Unity-webview rendering technique

WebViewObject.m

- (void)update:(int)x y:(int)y deltaY:(float)deltaY buttonDown:(BOOL)buttonDown buttonPress:(BOOL)buttonPress buttonRelease:(BOOL)buttonRelease keyPress:(BOOL)keyPress keyCode:(unsigned short)keyCode keyChars:(const char*)keyChars
{
    // [..] Updates internal state, sends through click events to user agent etc.

    @synchronized(self) {
        if (bitmap == nil)
            bitmap = [[webView bitmapImageRepForCachingDisplayInRect:webView.frame] retain];
        memset([bitmap bitmapData], 0, [bitmap bytesPerRow] * [bitmap pixelsHigh]);
        [webView cacheDisplayInRect:webView.frame toBitmapImageRep:bitmap];
        needsDisplay = YES; // TODO (bitmap == nil || [view needsDisplay]);
    }
}

- (void)render
{
    @synchronized(self) {
        if (webView == nil)
            return;
        if (!needsDisplay)
            return;
        if (bitmap == nil)
            return;

        int samplesPerPixel = (int)[bitmap samplesPerPixel];
        int rowLength = 0;
        int unpackAlign = 0;
        glGetIntegerv(GL_UNPACK_ROW_LENGTH, &rowLength);
        glGetIntegerv(GL_UNPACK_ALIGNMENT, &unpackAlign);
        glPixelStorei(GL_UNPACK_ROW_LENGTH, (GLint)[bitmap bytesPerRow] / samplesPerPixel);
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
        glBindTexture(GL_TEXTURE_2D, textureId);
        if (![bitmap isPlanar] && (samplesPerPixel == 3 || samplesPerPixel == 4)) {
            glTexSubImage2D(
                GL_TEXTURE_2D,
                0,
                0,
                0,
                (GLsizei)[bitmap pixelsWide],
                (GLsizei)[bitmap pixelsHigh],
                samplesPerPixel == 4 ? GL_RGBA : GL_RGB,
                GL_UNSIGNED_BYTE,
                [bitmap bitmapData]);
        }
        glPixelStorei(GL_UNPACK_ROW_LENGTH, rowLength);
        glPixelStorei(GL_UNPACK_ALIGNMENT, unpackAlign);
    }
}