From f6b070da5e337d13bd08ca488a0140d8facef8b8 Mon Sep 17 00:00:00 2001
From: "bsalomon@google.com"
 <bsalomon@google.com@2bbb7eff-a529-9590-31e7-b0007b416f81>
Date: Fri, 27 Apr 2012 14:25:44 +0000
Subject: [PATCH] Clamp requested MSAA sample count to GL_MAX_SAMPLES

Review URL: http://codereview.appspot.com/6135044/



git-svn-id: http://skia.googlecode.com/svn/trunk@3777 2bbb7eff-a529-9590-31e7-b0007b416f81
---
 src/gpu/gl/GrGLCaps.cpp | 7 +++++++
 src/gpu/gl/GrGLCaps.h   | 6 ++++++
 src/gpu/gl/GrGpuGL.cpp  | 2 ++
 3 files changed, 15 insertions(+)

diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index c7e9380c00..797abb4d80 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -20,6 +20,7 @@ void GrGLCaps::reset() {
     fStencilFormats.reset();
     fStencilVerifiedColorConfigs.reset();
     fMSFBOType = kNone_MSFBOType;
+    fMaxSampleCount = 0;
     fCoverageAAType = kNone_CoverageAAType;
     fMaxFragmentUniformVectors = 0;
     fRGBA8RenderbufferSupport = false;
@@ -45,6 +46,7 @@ GrGLCaps& GrGLCaps::operator = (const GrGLCaps& caps) {
     fStencilVerifiedColorConfigs = caps.fStencilVerifiedColorConfigs;
     fMaxFragmentUniformVectors = caps.fMaxFragmentUniformVectors;
     fMSFBOType = caps.fMSFBOType;
+    fMaxSampleCount = caps.fMaxSampleCount;
     fCoverageAAType = caps.fCoverageAAType;
     fMSAACoverageModes = caps.fMSAACoverageModes;
     fRGBA8RenderbufferSupport = caps.fRGBA8RenderbufferSupport;
@@ -206,6 +208,11 @@ void GrGLCaps::initFSAASupport(const GrGLContextInfo& ctxInfo) {
                     compareProc);
         }
     }
+    if (kNone_MSFBOType != fMSFBOType) {
+        GR_GL_GetIntegerv(ctxInfo.interface(),
+                          GR_GL_MAX_SAMPLES,
+                          &fMaxSampleCount);
+    }
 }
 
 const GrGLCaps::MSAACoverageMode& GrGLCaps::getMSAACoverageMode(
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 31c4392a10..eb095765c6 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -136,6 +136,11 @@ public:
      */
     MSFBOType msFBOType() const { return fMSFBOType; }
 
+    /**
+     * Reports the maximum number of samples supported.
+     */
+    int maxSampleCount() const { return fMaxSampleCount; }
+    
     /**
      * Reports the type of coverage sample AA support.
      */
@@ -257,6 +262,7 @@ private:
 
     int fMaxFragmentUniformVectors;
     MSFBOType fMSFBOType;
+    int fMaxSampleCount;
     CoverageAAType fCoverageAAType;
     SkTDArray<MSAACoverageMode> fMSAACoverageModes;
 
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index a9b345bdba..9abd01c966 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -866,6 +866,8 @@ bool renderbuffer_storage_msaa(GrGLContextInfo& ctxInfo,
         created = (GR_GL_NO_ERROR == CHECK_ALLOC_ERROR(ctxInfo.interface()));
     }
     if (!created) {
+        // glRBMS will fail if requested samples is > max samples.
+        sampleCount = GrMin(sampleCount, ctxInfo.caps().maxSampleCount());
         GL_ALLOC_CALL(ctxInfo.interface(),
                       RenderbufferStorageMultisample(GR_GL_RENDERBUFFER,
                                                      sampleCount,