From cb7385bc1b6bcf6800c4af5c50f4f8652b3d233c Mon Sep 17 00:00:00 2001
From: s473621 <marsau@st.amu.edu.pl>
Date: Sat, 3 Feb 2024 21:03:12 +0100
Subject: [PATCH] adding pbr shader for plants.......?...?..?

---
 PlanetCreator/cw 6/shaders/shader_pbr.frag | 67 ++++++++++++++--------
 PlanetCreator/cw 6/src/ex_6_1.hpp          |  3 +-
 2 files changed, 46 insertions(+), 24 deletions(-)

diff --git a/PlanetCreator/cw 6/shaders/shader_pbr.frag b/PlanetCreator/cw 6/shaders/shader_pbr.frag
index f071342..9f2a55b 100644
--- a/PlanetCreator/cw 6/shaders/shader_pbr.frag	
+++ b/PlanetCreator/cw 6/shaders/shader_pbr.frag	
@@ -1,9 +1,15 @@
 #version 430 core
+#define PI 3.14159265359
 
 float AMBIENT = 0.1;
 
+uniform vec3 albedo;
+uniform float metallic;
+uniform float roughness;
 uniform vec3 color;
 uniform vec3 lightPos;
+uniform vec3 viewPos;
+uniform vec3 ambientColor;
 uniform sampler2D colorTexture;
 
 in vec3 fragNormal;
@@ -12,40 +18,55 @@ in vec2 texCoords;
 
 out vec4 outColor;
 
-uniform float shininess;
-uniform vec3 ambientColor;
-uniform vec3 specularColor;
-uniform vec3 emissiveColor;
-uniform float opticalDensity;
-uniform float dissolve;
-uniform int illuminationModel;
+float specularD(float NdotH, float roughness)
+{
+    float alpha = roughness * roughness;
+    float alpha2 = alpha * alpha;
+    float cos2ThetaH = NdotH * NdotH;
+
+    float expTerm = (cos2ThetaH - 1.0) / (alpha2 * cos2ThetaH);
+    return exp(expTerm) / (PI * alpha2 * pow(cos2ThetaH + alpha2 - 1.0, 2.0));
+}
+
+vec3 specularF(float LdotH, vec3 F0)
+{
+    return F0 + (vec3(1.0) - F0) * pow(1.0 - LdotH, 5.0);
+}
+
+float specularG(float NdotL, float NdotV, float roughness)
+{
+    float k = (roughness + 1.0) * (roughness + 1.0) / 8.0;
+
+    float GL = NdotL / (NdotL * (1.0 - k) + k);
+    float GV = NdotV / (NdotV * (1.0 - k) + k);
+
+    return GL * GV;
+}
 
 void main()
 {
-    vec3 lightDir = normalize(lightPos - fragPosition);
     vec3 normal = normalize(fragNormal);
-    float diffuse = max(0.0, dot(normal, lightDir));
+    vec3 viewDir = normalize(viewPos - fragPosition);
+    vec3 lightDir = normalize(lightPos - fragPosition);
 
-  
-    vec3 lambertian = texture(colorTexture, texCoords).rgb * diffuse;
+    vec3 F0 = vec3(0.04); 
+    F0 = mix(F0, albedo, metallic);
 
-  
-    vec3 viewDir = normalize(-fragPosition);
-    vec3 halfwayDir = normalize(lightDir + viewDir);
-    float specular = pow(max(0.0, dot(normal, halfwayDir)), shininess);
-    vec3 blinnPhong = specularColor * specular;
+    float NdotL = max(dot(normal, lightDir), 0.0);
+    float NdotV = max(dot(normal, viewDir), 0.0);
 
-   
-    vec3 emissive = emissiveColor;
+    vec3 H = normalize(lightDir + viewDir);
+    float NdotH = max(dot(normal, H), 0.0);
+    float LdotH = max(dot(lightDir, H), 0.0);
+    vec3 albedo = texture(colorTexture, texCoords).rgb;
+    albedo *= 2.0;
+    vec3 specular = F0 * (specularD(NdotH, roughness) * specularF(LdotH, F0) * specularG(NdotL, NdotV, roughness)) / (4.0 * NdotL * NdotV);
 
+    vec3 diffuse = (1.0 - F0) * albedo / PI;
 
     vec3 ambient = ambientColor * AMBIENT;
 
-   
-    vec3 finalColor = lambertian + blinnPhong + emissive + ambient;
-
-    
-    finalColor *= (1.0 - dissolve);
+    vec3 finalColor = ambient + (diffuse + specular) * NdotL;
 
     outColor = vec4(finalColor, 1.0);
 }
diff --git a/PlanetCreator/cw 6/src/ex_6_1.hpp b/PlanetCreator/cw 6/src/ex_6_1.hpp
index 7f88d68..1e4e03d 100644
--- a/PlanetCreator/cw 6/src/ex_6_1.hpp	
+++ b/PlanetCreator/cw 6/src/ex_6_1.hpp	
@@ -399,7 +399,8 @@ void drawObjectTexture_plant(Core::RenderContext& context, glm::mat4 modelMatrix
 	glUniform1f(glGetUniformLocation(program, "opticalDensity"), material.Ni);
 	//glUniform1f(glGetUniformLocation(program, "dissolve"), material.d);
 	glUniform1i(glGetUniformLocation(program, "illuminationModel"), material.illum);
-
+	glUniform1f(glGetUniformLocation(program, "metallic"), 0.05);
+	glUniform1f(glGetUniformLocation(program, "roughness"), 0.2);
 	Core::DrawContext(context);
 	glUseProgram(0);
 }