Getting GLuint texture from NSImage

Question

I'm working on a mac os app using Syphon-SDK. Syphon is a service that "publishes" render data making it available to video handling tools to use it as an input source.

The sample project (available here: http://syphon.v002.info/) gets the rendering data from a Quartz Composer file and publishes it.

On my project I have to render a static NSImage, and for that I have to use OpenGL, and then publish the resulting texture.

Answer 1

here's the thing:

- (void)textureFromImage:(NSImage*)theImg textureName:(GLuint*)texName
{
    NSBitmapImageRep* bitmap = [NSBitmapImageRep alloc];
    int samplesPerPixel = 0;
    NSSize imgSize = [theImg size];

    [theImg lockFocus];
    [bitmap initWithFocusedViewRect:
                    NSMakeRect(0.0, 0.0, imgSize.width, imgSize.height)];
    [theImg unlockFocus];

    // Set proper unpacking row length for bitmap.
    glPixelStorei(GL_UNPACK_ROW_LENGTH, [bitmap pixelsWide]);

    // Set byte aligned unpacking (needed for 3 byte per pixel bitmaps).
    glPixelStorei (GL_UNPACK_ALIGNMENT, 1);

    // Generate a new texture name if one was not provided.
    if (*texName == 0)
        glGenTextures (1, texName);
    glBindTexture (GL_TEXTURE_RECTANGLE_EXT, *texName);

    // Non-mipmap filtering (redundant for texture_rectangle).
    glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_MIN_FILTER,  GL_LINEAR);
    samplesPerPixel = [bitmap samplesPerPixel];

    // Nonplanar, RGB 24 bit bitmap, or RGBA 32 bit bitmap.
    if(![bitmap isPlanar] &&
        (samplesPerPixel == 3 || samplesPerPixel == 4))
    {
        glTexImage2D(GL_TEXTURE_RECTANGLE_EXT, 0,
            samplesPerPixel == 4 ? GL_RGBA8 : GL_RGB8,
            [bitmap pixelsWide],
            [bitmap pixelsHigh],
            0,
            samplesPerPixel == 4 ? GL_RGBA : GL_RGB,
            GL_UNSIGNED_BYTE,
            [bitmap bitmapData]);
    }
    else
    {
        // Handle other bitmap formats.
    }

    // Clean up.
    [bitmap release];
}

hope it helps someone else