Using OpenGL

[Mike Parker via Digitalmars-d-learn]

On Thursday, 15 September 2016 at 19:03:22 UTC, Darren wrote:

>
> This is the code I'm using: 
> https://dfcode.wordpress.com/2016/09/15/texcodewip/
> (The code for the shaders is at the bottom)
>
> For comparison, this is the code I'm trying to make work:
> http://www.learnopengl.com/code_viewer.php?code=getting-started/textures

I don't have time to try and test this myself, but this looks 
like a potential problem here:

```
auto textureFormat = surface.format.format;
glTexImage2D(GL_TEXTURE_2D, 0, surface.format.BytesPerPixel, 
surface.w, surface.h, 0, textureFormat, GL_UNSIGNED_BYTE, 
surface.pixels);
```

You're passing an SDL enum value to OpenGL, which knows 
absolutely nothing about SDL enum values. Rather than passing 
surface.format.format directly to OGL, you need to first match it 
to the appropriate OGL format enum and pass *that*, which is what 
I tried to explain in my previous post. This is easily done by 
making a function which contains a switch statement iterating all 
of the SDL_PIXELFORMAT_* values and returning the equivalent GL_* 
value.

At any rate, if you're using the same image as the example, you 
don't need to do that in this specific case. You can safely 
ignore surface.format.format and simply pass GL_RGB, which is 
what the example uses. You only need to do the SDL->GL conversion 
for a texture loader that is intended to load multiple pixel 
formats.