feat(viewport): add depth testing and grid opacity

src/gui/viewport/GLGrid.cpp

@@ -14,11 +14,74 @@ void GLGrid::init()
     glBindVertexArray(vao);
 
     initBuffers();
+    initShaderProgram();
 
     // unbind vertex array
     glBindVertexArray(0);
 }
 
+void GLGrid::initShaderProgram()
+{
+    // vertex shader
+    const std::string vertexShaderSource = "#version 330 core\n"
+    "uniform mat4 uView;\n"
+    "uniform mat4 uProj;\n"
+    "layout (location = 0) in vec3 aPos;\n"
+    "void main()\n"
+    "{\n"
+    "   gl_Position = uProj * uView * vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+    "}\n";
+    // shader type
+    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
+    // convert source
+    const GLchar* vertexShaderSourceC = vertexShaderSource.c_str();
+    // create shader object
+    glShaderSource(vertexShader, 1, &vertexShaderSourceC, NULL);
+    // compile shader object
+    glCompileShader(vertexShader);
+
+    
+    // log shader error
+    int  success;
+    char infoLog[512];
+    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
+    if(!success)
+    {
+        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
+        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
+    }
+    else
+    {
+        std::cout << "success\n";
+
+    }
+    
+    
+    // fragment shader
+    const std::string fragmentShaderSource = "#version 330 core\n"
+    "out vec4 FragColor;\n"
+    "void main()\n"
+    "{\n"
+    "    FragColor = vec4(0.53f, 0.53f, 0.53f, 0.1f);\n"
+    "}\n";
+    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+    const GLchar* fragmentShaderSourceC = fragmentShaderSource.c_str();
+    glShaderSource(fragmentShader, 1, &fragmentShaderSourceC, NULL);
+    glCompileShader(fragmentShader);
+
+    // create shader program
+    shaderProgram = glCreateProgram();
+    // attach shaders
+    glAttachShader(shaderProgram, vertexShader);
+    glAttachShader(shaderProgram, fragmentShader);
+    // link program
+    glLinkProgram(shaderProgram);
+    
+    // delete shaders now that the program is complete
+    glDeleteShader(vertexShader);
+    glDeleteShader(fragmentShader);
+}
+
 void GLGrid::initBuffers()
 {
     constexpr int gridLen = 20;
@@ -57,8 +120,14 @@ void GLGrid::unbind()
     glBindVertexArray(0);
 }
 
+void GLGrid::useProgram()
+{
+    glUseProgram(shaderProgram);
+}
+
 void GLGrid::draw()
 {
     bind();
+    useProgram();
     glDrawArrays(GL_LINES, 0, vertices.size());
 }

src/gui/viewport/GLGrid.h

@@ -9,10 +9,13 @@ public:
     GLGrid();
     GLuint vao;
     GLuint vbo;
+    GLuint shaderProgram;
     std::vector<glm::vec3> vertices;
 
     void init();
     void initBuffers();
+    void initShaderProgram();
+    void useProgram();
     void bind();
     void unbind();
     void draw();

src/gui/viewport/ViewportGLWidget.cpp

@@ -11,6 +11,10 @@ void ViewportGLWidget::initializeGL()
 {
     initializeOpenGLFunctions();
 
+    glEnable(GL_DEPTH_TEST);
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
     triangleMesh_ = std::make_unique<GLMesh>();
     gridMesh_ = std::make_unique<GLGrid>();
 
@@ -102,9 +106,8 @@ void ViewportGLWidget::paintGL()
 {
 
 
-    glClear(GL_COLOR_BUFFER_BIT);
+    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
 
-    glUseProgram(shaderProgram);
 
     glm::mat4 projMatrix = glm::perspective(
         glm::radians(45.0f),                  // FOV
@@ -113,15 +116,21 @@ void ViewportGLWidget::paintGL()
         100.0f                                // far plane
     );
 
+    gridMesh_->useProgram();
+    glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "uProj"), 1, GL_FALSE, glm::value_ptr(projMatrix));
+    curCamera.setUniform(glGetUniformLocation(shaderProgram, "uView"));
 
+
+    gridMesh_->draw();
+
+    glUseProgram(shaderProgram);
     GLint projMLoc = glGetUniformLocation(shaderProgram, "uProj");
     glUniformMatrix4fv(projMLoc, 1, GL_FALSE, glm::value_ptr(projMatrix));
 
     GLint viewMLoc = glGetUniformLocation(shaderProgram, "uView");
     curCamera.setUniform(viewMLoc);
 
-
-    gridMesh_->draw();
     triangleMesh_->draw();
 
+
 }