agent_compositor_test/documents/session-logs/2026-07-12.md

Session Log — 2026-07-12

RHI Global Context Refactor

Reviewed the user's staged changes to the Vulkan RHI backend. The changes encompassed:

Global Context Adoption

• RHI functions no longer take allocator parameters
• _G_RHI_CONTEXT provides allocator (user-facing objects) and tmp (short-lived temporaries)
• prRhiInit(void) / prRhiDestroy(void) manage the global context

KTX Texture Bug Fix

• Original implementation only copied mip level 0
• Fixed to iterate all mip levels using ktxTexture_GetImageOffset()
• Final layout changed from VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL to VK_IMAGE_LAYOUT_READ_ONLY_OPTIMAL

Frame-by-Frame Command Batching Pattern

• Commands that run every frame avoid arena allocation
• Use stack arrays with while-loop to batch operations in fixed-size chunks
• Applied to: prRhiCmdBindDescriptorSets, prRhiCmdBindVertexBuffers, prRhiCmdCopyBufferToImage

API Simplifications

• prRhiCreateCommandPool: removed desc parameter, uses device->queue_family_index
• prRhiFreeCommandBuffers: removed count parameter, uses wpArrayCount
• prRhiAllocateDescriptorSet: changed u32 variable_count to WpU32Array variable_descriptor_counts
• prRhiCmdBindVertexBuffers: changed raw pointer + count to WpU64Array

New Pipeline Configuration

• Added polygon_mode, cull_mode, front_face to rasterization
• Added depth_test_enable, depth_write_enable, depth_compare_op
• Added vertex_shader_entry_point, fragment_shader_entry_point (not hardcoded to "main")
• Added line_width, multisample_count

Code Style Updates

• All Vulkan info structs use C99 designated initializers
• Removed unnecessary type casts on opaque struct handles
• Added braces to all single-line if statements
• Braces rule moved from prism-rhi skill to AGENTS.md formatting section

Documentation Updates

• Updated prism-rhi skill with all new conventions
• Updated AGENTS.md with frame-by-frame batching pattern
• Moved braces rule to AGENTS.md (not RHI-specific)