Add a GL cap for instanced rendering to floating point

We have observed on OS X that instanced draws don't always behave
correctly when the framebuffer is floating point.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2095183002

Review-Url: https://codereview.chromium.org/2095183002

2 files changed, 14 insertions, 0 deletions

diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 9dd0fbe36e..431390697b 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -40,6 +40,7 @@ GrGLCaps::GrGLCaps(const GrContextOptions& contextOptions,
     fDrawIndirectSupport = false;
     fMultiDrawIndirectSupport = false;
     fBaseInstanceSupport = false;
+    fCanDrawIndirectToFloat = false;
     fUseNonVBOVertexAndIndexDynamicData = false;
     fIsCoreProfile = false;
     fBindFragDataLocationSupport = false;
@@ -530,6 +531,14 @@ void GrGLCaps::init(const GrContextOptions& contextOptions,
         fBaseInstanceSupport = ctxInfo.hasExtension("GL_EXT_base_instance");
     }
 
+    // OS X doesn't seem to write correctly to floating point textures when using glDraw*Indirect,
+    // regardless of the underlying GPU.
+#ifndef SK_BUILD_FOR_MAC
+    if (fDrawIndirectSupport) {
+        fCanDrawIndirectToFloat = true;
+    }
+#endif
+
     this->initShaderPrecisionTable(ctxInfo, gli, glslCaps);
 
     if (contextOptions.fUseShaderSwizzling) {
@@ -1112,6 +1121,7 @@ SkString GrGLCaps::dump() const {
     r.appendf("Draw indirect support: %s\n", (fDrawIndirectSupport ? "YES" : "NO"));
     r.appendf("Multi draw indirect support: %s\n", (fMultiDrawIndirectSupport ? "YES" : "NO"));
     r.appendf("Base instance support: %s\n", (fBaseInstanceSupport ? "YES" : "NO"));
+    r.appendf("Can draw indirect to float: %s\n", (fCanDrawIndirectToFloat ? "YES" : "NO"));
     r.appendf("Use non-VBO for dynamic data: %s\n",
              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
     r.appendf("RGBA 8888 pixel ops are slow: %s\n", (fRGBA8888PixelsOpsAreSlow ? "YES" : "NO"));
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 0cb353aa9f..1ccdf3e79c 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -307,6 +307,9 @@ public:
     /// Are the baseInstance fields supported in indirect draw commands?
     bool baseInstanceSupport() const { return fBaseInstanceSupport; }
 
+    /// Does the platform have known issuses rendering to floating point when using glDraw*Indirect?
+    bool canDrawIndirectToFloat() const { return fCanDrawIndirectToFloat; }
+
     /// Use indices or vertices in CPU arrays rather than VBOs for dynamic content.
     bool useNonVBOVertexAndIndexDynamicData() const { return fUseNonVBOVertexAndIndexDynamicData; }
 
@@ -398,6 +401,7 @@ private:
     bool fDrawIndirectSupport : 1;
     bool fMultiDrawIndirectSupport : 1;
     bool fBaseInstanceSupport : 1;
+    bool fCanDrawIndirectToFloat : 1;
     bool fUseNonVBOVertexAndIndexDynamicData : 1;
     bool fIsCoreProfile : 1;
     bool fBindFragDataLocationSupport : 1;