[英]OpenGL GLFW simple cube not rendering
有人可以告訴我這段代碼有什么問題嗎,它沒有顯示帶有簡單頂點和片段着色器的簡單立方體,似乎我已經正確初始化了gl和GLFW,創建了着色器,將它們編譯並鏈接,創建了模型查看投影矩陣,並將它們傳遞給着色器,我看不到為什么不渲染。
#include <iostream>
#include <fstream>
#include <GL\glew.h>
#include <GLFW\glfw3.h>
#include <glm\glm.hpp>
#include <glm\gtc\matrix_transform.hpp>
#include <glm\gtc\type_ptr.hpp>
using namespace std;
using namespace glm;
int g_gl_width = 800;
int g_gl_height = 600;
GLFWwindow* g_window = NULL;
void glfw_error_callback(int error, const char* description) {
cerr << description << endl;
}
void glfw_window_size_callback(GLFWwindow* window, int width, int height) {
g_gl_width = width;
g_gl_height = height;
}
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
}
void mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
{
}
int main(int argc, char * argv []){
glfwSetErrorCallback(glfw_error_callback);
if (!glfwInit()) {
cerr << "ERROR: could not start GLFW3\n" << endl;
return false;
}
g_window = glfwCreateWindow(
g_gl_width, g_gl_height, "Extended Init.", NULL, NULL
);
if (!g_window) {
cerr << "ERROR: could not open window with GLFW3\n" << endl;
glfwTerminate();
return false;
}
glfwSetWindowSizeCallback(g_window, glfw_window_size_callback);
glfwMakeContextCurrent(g_window);
glfwSetMouseButtonCallback(g_window, mouse_button_callback);
glfwSetScrollCallback(g_window, scroll_callback);
glfwWindowHint(GLFW_SAMPLES, 4);
glewExperimental = GL_TRUE;
glewInit();
const GLubyte* renderer = glGetString(GL_RENDERER);
const GLubyte* version = glGetString(GL_VERSION);
cout << "Renderer: " << renderer;
cout << "OpenGL version supported: " << version;
glEnable(GL_DEPTH_TEST); // enable depth-testing
glDepthFunc(GL_LESS); // depth-testing interprets a smaller value as "closer"
glEnable(GL_CULL_FACE); // cull face
glCullFace(GL_BACK); // cull back face
glClearColor(0.2f, 0.2f, 0.2f, 1.0f);
glViewport(0, 0, g_gl_width, g_gl_height);
GLfloat points[] = {
-1.0f, -1.0f, -1.0f, // triangle 1 : begin
-1.0f, -1.0f, 1.0f,
-1.0f, 1.0f, 1.0f, // triangle 1 : end
1.0f, 1.0f, -1.0f, // triangle 2 : begin
-1.0f, -1.0f, -1.0f,
-1.0f, 1.0f, -1.0f, // triangle 2 : end
1.0f, -1.0f, 1.0f,
-1.0f, -1.0f, -1.0f,
1.0f, -1.0f, -1.0f,
1.0f, 1.0f, -1.0f,
1.0f, -1.0f, -1.0f,
-1.0f, -1.0f, -1.0f,
-1.0f, -1.0f, -1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f, 1.0f, -1.0f,
1.0f, -1.0f, 1.0f,
-1.0f, -1.0f, 1.0f,
-1.0f, -1.0f, -1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f, -1.0f, 1.0f,
1.0f, -1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f, -1.0f, -1.0f,
1.0f, 1.0f, -1.0f,
1.0f, -1.0f, -1.0f,
1.0f, 1.0f, 1.0f,
1.0f, -1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f, 1.0f, -1.0f,
-1.0f, 1.0f, -1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f, -1.0f,
-1.0f, 1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f, 1.0f,
1.0f, -1.0f, 1.0f
};
GLuint vao;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
GLuint vbo;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(
GL_ARRAY_BUFFER,
3 * 36 * sizeof(GLfloat),
points,
GL_STATIC_DRAW
);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(0);
const char* vertex_shader =
"#version 410\n"
"layout(location = 0) in vec3 vertex_position;\n"
"uniform mat4 model, view, projection;\n"
"void main() {\n"
" gl_Position = projection * view * model * vec4(vertex_position, 1.0);\n"
"}\n";
const char* fragment_shader =
"#version 410\n"
"void main() {\n"
" gl_FragColor = vec4(1.0f, 0.0f, 0.0f, 1.0);\n"
"}\n";
GLuint vs = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vs, 1, &vertex_shader, NULL);
glCompileShader(vs);
GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fs, 1, &fragment_shader, NULL);
glCompileShader(fs);
GLuint shader_programme = glCreateProgram();
glAttachShader(shader_programme, fs);
glAttachShader(shader_programme, vs);
glLinkProgram(shader_programme);
mat4 projection = glm::perspective(90.0f, (float)(g_gl_width / g_gl_height), 0.1f, 100.0f);
mat4 view = glm::mat4(1.0f);
view = glm::translate(view, vec3(0.0f, 0.0f, 0.0f));
view = glm::rotate(view, 0.0f, vec3(0.0f, 0.0f, 1.0f));
view = glm::rotate(view, 0.0f, vec3(0.0f, 1.0f, 0.0f));
view = glm::rotate(view, 0.0f, vec3(1.0f, 0.0f, 0.0f));
mat4 model = glm::mat4(1.0f);
model = glm::translate(model, vec3(0.0f, 0.0f, 0.0f));
model = glm::rotate(model, 0.0f, vec3(0.0f, 0.0f, 1.0f));
model = glm::rotate(model, 0.0f, vec3(0.0f, 1.0f, 0.0f));
model = glm::rotate(model, 0.0f, vec3(1.0f, 0.0f, 0.0f));
int model_mat_location = glGetUniformLocation(shader_programme, "model");
glUniformMatrix4fv(model_mat_location, 1, GL_FALSE, glm::value_ptr(model));
int view_mat_location = glGetUniformLocation(shader_programme, "view");
glUniformMatrix4fv(view_mat_location, 1, GL_FALSE, glm::value_ptr(view));
int proj_mat_location = glGetUniformLocation(shader_programme, "projection");
glUniformMatrix4fv(proj_mat_location, 1, GL_FALSE, glm::value_ptr(projection));
glUseProgram(shader_programme);
while (!glfwWindowShouldClose(g_window)) {
glfwMakeContextCurrent(g_window);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glViewport(0, 0, g_gl_width, g_gl_height);
glBindVertexArray(vao);
glUseProgram(shader_programme);
glDrawArrays(GL_TRIANGLES, 0, 36);
if (GLFW_PRESS == glfwGetKey(g_window, GLFW_KEY_ESCAPE)) {
glfwSetWindowShouldClose(g_window, 1);
}
glfwPollEvents();
glfwSwapBuffers(g_window);
}
glfwTerminate();
return 0;
}
編輯:
我還想指出,我在代碼中還有另一個錯誤
mat4 view = glm::mat4(1.0f);
glm::translate(view, vec3(0.0f, 0.0f, 0.0f));
glm::rotate(view, 0.0f, vec3(0.0f, 0.0f, 1.0f));
glm::rotate(view, 0.0f, vec3(0.0f, 1.0f, 0.0f));
glm::rotate(view, 0.0f, vec3(1.0f, 0.0f, 0.0f));
本來應該:
mat4 view = glm::mat4(1.0f);
view = glm::translate(view, vec3(0.0f, 0.0f, 0.0f));
view = glm::rotate(view, 0.0f, vec3(0.0f, 0.0f, 1.0f));
view = glm::rotate(view, 0.0f, vec3(0.0f, 1.0f, 0.0f));
view = glm::rotate(view, 0.0f, vec3(1.0f, 0.0f, 0.0f));
和模型。
問題可能出在此代碼中。
int model_mat_location = glGetUniformLocation(shader_programme, "model");
glUniformMatrix4fv(model_mat_location, 1, GL_FALSE, glm::value_ptr(model));
int view_mat_location = glGetUniformLocation(shader_programme, "view");
glUniformMatrix4fv(view_mat_location, 1, GL_FALSE, glm::value_ptr(view));
int proj_mat_location = glGetUniformLocation(shader_programme, "projection");
glUniformMatrix4fv(proj_mat_location, 1, GL_FALSE, glm::value_ptr(projection));
glUseProgram(shader_programme);
嘗試對統一值進行任何更改之前,需要調用glUseProgram
。 分別為每個着色器分配location
變量,這意味着對於程序1,位置將在[0,1,2,3,...]范圍內,對於程序2,位置也將在[ 0,1,2,3,...]。 因此,在沒有活動程序的情況下調用glUniform*
意味着OpenGL不知道您要為其更新制服的程序,因此也不知道如何應用要傳遞的值。
另外,您可能還需要更改以下代碼:
mat4 view = glm::mat4(1.0f);
glm::translate(view, vec3(0.0f, 0.0f, 0.0f));
glm::rotate(view, 0.0f, vec3(0.0f, 0.0f, 1.0f));
glm::rotate(view, 0.0f, vec3(0.0f, 1.0f, 0.0f));
glm::rotate(view, 0.0f, vec3(1.0f, 0.0f, 0.0f));
盡管此代碼從根本上沒有什么錯,但這將把相機放在立方體內。 啟用人臉剔除后,您可能實際上將看不到任何東西,因為所有人臉都將背對您。 為了進行測試,請考慮使用glm::lookAt
。
mat4 view = glm::lookAt(vec3(3, 3, 1), vec3(0, 0, 0), vec3(0, 1, 0));
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