Texturing; OBJ loader

texture.hh

@@ -0,0 +1,95 @@
+#ifndef __OPENGLPLAYGROUND_TEXTURE_HH__
+#define __OPENGLPLAYGROUND_TEXTURE_HH__
+
+#include <string>
+#include <cstdio>
+#include <cassert>
+#include <algorithm>
+
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_image.h>
+
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+
+#include "common.hh"
+
+static unsigned ilog2(unsigned in)
+{
+  unsigned ret = 0u;
+  while (in >>= 1) ++ret;
+  return ret;
+}
+
+class Texture2D {
+public:
+  Texture2D(unsigned width, unsigned height) {
+    _glCreate(width, height);
+  }
+
+  Texture2D(std::string const& file) {
+    SDL_Surface *surf = IMG_Load(file.c_str());
+    if (!surf)
+      throw SDLException();
+
+    try {
+      _glCreate(surf->w, surf->h);
+      try {
+	assert(surf->format->format == SDL_PIXELFORMAT_RGB24); // TODO: Proper support of many formats
+	if (SDL_MUSTLOCK(surf))
+	  SDL_LockSurface(surf);
+	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, surf->w, surf->h, GL_RGB, GL_UNSIGNED_BYTE, surf->pixels);
+	glGenerateMipmap(GL_TEXTURE_2D);
+	checkGlError();
+      } catch(...) {
+	glDeleteTextures(1, &_texID);
+	throw;
+      }
+    }
+    catch(...) {
+      SDL_FreeSurface(surf);
+      throw;
+    }
+    SDL_FreeSurface(surf);
+  }
+  
+  ~Texture2D() {
+    glDeleteTextures(1, &_texID);
+  }
+
+  void bind() {
+    glBindTexture(GL_TEXTURE_2D, _texID);
+    checkGlError();
+  }
+  
+private:
+
+  void _glCreate(unsigned width, unsigned height) {
+    glGenTextures(1, &_texID);
+    checkGlError();
+    try {
+      glBindTexture(GL_TEXTURE_2D, _texID);
+      unsigned logWidth = ilog2(width), logHeight = ilog2(height);
+      unsigned levels = std::max(logWidth,logHeight)+1u;
+      if(SDL_GL_ExtensionSupported("GL_ARB_texture_storage"))
+	glTexStorage2D(GL_TEXTURE_2D, levels, GL_RGB8, width, height);
+      else {
+	std::printf("Warning: extension GL_ARB_texture_storage not supported!\n");
+	for (unsigned i = 0u; i < levels; ++i)
+	  {
+	    glTexImage2D(GL_TEXTURE_2D, i, GL_RGB8, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+	    width = std::max(1u, (width / 2u));
+	    height = std::max(1u, (height / 2u));
+	  }
+      }
+      checkGlError();
+    } catch(...) {
+      glDeleteTextures(1, &_texID);
+    }
+  }
+  
+  GLuint _texID;
+};
+
+
+#endif