2 files changed, 177 insertions, 0 deletions
diff --git a/source/lessons/models/shaders/model/model.fs.glsl b/source/lessons/models/shaders/model/model.fs.glsl
new file mode 100644
index 0000000..87da0b6
--- /dev/null
+++ b/source/lessons/models/shaders/model/model.fs.glsl
@@ -0,0 +1,152 @@
+#version 330 core
+
+#define MAX_TEXTURES 32
+struct Material {
+  sampler2D diffuse[MAX_TEXTURES];
+  sampler2D specular[MAX_TEXTURES];
+  float shininess;
+};
+
+struct DirectionalLight {
+  vec3 direction;
+
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+};
+
+struct PointLight {
+  vec3 position;
+
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+
+  // attentuation factors
+  float kC;
+  float kL;
+  float kQ;
+};
+
+struct SpotLight {
+  vec3 position;
+
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+
+  // attenuation factors
+  float kC;
+  float kL;
+  float kQ;
+
+  // vector for the direction directly in front of the spotlight
+  vec3 front;
+
+  // spot radius
+  float radius_inner;
+  float radius_outer; // to smooth out the light
+
+};
+
+// this is the result of a light creation. This contains the multipliers for each kind of a light we want
+// to have.
+struct LightFactor {
+  vec3 ambient;
+  vec3 diffuse;
+  vec3 specular;
+};
+
+in vec2 TexCoords;
+in vec3 FragNormal;
+in vec3 VertexWorldPos;
+uniform Material material;
+uniform PointLight pointLight;
+uniform DirectionalLight dirLight;
+uniform vec3 cameraPosition;
+
+out vec4 FragColor;
+
+LightFactor make_directional_light(DirectionalLight light, vec3 CONST_viewDir) {
+  LightFactor res;
+
+  vec3 DL_lightDir = normalize(-light.direction);
+  res.ambient = light.ambient;
+
+  float DL_diffuseStrength = max(dot(DL_lightDir, FragNormal), 0.0);
+  res.diffuse = light.diffuse * DL_diffuseStrength;
+
+  vec3  DL_reflectDir	    = reflect(-DL_lightDir, FragNormal);
+  float DL_specularity		= max(dot(CONST_viewDir, DL_reflectDir), 0.0);
+  float DL_shinePower			= pow(DL_specularity, material.shininess);
+  res.specular	= light.specular * DL_shinePower;
+
+  return res;
+};
+
+LightFactor make_point_light(PointLight light, vec3 CONST_viewDir) {
+  LightFactor res;
+
+  float PL_lightDistance = length(light.position - VertexWorldPos);
+  float PL_attenuationFactor = 1.0 / 
+  (light.kC + (light.kL * PL_lightDistance) + (light.kQ * PL_lightDistance * PL_lightDistance));
+  res.ambient = PL_attenuationFactor * light.ambient;
+
+  vec3 PL_lightDir = normalize(light.position - VertexWorldPos);
+  float PL_diffuseStrength = max(dot(PL_lightDir, FragNormal), 0.0);
+  res.diffuse = PL_attenuationFactor * light.diffuse * PL_diffuseStrength;
+
+  vec3  PL_reflectDir		= reflect(-PL_lightDir, FragNormal);
+  float PL_specularity	= max(dot(CONST_viewDir, PL_reflectDir), 0.0);
+  float PL_shinePower		= pow(PL_specularity, material.shininess);
+  res.specular		      = PL_attenuationFactor * PL_shinePower * light.specular;
+
+  return res;
+}
+
+LightFactor make_spot_light(SpotLight light, vec3 CONST_viewDir) {
+  LightFactor res;
+
+  float SL_lightDistance = length(light.position - VertexWorldPos);
+  float SL_attenuationFactor = 1.0 / 
+  (light.kC + (light.kL * SL_lightDistance) + (light.kQ * SL_lightDistance * SL_lightDistance));
+  vec3 SL_lightDir = normalize(light.position - VertexWorldPos);
+
+  res.ambient = SL_attenuationFactor * light.ambient;
+
+  float SL_diffAmount = dot(SL_lightDir, normalize(-light.front));
+  float SL_spotLightFadeFactor = clamp((SL_diffAmount - light.radius_outer)/(light.radius_inner - light.radius_outer), 0.0f, 1.0f);
+  float SL_diffuseStrength = max(dot(SL_lightDir, FragNormal), 0.0);
+  res.diffuse = SL_spotLightFadeFactor * SL_attenuationFactor * light.diffuse * SL_diffuseStrength;
+
+  vec3  SL_reflectDir		= reflect(-SL_lightDir, FragNormal);
+  float SL_specularity	= max(dot(CONST_viewDir, SL_reflectDir), 0.0);
+  float SL_shinePower		= pow(SL_specularity, material.shininess);
+  res.specular		      = SL_spotLightFadeFactor * SL_attenuationFactor * SL_shinePower * light.specular;
+
+  return res;
+}
+
+void main() {
+  vec3 CONST_viewDir		= normalize(cameraPosition - VertexWorldPos);
+  vec3 combinedAmbience = vec3(0.0);
+  vec3 combinedDiffuse  = vec3(0.0);
+  vec3 combinedSpecular = vec3(0.0);
+
+  LightFactor DL_factors = make_directional_light(dirLight, CONST_viewDir);
+  combinedAmbience += DL_factors.ambient;
+  combinedDiffuse += DL_factors.diffuse;
+  combinedSpecular += DL_factors.specular;
+
+  //LightFactor PL_factors = make_point_light(pointLight, CONST_viewDir);
+  //combinedAmbience += PL_factors.ambient;
+  //combinedDiffuse += PL_factors.diffuse;
+  //combinedSpecular += PL_factors.specular;
+
+  vec3 ambientLight  = combinedAmbience * vec3(texture(material.diffuse[0],  TexCoords));
+  vec3 diffuseLight  = combinedDiffuse  * vec3(texture(material.diffuse[0],  TexCoords));
+  vec3 specularLight = combinedSpecular * vec3(texture(material.specular[0], TexCoords));
+
+  vec3 color = ambientLight + diffuseLight + specularLight;
+  FragColor = vec4(color, 1.0);
+};
diff --git a/source/lessons/models/shaders/model/model.vs.glsl b/source/lessons/models/shaders/model/model.vs.glsl
new file mode 100644
index 0000000..da394cf
--- /dev/null
+++ b/source/lessons/models/shaders/model/model.vs.glsl
@@ -0,0 +1,25 @@
+#version 330 core
+layout(location=0) in vec3 aPos;
+layout(location=1) in vec3 aNormal;
+layout(location=2) in vec2 aTex;
+
+uniform mat4 Model;
+uniform mat4 View;
+uniform mat4 Projection;
+
+out vec2 TexCoords;
+out vec3 VertexWorldPos;
+out vec3 FragNormal;
+
+// @note: I still do not fully understand how the FragNormal calculation works. Need to make sure I intuitively 
+// get that
+
+void main() {
+  gl_Position = Projection*View*Model*vec4(aPos, 1.0);
+
+  VertexWorldPos = vec3(Model * vec4(aPos, 1.0));
+  FragNormal = mat3(transpose(inverse(Model))) * aNormal;
+  FragNormal = normalize(FragNormal);
+  TexCoords = aTex;
+};
+