SDL_image & OpenGL Problem
- by Dylan
i've been following tutorials online to load textures using SDL and display them on a opengl quad. but ive been getting weird results that no one else on the internet seems to be getting...
so when i render the texture in opengl i get something like this.
http://www.kiddiescissors.com/after.png
when the original .bmp file is this:
http://www.kiddiescissors.com/before.bmp
ive tried other images too, so its not that this particular image is corrupt. it seems like my rgb channels are all jumbled or something. im pulling my hair out at this point.
heres the relevant code from my init() function
if ( SDL_Init(SDL_INIT_VIDEO) != 0 ) {
return 1;
}
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
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_MULTISAMPLEBUFFERS, 1);
SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 4);
SDL_SetVideoMode(WINDOW_WIDTH, WINDOW_HEIGHT, 32, SDL_HWSURFACE | SDL_GL_DOUBLEBUFFER | SDL_OPENGL);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(50, (GLfloat)WINDOW_WIDTH/WINDOW_HEIGHT, 1, 50);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glEnable(GL_DEPTH_TEST);
glEnable(GL_MULTISAMPLE);
glEnable(GL_TEXTURE_2D);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
heres the code that is called when my main player object (the one with which this sprite is associated) is initialized
texture = 0;
SDL_Surface* surface = IMG_Load("i.bmp");
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, surface->w, surface->h, 0, GL_RGB, GL_UNSIGNED_BYTE, surface->pixels);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
SDL_FreeSurface(surface);
and then heres the relevant code from my display function
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glColor4f(1, 1, 1, 1);
glPushMatrix();
glBindTexture(GL_TEXTURE_2D, texture);
glTranslatef(getCenter().x, getCenter().y, 0);
glRotatef(getAngle()*(180/M_PI), 0, 0, 1);
glTranslatef(-getCenter().x, -getCenter().y, 0);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex3f(getTopLeft().x, getTopLeft().y, 0);
glTexCoord2f(0, 1);
glVertex3f(getTopLeft().x, getTopLeft().y + size.y, 0);
glTexCoord2f(1, 1);
glVertex3f(getTopLeft().x + size.x, getTopLeft().y + size.y, 0);
glTexCoord2f(1, 0);
glVertex3f(getTopLeft().x + size.x, getTopLeft().y, 0);
glEnd();
glPopMatrix();
let me know if i left out anything important... or if you need more info from me.
thanks a ton,
-Dylan
