OpenGL texture won't map - white square? - c++

Question

Alright, so I'm using cairo to turn an SVG into image data for openGL textures.
That part works.
But now the texture I'm using won't map to the quad I'm making. It's just showing up as a blank square.
Is there something up with the order I'm calling things in or is there some secret function I forgot to use?
const int SCREEN_WIDTH = 1280;
const int SCREEN_HEIGHT = 720;
const int SCREEN_BPP = 32;
int frame = 0;
SDL_Event event;
bool quit;
GLuint texture[1];
int main(int argc, char *argv[]) {
g_type_init();
rsvg_init();
SDL_Surface *screen = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP, SDL_OPENGL );
SDL_WM_SetCaption ("Cairo", NULL);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
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);
/*2D stuff - it worked here
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho( 0, SCREEN_WIDTH, SCREEN_HEIGHT, 0, -1, 1 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glEnable (GL_BLEND);
glEnable (GL_TEXTURE_2D);
glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable (GL_TEXTURE_2D);
glEnable(GL_LIGHTING);
glEnable(GL_COLOR_MATERIAL);
*/
//An attempt at setting up 3D stuff
glEnable(GL_TEXTURE_2D);
glMatrixMode( GL_MODELVIEW );
glMatrixMode( GL_PROJECTION );
glViewport(0,0,SCREEN_WIDTH, SCREEN_HEIGHT);
glShadeModel(GL_SMOOTH);
glClearColor(0.0,0.0,0.0,0.0);
glClearDepth(1.0);
glBlendFunc(GL_SRC_ALPHA, GL_ONE);
glEnable(GL_BLEND);
//glLoadIdentity();
float FlowerWidth = .5;
float FlowerHeight = .5;
float FlowerTextureWidth = 80;
float FlowerTextureHeight = 80;
float FlowerScaleWidth = 1;
float FlowerScaleHeight = 1;
cairo_surface_t* Flower;
cairo_t* context;
Flower = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, FlowerTextureWidth, FlowerTextureHeight);
context = cairo_create(Flower);
const gchar* Filename = "resources/area/haneda/lavender.svg";
RsvgHandle* SvgData = rsvg_handle_new_from_file(Filename, NULL);
rsvg_handle_render_cairo_sub(SvgData, context,"#1000");
unsigned char *buffer = cairo_image_surface_get_data(Flower);
cairo_surface_write_to_png(Flower,"flower.png");
//Make a texture
glGenTextures(1, &texture[1]);
glBindTexture(GL_TEXTURE_2D, texture[1]);
glPixelStoref(GL_UNPACK_ALIGNMENT, 1);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glGetError();
//or am I supposed to use GL_TEXTURE_2D?
glTexImage2D(GL_TEXTURE_2D,
0,
GL_RGBA,
FlowerHeight,
FlowerWidth,
0,
GL_BGRA,
GL_UNSIGNED_BYTE,
buffer);
//done
while (quit==false) {
while(SDL_PollEvent(&event)) {
if(event.type == SDL_QUIT) {
quit = true;
}
}
/*
FlowerScaleWidth+=.001;
FlowerScaleHeight+=.001;
cairo_scale(context,FlowerScaleWidth,FlowerScaleHeight);
*/
glBindTexture (GL_TEXTURE_2D, texture[1]);
glBegin (GL_QUADS);
glTexCoord2f (0.0, 0.0);
glVertex3f (0.0, 0.0, 0.0);
glTexCoord2f (FlowerWidth, 0.0);
glVertex3f (FlowerWidth, 0.0, 0.0);
glTexCoord2f (FlowerWidth, FlowerHeight);
glVertex3f (FlowerWidth, FlowerHeight, 0.0);
glTexCoord2f (0.0, FlowerHeight);
glVertex3f (0.0, FlowerHeight, 0.0);
glEnd ();
glDeleteTextures(1, &texture[1]);
cairo_save (context);
cairo_set_source_rgba (context, 0, 0, 0, 0);
cairo_set_operator (context, CAIRO_OPERATOR_SOURCE);
cairo_paint (context);
cairo_restore (context);
SDL_GL_SwapBuffers();
//glClear( GL_COLOR_BUFFER_BIT );
//SDL_Delay(100);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glGetError();
SDL_Delay(400);
}
}

Answer 1

For some reason, you've made an int array of length 1, but you pass the (non-existing) element 2 to glGenTextures. That reads beyond the array bounds and is undefined behavior. You also seem to delete the texture name inside your rendering loop. The same illegal indexing is used there too, as well in your call to glBindTexture.