c – 使用Gtk的OpenGL,尽管背景被清除,但仍未绘制形状

2019年7月27日 220次阅读

我想让OpenGL与gtk一起工作.它似乎是工作尺寸我能够清除背景颜色.然而,当我去绘画时,它不存在.我错过了什么.我把眼睛放在10,10,10,我正在看原点.我应该在原点附近看到一个后三角形.

#include <gtk/gtk.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <iostream>

GtkWidget* wnd;
GtkWidget* glarea;

static gboolean render(GtkGLArea *area, GdkGLContext *context)
{
    int w = gtk_widget_get_allocated_width(GTK_WIDGET(area));
    int h = gtk_widget_get_allocated_height(GTK_WIDGET(area));
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(180, (double)w / (double)h, 0.1, 100.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(10, 10, 10, 0, 0, 0, 0, 1, 0);

    glClearColor(1, 1, 1, 0);
    glClear(GL_COLOR_BUFFER_BIT);

    glColor3f(0, 0, 0);
    glBegin(GL_TRIANGLES);
    glVertex3f(0, 0, 0);
    glVertex3f(-1, 2, -1);
    glVertex3f(1, 3, 2);
    glEnd();

    return TRUE;
}

int main(int argc, char *argv[])
{
    gtk_init(&argc, &argv);
    wnd = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    glarea = gtk_gl_area_new();

    gtk_container_add(GTK_CONTAINER(wnd), glarea);
    g_signal_connect(wnd, "destroy", gtk_main_quit, 0);

    g_signal_connect(glarea, "render", G_CALLBACK(render), NULL);

    gtk_widget_show_all(wnd);
    gtk_main();
    return 0;
}

最佳答案 资料来源：
Emanuele Bassi’s blog – GTK+ developer

[…] The OpenGL support inside GTK+ requires core GL profiles, and thus it won’t work with the fixed pipeline API that was common until OpenGL 3.2 and later versions. this means that you won’t be able to use API like glRotatef(), or glBegin()/glEnd() pairs, or any of that stuff.

解决方案：删除固定功能管道.

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