Implement normal map generation for floating point images.

src/nvimage/NormalMap.cpp

@@ -36,9 +36,9 @@ using namespace nv;
 // Create normal map using the given kernels.
 static FloatImage * createNormalMap(const Image * img, FloatImage::WrapMode wm, Vector4::Arg heightWeights, const Kernel2 * kdu, const Kernel2 * kdv)
 {
-	nvCheck(kdu != NULL);
-	nvCheck(kdv != NULL);
-	nvCheck(img != NULL);
+	nvDebugCheck(kdu != NULL);
+	nvDebugCheck(kdv != NULL);
+	nvDebugCheck(img != NULL);
 	
 	const uint w = img->width();
 	const uint h = img->height();
@@ -75,10 +75,54 @@ static FloatImage * createNormalMap(const Image * img, FloatImage::WrapMode wm,
 }
 
 
+// Create normal map using the given kernels.
+static FloatImage * createNormalMap(const FloatImage * img, FloatImage::WrapMode wm, const Kernel2 * kdu, const Kernel2 * kdv)
+{
+	nvDebugCheck(kdu != NULL);
+	nvDebugCheck(kdv != NULL);
+	nvDebugCheck(img != NULL);
+
+	#pragma message(NV_FILE_LINE "Height scale parameter should go away. It should be a sensible value that produces good results when the heightmap is in the [0, 1] range.")
+	const float heightScale = 1.0f / 16.0f;
+
+	const uint w = img->width();
+	const uint h = img->height();
+
+	AutoPtr<FloatImage> img_out(new FloatImage());
+	img_out->allocate(4, w, h);
+
+	for (uint y = 0; y < h; y++)
+	{
+		for (uint x = 0; x < w; x++)
+		{
+			const float du = img->applyKernel(kdu, x, y, 3, wm);
+			const float dv = img->applyKernel(kdv, x, y, 3, wm);
+
+			Vector3 n = normalize(Vector3(du, dv, heightScale));
+
+			img_out->setPixel(n.x(), x, y, 0);
+			img_out->setPixel(n.y(), x, y, 1);
+			img_out->setPixel(n.z(), x, y, 2);
+		}
+	}
+
+	// Copy alpha channel.
+	for (uint y = 0; y < h; y++)
+	{
+		for (uint x = 0; x < w; x++)
+		{
+			img_out->setPixel(img->pixel(x, y, 3), x, y, 3);
+		}
+	}
+
+	return img_out.release();
+}
+
+
 /// Create normal map using the given filter.
 FloatImage * nv::createNormalMap(const Image * img, FloatImage::WrapMode wm, Vector4::Arg heightWeights, NormalMapFilter filter /*= Sobel3x3*/)
 {
-	nvCheck(img != NULL);
+	nvDebugCheck(img != NULL);
 	
 	// Init the kernels.
 	Kernel2 * kdu = NULL;
@@ -115,7 +159,7 @@ FloatImage * nv::createNormalMap(const Image * img, FloatImage::WrapMode wm, Vec
 /// Create normal map combining multiple sobel filters.
 FloatImage * nv::createNormalMap(const Image * img, FloatImage::WrapMode wm, Vector4::Arg heightWeights, Vector4::Arg filterWeights)
 {
-	nvCheck(img != NULL);
+	nvDebugCheck(img != NULL);
 
 	Kernel2 * kdu = NULL;
 	Kernel2 * kdv = NULL;
@@ -130,10 +174,32 @@ FloatImage * nv::createNormalMap(const Image * img, FloatImage::WrapMode wm, Vec
 	return ::createNormalMap(img, wm, heightWeights, kdu, kdv);
 }
 
+
+FloatImage * nv::createNormalMap(const FloatImage * img, FloatImage::WrapMode wm, Vector4::Arg filterWeights)
+{
+	nvDebugCheck(img != NULL);
+
+	Kernel2 * kdu = NULL;
+	Kernel2 * kdv = NULL;
+
+	kdu = new Kernel2(9);
+	kdu->initBlendedSobel(filterWeights);
+	kdu->normalize();
+
+	kdv = new Kernel2(*kdu);
+	kdv->transpose();
+
+	return ::createNormalMap(img, wm, kdu, kdv);
+}
+
+
 /// Normalize the given image in place.
 void nv::normalizeNormalMap(FloatImage * img)
 {
-	nvCheck(img != NULL);
+	nvDebugCheck(img != NULL);
+
+#pragma messsage(NV_FILE_LINE "Pack and expand normals explicitly")
+
 	img->expandNormals(0);
 	img->normalize(0);
 	img->packNormals(0);

src/nvimage/NormalMap.h

@@ -41,10 +41,12 @@ namespace nv
 		NormalMapFilter_Sobel9x9,	// very large
 	};
 
+	// @@ These two functions should be deprecated:
 	FloatImage * createNormalMap(const Image * img, FloatImage::WrapMode wm, Vector4::Arg heightWeights, NormalMapFilter filter = NormalMapFilter_Sobel3x3);
-
 	FloatImage * createNormalMap(const Image * img, FloatImage::WrapMode wm, Vector4::Arg heightWeights, Vector4::Arg filterWeights);
 
+	FloatImage * createNormalMap(const FloatImage * img, FloatImage::WrapMode wm, Vector4::Arg filterWeights);
+
 	void normalizeNormalMap(FloatImage * img);
 
 	// @@ Add generation of DU/DV maps.