png loading code is useful for all platforms

NOMADVRLib/LoadPNG.cpp

+/*
+# Copyright 2016-2018 The NOMAD Developers Group
+ #
+ # Licensed under the Apache License, Version 2.0 (the "License");
+ # you may not use this file except in compliance with the License.
+ # You may obtain a copy of the License at
+ #
+ #     http://www.apache.org/licenses/LICENSE-2.0
+ #
+ # Unless required by applicable law or agreed to in writing, software
+ # distributed under the License is distributed on an "AS IS" BASIS,
+ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ # See the License for the specific language governing permissions and
+ # limitations under the License.
+*/
+
+#include <vector>
+#include "LoadPNG.h"
+#include "LodePNG/lodepng.h"
+
+GLuint LoadPNG (const char *image)
+{
+	GLuint m_iTexture;
+	glGenTextures(1, &m_iTexture);
+	glBindTexture(GL_TEXTURE_2D, m_iTexture);
+
+	std::vector<unsigned char> imageRGBA;
+	unsigned nImageWidth, nImageHeight;
+	unsigned nError = lodepng::decode(imageRGBA, nImageWidth, nImageHeight,
+			image);
+	
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, nImageWidth, nImageHeight,
+			0, GL_RGBA, GL_UNSIGNED_BYTE, &imageRGBA[0]);
+
+	glGenerateMipmap(GL_TEXTURE_2D);
+
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+
+	//rgh fixme: revise this if texture sampling is too slow
+	GLfloat fLargest;
+	glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &fLargest);
+	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, fLargest);
+	
+	glBindTexture( GL_TEXTURE_2D, 0 );
+
+	return m_iTexture;
+}
\ No newline at end of file

NOMADVRLib/LoadPNG.h

+/*
+# Copyright 2016-2018 The NOMAD Developers Group
+ #
+ # Licensed under the Apache License, Version 2.0 (the "License");
+ # you may not use this file except in compliance with the License.
+ # You may obtain a copy of the License at
+ #
+ #     http://www.apache.org/licenses/LICENSE-2.0
+ #
+ # Unless required by applicable law or agreed to in writing, software
+ # distributed under the License is distributed on an "AS IS" BASIS,
+ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ # See the License for the specific language governing permissions and
+ # limitations under the License.
+*/
+
+#ifndef LOADPNG_H
+#define LOADPNG_H
+#include "NOMADVRLib/MyGL.h"
+
+GLuint LoadPNG (const char *image);
+
+#endif