engine/src/core-data/Common/ShaderLib/Texture.glsllib

#import "Common/ShaderLib/Common.glsllib"

vec3 Texture_GetNormal(in sampler2D normalMap, in vec2 texCoord){
    #ifdef NORMAL_LATC
        return Common_UnpackNormalLA( texture2D(normalMap, texCoord) );
    #else
        return Common_UnpackNormal( texture2D(normalMap, texCoord).rgb );
    #endif
}

#ifdef DXT_YCOCG
const mat4 ycocg_mat = mat4( 1.0, -1.0,  0.0,                 1.0,
                             0.0,  1.0, -0.5 * 256.0 / 255.0, 1.0,
                            -1.0, -1.0,        256.0 / 255.0, 1.0,
                             0.0,  0.0,  0.0,                 0.0 );
#endif

vec4 Texture_GetColor(in sampler2D colorMap, in vec2 texCoord){
    #ifdef DXT_YCOCG
        vec4 color = texture2D(colorMap, texCoord);
        // fast YCoCg decode:
        color.z = 1.0 / ((color.z * ( 255.0 / 8.0 )) + 1.0);
        color.xy *= color.z;
        return color * ycocg_mat;

        // slow decode:
        //float Y = color.a;
        //float scale = 1.0 / ((255.0 / 8.0) * color.b + 1.0);
        //const float offset = 128.0 / 255.0;
        //float Co = (color.r - offset) * scale;
        //float Cg = (color.g - offset) * scale;

        //float R = Y + Co - Cg;
        //float G = Y + Cg;
        //float B = Y - Co - Cg;

        //return vec4(R, G, B, 1.0);
    #else
        return texture2D(colorMap, texCoord);
    #endif
}