fshader.glsl

#ifdef GL_ES
// Set default precision to medium
precision mediump int;
precision mediump float;
#endif

uniform mat3 n_matrix;
uniform sampler2D texture;

uniform struct Light {
    vec3 position;
    vec3 intensities;
} light;

uniform bool b_transparent;

varying vec2 v_texcoord;
varying vec4 v_position;
varying vec3 v_normal;

void main()
{
    
    vec3 normal = normalize(n_matrix * v_normal);

    vec3 surfaceToLight = light.position - v_position;
    
    float brightness = dot(normal, surfaceToLight) / (length(surfaceToLight) * length(normal));
    brightness = clamp(brightness, 0, 1);

	// Set fragment color from texture
	vec4 surfaceColor = vec4(texture2D(texture, v_texcoord));

	if(!b_transparent)
	{
		surfaceColor.a = 1.0f;
	}

	gl_FragColor = vec4(brightness * light.intensities * surfaceColor.rgb, surfaceColor.a);
}