VertexLayout.hpp

Go to the documentation of this file.

#pragma once
 
#include "NDData.hpp"
 
namespace MayaFlux::Kakshya {
 
/**
 * @struct VertexAttributeLayout
 * @brief Semantic description of a single vertex attribute
 *
 * Describes one component of vertex data without exposing Vulkan types.
 * The modality encodes everything needed (3D position, 2D texture coords, etc.)
 */
struct VertexAttributeLayout {
    /**
     * Semantic type of this attribute
     * e.g., VERTEX_POSITIONS_3D → vec3, TEXTURE_COORDS_2D → vec2
     */
    DataModality component_modality;
 
    /**
     * Byte offset of this attribute within one vertex
     * e.g., position at 0, normal at 12, color at 24
     */
    uint32_t offset_in_vertex = 0;
 
    /**
     * Optional name for debugging/introspection
     * e.g., "position", "normal", "texCoord"
     */
    std::string name;
};
 
/**
 * @struct VertexLayout
 * @brief Complete description of vertex data layout in a buffer
 *
 * Fully semantic and backend-agnostic. Portal layer translates to Vulkan.
 * Derived from buffer's modality and dimensions.
 */
struct VertexLayout {
    /**
     * Total number of vertices in this buffer
     */
    uint32_t vertex_count = 0;
 
    /**
     * Total bytes per vertex (stride in Vulkan terms)
     * e.g., 3 floats (position) + 3 floats (normal) = 24 bytes
     */
    uint32_t stride_bytes = 0;
 
    /**
     * All attributes that make up one vertex
     * Ordered by shader location (0, 1, 2, ...)
     */
    std::vector<VertexAttributeLayout> attributes;
 
    /**
     * Helper: compute stride from attributes if not explicitly set
     */
    void compute_stride()
    {
        if (stride_bytes == 0 && !attributes.empty()) {
            uint32_t max_offset = 0;
            uint32_t last_size = 0;
 
            for (const auto& attr : attributes) {
                uint32_t attr_size = modality_size_bytes(attr.component_modality);
                max_offset = std::max(max_offset, attr.offset_in_vertex);
                if (attr.offset_in_vertex == max_offset) {
                    last_size = attr_size;
                }
            }
 
            stride_bytes = max_offset + last_size;
        }
    }
 
private:
    /**
     * Get size in bytes for a given modality
     * Mirrors VKBuffer::get_format() logic
     */
    static uint32_t modality_size_bytes(DataModality mod)
    {
        switch (mod) {
        case DataModality::VERTEX_POSITIONS_3D:
        case DataModality::VERTEX_NORMALS_3D:
        case DataModality::VERTEX_TANGENTS_3D:
        case DataModality::VERTEX_COLORS_RGB:
            return sizeof(glm::vec3);
 
        case DataModality::TEXTURE_COORDS_2D:
            return sizeof(glm::vec2);
 
        case DataModality::VERTEX_COLORS_RGBA:
            return sizeof(glm::vec4);
 
        case DataModality::AUDIO_1D:
        case DataModality::AUDIO_MULTICHANNEL:
            return sizeof(double);
 
        default:
            return 4; // Conservative default
        }
    }
};
 
} // namespace MayaFlux::Buffers