udemy_opengl/shaders/shader.frag
2025-07-07 20:00:35 -06:00

130 lines
3.3 KiB
GLSL

#version 460 core
in vec4 vertex_color;
in vec2 texture_coord;
in vec3 normal;
in vec3 frag_pos;
out vec4 color;
// Must match the same as in math.h
const int MAX_POINT_LIGHTS = 3;
const int MAX_SPOT_LIGHTS = 3;
struct Light {
vec3 color;
float ambient_intensity;
float diffuse_intensity;
};
struct Directional_Light {
Light light;
vec3 direction;
};
struct Point_Light {
Light light;
vec3 position;
float constant;
float linear;
float exponent;
};
struct Spot_Light {
Point_Light point_light;
vec3 direction;
float edge;
};
struct Material {
float shininess;
float specular_intensity;
};
uniform Directional_Light sun;
uniform Point_Light point_lights[MAX_POINT_LIGHTS];
uniform Spot_Light spot_lights[MAX_SPOT_LIGHTS];
uniform int point_light_count;
uniform int spot_light_count;
uniform sampler2D tex;
uniform Material material;
uniform vec3 eye_position;
vec4 calculate_light_by_direction(Light light, vec3 direction) {
vec4 ambient_color = vec4(light.color, 1.0f) * light.ambient_intensity;
float diffuse_factor = max(dot(normalize(normal), normalize(direction)), 0.0f);
vec4 diffuse_color = vec4(light.color * light.diffuse_intensity * diffuse_factor, 1.0f);
vec4 specular_color = vec4(0, 0, 0, 0);
if (diffuse_factor > 0.0f) {
vec3 frag_to_eye = normalize(eye_position - frag_pos);
vec3 reflected_vertex = normalize(reflect(direction, normalize(normal)));
float specular_factor = dot(frag_to_eye, reflected_vertex);
if (specular_factor > 0.0f) {
specular_factor = pow(specular_factor, material.shininess);
specular_color = vec4(light.color * material.specular_intensity * specular_factor, 1.0f);
}
}
return ambient_color + diffuse_color + specular_color;
}
vec4 calculate_point_light(Point_Light point_light) {
vec3 direction = frag_pos - point_light.position;
float distance = length(direction);
direction = normalize(direction);
vec4 light_color = calculate_light_by_direction(point_light.light, direction);
float attentuation = point_light.exponent * distance * distance + point_light.linear * distance + point_light.constant;
return (light_color / attentuation);
}
vec4 calculate_point_lights() {
vec4 final_color = vec4(0, 0, 0, 0);
for (int i=0; i<point_light_count; i++) {
final_color += calculate_point_light(point_lights[i]);
}
return final_color;
}
vec4 calculate_spot_light(Spot_Light spot_light) {
vec3 ray_direction = normalize(frag_pos - spot_light.point_light.position);
float spot_light_factor = dot(ray_direction, spot_light.direction);
if (spot_light_factor > spot_light.edge) {
vec4 light_color = calculate_point_light(spot_light.point_light);
return light_color * (1.0f - (1.0f - spot_light_factor)*(1.0f/(1.0f - spot_light.edge)));
}
return vec4(0, 0, 0, 0);
}
vec4 calculate_spot_lights() {
vec4 final_color = vec4(0, 0, 0, 0);
for (int i=0; i<spot_light_count; i++) {
final_color += calculate_spot_light(spot_lights[i]);
}
return final_color;
}
void main() {
vec4 final_color = calculate_light_by_direction(sun.light, sun.direction);
final_color += calculate_point_lights();
final_color += calculate_spot_lights();
color = texture(tex, texture_coord) * final_color;
}