OpenGL

OpenGL

OpenGL 3 and OpenGL 4 with GLSL

Changelog

v3.2.1

Security and correctness fixes across all 52 examples:

• Fixed Example36 SSBO allocation (std430 stride was 24 B instead of 32 B — 25 % undersized).
• Added missing glMemoryBarrier calls in Examples 21, 30, 36, 45.
• Fixed glUniform4fv/glUniform2fv count (vec4/vec2 elements, not floats) in Example15.
• Moved 900 KB stack arrays to static storage in Examples 29, 37.
• Fixed glDeleteRenderbuffers on texture names in Examples 12, 34.
• Added NULL-source guards for glusFileLoadText in Examples 47, 51, 52.
• Added missing glViewport in Example27 reshape().
• Fixed resource leaks (programs, VAOs, VBOs, text files) in Examples 09, 12, 14, 22, 27, 31, 35, 36, 50.
• Fixed fur VAO attribute locations in Example26.
• Fixed glDrawBuffer(GL_COLOR_ATTACHMENT0) on default framebuffer in Examples 28, 31.
• Fixed double angle advancement in Example19.
• Fixed Gerstner wave steepness index in Example15.
• Added FBO completeness checks in Examples 09, 33, 48, 49, 50.
• Checked GLUS return values across all examples (316 call sites).
• Replaced deprecated FetchContent_Populate in root CMakeLists.txt.
• Requires GLUS v1.1.1.

v3.2.0

• Migrated the glTF examples (48-52) onto the GLUS glTF 2.0 loader (glusGltfLoadScene / glusGltfGetCgltfData). GLUS now provides cgltf + stb_image and exposes GLUS_SHADER_DIR; the copied OpenGL/GLUS/ folder is gone.
• Requires GLUS v1.1.0. GLUS is taken from the sibling local checkout ../GLUS when present, otherwise fetched from McNopper/GLUS.
• Refreshed screenshots.

v3.1.1

• Added Example52 – 3D Gaussian Splatting with view-direction SH rotation.
• Example51: corrected spherical-harmonics handling for rotated splat nodes (Wigner-D bridged to the glTF/3DGS SH sign convention via the Condon-Shortley phase).
• Both splatting examples: auto-rotation is off by default and toggles with Space.
• Requires GLUS v1.0.1 (band-3 SH rotation fix).

License

The project is distributed under the MIT License — see LICENSE.

These examples are built on GLUS (MIT), which bundles glfw, glew, cgltf and stb — their notices live in the GLUS third-party file. The dependencies and bundled assets added by this repository — McNopper/EGL (MIT) and the Einstein / phoenix 3D models (CC-BY-4.0) — are documented in THIRD-PARTY.md; per-example attributions are noted in each example's section below.

Build Instructions

Prerequisites

Required:

• CMake 3.14 or higher - Download
• C/C++ Compiler:
  • Windows: Visual Studio 2013+ (MSVC)
  • Linux: GCC or Clang
  • macOS: Xcode Command Line Tools
• Git - For fetching dependencies
• OpenGL 3.2+ compatible graphics driver

Verify Installation

Check if CMake is installed:

cmake --version

Should show version 3.14 or higher.

Check if Git is installed:

git --version

Building

Dependencies (GLUS, GLFW and GLEW) are automatically downloaded and built via CMake FetchContent. GLUS is taken from the sibling local checkout ../GLUS when present (multi-repo development layout), and otherwise fetched from its own repository at github.com/McNopper/GLUS. GLUS in turn provides cgltf and stb_image, and exposes its shader directory through the GLUS_SHADER_DIR compile definition.

Windows (Visual Studio):

mkdir build && cd build
cmake ..
cmake --build .

Linux / macOS:

mkdir build && cd build
cmake ..
make

Executables will be in the Binaries/ directory.

Dependencies

All dependencies are automatically fetched and built:

• GLFW 3.4 - Windowing and input
• GLEW 2.2.0 - OpenGL Extension Wrangler
• OpenGL 3.2+ - System graphics library

Examples

All examples demonstrate various OpenGL 3.x and 4.x features with GLSL shaders.

• Example01 - Basic window and OpenGL 3 initialization
• Example02 - Rendering of a triangle
• Example03 - Grey filter
• Example04 - Perspective rendering of a cube
• Example05 - Phong rendering of a sphere
• Example06 - Texturing of a cube
• Example07 - Normal mapping
• Example08 - Environment/cube mapping
• Example09 - GPU Particles
• Example10 - Geometry shader
• Example11 - Reflection and refraction
• Example12 - Shadow mapping
• Example13 - Simple tessellation (OpenGL 4.1)
• Example14 - Terrain rendering (OpenGL 4.1)
• Example15 - Water rendering
• Example16 - Model loading and rendering
• Example17 - Clipping planes and two sided rendering
• Example18 - Using stencil buffer and clipping planes
• Example19 - Render to texture and planar reflection
• Example20 - Texture matrix, alpha blending and discarding
• Example21 - Compute shader (OpenGL 4.3)
• Example22 - Shadow volumes
• Example23 - Displacement mapping (OpenGL 4.1)
• Example24 - Erode effect using perlin noise
• Example25 - Model with groups and materials
• Example26 - Fur rendering
• Example27 - Projection shadow for directional light
• Example28 - Screen space ambient occlusion (SSAO) (OpenGL 4.1)
• Example29 - CPU ray tracing
• Example30 - GPU ray tracing using compute shader (OpenGL 4.3)
• Example31 - Many lights using deferred shading (OpenGL 4.1)
• Example32 - BRDF and IBL rendering (OpenGL 4.1)
• Example33 - Real-Time BRDF and IBL rendering (OpenGL 4.1)
• Example34 - Subsurface scattering
• Example35 - Order independent transparency using depth peeling
• Example36 - Order independent transparency using linked list (OpenGL 4.4)
• Example37 - CPU ray marching
• Example38 - Basic usage of program pipeline and separable programs (OpenGL 4.1)
• Example39 - Basic usage of program pipeline, separable programs and shader subroutines (OpenGL 4.1)
• Example40 - Cloth simulation using compute shader (OpenGL 4.3)
• Example41 - Ocean wave height/normal map calculation with FFT using compute shader (OpenGL 4.3)
• Example42 - Fast Approximate Anti Aliasing - FXAA (OpenGL 4.3)
• Example43 - Scene with several models having groups and materials
• Example44 - Conservative rasterization
• Example45 - GPU voxelization (OpenGL 4.4)
• Example46 - Voxel cone tracing - Global illumination (OpenGL 4.6)
• Example47 - 3D spatial colour sort — RGB cube (OpenGL 4.6)
• Example48 - glTF 2.0 PBR renderer with Image-Based Lighting (OpenGL 4.6)
• Example49 - glTF 2.0 PBR + IBL + Skeletal Animation (OpenGL 4.6)
• Example50 - Rec.2020 HDR via EGL (OpenGL 4.6)
• Example51 - 3D Gaussian Splatting via KHR_gaussian_splatting (OpenGL 4.6)
• Example52 - 3D Gaussian Splatting with view-direction SH rotation (OpenGL 4.6)

Example01 - Basic window and OpenGL 3 initialization

Example02 - Rendering of a triangle

Example03 - Grey filter

Example04 - Perspective rendering of a cube

Example05 - Phong rendering of a sphere

Example06 - Texturing of a cube

Example07 - Normal mapping

Example08 - Environment/cube mapping

Example09 - GPU Particles

Example10 - Geometry shader

Example11 - Reflection and refraction

Example12 - Shadow mapping

Example13 - Simple tessellation (OpenGL 4.1)

Example14 - Terrain rendering (OpenGL 4.1)

Example15 - Water rendering

Example16 - Model loading and rendering

Example17 - Clipping planes and two sided rendering

Example18 - Using stencil buffer and clipping planes

Example19 - Render to texture and planar reflection

Example20 - Texture matrix, alpha blending and discarding

Example21 - Compute shader (OpenGL 4.3)

Example22 - Shadow volumes

Example23 - Displacement mapping (OpenGL 4.1)

Example24 - Erode effect using perlin noise

Example25 - Model with groups and materials

Example26 - Fur rendering

Example27 - Projection shadow for directional light

Example28 - Screen space ambient occlusion (SSAO) (OpenGL 4.1)

Example29 - CPU ray tracing

Example30 - GPU ray tracing using compute shader (OpenGL 4.3)

Example31 - Many lights using deferred shading (OpenGL 4.1)

Example32 - BRDF and IBL rendering (OpenGL 4.1)

Example33 - Real-Time BRDF and IBL rendering (OpenGL 4.1)

Example34 - Subsurface scattering

Example35 - Order independent transparency using depth peeling

Example36 - Order independent transparency using linked list (OpenGL 4.4)

Example37 - CPU ray marching

Example38 - Basic usage of program pipeline and separable programs (OpenGL 4.1)

Example39 - Basic usage of program pipeline, separable programs and shader subroutines (OpenGL 4.1)

Example40 - Cloth simulation using compute shader (OpenGL 4.3)

Example41 - Ocean wave height/normal map calculation with FFT using compute shader (OpenGL 4.3)

Example42 - Fast Approximate Anti Aliasing - FXAA (OpenGL 4.3)

Example43 - Scene with several models having groups and materials

Example44 - Conservative rasterization

Example45 - GPU voxelization (OpenGL 4.4)

Example46 - Voxel cone tracing - Global illumination (OpenGL 4.6)

Real-time global illumination using voxel cone tracing based on [C