好的，我有这个程序。 （并非所有代码都显示），基本上绘制了一个球体，但是当我试图将一个统一变量传递到顶点着色器时问题出现了。 我只有3个文件。 Sphere.cpp，Sphere.h，main.cpp和Vertex / Fragment Shaders ofc。
以下是我的代码的用法：
首先，我做了所有必要的计算并将点存储到Vertex数组中。 然后我称之为（在main.cpp中）：
void SetupGemetry() {
//Allocate 5 VBOs
glGenBuffers(5, vbo);
}
这是非常直接的前进。
其次我称之为（在main.cpp中）：
Sphere *planet_1 = new Sphere(sphere_start ,sphere_end);
这又是相当直接的。 现在注意所有球体代码都位于不同的文件中（在Sphere.cpp中）。 这是：
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <GL/glew.h>
#include <GL/glfw.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <stdlib.h>
#include <vector>
#include <iostream>
#include "Sphere.h"
int start_sphere, end_sphere;
//these will contain the vertex and shader contents
GLchar *sphere_vertexsource, *sphere_fragmentsource;
//this will be used to access the shaders
GLuint sphere_vertexshader, sphere_fragmentshader;
//declaring a shader program
GLuint sphere_shaderprogram;
Sphere::Sphere (int a, int b)
{
start_sphere = a;
end_sphere = b;
SetupShaders_sphere();
}
//reading hte files (shaders)!
char* Sphere::filetobuf_sphere(char *file)
{
FILE *fptr;
long length;
char *buf;
fptr = fopen(file, "r"); /* Open file for reading */
if (!fptr) /* Return NULL on failure */
return NULL;
fseek(fptr, 0, SEEK_END); /* Seek to the end_sphere of the file */
length = ftell(fptr); /* Find out how many bytes into the file we are */
buf = (char*)malloc(length + 1); /* Allocate a buffer for the entire length of the file plus a null terminator */
fseek(fptr, 0, SEEK_SET); /* Go back to the beginning of the file */
fread(buf, length, 1, fptr); /* Read the contents of the file in to the buffer */
fclose(fptr); /* Close the file */
buf[length] = 0; /* Null terminator */
return buf; /* Return the buffer */
}
void Sphere::SetupShaders_sphere(void){
// Read our shaders into the appropriate buffers
sphere_vertexsource = filetobuf_sphere("vertex_shader_sphere.vert");
sphere_fragmentsource = filetobuf_sphere("fragment_shader_sphere.frag");
//Assign our handles a "name" to new shader objects
sphere_vertexshader = glCreateShader(GL_VERTEX_SHADER);
sphere_fragmentshader = glCreateShader(GL_FRAGMENT_SHADER);
// Associate the source code buffers with each handle
glShaderSource(sphere_vertexshader, 1, (const GLchar**)&sphere_vertexsource, 0);
glShaderSource(sphere_fragmentshader, 1, (const GLchar**)&sphere_fragmentsource, 0);
//Setting them up by compiling, attaching and linking them!
glCompileShader(sphere_vertexshader);
glCompileShader(sphere_fragmentshader);
sphere_shaderprogram = glCreateProgram();
glAttachShader(sphere_shaderprogram, sphere_vertexshader);
glAttachShader(sphere_shaderprogram, sphere_fragmentshader);
glBindAttribLocation(sphere_shaderprogram, 0, "in_Position");
glBindAttribLocation(sphere_shaderprogram, 1, "in_Color");
glBindAttribLocation(sphere_shaderprogram, 2, "in_vertexUV");
glLinkProgram(sphere_shaderprogram);
glUseProgram(sphere_shaderprogram);
printf("Sphere Shaders Loaded!\n");
}
void Sphere::render_sphere(int i, glm::vec3 center)
{
int position_factor;
GLfloat angle;
const double PI = 3.1415926535897;
GLfloat time, theta_angle, r, x_cord, z_cord, radius;
GLfloat period = 600;
angle = (GLfloat) (i/40 % 360);
time = (GLfloat) (i%600);
r= 1.5;
theta_angle = (2*PI*time)/period;
//PROJECTION
glm::mat4 Projection = glm::perspective(45.0f, 1.0f, 0.1f, 100.0f);
//VIEW
glm::mat4 View = glm::mat4(1.);
View = glm::translate(View, center); // x, y, z position ?
//View = glm::rotate(View, angle * -1.0f, glm::vec3(1.f, 0.f, 0.f));
View = glm::rotate(View, angle * 0.5f, glm::vec3(0.f, 1.f, 0.f));
//View = glm::rotate(View, angle * 0.5f, glm::vec3(0.f, 0.f, 1.f));
//MODEL
// for scaling down to 0.5 >> glm::scale(glm::mat4(1.0f),glm::vec3(0.5f));
// original >> glm::mat4(1.0);
glm::mat4 Model = glm::scale(glm::mat4(1.0f),glm::vec3(0.3f));
//Rotation Calculations
if(theta_angle <= 2*PI || theta_angle >= 0)
{
x_cord = radius*cos(theta_angle);
z_cord = radius*sin(theta_angle);
}
glm::vec3 Position_test = glm::vec3(x_cord, 0.f, z_cord);
glUniform3fv(glGetUniformLocation(sphere_shaderprogram, "d_pos"), 1, glm::value_ptr(Position_test));
glm::mat4 MVP = Projection * View * Model;
glUniformMatrix4fv(glGetUniformLocation(sphere_shaderprogram, "MVP_matrix"), 1, GL_FALSE, glm::value_ptr(MVP));
//Transfer additional information to the vertex shader
//glm::mat4 MV = Model * View;
//glUniformMatrix4fv(glGetUniformLocation(sphere_shaderprogram, "MV_matrix"), 1, GL_FALSE, glm::value_ptr(MV));
glClearColor(0.0, 0.0, 0.0, 1.0);
glDrawArrays(GL_LINE_STRIP, start_sphere, end_sphere );
}
第三，我调用了一个“while”循环（在main.cpp中）：
while( running )
{
//glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
setBuffer(0,no_sphere_vertices, sphere_vertices);
planet_1->render_sphere(k, planet_1_center);
k++;
glfwSwapBuffers();
running = !(glfwGetKey( GLFW_KEY_ESC ) | glfwGetKey( 'Q' ) | glfwGetKey( 'q' )) && glfwGetWindowParam( GLFW_OPENED );
}
就是这样！
现在问题出现在这些行中（在Sphere.cpp中）：
glm::vec3 Position_test = glm::vec3(x_cord, 0.f, z_cord);
glUniform3fv(glGetUniformLocation(sphere_shaderprogram, "d_pos"), 1, glm::value_ptr(Position_test));
顺便说一下，我的Vertex Shader很简单：
#version 330
precision highp float;
//setting the in coming variables!
layout(location = 0) in vec3 in_Position; //declare position
layout(location = 1) in vec3 in_Color;
layout(location = 2) in vec3 in_vertexUV;
//Variables
uniform mat4 MVP_matrix; //Model View Projection Matrix
uniform vec3 d_pos; // the position difference
vec3 const_color; //a blue constant color declared below
out vec3 ex_Color;
void main(void) {
gl_Position = MVP_matrix * vec4(in_Position+d_pos, 1.0);
const_color = in_Color;
ex_Color = const_color ;
}
另一个奇怪的部分是，如果将我的所有代码移到SINGLE文件中，动画效果很好。但是当我将代码保存在单独的文件中时，似乎“传递统一变量”到顶点数据不起作用，因此我只是得到一个不移动的球体。 我正在以错误的顺序加载某些东西？
答案 0 :(得分：0)
A - 无论具体问题如何，我都想知道为什么你不能根据模型矩阵移动对象，而是根据d_pos统一进行移动。它看起来是一个无用的“每顶点”操作，因为计算需要“按顶点”进行评估：
vec4（in_Position + d_pos，1.0）;
如果您使用模型矩阵执行移动操作，则计算仅执行一次（在模型矩阵更改级别）。
B-我建议您检查此操作的输出并检查输出
glGetUniformLocation（sphere_shaderprogram，“d_pos”）
C-检查glLinkProgram的输出，看看编译阶段是否一切顺利