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Software Requirements Specification

grender_cpu Module​

1. Overview

This document specifies the software requirements for the grender_cpu module.

grender_cpu is a CPU-based rendering backend module within the Grap rendering system.
The module implements rendering functionality using CPU memory buffers and integrates with the rendering interfaces defined by the grender module.

The implementation structure and responsibilities described in this document are derived directly from the current source code layout.

2. Scope

The grender_cpu module provides the following functional responsibilities derived from the existing source code.

  • CPU render device implementation
  • framebuffer memory management
  • vertex processing stage
  • primitive clipping stage
  • rasterization stage
  • fragment operations

The module acts as a rendering backend implementation and operates within the Grap rendering architecture.

3. Module Structure

The current module directory structure is defined as follows.

grender_cpu/ ├─ common/ │ └─ cpu_types.hpp ├─ device/ │ ├─ cpu_render_device.hpp │ └─ cpu_render_device.cpp ├─ framebuffer/ │ ├─ color_buffer.hpp │ ├─ depth_buffer.hpp │ └─ framebuffer_view.hpp ├─ pipeline/ │ ├─ vertex_stage.hpp │ ├─ vertex_stage.cpp │ ├─ clipper.hpp │ ├─ clipper.cpp │ ├─ fragment_ops.hpp │ ├─ fragment_ops.cpp │ └─ raster/ │ ├─ raster_types.hpp │ ├─ raster_context.hpp │ ├─ edge_function.hpp │ ├─ barycentric.hpp │ ├─ triangle_rasterizer.hpp │ ├─ triangle_rasterizer.cpp │ ├─ line_rasterizer.hpp │ ├─ line_rasterizer.cpp │ ├─ point_rasterizer.hpp │ └─ point_rasterizer.cpp └─ tests/

4. Functional Areas

Based on the code organization, the module is divided into the following functional areas.

4.1 Common Types​

Source Location

common/cpu_types.hpp

This component defines CPU-side types used across the renderer.

4.2 Rendering Device​

Source Location

device/cpu_render_device.hpp
device/cpu_render_device.cpp

This component implements the CPU render device used by the rendering backend.

4.3 Framebuffer Management​

Source Location

framebuffer/color_buffer.hpp
framebuffer/depth_buffer.hpp
framebuffer/framebuffer_view.hpp

These components define the framebuffer structures used by the renderer.

Framebuffer related components include

  • color buffer
  • depth buffer
  • framebuffer view abstraction

4.4 Rendering Pipeline​

Source Location

pipeline/

The rendering pipeline is divided into several stages based on the source code organization.

Vertex Stage​

Source Files

pipeline/vertex_stage.hpp
pipeline/vertex_stage.cpp

Responsible for processing vertex data before rasterization.

Primitive Clipping​

Source Files

pipeline/clipper.hpp
pipeline/clipper.cpp

Responsible for performing primitive clipping operations.

Fragment Operations​

Source Files

pipeline/fragment_ops.hpp
pipeline/fragment_ops.cpp

Responsible for fragment-level operations during rasterization.

Rasterization​

Source Location

pipeline/raster/

Rasterization components are divided into several implementation units.

Rasterization related files include

raster_types.hpp
raster_context.hpp
edge_function.hpp
barycentric.hpp
triangle_rasterizer.hpp
triangle_rasterizer.cpp
line_rasterizer.hpp
line_rasterizer.cpp
point_rasterizer.hpp
point_rasterizer.cpp

These components implement primitive rasterization functionality.

5. Testing

Source Location

tests/

The tests directory contains test programs used to verify the functionality of the CPU renderer components.

6. Dependencies

The grender_cpu module depends on the following Grap modules.

  • grender
  • ghost

These dependencies are defined in the module build configuration.

7. Constraints

The module implementation is constrained by the following conditions.

  • The renderer operates entirely on CPU memory buffers.
  • Rendering output is written into framebuffer structures.
  • The module must integrate with the grender rendering interface.
  • The module must operate within the Grap module architecture.

8. Summary

The grender_cpu module provides a CPU-based rendering backend for the Grap rendering system.

The implementation is structured into the following major components.

  • common types
  • render device implementation
  • framebuffer management
  • rendering pipeline
  • rasterization components
  • tests

The structure and requirements described in this document are derived from the current module source code organization.