect coverage with DMSAA

Here we pivot and handle DMSAA differently depending on platform:

1) Desktop GL and EXT_multisample_compatibility: Here it's easy to use
   all our existing coverage ops because we can just call
   glDisable(GL_MULTISAMPLE). So we only trigger MSAA for paths and
   use the coverage ops for everything else with MSAA disabled.

2) EXT_multisampled_render_to_to_texture (86% adoption on Android):
   The assumption here is that MSAA is almost free. So we just allow
   MSAA to be triggered often and don't worry about it.

Devices that neither support #1 nor #2 just don't get DMSAA for now.

Bug: skia:11396
Change-Id: I53ad840216ea6d88ae69eece6f7a062f9e82dad7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/421019
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

src/gpu/GrSurfaceDrawContext.cpp

diff --git a/src/gpu/GrSurfaceDrawContext.cpp b/src/gpu/GrSurfaceDrawContext.cpp
index 7dd213b..2240135 100644
--- a/src/gpu/GrSurfaceDrawContext.cpp
+++ b/src/gpu/GrSurfaceDrawContext.cpp
@@ -297,10 +297,10 @@
 }
 
 inline GrAAType GrSurfaceDrawContext::chooseAAType(GrAA aa) {
-    if (fCanUseDynamicMSAA) {
-        // Trigger dmsaa by default if the render target has it. Coverage ops that know how to
-        // handle both single and multisample targets without popping will do so without calling
-        // chooseAAType.
+    if (fCanUseDynamicMSAA && !this->caps()->multisampleDisableSupport()) {
+        // Trigger dmsaa by default if we have it and we can't disable multisample. The few coverage
+        // ops we have that know how to handle both single and multisample targets without popping
+        // will do so without calling chooseAAType.
         return GrAAType::kMSAA;
     }
     if (GrAA::kNo == aa) {
@@ -730,7 +730,7 @@
                !this->caps()->reducedShaderMode()) {
         // Only use the StrokeRectOp for non-empty rectangles. Empty rectangles will be processed by
         // GrStyledShape to handle stroke caps and dashing properly.
-        GrAAType aaType = (fCanUseDynamicMSAA) ? GrAAType::kCoverage : this->chooseAAType(aa);
+        GrAAType aaType = this->chooseAAType(aa);
         GrOp::Owner op = GrStrokeRectOp::Make(
                 fContext, std::move(paint), aaType, viewMatrix, rect, stroke);
         // op may be null if the stroke is not supported or if using coverage aa and the view matrix
@@ -1070,7 +1070,7 @@
         op = GrFillRRectOp::Make(fContext, std::move(paint), viewMatrix, rrect, rrect.rect(),
                                  GrAA(aaType != GrAAType::kNone));
     }
-    if (!op && (GrAAType::kCoverage == aaType || fCanUseDynamicMSAA)) {
+    if (!op && GrAAType::kCoverage == aaType) {
         assert_alive(paint);
         op = GrOvalOpFactory::MakeRRectOp(
                 fContext, std::move(paint), viewMatrix, rrect, stroke, this->caps()->shaderCaps());
@@ -1383,7 +1383,7 @@
         op = GrFillRRectOp::Make(fContext, std::move(paint), viewMatrix, SkRRect::MakeOval(oval),
                                  oval, GrAA(aaType != GrAAType::kNone));
     }
-    if (!op && (GrAAType::kCoverage == aaType || fCanUseDynamicMSAA)) {
+    if (!op && GrAAType::kCoverage == aaType) {
         assert_alive(paint);
         op = GrOvalOpFactory::MakeOvalOp(fContext, std::move(paint), viewMatrix, oval, style,
                                          this->caps()->shaderCaps());
@@ -1416,7 +1416,7 @@
     AutoCheckFlush acf(this->drawingManager());
 
     GrAAType aaType = this->chooseAAType(aa);
-    if (GrAAType::kCoverage == aaType || fCanUseDynamicMSAA) {
+    if (GrAAType::kCoverage == aaType) {
         const GrShaderCaps* shaderCaps = this->caps()->shaderCaps();
         GrOp::Owner op = GrOvalOpFactory::MakeArcOp(fContext,
                                                     std::move(paint),