OpenGL不显示中间颜色

Question

我正在使用 OpenGL 导入 .obj 和 .stl 文件并尝试为每个面着色。作为我可以为对象着色的概念证明，我按照导入的顺序为每个顶点分配了一个整数（第一个顶点为 1，第二个顶点为 2，第三个顶点为 3，依此类推）接下来，我创建了一个将顶点的索引映射到 RGB 值的函数。当我画完所有的脸时，这些脸只有几种不同的颜色——而且没有颜色过渡。换句话说，我看到的颜色并没有平滑过渡——相反，有一些定义的颜色，它们之间有相当明确的线条。 这让我有一种预感，OpenGL 可能不会按照我想要的方式显示颜色，所以我在我的createVertexArray 方法中将所有面的所有顶点设置为橙色——它初始化了glBufferData。输出显示模型黄色而不是橙色。这可能是什么原因造成的？

RGB 255,162,0 为橙色

创建顶点数组：

 void createVertexArray(std::vector<triangle> & facet, std::map<vec3d, GLfloat> & vecMagMap, float* vertices, std::vector<GLfloat> mags, GLfloat j_min, GLfloat j_max)
{
     const int NUM_FACETS = facet.size();
     std::cout << "\nNUMFACETS: " << NUM_FACETS << "\n";
     int count = 0;
     hsv temp;
     rgb tempRGB;
     int tempH = 0;
     for (int facet_index = 0; facet_index < NUM_FACETS; facet_index++){
         tempRGB = getColor(vecMagMap[facet[facet_index].point[0]], 0, vecMagMap.size());
         temp = rgb2hsv(tempRGB);
         //if (tempH != temp.h){ std::cout << tempH << "\n"; tempH = temp.h; }
             vertices[count + 0] = facet[facet_index].point[0].x;
             vertices[count + 1] = facet[facet_index].point[0].y;
             vertices[count + 2] = facet[facet_index].point[0].z;
             vertices[count + 3] = facet[facet_index].normal.x;
             vertices[count + 4] = facet[facet_index].normal.y;
             vertices[count + 5] = facet[facet_index].normal.z;
             vertices[count + 6] = 255;
             vertices[count + 7] = 162;
             vertices[count + 8] = 0;
             vertices[count + 9] = 1.0;
             vertices[count + 10] = facet[facet_index].point[1].x;
             vertices[count + 11] = facet[facet_index].point[1].y;
             vertices[count + 12] = facet[facet_index].point[1].z;
             vertices[count + 13] = facet[facet_index].normal.x;
             vertices[count + 14] = facet[facet_index].normal.y;
             vertices[count + 15] = facet[facet_index].normal.z;
             vertices[count + 16] = 255; 
             vertices[count + 17] = 162;
             vertices[count + 18] = 0;
             vertices[count + 19] = 1.0;
             vertices[count + 20] = facet[facet_index].point[2].x;
             vertices[count + 21] = facet[facet_index].point[2].y;
             vertices[count + 22] = facet[facet_index].point[2].z;
             vertices[count + 23] = facet[facet_index].normal.x;
             vertices[count + 24] = facet[facet_index].normal.y;
             vertices[count + 25] = facet[facet_index].normal.z;
             vertices[count + 26] = 255; 
             vertices[count + 27] = 162;
             vertices[count + 28] = 0;
             vertices[count + 29] = 1.0;
             count += 30;
     }
 }

我绘制的主要部分：

glGenBuffers(1, &bufferID);
glBindBuffer(GL_ARRAY_BUFFER, bufferID);
glBufferData(GL_ARRAY_BUFFER,facet.size()*30*sizeof(GLfloat),vertices,GL_STATIC_DRAW);
     glPolygonMode(GL_FRONT,  // options: GL_FRONT, GL_BACK, GL_FRONT_AND_BACK
              GL_FILL);  // options: GL_POINT, GL_LINE, GL_FILL (default)
     glShadeModel(GL_SMOOTH); // shading model
     scale = 5.0*scale_0;     // initial scale
     delta = 0.010*scale_0;   // change in scale
     int frame = 0;
     while(running){
         drawGeometry(argv, window, scale, frame,vertices, 3*facet.size(),move_x, move_y, move_z,rotate_x, rotate_y, rotate_z);// render objects in the window
         if(!pause){rotate_x += drot_x;rotate_y += drot_y;rotate_z += drot_z;}
         glfwSwapBuffers(window);// swap front and back buffers
         glfwPollEvents();// poll for and processs events
     }

Answer 1

OpenGL 可能在绘制它们之前将这些浮点颜色值限制在 [0.0-1.0] 范围内。所以 RGB(255, 162, 0) -> RGBF(1.0, 1.0, 0.0) == RGB(255, 255, 0)，也就是黄色。

使用 [0.0-1.0] 范围内的浮点颜色或使用 GLubyte 和 GL_UNSIGNED_BYTE 的数组作为（我假设）您的 glColorPointer() 调用的 type 参数。