This is a CPU-only, learning-oriented software renderer. The goal is to make a clear and readable implementation of a classic rasterization pipeline and the core bits of PBR.

Heads-up: PBRShader is still work-in-progress, and there are known bugs to fix. This is intentional for learning and iteration.

1. Update example asset paths to match your machine (or make them relative to the project root assets/):

• examples/pbr_chandelier.cpp
• examples/african_head.cpp

2. Build and run with xmake:

xmake -y
xmake run pointcloud
# others:
# xmake run african_head
# xmake run triangles
# xmake run wireframe
# xmake run pointcloud

• Core pipeline

  • Vertex processing → clipping → perspective divide → rasterization → fragment shading → output
  • Triangle rasterizer using bounding-box scan and edge functions
  • Perspective-correct interpolation for attributes and depth
  • Viewport transform and depth buffer testing

• Clipping

  • Lines: Liang–Barsky
  • Triangles: Sutherland–Hodgman (to clip space, then retriangulate)

• Shaders

  • FlatShader: solid vertex color
  • TexturedShader: textured with UVs
  • PBRShader (WIP): physically based BRDF with metallic-roughness inputs

• Texturing

  • SamplerState: address (Clamp/Repeat/Mirror/Border), filtering (Nearest/Bilinear), mip filter (None/Nearest/Linear)
  • Mipmap generation: simple 2×2 box downsampling
  • UV origin configurable (TopLeft / BottomLeft)
  • Per-texture color space: sRGB vs Linear
  • Screen-space UV gradients for LOD selection (finite differences on neighbors)

• Color & output

  • Internal linear space processing
  • Exposure (EV) + tone mapping: Linear→sRGB, Reinhard, ACES

• IO & assets

  • glTF (TinyGLTF): loads positions / normals / texcoord0 (+ optional tangent/texcoord1), factors, texture paths, and KHR_texture_transform
  • Images via stb_image
  • For simplicity, the glTF loader takes the first mesh/primitive

• Framework

  • Window/input (minifb), Orbit camera controller, Perspective/Orthographic cameras
  • Ground plane and XYZ axes helpers for scene orientation

• Examples

  • pbr_chandelier.cpp (PBR, glTF)
  • african_head.cpp (textured OBJ)
  • triangles.cpp, wireframe.cpp, pointcloud.cpp

• PBRShader: WIP (features are being filled in and tuned)
• Some known bugs remain;
• Extras like IBL/shadows/clearcoat are intentionally left out for now