glDrawPixels + FreeImage need help

OpenGL OpenGL: Basic Coding
1

Hi,
I want to load a PNG file with freeimage and then render it with glDrawPixels but it dont work.

void ImageLoader::LoadImage(const char *filename){

	FREE_IMAGE_FORMAT fif = FIF_UNKNOWN;
	FIBITMAP *dib(0);

	fif = FreeImage_GetFileType(filename, 0);

	if(fif == FIF_UNKNOWN)
		fif = FreeImage_GetFIFFromFilename(filename);

	if(FreeImage_FIFSupportsReading(fif))
		dib = FreeImage_Load(fif, filename);

	bits = FreeImage_GetBits(dib);

	width = FreeImage_GetWidth(dib);
	height = FreeImage_GetHeight(dib);

	FreeImage_Unload(dib);


}

This functon loads a file and then I render it:


	ImageLoader pic;
	pic.LoadImage("C:\\pic.png");


...


glClearColor(0.9, 0.9, 0.9, 0.0);
		glClear(GL_COLOR_BUFFER_BIT);

		glRasterPos2i(10,10);
		glDrawPixels(pic.width, pic.height, GL_RGBA, GL_INT, pic.bits);

		glfwSwapBuffers();

Can someone help me? I dont want to use a texture.

2

OK, I try to ask in another way:
How can I load files with freeimage and render it with glDrawPixels?

3

glDrawPixels() is a bad choice. People usually draw quads and plaster them with 2D textures. Another option are point sprites and some extensions.

opengl faq

You can also google for 2D with opengl or somesuch, there’s a ton of resources. Maybe you can try to do it without the FreeImage library at first, for testing. There’s:

stb_image

4 
bits = FreeImage_GetBits(dib);
...
FreeImage_Unload(dib);

You are taking the pointer to the picture data and the you destroy the picture.

glDrawPixels(pic.width, pic.height, GL_RGBA, GL_INT, pic.bits);

DrawPixel as already saw is not the best choise but should work. Are you sure that the picture is RGBA and not only RGB? Also why you use GL_INT? The picture should be 8bit per channel, so GL_UNSIGNED_BYTE. If you will send RGB data take care of the pack_alignment parameter of the pixel store function

Also when you ask a question is better specify what do you see on the screen or post a screen shot. “Don’t work” can be “black screen”, “I see random pixel”, “distorted image” .

ps: by the way. FreeImage let you query the number of bit per pixel and all the data you need.