C ++ OpenGL，GLFW绘制简单的多维数据集 [英] C++ OpenGL, GLFW Drawing a simple cube
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问题描述
因此，我试图在openGL和GLFW中绘制一个简单的立方体.
So, I am trying to draw a simple cube in openGL and GLFW.
在下面的代码中，我可以绘制立方体，但它只是显示为一个简单的矩形.这是怎么回事?
In the code below, I can draw the cube, but it just appears as a simple rectangle. what is happening here?
我尝试过"glTransformf(0,0，-10);"，但是如果我做的事情少于-2，则立方体消失了.在-2处，出现正面.在默认位置0，我可以看到立方体的背面.
I've tried "glTransformf(0,0,-10);", but if I do anything less than -2, than the cube dissappears. at -2, the front face side appears. at the default position of 0, I can see the back side of the cube.
此外，当我尝试旋转它时，显示的只是一个矩形，它从窗口的顶部移动到底部.看起来很奇怪.
also, when I try to rotate it, all that shows up is a rectangle moving from the top of the window, to the bottom. Seems very odd.
任何人都可以帮助我找出为什么该程序具有这种方式吗?
Can anyone help me find out why the program is behaving this way?
#if defined(_WIN32) || defined(_WIN64)
#include <windows.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <fstream>
#define GLEW_STATIC
#include <GL/glew.h>
#include <GL/gl.h>
#include <GLFW/glfw3.h>
const char* gameTitle = "TEST";
GLFWwindow* window;
GLfloat vertices[] =
{
-1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1,
1, -1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1,
-1, -1, -1, -1, -1, 1, 1, -1, 1, 1, -1, -1,
-1, 1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1,
-1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1,
-1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1, 1
};
GLfloat colors[] =
{
0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0,
1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0,
0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0,
0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0,
0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0,
0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1
};
static void controls(GLFWwindow* window, int key, int scancode, int action, int mods)
{
if(action == GLFW_PRESS)
if(key == GLFW_KEY_ESCAPE)
glfwSetWindowShouldClose(window, GL_TRUE);
}
bool initWindow(const int resX, const int resY)
{
if(!glfwInit())
{
fprintf(stderr, "Failed to initialize GLFW\n");
return false;
}
glfwWindowHint(GLFW_SAMPLES, 4); // 4x antialiasing
// Open a window and create its OpenGL context
window = glfwCreateWindow(resX, resY, gameTitle, NULL, NULL);
if(window == NULL)
{
fprintf(stderr, "Failed to open GLFW window.\n");
glfwTerminate();
return false;
}
glfwMakeContextCurrent(window);
glfwSetKeyCallback(window, controls);
// Get info of GPU and supported OpenGL version
printf("Renderer: %s\n", glGetString(GL_RENDERER));
printf("OpenGL version supported %s\n", glGetString(GL_VERSION));
glEnable(GL_DEPTH_TEST); // Depth Testing
glDepthFunc(GL_LEQUAL);
glDisable(GL_CULL_FACE);
glCullFace(GL_BACK);
return true;
}
static void drawCube()
{
static float alpha = 0;
glMatrixMode(GL_PROJECTION_MATRIX);
glLoadIdentity();
glTranslatef(0,0,-2);
glMatrixMode(GL_MODELVIEW_MATRIX);
//attempt to rotate cube
//glRotatef(alpha, 1, 0, 0);
/* We have a color array and a vertex array */
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glVertexPointer(3, GL_FLOAT, 0, vertices);
glColorPointer(3, GL_FLOAT, 0, colors);
/* Send data : 24 vertices */
glDrawArrays(GL_QUADS, 0, 24);
/* Cleanup states */
glDisableClientState(GL_COLOR_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
alpha += 0.1;
}
static void display()
{
glClearColor(0.0, 0.8, 0.3, 1.0);
while(!glfwWindowShouldClose(window))
{
// Draw stuff
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
drawCube();
// Update Screen
//glFlush();
glfwSwapBuffers(window);
// Check for any input, or window movement
glfwPollEvents();
// Scale to window size
GLint windowWidth, windowHeight;
glfwGetWindowSize(window, &windowWidth, &windowHeight);
glViewport(0, 0, windowWidth, windowHeight);
}
}
int main(int argc, char** argv)
{
if(initWindow(1024, 620))
{
display();
}
printf("Goodbye!\n");
glfwDestroyWindow(window);
glfwTerminate();
return 0;
}
推荐答案
- 全局性不好.
- 您永远不会设置(有意义的)投影矩阵.
- 不要滥用投影矩阵堆栈.
- 请勿在
drawCube()，单一职责原则以及所有其他方面设置矩阵. - 在尝试绘制之前，先设置视口.
- C ++具有C标头的
c前缀版本(stdio.h->cstdio).改用那些.
- Globals are bad.
- You never set a (meaningful) projection matrix.
- Abuse not the projection matrix stack.
- Don't set your matrices in
drawCube(), single responsibility principle and all that. - Set your viewport before trying to draw.
- C++ has
c-prefixed versions (stdio.h->cstdio) of the C headers. Use those instead.
一起:
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <cstdio>
void controls(GLFWwindow* window, int key, int scancode, int action, int mods)
{
if(action == GLFW_PRESS)
if(key == GLFW_KEY_ESCAPE)
glfwSetWindowShouldClose(window, GL_TRUE);
}
GLFWwindow* initWindow(const int resX, const int resY)
{
if(!glfwInit())
{
fprintf(stderr, "Failed to initialize GLFW\n");
return NULL;
}
glfwWindowHint(GLFW_SAMPLES, 4); // 4x antialiasing
// Open a window and create its OpenGL context
GLFWwindow* window = glfwCreateWindow(resX, resY, "TEST", NULL, NULL);
if(window == NULL)
{
fprintf(stderr, "Failed to open GLFW window.\n");
glfwTerminate();
return NULL;
}
glfwMakeContextCurrent(window);
glfwSetKeyCallback(window, controls);
// Get info of GPU and supported OpenGL version
printf("Renderer: %s\n", glGetString(GL_RENDERER));
printf("OpenGL version supported %s\n", glGetString(GL_VERSION));
glEnable(GL_DEPTH_TEST); // Depth Testing
glDepthFunc(GL_LEQUAL);
glDisable(GL_CULL_FACE);
glCullFace(GL_BACK);
return window;
}
void drawCube()
{
GLfloat vertices[] =
{
-1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1,
1, -1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1,
-1, -1, -1, -1, -1, 1, 1, -1, 1, 1, -1, -1,
-1, 1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1,
-1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1,
-1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1, 1
};
GLfloat colors[] =
{
0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0,
1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0,
0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0,
0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0,
0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0,
0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1
};
static float alpha = 0;
//attempt to rotate cube
glRotatef(alpha, 0, 1, 0);
/* We have a color array and a vertex array */
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glVertexPointer(3, GL_FLOAT, 0, vertices);
glColorPointer(3, GL_FLOAT, 0, colors);
/* Send data : 24 vertices */
glDrawArrays(GL_QUADS, 0, 24);
/* Cleanup states */
glDisableClientState(GL_COLOR_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
alpha += 1;
}
void display( GLFWwindow* window )
{
while(!glfwWindowShouldClose(window))
{
// Scale to window size
GLint windowWidth, windowHeight;
glfwGetWindowSize(window, &windowWidth, &windowHeight);
glViewport(0, 0, windowWidth, windowHeight);
// Draw stuff
glClearColor(0.0, 0.8, 0.3, 1.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_PROJECTION_MATRIX);
glLoadIdentity();
gluPerspective( 60, (double)windowWidth / (double)windowHeight, 0.1, 100 );
glMatrixMode(GL_MODELVIEW_MATRIX);
glTranslatef(0,0,-5);
drawCube();
// Update Screen
glfwSwapBuffers(window);
// Check for any input, or window movement
glfwPollEvents();
}
}
int main(int argc, char** argv)
{
GLFWwindow* window = initWindow(1024, 620);
if( NULL != window )
{
display( window );
}
glfwDestroyWindow(window);
glfwTerminate();
return 0;
}
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