globjects | C++ library strictly wrapping OpenGL objects | Game Engine library

I have been playing around with OpenGL and shaders and got myself into shadow mapping.

Trying to follow tutorials on the Internet (ogldev and learnopengl), got some unexpected results.

The issue is best described with few screenshots (I have added a static quad with depth framebuffer for debugging):

Somehow I managed to get shadows to be rendered on a ground quad once, with a static light (this commit). But the shadow pattern is, again, incorrect. I strongly suspect model transformation matrix calculaitons on this:

The way I render the scene is quite straightforward:

1. create the pipelines:

• for mapping the shadows (filling the depth frame buffer)
• for rendering the scene using the depth frame buffer
• (extra) debugging one, rendering depth frame buffer to a static quad on a screen

1. fill the depth frame buffer: using the shadow mapping pipeline, render the scene from the light point, using orthographic projection
2. render the shaded scene: using the rendering pipeline and depth frame buffer bind as the first texture, render the scene from a camera point, using perspective projection

Seems like the algorithm in all those tutorials on shadow mapping out there. Yet, instead of a mouray effect (like in all of the tutorials), I get no shadow on the bottom plane whatsoever and weird artifacts (incorrect shadow mapping) on the 3D (chicken) model.

Interestingly enough, if I do not render (for both the shadow mapping and final rendering pass) the chicken model, the plane is lit with the same weird pattern:

I also had to remove any normal transformations from the fragment shader and disable face culling to make the ground plane lit. With front-face culling the plane does not appear in the shadow map (depth buffer).

I assume the following might be causing this issue:

• wrong depth frame buffer setup (data format or texture parameters)
• flipped depth frame buffer texture
• wrong shadow calculations in rendering shaders
• wrong light matrices (view & projection) setup
• wrong matrix calculations in the rendering shaders (given the model transformation matrices for both chicken model and the quad contain both rotation and scaling)

Unfortunately, I ran out of ideas even on how to assess the above assumptions.

Looking for any help on the matter (also feel free to criticize any of my approaches, including C++, CMake, OpenGL and computer graphics).

The full solution source code is available on GitHub, but for convenience I have placed the heavily cut source code below.

shadow-mapping.vert: