From c5d4d904634a52a7fb0aead7f0601eb850860f5c Mon Sep 17 00:00:00 2001
From: Anselme <anselme.francois@gmail.com>
Date: Thu, 28 Apr 2016 16:17:17 +0200
Subject: [PATCH] bug fixes (normal mapping, directionnal lighting)

---
 shaders/forward.frag.glsl |  4 +--
 shaders/forward.vert.glsl |  4 +--
 src/forwardmodule.cpp     |  2 +-
 src/light.cpp             |  4 +--
 src/mesh.cpp              | 73 ++++++++++++++++-----------------------
 5 files changed, 36 insertions(+), 51 deletions(-)

diff --git a/shaders/forward.frag.glsl b/shaders/forward.frag.glsl
index 571c570..3bfb81f 100644
--- a/shaders/forward.frag.glsl
+++ b/shaders/forward.frag.glsl
@@ -75,7 +75,7 @@ void main(void) {
 #endif
 
 #ifdef NORMAL_MAP
-    vec3 normal = normalize(texture(normalMap, varTexCoord).xyz * tangentSpace);
+    vec3 normal = normalize((texture(normalMap, varTexCoord).xyz*2 - 1) * tangentSpace);
 #else
     vec3 normal = normalize(varNormal);
 #endif
@@ -112,7 +112,7 @@ void main(void) {
 #endif
 
 #ifdef AMBIENT_LIGHT
-    outColor = vec4(ambient+diffuse*0.1f, 1);
+    outColor = vec4(diffuse*0, 1);
 #else
     vec3 light = phongLighting(diffuse, specular, materialNs, lightColor, normal, lightDirInView, halfVecInView);
     outColor = vec4(light*shadow*(1+cos(1.57 + att*1.57)), 1);
diff --git a/shaders/forward.vert.glsl b/shaders/forward.vert.glsl
index aebb2de..38a409a 100644
--- a/shaders/forward.vert.glsl
+++ b/shaders/forward.vert.glsl
@@ -75,8 +75,8 @@ void main(void) {
 
 #ifdef NORMAL_MAP
     tangentSpace = transpose(mat3(normalize(normalMatrix*inTangent),
-                                                              normalize(normalMatrix*inBinormal),
-                                                              normalize(normalMatrix*inNormal)));
+                                  normalize(normalMatrix*inBinormal),
+                                  normalize(normalMatrix*inNormal)));
 #else
     varNormal = normalize(normalMatrix*inNormal);
 #endif
diff --git a/src/forwardmodule.cpp b/src/forwardmodule.cpp
index a1655c5..baad211 100644
--- a/src/forwardmodule.cpp
+++ b/src/forwardmodule.cpp
@@ -16,7 +16,7 @@ void ForwardModule::renderGL(Camera* myCamera, Scene* scene)
     {
         for(Light *light : p.lights)
         {
-            if(light->getFlags() & Light::AMBIENT_FLAG)
+            if(light->getFlags() & (1 << Light::AMBIENT_FLAG))
             {
                 // render ambient lighting (opaque)
                 glEnable(GL_DEPTH_TEST);
diff --git a/src/light.cpp b/src/light.cpp
index 8c30571..50ff93f 100644
--- a/src/light.cpp
+++ b/src/light.cpp
@@ -117,11 +117,11 @@ void Light::generateShadowMap(Scene* scene)
         geometryIt->isValid(); geometryIt->next())
     {
         GeometryNode* node = geometryIt->getItem();
-        if(node->mesh->getFlags() & Mesh::MESH_SHADOWED)
+        if(node->mesh->getFlags() & (1 << Mesh::MESH_SHADOWED))
         {
             // compute matrix attributes
             glm::mat4 lightMVP = getProjectionMatrix() * (getViewMatrix() * node->modelMatrix);
-            int hasAlpha = (node->mesh->getFlags() & Mesh::MATERIAL_ALPHA_MASK) > 0;
+            int hasAlpha = (node->mesh->getFlags() & (1 << Mesh::MATERIAL_ALPHA_MASK)) > 0;
             shaders[hasAlpha]->bind();
             shaders[hasAlpha]->bindMat4(shaders[hasAlpha]->getLocation("MVP"), lightMVP);
             node->mesh->draw(shaders[hasAlpha], false, hasAlpha, false);
diff --git a/src/mesh.cpp b/src/mesh.cpp
index 720b17b..2c88be1 100644
--- a/src/mesh.cpp
+++ b/src/mesh.cpp
@@ -66,7 +66,7 @@ void Mesh::clearBuffers()
 void Mesh::initGL()
 {
     destroyGL();
-
+    
     // create VAO
     glGenVertexArrays(1, &vao);
     glBindVertexArray(vao);
@@ -89,8 +89,8 @@ void Mesh::initGL()
         if(!tangents.empty())
         {
             auto tangentsBuffer = new TBuffer<Tangents>(tangents, Buffer::VBO);
-            tangentsBuffer->setVertexAttrib(3, 3);
-            tangentsBuffer->setVertexAttrib(4, 3);
+            tangentsBuffer->setVertexAttrib(3, 3, 0);
+            tangentsBuffer->setVertexAttrib(4, 3, sizeof(glm::vec3));
             addBuffer(tangentsBuffer, TANGENT_BUFFER);
         }
     }
@@ -291,10 +291,7 @@ void Mesh::mergeVertices()
         if(deleted[indices[i]])
         {
             if(!tangents.empty())
-            {
                 tangents[*(ret.first)].tangent += tangents[indices[i]].tangent;
-                tangents[*(ret.first)].binormal += tangents[indices[i]].binormal;
-            }
             indices[i] = *(ret.first);
         }
     }
@@ -330,10 +327,16 @@ void Mesh::mergeVertices()
         normals.resize(normals.size()-offset);
     if(!tangents.empty())
         tangents.resize(tangents.size()-offset);
-    for(Tangents &t : tangents)
+    for(int i=0; i<tangents.size(); ++i)
     {
-        t.tangent = glm::normalize(t.tangent);
-        t.binormal = glm::normalize(t.binormal);
+        glm::vec3 &T = tangents[i].tangent;
+        const glm::vec3 &N = normals[i];
+        
+        T = glm::normalize(T);
+        // re-orthogonalize T with respect to N
+        T = glm::normalize(T - glm::dot(T, N) * N);
+        // then retrieve perpendicular vector B with the cross product of T and N
+        tangents[i].binormal = glm::normalize(glm::cross(T, N));
     }
 }
 
@@ -377,41 +380,23 @@ void Mesh::computeTangents()
         int vertexId2 = indices[j+2];
 
         const glm::vec3 &v1 = positions3D[vertexId0];
-        const glm::vec3 &v2 = positions3D[vertexId1];
-        const glm::vec3 &v3 = positions3D[vertexId2];
-
+        glm::vec3 edge1 = positions3D[vertexId1] - v1;
+        glm::vec3 edge2 = positions3D[vertexId2] - v1;
+        
         const glm::vec2& w1 = texCoords[vertexId0];
-        const glm::vec2& w2 = texCoords[vertexId1];
-        const glm::vec2& w3 = texCoords[vertexId2];
-
-        float x1 = v2.x - v1.x;
-        float x2 = v3.x - v1.x;
-        float y1 = v2.y - v1.y;
-        float y2 = v3.y - v1.y;
-        float z1 = v2.z - v1.z;
-        float z2 = v3.z - v1.z;
-
-        float s1 = w2.x - w1.x;
-        float s2 = w3.x - w1.x;
-        float t1 = w2.y - w1.y;
-        float t2 = w3.y - w1.y;
-
-        float r = 1.0f / (s1 * t2 - s2 * t1);
-        glm::vec3 sdir((t2 * x1 - t1 * x2) * r, (t2 * y1 - t1 * y2) * r,
-                (t2 * z1 - t1 * z2) * r);
-        glm::vec3 tdir((s1 * x2 - s2 * x1) * r, (s1 * y2 - s2 * y1) * r,
-                (s1 * z2 - s2 * z1) * r);
-
-        Tangents& tan1 = tangents[vertexId0];
-        Tangents& tan2 = tangents[vertexId1];
-        Tangents& tan3 = tangents[vertexId2];
-
-        tan1.tangent += sdir;
-        tan2.tangent += sdir;
-        tan3.tangent += sdir;
-
-        tan1.binormal += tdir;
-        tan2.binormal += tdir;
-        tan3.binormal += tdir;
+        glm::vec2 deltaUV1 = texCoords[vertexId1] - w1;
+        glm::vec2 deltaUV2 = texCoords[vertexId2] - w1;
+        
+        float f = 1.0f / (deltaUV1.x * deltaUV2.y - deltaUV2.x * deltaUV1.y);
+        
+        glm::vec3 tangentDir = deltaUV2.y * edge1 - deltaUV1.y * edge2;
+        tangentDir = glm::normalize(tangentDir*f);
+        
+        glm::vec3 binormalDir = deltaUV1.x * edge2 - deltaUV2.x * edge1;
+        binormalDir = glm::normalize(binormalDir*f);
+        
+        tangents[vertexId0] = {tangentDir, binormalDir};
+        tangents[vertexId1] = {tangentDir, binormalDir};
+        tangents[vertexId2] = {tangentDir, binormalDir};
     }
 }