Redefine the meaning of sample counts in GPU backend.

Old: 0  -> nonMSAA
     1+ -> MSAA

New:
     0  -> error/unsupported
     1  -> nonMSAA
     2+ -> MSAA

We still allow 0 to mean nonMSAA in three sets of public APIs for backwards compatibility:

1) SkSurface factories
2) GrBackendRenderTarget constructors
3) GrCaps::getSampleCnt()'s requestedCount parameter

However, we immediately clamp to 1 and treat 0 as invalid/non-renderable internally.

This also changes the behavior when using a large sample count. We now fail in that case rather than using the largest sample available sample count. GrCaps::getSampleCount() will return 0 in this case.


Bug: skia:
Change-Id: Ida22c6b22c1365e563c9046b611e88bf5eb3ff33
Reviewed-on: https://skia-review.googlesource.com/101560
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/PathRendererCacheTests.cpp b/tests/PathRendererCacheTests.cpp
index 15b1faa4ba..19197b0d5f 100644
--- a/tests/PathRendererCacheTests.cpp
+++ b/tests/PathRendererCacheTests.cpp
@@ -80,8 +80,8 @@ static void test_path(skiatest::Reporter* reporter,
     GrResourceCache* cache = ctx->contextPriv().getResourceCache();
 
     sk_sp<GrRenderTargetContext> rtc(ctx->makeDeferredRenderTargetContext(
-            SkBackingFit::kApprox, 800, 800, kRGBA_8888_GrPixelConfig, nullptr, 0,
-            GrMipMapped::kNo, kTopLeft_GrSurfaceOrigin));
+            SkBackingFit::kApprox, 800, 800, kRGBA_8888_GrPixelConfig, nullptr, 1, GrMipMapped::kNo,
+            kTopLeft_GrSurfaceOrigin));
     if (!rtc) {
         return;
     }