Keskustelu: Ohjelmointikysymykset: C++: OpenGL tekstuuriongelma

#include "SDL.h"
#include "SDL_image.h"
#include "SDL_opengl.h"

GLuint loadTexture(const char* path);

SDL_Surface *screen;

int main(int argc, char** argv)
{
	SDL_Init(SDL_INIT_EVERYTHING);

	//Set OpenGL memory usage
	SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
	SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
	SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
	SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
	SDL_GL_SetAttribute(SDL_GL_BUFFER_SIZE, 32);
	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

	screen = SDL_SetVideoMode(800, 600, 32, SDL_OPENGL);
	SDL_WM_SetCaption("OpenGL Test", NULL);

	//Specific the clear color
	glClearColor(1,1,1,1); //RED,GREEN,BLUE,ALPHA

	//What portion of the screen we will display
	glViewport(0, 0, 800, 600);

	//Shader model - Use this
	glShadeModel(GL_SMOOTH);

	//2D rendering
	glMatrixMode(GL_PROJECTION);

	//"Save" it
	glLoadIdentity();

	//Disable depth checking
	glDisable(GL_DEPTH_TEST);

	//We enable blending of textures and set how we are going to blend it
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	SDL_Event event;

	int closeGame = 0;

	//background texture
	GLuint background = 0;
	background = loadTexture("C:\\Users\\Matias\\Desktop\\gPower2D\\gPower2D\\gPower2D\\Data\\Images\\background.png");

	while(!closeGame)
	{
		while(SDL_PollEvent(&event))
		{
			if(event.type == SDL_QUIT) closeGame = 1;
		}

		//start rendering
		glClear(GL_COLOR_BUFFER_BIT);
		glPushMatrix(); //Start rendering phase
		glOrtho(0, 800, 600, 0,-1,1); //Set the matrix
		glColor4ub(255, 255, 255, 255); //White color

		glEnable(GL_BLEND);
		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
		glEnable(GL_SMOOTH);

		glEnable(GL_TEXTURE_2D);
		glBindTexture(GL_TEXTURE_2D, background);

		glBegin(GL_QUADS);

		glTexCoord2d(0,0); glVertex2f(0, 0); //Upper-left corner
		glTexCoord2d(1,0); glVertex2f(800, 0); //Upper-right corner
		glTexCoord2d(1,1); glVertex2f(800, 600); //Down-right corner
		glTexCoord2d(0,1); glVertex2f(0, 600); //Down-left corner

		glEnd();

		glDisable(GL_TEXTURE_2D);

		glDisable(GL_BLEND);
		glPopMatrix();
		SDL_GL_SwapBuffers();
	}

	SDL_Quit();

	return 0;
}

GLuint loadTexture(const char* path)
{
   SDL_Surface* surface = IMG_Load(path);
   GLuint texture;

   glPixelStorei(GL_UNPACK_ALIGNMENT,4);
   glGenTextures(1, &texture);
   glBindTexture(GL_TEXTURE_2D, texture);
   SDL_PixelFormat *format = surface->format;
   if (format->Amask)
   {
      gluBuild2DMipmaps(GL_TEXTURE_2D, 4,
         surface->w, surface->h, GL_RGBA,GL_UNSIGNED_BYTE, surface->pixels);
   }
   else
   {
      gluBuild2DMipmaps(GL_TEXTURE_2D, 3,
         surface->w, surface->h, GL_RGB, GL_UNSIGNED_BYTE, surface->pixels);
   }

   SDL_FreeSurface(surface);

   return texture;
}