refactor(engine): make shaders a renderer detail

1 files changed, 133 insertions, 0 deletions

diff --git a/engine/src/renderer/opengl/glsl/light.glsl b/engine/src/renderer/opengl/glsl/light.glsl
new file mode 100644
index 0000000..1bc23a4
--- /dev/null
+++ b/engine/src/renderer/opengl/glsl/light.glsl
@@ -0,0 +1,133 @@
+#version 330 core
+
+#ifndef LIGHT_GLSL
+#define LIGHT_GLSL
+
+#preinclude "vertex_data.glsl"
+
+struct Material
+{
+	vec3 ambient;
+	vec3 diffuse;
+	vec3 specular;
+	sampler2D ambient_map;
+	sampler2D diffuse_map;
+	sampler2D specular_map;
+	float shininess;
+};
+
+struct LightPhong
+{
+	vec3 diffuse;
+	vec3 specular;
+};
+
+struct AttenuationProperties
+{
+	float constant;
+	float linear;
+	float quadratic;
+};
+
+struct PointLight
+{
+	LightPhong phong;
+	vec3 position;
+	AttenuationProperties attenuation_props;
+};
+
+struct DirectionalLight
+{
+	LightPhong phong;
+	vec3 direction;
+};
+
+struct CalculatedLight
+{
+	vec3 diffuse;
+	vec3 specular;
+};
+
+vec3 calc_ambient_light(in Material material, in vec2 texture_coords)
+{
+	return vec3(texture(material.ambient_map, texture_coords)) * material.ambient;
+}
+
+vec3 calc_diffuse_light(
+	in Material material,
+	in LightPhong light_phong,
+	in vec3 light_dir,
+	in vec3 norm,
+	in vec2 texture_coords
+)
+{
+	float diff = max(dot(norm, light_dir), 0.0);
+
+	return light_phong.diffuse * (
+		diff * (vec3(texture(material.diffuse_map, texture_coords)) * material.diffuse)
+	);
+}
+
+vec3 calc_specular_light(
+	in Material material,
+	in LightPhong light_phong,
+	in vec3 light_dir,
+	in vec3 norm,
+	in vec3 view_pos,
+	in vec3 frag_pos,
+	in vec2 texture_coords
+)
+{
+	vec3 view_direction = normalize(view_pos - frag_pos);
+
+	vec3 reflect_direction = reflect(-light_dir, norm);
+
+	float spec =
+		pow(max(dot(view_direction, reflect_direction), 0.0), material.shininess);
+
+	return light_phong.specular * (
+		spec * (vec3(texture(material.specular_map, texture_coords)) * material.specular)
+	);
+}
+
+float calc_attenuation(in PointLight point_light, in vec3 position)
+{
+	float light_distance = length(point_light.position - position);
+
+	return 1.0 / (point_light.attenuation_props.constant
+		+ point_light.attenuation_props.linear
+		* light_distance + point_light.attenuation_props.quadratic
+		* pow(light_distance, 2));
+}
+
+void calc_light(
+	in vec3 light_direction,
+	in LightPhong light_phong,
+	in VertexData vertex_data,
+	in vec3 view_pos,
+	in Material material,
+	out CalculatedLight calculated_light
+)
+{
+	vec3 norm = normalize(vertex_data.world_space_normal);
+
+	calculated_light.diffuse = calc_diffuse_light(
+		material,
+		light_phong,
+		light_direction,
+		norm,
+		vertex_data.texture_coords
+	);
+
+	calculated_light.specular = calc_specular_light(
+		material,
+		light_phong,
+		light_direction,
+		norm,
+		view_pos,
+		vertex_data.world_space_pos,
+		vertex_data.texture_coords
+	);
+}
+
+#endif