Physically based rendering with textures

.gitattributes

@@ -1,3 +1,4 @@
 *.obj filter=lfs diff=lfs merge=lfs -text
 *.mtl filter=lfs diff=lfs merge=lfs -text
 *.jpg filter=lfs diff=lfs merge=lfs -text
+*.png filter=lfs diff=lfs merge=lfs -text

Shaders/pbr.fs

@@ -7,10 +7,11 @@ in vec3 Normal;
 
 uniform vec3 camPos;
 
-uniform vec3 albedo;
+uniform sampler2D albedoMap;
-uniform float metallic;
+uniform sampler2D metallicMap;
-uniform float roughness;
+uniform sampler2D normalMap;
-uniform float ao;
+uniform sampler2D roughnessMap;
+uniform sampler2D aoMap;
 
 uniform vec3 lightPositions[4];
 uniform vec3 lightColors[4];
@@ -59,8 +60,31 @@ float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
     return ggx1 * ggx2;
 }
 
-void main(){
+vec3 getNormalFromNormalMap(){
+    vec3 tangentNormal = texture(normalMap, TexCoords).xyz * 2.0 - 1.0;
+
+    vec3 Q1 = dFdx(WorldPos);
+    vec3 Q2 = dFdy(WorldPos);
+    vec2 st1 = dFdx(TexCoords);
+    vec2 st2 = dFdy(TexCoords);
+
     vec3 N = normalize(Normal);
+    vec3 T = normalize(Q1 *st2.t - Q2*st1.t);
+    vec3 B = -normalize(cross(N, T));
+    mat3 TBN = mat3(T, B, N);
+
+    return normalize(TBN * tangentNormal);
+}
+
+void main(){
+
+    vec3 albedo = pow(texture(albedoMap, TexCoords).rgb, vec3(2.2));
+    float metallic = texture(metallicMap, TexCoords).r;
+    float roughness = texture(roughnessMap, TexCoords).r;
+    float ao = texture(aoMap, TexCoords).r;
+
+
+    vec3 N = getNormalFromNormalMap();
     vec3 V = normalize(camPos - WorldPos);
     
     vec3 F0 = vec3(0.04);
@@ -98,8 +122,9 @@ void main(){
     vec3 ambient = vec3(0.03) * albedo * ao;
     vec3 color = ambient + Lo;
 
-    // Gamma correct the result 
+    // HDR tonemapping
     color = color / (color + vec3(1.0));
+    // gamma correct
     color = pow(color, vec3(1.0/2.2));
 
     FragColor = vec4(color, 1.0);

src/Renderer/Renderer.cpp

@@ -10,6 +10,7 @@
 #include <glm/gtc/matrix_transform.hpp>
 #include <glm/gtc/type_ptr.hpp>
 #include "../Primitives/Scene.h"
+#include "../model.h"
 static enum class RenderPass {
     NONE = 0,
     SKYBOX,
@@ -37,7 +38,11 @@ glm::vec3 lightColors[] = {
 int nrRows = 7;
 int nrColumns = 7;
 float spacing = 2.5;
-
+unsigned int albedo;
+unsigned int normal;
+unsigned int metallic;
+unsigned int roughness;
+unsigned int ao;
 void Renderer::Setup()
 {
     // Create ScreenVAO
@@ -70,6 +75,14 @@ void Renderer::Setup()
     shaders[static_cast<int>(RenderPass::PBR)] = Shader();
     shaders[static_cast<int>(RenderPass::PBR)].Load("../Shaders/pbr.vs", "../Shaders/pbr.fs");
 
+
+    albedo = TextureFromFile("../Textures/rusted_iron/albedo.png", ".");
+    normal = TextureFromFile("../Textures/rusted_iron/normal.png", ".");
+    metallic = TextureFromFile("../Textures/rusted_iron/metallic.png", ".");
+    roughness = TextureFromFile("../Textures/rusted_iron/roughness.png", ".");
+    ao = TextureFromFile("../Textures/rusted_iron/ao.png",".");
+
+
 }
 
 void Renderer::resize(int width, int height ) {
@@ -116,7 +129,6 @@ void Renderer::resize(int width, int height ) {
 
 
 
-
 unsigned int sphereVAO = 0;
 unsigned int indexCount;
 void renderSphere() {
@@ -232,6 +244,7 @@ void Renderer::Render(Scene& scene)
     auto centeredView = glm::mat4(glm::mat3(scene.MainCamera.GetViewMatrix()));
     shader.setMat4("view", centeredView);
 
+    glActiveTexture(GL_TEXTURE0);
     scene.skybox.Bind();
 
     glDrawArrays(GL_TRIANGLES, 0, 36);
@@ -266,20 +279,38 @@ void Renderer::Render(Scene& scene)
     shader = shaders.at(static_cast<int>(RenderPass::PBR));
 
     shader.use();
-    shader.setVec3("albedo", glm::vec3(0.5f, 0.0f, 0.0f));
+    shader.setInt("albedoMap", 0);
-    shader.setFloat("ao", 1.0f);
+    shader.setInt("normalMap", 1);
+    shader.setInt("metallicMap", 2);
+    shader.setInt("roughnessMap", 3);
+    shader.setInt("aoMap", 4);
+
     shader.setMat4("projection", projection);
     view = scene.MainCamera.GetViewMatrix();
     shader.setMat4("view", view);
     shader.setVec3("camPos", scene.MainCamera.Position);
 
+    glActiveTexture(GL_TEXTURE0);
+    glBindTexture(GL_TEXTURE_2D, albedo);
+
+    glActiveTexture(GL_TEXTURE1);
+    glBindTexture(GL_TEXTURE_2D, normal);
+
+    glActiveTexture(GL_TEXTURE2);
+    glBindTexture(GL_TEXTURE_2D, metallic);
+
+    glActiveTexture(GL_TEXTURE3);
+    glBindTexture(GL_TEXTURE_2D, roughness);
+
+
+    glActiveTexture(GL_TEXTURE4);
+    glBindTexture(GL_TEXTURE_2D, ao);
+
+
     model = glm::mat4(1.0f);
     for (int row = 0; row < nrRows; ++row) {
-        shader.setFloat("metallic", (float)row / (float)nrRows);
         for (int col = 0; col < nrColumns; ++col) {
 
-            shader.setFloat("roughness", glm::clamp((float)col / (float)nrColumns, 0.05f, 1.0f));
-
             model = glm::mat4(1.0f);
             model = glm::translate(model, glm::vec3(
                 (col - (nrColumns / 2)) * spacing,

src/model.h

@@ -21,3 +21,5 @@ class Model {
         Mesh processMesh(aiMesh* mesh, const aiScene* scene);
         std::vector<Texture> loadMaterialTextures(aiMaterial* mat, aiTextureType type, std::string typeName );
 };
+
+unsigned int TextureFromFile(const char* path, const std::string& directory);