Add .obj loading and rendering

.gitignore

@@ -5,7 +5,6 @@
 *.slo
 *.lo
 *.o
-*.obj
 *.vs
 
 # Precompiled Headers

example/MonkeyFlat.mtl

@@ -0,0 +1,10 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl None
+Ns 0
+Ka 0.000000 0.000000 0.000000
+Kd 0.8 0.8 0.8
+Ks 0.8 0.8 0.8
+d 1
+illum 2

example/MonkeySmooth.mtl

@@ -0,0 +1,10 @@
+# Blender MTL File: 'None'
+# Material Count: 1
+
+newmtl None
+Ns 0
+Ka 0.000000 0.000000 0.000000
+Kd 0.8 0.8 0.8
+Ks 0.8 0.8 0.8
+d 1
+illum 2

example/src/MeshRenderComponent.h

@@ -0,0 +1,179 @@
+#include <string>
+#include <vector>
+
+#ifndef HMME_MESH_RENDER_COMPONENT_H
+#define HMME_MESH_RENDER_COMPONENT_H
+
+#include "tiny_obj_loader.h"
+
+class MeshRenderComponent : public RenderComponent {
+public:
+    bool didLoad = false;
+
+    struct Shape {
+        GLuint vaoID = 0;
+        GLuint vertexBufferID = 0;
+        GLuint normalBufferID = 0;
+        GLuint uvBufferID = 0;
+        GLuint colorBufferID = 0;
+        int numVerts = 0;
+    };
+    std::vector<Shape> renderShapes;
+
+    MeshRenderComponent(const char *filename) {
+        // Load the model
+        tinyobj::attrib_t attrib;
+        std::vector<tinyobj::shape_t> shapes;
+        std::vector<tinyobj::material_t> materials;
+
+        std::string err;
+        bool ret = tinyobj::LoadObj(&attrib, &shapes, &materials, &err, filename);
+          
+        if (!err.empty()) { // `err` may contain warning message.
+            printf("Failed to load mesh: %s\n", err.c_str());
+        }
+
+        if (!ret) {
+            return;
+        }
+
+        for (auto shape : shapes) {
+            std::vector<tinyobj::real_t> vertices;
+            std::vector<tinyobj::real_t> normals;
+            std::vector<tinyobj::real_t> uvs;
+            std::vector<tinyobj::real_t> colors;
+
+            for (auto indices : shape.mesh.indices) {
+                if (indices.vertex_index > -1) {
+                    for (int i = 0; i < 3; i++) {
+                        int attribIndex = 3 * indices.vertex_index + i;
+                        vertices.push_back(attrib.vertices[attribIndex]);
+                        colors.push_back(attrib.colors[attribIndex]);
+                    }
+                }
+                if (indices.normal_index > -1) {
+                    for (int i = 0; i < 3; i++) {
+                        int attribIndex = 3 * indices.normal_index + i;
+                        normals.push_back(attrib.normals[attribIndex]);
+                    }
+                }
+                if (indices.texcoord_index > -1) {
+                    for (int i = 0; i < 2; i++) {
+                        int attribIndex = 2 * indices.texcoord_index + i;
+                        uvs.push_back(attrib.texcoords[attribIndex]);
+                    }
+                }
+            }
+
+            Shape s; // the new shape to insert into our list
+
+            glGenVertexArrays(1, &s.vaoID);
+
+            if (!vertices.empty()) {
+                glGenBuffers(1, &s.vertexBufferID);
+                glBindBuffer(GL_ARRAY_BUFFER, s.vertexBufferID);
+                glBufferData(GL_ARRAY_BUFFER, sizeof(tinyobj::real_t) * vertices.size(), &vertices.front(), GL_STATIC_DRAW);
+
+                glGenBuffers(1, &s.colorBufferID);
+                glBindBuffer(GL_ARRAY_BUFFER, s.colorBufferID);
+                glBufferData(GL_ARRAY_BUFFER, sizeof(tinyobj::real_t) * colors.size(), &colors.front(), GL_STATIC_DRAW);
+            }
+            
+            if (!normals.empty()) {
+                glGenBuffers(1, &s.normalBufferID);
+                glBindBuffer(GL_ARRAY_BUFFER, s.normalBufferID);
+                glBufferData(GL_ARRAY_BUFFER, sizeof(tinyobj::real_t) * normals.size(), &normals.front(), GL_STATIC_DRAW);
+            }
+
+            if (!uvs.empty()) {
+                glGenBuffers(1, &s.uvBufferID);
+                glBindBuffer(GL_ARRAY_BUFFER, s.uvBufferID);
+                glBufferData(GL_ARRAY_BUFFER, sizeof(tinyobj::real_t) * uvs.size(), &uvs.front(), GL_STATIC_DRAW);
+            }
+
+            s.numVerts = vertices.size() / 3;
+
+            renderShapes.push_back(s);
+        }
+
+        didLoad = true;
+    }
+
+    void Draw() override {
+        if (!didLoad) {
+            return;
+        }
+
+        for (auto s : renderShapes) {
+            glBindVertexArray(s.vaoID);
+
+            // 1st attribute buffer : vertices
+            glEnableVertexAttribArray(0);
+            glBindBuffer(GL_ARRAY_BUFFER, s.vertexBufferID);
+            glVertexAttribPointer(
+               0,                  // attribute 0. No particular reason for 0, but must match the layout in the shader.
+               3,                  // size
+               GL_FLOAT,           // type
+               GL_FALSE,           // normalized?
+               0,                  // stride
+               (void*)0            // array buffer offset
+            );
+
+            // 2nd attribute buffer : colors
+            glEnableVertexAttribArray(1);
+            glBindBuffer(GL_ARRAY_BUFFER, s.colorBufferID);
+            glVertexAttribPointer(
+                1,                 // attribute. No particular reason for 1, but must match the layout in the shader.
+                3,                 // size
+                GL_FLOAT,          // type
+                GL_FALSE,          // normalized?
+                0,                 // stride
+                (void*)0           // array buffer offset
+            );
+
+            if (s.normalBufferID != 0) {
+                // 3rd attribute buffer : normals
+                glEnableVertexAttribArray(2);
+                glBindBuffer(GL_ARRAY_BUFFER, s.normalBufferID);
+                glVertexAttribPointer(
+                    2,                 // must match the layout in the shader
+                    3,                 // size
+                    GL_FLOAT,          // type
+                    GL_FALSE,          // normalized?
+                    0,                 // stride
+                    (void*)0           // array buffer offset
+                );
+            }
+
+            if (s.uvBufferID != 0) {
+                // 4th attribute buffer : uvs
+                glEnableVertexAttribArray(3);
+                glBindBuffer(GL_ARRAY_BUFFER, s.normalBufferID);
+                glVertexAttribPointer(
+                    3,                 // must match the layout in the shader
+                    2,                 // size
+                    GL_FLOAT,          // type
+                    GL_FALSE,          // normalized?
+                    0,                 // stride
+                    (void*)0           // array buffer offset
+                );
+            }
+            
+            // Shader??
+
+            // Draw the triangle!
+            glDrawArrays(GL_TRIANGLES, 0, s.numVerts); // Starting from vertex 0; 3 vertices total -> 1 triangle
+            
+            glDisableVertexAttribArray(0);
+            glDisableVertexAttribArray(1);
+            if (s.normalBufferID != 0) {
+                glDisableVertexAttribArray(2);
+            }
+            if (s.uvBufferID != 0) {
+                glDisableVertexAttribArray(3);
+            }
+        }
+    }
+};
+
+#endif

example/src/fragment.glsl

@@ -1,9 +1,16 @@
 #version 330 core
 
+in vec3 fragmentPosition_world;
 in vec3 fragmentColor;
+in vec3 fragmentNormal_world;
+in vec2 fragmentUV;
 
 out vec3 color;
 
 void main() {
-    color = fragmentColor;
+    vec3 toLight_world = normalize(vec3(1, 1, 1));
+
+    float cosTheta = clamp(dot(normalize(fragmentNormal_world), toLight_world), 0.1, 1);
+
+    color = cosTheta * fragmentColor;
 }

example/src/main.cpp

@@ -10,6 +10,7 @@
 
 #include "Entity.h"
 #include "Cube.h"
+#include "MeshRenderComponent.h"
 
 void TickTree(Entity *e, float deltaSeconds);
 void ComputeModelMatrices(Entity *ep, hmm_mat4 parentModelMatrix);
@@ -57,7 +58,9 @@ int main()
 
     // Get a handle for our "MVP" uniform
     // Only during the initialisation
-    GLuint MatrixID = glGetUniformLocation(programID, "MVP");
+    GLuint uniformID_M = glGetUniformLocation(programID, "M");
+    GLuint uniformID_V = glGetUniformLocation(programID, "V");
+    GLuint uniformID_MVP = glGetUniformLocation(programID, "MVP");
 
     // Enable depth test
     glEnable(GL_DEPTH_TEST);
@@ -66,13 +69,14 @@ int main()
 
     Cube root = Cube();
 
-    Cube child = Cube();
+    Entity child = Entity();
     child.position = HMM_Vec3(2.1f, 0.0f, 0.0f);
+    child.renderComponent = new MeshRenderComponent("MonkeySmooth.obj");
 
-    Cube c = Cube();
+    // Cube c = Cube();
-    child.position = HMM_Vec3(2.1f, 0.0f, 0.0f);
+    // child.position = HMM_Vec3(2.1f, 0.0f, 0.0f);
 
-    child.AddChild(&c);
+    // child.AddChild(&c);
     root.AddChild(&child);
 
     bool hasTicked = false;
@@ -107,8 +111,13 @@ int main()
                 // Use our shader
                 glUseProgram(programID);
 
+                // Send uniforms
+                glUniformMatrix4fv(uniformID_M, 1, GL_FALSE, &e->modelMatrix.Elements[0][0]);
+
+                glUniformMatrix4fv(uniformID_V, 1, GL_FALSE, &view.Elements[0][0]);
+
                 hmm_mat4 mvp = vp * e->modelMatrix;
-                glUniformMatrix4fv(MatrixID, 1, GL_FALSE, &mvp.Elements[0][0]);
+                glUniformMatrix4fv(uniformID_MVP, 1, GL_FALSE, &mvp.Elements[0][0]);
 
                 e->renderComponent->Draw();
             }

example/src/tiny_obj_loader.cpp

@@ -0,0 +1,2 @@
+#define TINYOBJLOADER_IMPLEMENTATION
+#include "tiny_obj_loader.h"

example/src/vertex.glsl

@@ -1,15 +1,28 @@
 #version 330 core
 
-layout(location = 0) in vec3 vertexPosition_modelspace;
+// These match the values in glVertexAttribPointer
-// Notice that the "1" here equals the "1" in glVertexAttribPointer
+layout(location = 0) in vec3 vertexPosition_model;
 layout(location = 1) in vec3 vertexColor;
+layout(location = 2) in vec3 vertexNormal_model;
+layout(location = 3) in vec2 vertexUV;
 
+uniform mat4 M;
+uniform mat4 V;
 uniform mat4 MVP;
 
+out vec3 fragmentPosition_world;
 out vec3 fragmentColor;
+out vec3 fragmentNormal_world;
+out vec2 fragmentUV;
   
 void main(){
     // Output position of the vertex, in clip space : MVP * position
-    gl_Position = MVP * vec4(vertexPosition_modelspace, 1);
+    gl_Position = MVP * vec4(vertexPosition_model, 1);
+    fragmentPosition_world = (M * vec4(vertexPosition_model, 1)).xyz;
+
     fragmentColor = vertexColor;
+
+    fragmentNormal_world = (M * vec4(vertexNormal_model, 0)).xyz;
+
+    fragmentUV = vertexUV;
 }