Implement OES_texture_float_linear and OES_texture_half_float_linear extensions in WebGL.

Source/core/html/canvas/WebGLTexture.cpp

Index: Source/core/html/canvas/WebGLTexture.cpp
diff --git a/Source/core/html/canvas/WebGLTexture.cpp b/Source/core/html/canvas/WebGLTexture.cpp
index c8c23bd4be545a9c05708dcf75ca32171cb10ca0..c5d2bff5446ba69dec7f58f3b38cd8c397ccb980 100644
--- a/Source/core/html/canvas/WebGLTexture.cpp
+++ b/Source/core/html/canvas/WebGLTexture.cpp
@@ -48,6 +48,8 @@ WebGLTexture::WebGLTexture(WebGLRenderingContext* ctx)
     , m_isNPOT(false)
     , m_isComplete(false)
     , m_needToUseBlackTexture(false)
+    , m_isFloatType(false)
+    , m_isHalfFloatType(false)
 {
     setObject(ctx->graphicsContext3D()->createTexture());
 }
@@ -230,11 +232,17 @@ bool WebGLTexture::isNPOT() const
     return m_isNPOT;
 }
 
-bool WebGLTexture::needToUseBlackTexture() const
+bool WebGLTexture::needToUseBlackTexture(TextureExtensionFlag flag) const
 {
     if (!object())
         return false;
-    return m_needToUseBlackTexture;
+    if (m_needToUseBlackTexture)
+        return true;
+    if ((m_isFloatType && !(flag & TextureFloatLinearExtensionEnabled)) || (m_isHalfFloatType && !(flag && TextureHalfFloatLinearExtensionEnabled))) {
+        if (m_magFilter != GraphicsContext3D::NEAREST || (m_minFilter != GraphicsContext3D::NEAREST && m_minFilter != GraphicsContext3D::NEAREST_MIPMAP_NEAREST))
+            return true;
+    }
+    return false;
 }
 
 void WebGLTexture::deleteObjectImpl(GraphicsContext3D* context3d, Platform3DObject object)
@@ -340,6 +348,28 @@ void WebGLTexture::update()
             }
         }
     }
+    m_isFloatType = false;
+    if (m_isComplete)
+        m_isFloatType = m_info[0][0].type == GraphicsContext3D::FLOAT;
+    else {
+        for (size_t ii = 0; ii < m_info.size(); ++ii) {
+            if (m_info[ii][0].type == GraphicsContext3D::FLOAT) {
+                m_isFloatType = true;
+                break;
+            }
+        }
+    }

[Ken Russell (switch to Gerrit), 2013/05/20 19:46:45]

OK. It still isn't clear to me that scanning through all of the faces is
necessary, but improving this further can be left for a future optimization.

+    m_isHalfFloatType = false;
+    if (m_isComplete)
+        m_isHalfFloatType = m_info[0][0].type == GraphicsContext3D::HALF_FLOAT_OES;
+    else {
+        for (size_t ii = 0; ii < m_info.size(); ++ii) {
+            if (m_info[ii][0].type == GraphicsContext3D::HALF_FLOAT_OES) {
+                m_isHalfFloatType = true;
+                break;
+            }
+        }
+    }
 
     m_needToUseBlackTexture = false;
     // NPOT