si_normalmap

A very simple normal map generator written as a single header library.

Features:

• Convert color buffer to greyscale using either lightness, average or luminance methods(with SSE/AVX versions available)
• Convert greyscale buffer to a normal map with gaussian blur pre-filtering

Interface

typedef enum
{
    sinm_greyscale_none,
    sinm_greyscale_lightness,
    sinm_greyscale_average,
    sinm_greyscale_luminance,
    sinm_greyscale_count,
} sinm_greyscale_type;

void sinm_greyscale(const uint32_t *in, uint32_t *out, int32_t w, int32_t h, sinm_greyscale_type type);

uint32_t *sinm_normal_map(const uint32_t *in, int32_t w, int32_t h, float scale, float blurRadius, sinm_greyscale_type greyscaleType);

Basic Usage:

#define SI_NORMALMAP_IMPLEMENTATION
#include "si_normalmap.h"

int main()
{
    uint32_t *image = //...load pixels from some image;
    uint32_t *nm = sinm_normal_map(image, imageWidth, imageHeight, 1.0f, 2.0f, sinm_greyscale_average); 

    //... write normalmap to a file
    
    return 0;
}

Example(texture from opengameart.org):

Input:

Output:

Comparison of lighting without and with normal map(and a second "detail" normal map)