如何GL_POINTS
使用 OpenGL 沿点(不是坐标,而是坐标)的方向移动 2D 对象?
为了更好地理解我的代码:
我已将大部分代码拆分为不同的源代码,但这是实际创建形状和设置场景的代码:
void setupScene(int clearColor[]) {
glClearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
//glClearColor(250, 250, 250, 1.0); // Set the cleared screen colour to black.
glViewport(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT); // This sets up the viewport so that the coordinates (0, 0) are at the top left of the window.
// Set up the orthographic projection so that coordinates (0, 0) are in the top left.
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, WINDOW_WIDTH, WINDOW_HEIGHT, 0, -10, 10);
// Back to the modelview so we can draw stuff.
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear the screen and depth buffer.
}
void drawScene() {
setupScene((int[]){250, 250, 250, 1});
triangle(210, WINDOW_WIDTH, WINDOW_HEIGHT);
glBegin(GL_QUADS);
glColor3f(RGB(80), RGB(80), RGB(80));
glPushMatrix();
glTranslatef(400, 400, 0);
glVertex2d(200, 100);
glVertex2d(100, 100);
glVertex2d(100, 200);
glVertex2d(200, 200);
glPopMatrix();
glEnd();
glutSwapBuffers(); // Send the scene to the screen.
}
void update(int value) {
glutPostRedisplay(); // Tell GLUT that the display has changed.
glutTimerFunc(25, update, 0); // Tell GLUT to call update again in 25 milliseconds.
}
PS:对不起,如果我听起来像个菜鸟,但我刚从 Java 转向 C++,所以我可以做一些跨平台游戏。此外,我从未开发过游戏,只是开发了一些 Android、iOS 和黑莓应用程序。
解决方案
谢谢@paddy,我试图了解解决方案的使用glTranslatef
并附带解决方案。这是工作代码,它将创建一个 100x100 的正方形并将其移动到 400x200:
void setupScene(int clearColor[]) {
glClearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
//glClearColor(250, 250, 250, 1.0); // Set the cleared screen colour to black.
glViewport(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT); // This sets up the viewport so that the coordinates (0, 0) are at the top left of the window.
// Set up the orthographic projection so that coordinates (0, 0) are in the top left.
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, WINDOW_WIDTH, WINDOW_HEIGHT, 0, -10, 10);
// Back to the modelview so we can draw stuff.
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear the screen and depth buffer.
}
int a = 100;
int b = 200;
int x = 100;
int y = 100;
void drawScene() {
setupScene((int[]){250, 250, 250, 1});
triangle(210, WINDOW_WIDTH, WINDOW_HEIGHT);
glPushMatrix();
glTranslatef(x, y, 0);
glBegin(GL_QUADS);
glColor3f(RGB(80), RGB(80), RGB(80));
glVertex2d(b, a);
glVertex2d(a, a);
glVertex2d(a, b);
glVertex2d(b, b);
glEnd();
glPopMatrix();
glutSwapBuffers(); // Send the scene to the screen.
}
void update(int value) {
if (x != 400 && y != 200) {
x += 4;
y += 2;
}
glutPostRedisplay(); // Tell GLUT that the display has changed.
glutTimerFunc(25, update, 0); // Tell GLUT to call update again in 25 milliseconds.
}
OpenGL 比我想象的要容易得多。因为我一直对 C/C++ 感到恐惧,因为我已经习惯了 Java 和 JavaScript,但我真的很喜欢它的真棒、简单和优雅。感谢@paddy 帮助我。:)