在尝试使用SDL2 ...
在OpenGL上获得一个简单的三角形后，我得到一个黑屏我实际上使用OpenGL初始化窗口并使用对象名称＃34; EngineOpenGL＆＃34;启动GLEW。 ：http://pastebin.com/S4YDgY45
然后我开始一个应该渲染三角形的场景： ＆＃34; SceneOpenGL＆＃34; ：http://pastebin.com/GD4f5UDj
主文件：
#include <SDL.h>
#include <iostream>
#include <GL\glew.h>
#include "EngineOpenGl.h"
// DEBUG_MemoryLeaks
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
// _DEBUG
#include "SDLInitVideoException.h"
int main(int argc, char **argv) {
_CrtDumpMemoryLeaks();
EngineOpenGL * scene = new EngineOpenGL("OpenGL", 720, 1280);
try {
scene->init();
} catch (const SDLInitVideoException &e) {
delete scene;
std::cout << "Error while initialising SDL" << std::endl;
} catch (const SDLCreateWindowException &e) {
delete scene;
std::cout << "Error while initialising the window" << std::endl;
} catch (const SDLCreateContextGLException &e) {
delete scene;
std::cout << "Error while creating the contextGL" << std::endl;
} catch (const GLEWInitException &e) {
delete scene;
std::cout << "Error while initialising " << std::endl;
} catch (const SceneOpenGLException &e) {
delete scene;
std::cout << "Error while starting the scene" << std::endl;
}
scene->start();
delete scene;
// DEBUG_MemoryLeaks
_CrtDumpMemoryLeaks();
// _DEBUG
return 0;
}
FPS在控制台中显示fps，输入获取用户输入。
编辑：我实际上只是试图复制/通过代码来渲染三角形并保持不起作用......
#include "SceneOpenGl.h"
// Shader temporaire :
#include "Shader.h"
SceneOpenGL::SceneOpenGL(SDL_Window* window) {
if (window == NULL) {
throw new SceneOpenGLException();
}
// Engine
this->window = window;
// Tools
this->fps = new FPSCount();
this->input = new Input();
// Scene
this->run = false;
int w, h;
SDL_GetWindowSize(window, &w, &h);
this->projection = glm::perspective(70.0, (double)(w/h), 1.0, 100.0);
this->modelview = glm::mat4(1.0);
}
SceneOpenGL::~SceneOpenGL(){
delete fps;
delete input;
}
void SceneOpenGL::start() {
run = true;
// Test en attendant ObjectGL.show() //
GLfloat vertices[] = {
0.5f, 0.5f, 0.0f, // Top Right
0.5f, -0.5f, 0.0f, // Bottom Right
-0.5f, -0.5f, 0.0f, // Bottom Left
-0.5f, 0.5f, 0.0f // Top Left
};
GLuint indices[] = { // Note that we start from 0!
0, 1, 3, // First Triangle
1, 2, 3 // Second Triangle
};
// Build and compile our shader program
// Vertex shader
const GLchar* vertexShaderSource = "#version 330 core\n"
"layout (location = 0) in vec3 position;\n"
"void main()\n"
"{\n"
"gl_Position = vec4(position.x, position.y, position.z, 1.0);\n"
"}\0";
const GLchar* fragmentShaderSource = "#version 330 core\n"
"out vec4 color;\n"
"void main()\n"
"{\n"
"color = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
"}\n\0";
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);
// Check for compile time errors
GLint success;
GLchar 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;
}
// Fragment shader
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
// Check for compile time errors
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
}
// Link shaders
GLuint shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
// Check for linking errors
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
if (!success) {
glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
}
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
GLuint VBO, VAO, EBO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glGenBuffers(1, &EBO);
// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0); // Note that this is allowed, the call to glVertexAttribPointer registered VBO as the currently bound vertex buffer object so afterwards we can safely unbind
glBindVertexArray(0); // Unbind VAO (it's always a good thing to unbind any buffer/array to prevent strange bugs), remember: do NOT unbind the EBO, keep it bound to this VAO
// /Test //
while (run) {
// FPS flag
if (fps->flag()) {
std::cout << "FPS : " << fps->getFps() << std::endl;
}
// Input check/actions
input->updateEvents();
if (input->isKeyPush(SDL_SCANCODE_ESCAPE)) {
run = false;
}
// Cleaning last frame
glClear(GL_COLOR_BUFFER_BIT);
// Test //
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// Draw our first triangle
glUseProgram(shaderProgram);
glBindVertexArray(VAO);
//glDrawArrays(GL_TRIANGLES, 0, 6);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
// FPS add frame
fps->addFrame();
// Rendering
SDL_GL_SwapWindow(window);
}
}
答案 0 :(得分：2)
您绝不会将顶点数据加载到视频内存中。你有一行看起来像尝试将顶点加载到视频内存中：
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, vertices);
....但那不是那个功能所做的。
您需要创建并绑定顶点阵列和顶点缓冲区：
GLuint vertex_array_id;
glGenVertexArrays(1, &vertex_array_id);
glBindVertexArray(vertex_array_id);
GLuint vertex_buffer_id;
glGenBuffers(1, &vertex_buffer_id);
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer_id);
然后，在绑定此顶点数组和顶点缓冲区时，您需要向缓冲区显式提供数据：
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
然后使用glVertexAttribPointer指定数据的布局方式。
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 2, nullptr);
glEnableVertexAttribArray(0);
顺便说一句，所有这些代码都应该在循环之外。然后在绘制循环内，您只需调用glDrawArrays。