From 75975510f3bf5b1bfcf70a7f40695613bff0282e Mon Sep 17 00:00:00 2001
From: Brian Salomon <bsalomon@google.com>
Date: Tue, 2 Oct 2018 12:21:38 -0400
Subject: [PATCH] On ES2 + EXT_color_buffer_half_float cannot render to
 GL_R16F.

This extension only allows rendering to:

        <internalformat> = RGBA
        <format> = RGBA
        <type> = HALF_FLOAT_OES

BUG=angleproject:2567

Change-Id: I6a85544a1d2f9b95567466330f874fd4265f047c
Reviewed-on: https://skia-review.googlesource.com/158820
Reviewed-by: Yuly Novikov <ynovikov@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
---
 src/gpu/gl/GrGLCaps.cpp | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 5bc07e4c3d..73bdffd906 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -1756,7 +1756,8 @@ void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
     bool hasFP16Textures = false;
     bool rgIsTexturable = false;
     bool hasFP32RenderTargets = false;
-    bool hasFP16RenderTargets = false;
+    enum class HalfFPRenderTargetSupport { kNone, kRGBAOnly, kAll };
+    HalfFPRenderTargetSupport halfFPRenderTargetSupport = HalfFPRenderTargetSupport::kNone;
     // for now we don't support floating point MSAA on ES
     uint32_t fpRenderFlags = (kGL_GrGLStandard == standard) ? allRenderFlags : nonMSAARenderFlags;
 
@@ -1766,7 +1767,7 @@ void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
             hasFP16Textures = true;
             rgIsTexturable = true;
             hasFP32RenderTargets = true;
-            hasFP16RenderTargets = true;
+            halfFPRenderTargetSupport = HalfFPRenderTargetSupport::kAll;
         }
     } else {
         if (version >= GR_GL_VER(3, 0)) {
@@ -1786,14 +1787,15 @@ void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
             // For now we only enable rendering to fp32 on desktop, because on ES we'd have to solve
             // many precision issues and no clients actually want this yet.
             // hasFP32RenderTargets = true;
-            hasFP16RenderTargets = true;
+            halfFPRenderTargetSupport = HalfFPRenderTargetSupport::kAll;
         } else if (ctxInfo.hasExtension("GL_EXT_color_buffer_float")) {
             // For now we only enable rendering to fp32 on desktop, because on ES we'd have to
             // solve many precision issues and no clients actually want this yet.
             // hasFP32RenderTargets = true;
-            hasFP16RenderTargets = true;
+            halfFPRenderTargetSupport = HalfFPRenderTargetSupport::kAll;
         } else if (ctxInfo.hasExtension("GL_EXT_color_buffer_half_float")) {
-            hasFP16RenderTargets = true;
+            // This extension only enables half float support rendering for RGBA.
+            halfFPRenderTargetSupport = HalfFPRenderTargetSupport::kRGBAOnly;
         }
     }
 
@@ -1833,7 +1835,7 @@ void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
     if (textureRedSupport && hasFP16Textures) {
         redHalf.fFlags = ConfigInfo::kTextureable_Flag;
 
-        if (hasFP16RenderTargets) {
+        if (halfFPRenderTargetSupport == HalfFPRenderTargetSupport::kAll) {
             redHalf.fFlags |= fpRenderFlags;
         }
 
@@ -1856,7 +1858,7 @@ void GrGLCaps::initConfigTable(const GrContextOptions& contextOptions,
     if (hasFP16Textures) {
         fConfigTable[kRGBA_half_GrPixelConfig].fFlags = ConfigInfo::kTextureable_Flag;
         // ES requires 3.2 or EXT_color_buffer_half_float.
-        if (hasFP16RenderTargets) {
+        if (halfFPRenderTargetSupport != HalfFPRenderTargetSupport::kNone) {
             fConfigTable[kRGBA_half_GrPixelConfig].fFlags |= fpRenderFlags;
         }
     }