32 bpp floating point textures

This is VERY preliminary, but it was sufficient for me to get 32 bit floating point textures in a sample app

BUG=skia:
R=bsalomon@chromium.org, bsalomon@google.com

Author: joshualitt@chromium.org

Review URL: https://codereview.chromium.org/359803003

3 files changed, 26 insertions, 2 deletions

diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 8f2d4c1297..178550bd5c 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -444,6 +444,10 @@ void GrGLCaps::initConfigRenderableTable(const GrGLContextInfo& ctxInfo) {
         }
     }
 
+    if (this->isConfigTexturable(kRGBA_float_GrPixelConfig)) {
+        fConfigRenderSupport[kRGBA_float_GrPixelConfig][kNo_MSAA] = true;
+    }
+
     // If we don't support MSAA then undo any places above where we set a config as renderable with
     // msaa.
     if (kNone_MSFBOType == fMSFBOType) {
@@ -504,7 +508,7 @@ void GrGLCaps::initConfigTexturableTable(const GrGLContextInfo& ctxInfo, const G
     // First check version for support
     if (kGL_GrGLStandard == standard) {
         hasETC1 = hasCompressTex2D &&
-            (version >= GR_GL_VER(4, 3) || 
+            (version >= GR_GL_VER(4, 3) ||
              ctxInfo.hasExtension("GL_ARB_ES3_compatibility"));
     } else {
         hasETC1 = hasCompressTex2D &&
@@ -558,6 +562,19 @@ void GrGLCaps::initConfigTexturableTable(const GrGLContextInfo& ctxInfo, const G
     } else {
         fConfigTextureSupport[kR11_EAC_GrPixelConfig] = version >= GR_GL_VER(3, 0);
     }
+
+    // Check for floating point texture support
+    // NOTE: We disallow floating point textures on ES devices if linear
+    // filtering modes are not supported.  This is for simplicity, but a more
+    // granular approach is possible.  Coincidentally, floating point textures became part of
+    // the standard in ES3.1 / OGL 3.1, hence the shorthand
+    bool hasFPTextures = version >= GR_GL_VER(3, 1);
+    if (!hasFPTextures) {
+        hasFPTextures = ctxInfo.hasExtension("GL_ARB_texture_float") ||
+                        (ctxInfo.hasExtension("OES_texture_float_linear") &&
+                         ctxInfo.hasExtension("GL_OES_texture_float"));
+    }
+    fConfigTextureSupport[kRGBA_float_GrPixelConfig] = hasFPTextures;
 }
 
 bool GrGLCaps::readPixelsSupported(const GrGLInterface* intf,
diff --git a/src/gpu/gl/GrGLDefines.h b/src/gpu/gl/GrGLDefines.h
index 1e8d7cc278..77b7a15366 100644
--- a/src/gpu/gl/GrGLDefines.h
+++ b/src/gpu/gl/GrGLDefines.h
@@ -731,6 +731,7 @@
 #define GR_GL_RGB5_A1                        0x8057
 #define GR_GL_RGB565                         0x8D62
 #define GR_GL_RGBA8                          0x8058
+#define GR_GL_RGBA32F                        0x8814
 #define GR_GL_RGB8                           0x8051
 #define GR_GL_BGRA8                          0x93A1
 #define GR_GL_SRGB                           0x8C40
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index eddccc39f6..b66feb27c0 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -639,7 +639,8 @@ bool GrGpuGL::uploadTexData(const GrGLTexture::Desc& desc,
         if (glFlipY) {
             GL_CALL(PixelStorei(GR_GL_UNPACK_FLIP_Y, GR_GL_TRUE));
         }
-        GL_CALL(PixelStorei(GR_GL_UNPACK_ALIGNMENT, static_cast<GrGLint>(bpp)));
+        GL_CALL(PixelStorei(GR_GL_UNPACK_ALIGNMENT,
+              static_cast<GrGLint>(GrUnpackAlignment(dataConfig))));
     }
     bool succeeded = true;
     if (isNewTexture &&
@@ -2697,6 +2698,11 @@ bool GrGpuGL::configToGLFormats(GrPixelConfig config,
         case kR11_EAC_GrPixelConfig:
             *internalFormat = GR_GL_COMPRESSED_R11;
             break;
+        case kRGBA_float_GrPixelConfig:
+            *internalFormat = GR_GL_RGBA32F;
+            *externalFormat = GR_GL_RGBA;
+            *externalType = GR_GL_FLOAT;
+            break;
         default:
             return false;
     }