diff --git a/src/OpenGL/libGLESv2/Context.cpp b/src/OpenGL/libGLESv2/Context.cpp
index 23f004d..310209f 100644
--- a/src/OpenGL/libGLESv2/Context.cpp
+++ b/src/OpenGL/libGLESv2/Context.cpp
@@ -1645,6 +1645,27 @@
 	return mResourceManager->getProgram(mState.currentProgram);
 }
 
+Texture *Context::getTargetTexture(GLenum target) const
+{
+	Texture *texture = nullptr;
+
+	switch(target)
+	{
+	case GL_TEXTURE_2D:            texture = getTexture2D();       break;
+	case GL_TEXTURE_2D_ARRAY:      texture = getTexture2DArray();  break;
+	case GL_TEXTURE_3D:            texture = getTexture3D();       break;
+	case GL_TEXTURE_CUBE_MAP:      texture = getTextureCubeMap();  break;
+	case GL_TEXTURE_EXTERNAL_OES:  texture = getTextureExternal(); break;
+	case GL_TEXTURE_RECTANGLE_ARB: texture = getTexture2DRect();   break;
+	default:
+		return error(GL_INVALID_ENUM, nullptr);
+	}
+
+	ASSERT(texture);  // Must always have a default texture to fall back to.
+
+	return texture;
+}
+
 Texture2D *Context::getTexture2D() const
 {
 	return static_cast<Texture2D*>(getSamplerTexture(mState.activeSampler, TEXTURE_2D));
diff --git a/src/OpenGL/libGLESv2/Context.h b/src/OpenGL/libGLESv2/Context.h
index bb85011..b41fbef 100644
--- a/src/OpenGL/libGLESv2/Context.h
+++ b/src/OpenGL/libGLESv2/Context.h
@@ -640,6 +640,7 @@
 	GLenum getPixels(const GLvoid **data, GLenum type, GLsizei imageSize) const;
 	bool getBuffer(GLenum target, es2::Buffer **buffer) const;
 	Program *getCurrentProgram() const;
+	Texture *getTargetTexture(GLenum target) const;
 	Texture2D *getTexture2D() const;
 	Texture2D *getTexture2D(GLenum target) const;
 	Texture3D *getTexture3D() const;
diff --git a/src/OpenGL/libGLESv2/Texture.cpp b/src/OpenGL/libGLESv2/Texture.cpp
index 0266158..a02a7a0 100644
--- a/src/OpenGL/libGLESv2/Texture.cpp
+++ b/src/OpenGL/libGLESv2/Texture.cpp
@@ -686,8 +686,7 @@
 	image[0] = sharedImage;
 }
 
-// Tests for 2D texture sampling completeness. [OpenGL ES 3.0.5] section 3.8.13 page 160.
-bool Texture2D::isSamplerComplete(Sampler *sampler) const
+bool Texture2D::isBaseLevelDefined() const
 {
 	if(!image[mBaseLevel])
 	{
@@ -702,6 +701,17 @@
 		return false;
 	}
 
+	return true;
+}
+
+// Tests for 2D texture sampling completeness. [OpenGL ES 3.0.5] section 3.8.13 page 160.
+bool Texture2D::isSamplerComplete(Sampler *sampler) const
+{
+	if(!isBaseLevelDefined())
+	{
+		return false;
+	}
+
 	if(isMipmapFiltered(sampler))
 	{
 		if(!isMipmapComplete())
@@ -1042,8 +1052,7 @@
 	Texture::subImageCompressed(xoffset, yoffset, 0, width, height, 1, format, imageSize, pixels, image[CubeFaceIndex(target)][level]);
 }
 
-// Tests for cube map sampling completeness. [OpenGL ES 3.0.5] section 3.8.13 page 161.
-bool TextureCubeMap::isSamplerComplete(Sampler *sampler) const
+bool TextureCubeMap::isBaseLevelDefined() const
 {
 	for(int face = 0; face < 6; face++)
 	{
@@ -1060,6 +1069,17 @@
 		return false;
 	}
 
+	return true;
+}
+
+// Tests for cube map sampling completeness. [OpenGL ES 3.0.5] section 3.8.13 page 161.
+bool TextureCubeMap::isSamplerComplete(Sampler *sampler) const
+{
+	if(!isBaseLevelDefined())
+	{
+		return false;
+	}
+
 	if(!isMipmapFiltered(sampler))
 	{
 		if(!isCubeComplete())
@@ -1081,6 +1101,11 @@
 // Tests for cube texture completeness. [OpenGL ES 3.0.5] section 3.8.13 page 160.
 bool TextureCubeMap::isCubeComplete() const
 {
+	if(!isBaseLevelDefined())
+	{
+		return false;
+	}
+
 	if(image[0][mBaseLevel]->getWidth() <= 0 || image[0][mBaseLevel]->getHeight() != image[0][mBaseLevel]->getWidth())
 	{
 		return false;
@@ -1649,8 +1674,7 @@
 	image[0] = sharedImage;
 }
 
-// Tests for 3D texture sampling completeness. [OpenGL ES 3.0.5] section 3.8.13 page 160.
-bool Texture3D::isSamplerComplete(Sampler *sampler) const
+bool Texture3D::isBaseLevelDefined() const
 {
 	if(!image[mBaseLevel])
 	{
@@ -1666,6 +1690,17 @@
 		return false;
 	}
 
+	return true;
+}
+
+// Tests for 3D texture sampling completeness. [OpenGL ES 3.0.5] section 3.8.13 page 160.
+bool Texture3D::isSamplerComplete(Sampler *sampler) const
+{
+	if(!isBaseLevelDefined())
+	{
+		return false;
+	}
+
 	if(isMipmapFiltered(sampler))
 	{
 		if(!isMipmapComplete())
diff --git a/src/OpenGL/libGLESv2/Texture.h b/src/OpenGL/libGLESv2/Texture.h
index f27879d..495403a 100644
--- a/src/OpenGL/libGLESv2/Texture.h
+++ b/src/OpenGL/libGLESv2/Texture.h
@@ -148,6 +148,7 @@
 	virtual int getTopLevel() const = 0;
 	virtual bool requiresSync() const = 0;
 
+	virtual bool isBaseLevelDefined() const = 0;
 	virtual bool isSamplerComplete(Sampler *sampler) const = 0;
 	virtual bool isCompressed(GLenum target, GLint level) const = 0;
 	virtual bool isDepth(GLenum target, GLint level) const = 0;
@@ -220,6 +221,7 @@
 
 	void setSharedImage(egl::Image *image);
 
+	bool isBaseLevelDefined() const override;
 	bool isSamplerComplete(Sampler *sampler) const override;
 	bool isCompressed(GLenum target, GLint level) const override;
 	bool isDepth(GLenum target, GLint level) const override;
@@ -287,6 +289,7 @@
 	void copyImage(GLenum target, GLint level, GLenum internalformat, GLint x, GLint y, GLsizei width, GLsizei height, Renderbuffer *source);
 	void copySubImage(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint zoffset, GLint x, GLint y, GLsizei width, GLsizei height, Renderbuffer *source) override;
 
+	bool isBaseLevelDefined() const override;
 	bool isSamplerComplete(Sampler *sampler) const override;
 	bool isCompressed(GLenum target, GLint level) const override;
 	bool isDepth(GLenum target, GLint level) const override;
@@ -350,6 +353,7 @@
 
 	void setSharedImage(egl::Image *image);
 
+	bool isBaseLevelDefined() const override;
 	bool isSamplerComplete(Sampler *sampler) const override;
 	bool isCompressed(GLenum target, GLint level) const override;
 	bool isDepth(GLenum target, GLint level) const override;
diff --git a/src/OpenGL/libGLESv2/libGLESv2.cpp b/src/OpenGL/libGLESv2/libGLESv2.cpp
index a58563e..86ebabb 100644
--- a/src/OpenGL/libGLESv2/libGLESv2.cpp
+++ b/src/OpenGL/libGLESv2/libGLESv2.cpp
@@ -2108,35 +2108,11 @@
 
 	if(context)
 	{
-		es2::Texture *texture = nullptr;
+		es2::Texture *texture = context->getTargetTexture(target);
 
-		switch(target)
+		if(!texture)
 		{
-		case GL_TEXTURE_2D:
-			texture = context->getTexture2D();
-			break;
-		case GL_TEXTURE_CUBE_MAP:
-			{
-				TextureCubeMap *cube = context->getTextureCubeMap();
-				texture = cube;
-
-				if(!cube->isCubeComplete())
-				{
-					return error(GL_INVALID_OPERATION);
-				}
-			}
-			break;
-		case GL_TEXTURE_2D_ARRAY:
-			texture = context->getTexture2DArray();
-			break;
-		case GL_TEXTURE_3D:
-			texture = context->getTexture3D();
-			break;
-		case GL_TEXTURE_RECTANGLE_ARB:
-			texture = context->getTexture2DRect();
-			break;
-		default:
-			return error(GL_INVALID_ENUM);
+			return;
 		}
 
 		if(!IsMipmappable(texture->getFormat(target, texture->getBaseLevel())))
@@ -2144,6 +2120,23 @@
 			return error(GL_INVALID_OPERATION);
 		}
 
+		if(target == GL_TEXTURE_CUBE_MAP)
+		{
+			TextureCubeMap *cube = context->getTextureCubeMap();
+
+			if(!cube->isCubeComplete())
+			{
+				return error(GL_INVALID_OPERATION);
+			}
+		}
+
+		// [OpenGL ES 3.2]: "Otherwise, if levelbase is not defined, or if any dimension
+		// is zero, all mipmap levels are left unchanged. This is not an error."
+		if(!texture->isBaseLevelDefined())
+		{
+			return;
+		}
+
 		texture->generateMipmaps();
 	}
 }
@@ -3296,18 +3289,11 @@
 
 	if(context)
 	{
-		es2::Texture *texture;
+		es2::Texture *texture = context->getTargetTexture(target);
 
-		switch(target)
+		if(!texture)
 		{
-		case GL_TEXTURE_2D:            texture = context->getTexture2D();       break;
-		case GL_TEXTURE_2D_ARRAY:      texture = context->getTexture2DArray();  break;
-		case GL_TEXTURE_3D:            texture = context->getTexture3D();       break;
-		case GL_TEXTURE_CUBE_MAP:      texture = context->getTextureCubeMap();  break;
-		case GL_TEXTURE_EXTERNAL_OES:  texture = context->getTextureExternal(); break;
-		case GL_TEXTURE_RECTANGLE_ARB: texture = context->getTexture2DRect();   break;
-		default:
-			return error(GL_INVALID_ENUM);
+			return;
 		}
 
 		switch(pname)
@@ -3383,18 +3369,11 @@
 
 	if(context)
 	{
-		es2::Texture *texture;
+		es2::Texture *texture = context->getTargetTexture(target);
 
-		switch(target)
+		if(!texture)
 		{
-		case GL_TEXTURE_2D:            texture = context->getTexture2D();       break;
-		case GL_TEXTURE_2D_ARRAY:      texture = context->getTexture2DArray();  break;
-		case GL_TEXTURE_3D:            texture = context->getTexture3D();       break;
-		case GL_TEXTURE_CUBE_MAP:      texture = context->getTextureCubeMap();  break;
-		case GL_TEXTURE_EXTERNAL_OES:  texture = context->getTextureExternal(); break;
-		case GL_TEXTURE_RECTANGLE_ARB: texture = context->getTexture2DRect();   break;
-		default:
-			return error(GL_INVALID_ENUM);
+			return;
 		}
 
 		switch(pname)
@@ -4655,18 +4634,11 @@
 
 	if(context)
 	{
-		es2::Texture *texture;
+		es2::Texture *texture = context->getTargetTexture(target);
 
-		switch(target)
+		if(!texture)
 		{
-		case GL_TEXTURE_2D:            texture = context->getTexture2D();       break;
-		case GL_TEXTURE_2D_ARRAY:      texture = context->getTexture2DArray();  break;
-		case GL_TEXTURE_3D:            texture = context->getTexture3D();       break;
-		case GL_TEXTURE_CUBE_MAP:      texture = context->getTextureCubeMap();  break;
-		case GL_TEXTURE_EXTERNAL_OES:  texture = context->getTextureExternal(); break;
-		case GL_TEXTURE_RECTANGLE_ARB: texture = context->getTexture2DRect();   break;
-		default:
-			return error(GL_INVALID_ENUM);
+			return;
 		}
 
 		switch(pname)
@@ -4786,18 +4758,11 @@
 
 	if(context)
 	{
-		es2::Texture *texture;
+		es2::Texture *texture = context->getTargetTexture(target);
 
-		switch(target)
+		if(!texture)
 		{
-		case GL_TEXTURE_2D:            texture = context->getTexture2D();       break;
-		case GL_TEXTURE_2D_ARRAY:      texture = context->getTexture2DArray();  break;
-		case GL_TEXTURE_3D:            texture = context->getTexture3D();       break;
-		case GL_TEXTURE_CUBE_MAP:      texture = context->getTextureCubeMap();  break;
-		case GL_TEXTURE_EXTERNAL_OES:  texture = context->getTextureExternal(); break;
-		case GL_TEXTURE_RECTANGLE_ARB: texture = context->getTexture2DRect();   break;
-		default:
-			return error(GL_INVALID_ENUM);
+			return;
 		}
 
 		switch(pname)