如何使用 Python 和 PyGame 在 OpenGL 上显示二维形状

Question

我正在尝试使用 python、pygame 和 OpenGL 制作游戏，我想在屏幕中央制作一个十字准线，这样当他们环顾四周时，他们可以看到他们是什么要点击。我做到了，所以它隐藏了他们的光标并将其移动到 window 的中心，但我不知道如何在 pygame 中使形状位于 opengl 之上。我是 pygame 和 opengl 的初学者。这可能真的很容易，但我找不到我看过的答案。
请帮助您如何做并提前致谢。

如果你想确保你所做的在我的情况下有效，这是我的代码。

import pygame
import time
from pygame.locals import *
from OpenGL.GL import *
from OpenGL.GLU import *

block = [
    [0,1,0],
    [1,0,0],
    [1,0,1],
    [0,0,1],
    [1,1,0],
    [0,1,1]
]


def Cube(x,y,z):
    glBegin(GL_TRIANGLES)
    glColor3f(block[0][0], block[0][1], block[0][2])  # N
    glVertex3f(x + .5, y + 1, z + .5)
    glVertex3f(x - .5, y + 1, z + .5)
    glVertex3f(x - .5, y,     z + .5)
    glVertex3f(x - .5, y,     z + .5)
    glVertex3f(x + .5, y,     z + .5)
    glVertex3f(x + .5, y + 1, z + .5)
    glColor3f(block[1][0], block[1][1], block[1][2])  # S
    glVertex3f(x - .5, y + 1, z - .5)
    glVertex3f(x + .5, y + 1, z - .5)
    glVertex3f(x + .5, y,     z - .5)
    glVertex3f(x + .5, y,     z - .5)
    glVertex3f(x - .5, y,     z - .5)
    glVertex3f(x - .5, y + 1, z - .5)
    glColor3f(block[2][0], block[2][1], block[2][2])  # W
    glVertex3f(x + .5, y + 1, z - .5)
    glVertex3f(x + .5, y + 1, z + .5)
    glVertex3f(x + .5, y,     z + .5)
    glVertex3f(x + .5, y,     z + .5)
    glVertex3f(x + .5, y,     z - .5)
    glVertex3f(x + .5, y + 1, z - .5)
    glColor3f(block[3][0], block[3][1], block[3][2])  # E
    glVertex3f(x - .5, y + 1, z + .5)
    glVertex3f(x - .5, y + 1, z - .5)
    glVertex3f(x - .5, y,     z - .5)
    glVertex3f(x - .5, y,     z - .5)
    glVertex3f(x - .5, y,     z + .5)
    glVertex3f(x - .5, y + 1, z + .5)
    glColor3f(block[4][0], block[4][1], block[4][2])  # U
    glVertex3f(x + .5, y + 1, z - .5)
    glVertex3f(x - .5, y + 1, z - .5)
    glVertex3f(x - .5, y + 1, z + .5)
    glVertex3f(x - .5, y + 1, z + .5)
    glVertex3f(x + .5, y + 1, z + .5)
    glVertex3f(x + .5, y + 1, z - .5)
    glColor3f(block[5][0], block[5][1], block[5][2])  # D
    glVertex3f(x + .5, y, z - .5)
    glVertex3f(x + .5, y, z + .5)
    glVertex3f(x - .5, y, z + .5)
    glVertex3f(x - .5, y, z + .5)
    glVertex3f(x - .5, y, z - .5)
    glVertex3f(x + .5, y, z - .5)
    glEnd()
def main():
    controls = False
    pygame.init()

    display = (800,600)
    pygame.display.set_mode(display, DOUBLEBUF | OPENGL)
    glClearColor(0.0, 0.0, 0.0, 0.0)
    glClearDepth(1.0)

    glDepthMask(GL_TRUE)
    glDepthFunc(GL_LESS)
    glEnable(GL_DEPTH_TEST)
    glEnable(GL_CULL_FACE)
    glCullFace(GL_BACK)
    glFrontFace(GL_CCW)
    glShadeModel(GL_SMOOTH)
    glDepthRange(0.0,1.0)

    gluPerspective(45, (display[0]/display[1]), 0.1, 100.0)
    glTranslatef(0.0, 0.0, -5)
    while True:
        if controls:
            pygame.mouse.set_pos([400, 300])
            pygame.mouse.set_visible(False)
        else:
            pygame.mouse.set_visible(True)

        for event in pygame.event.get():
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_a:
                    controls = not controls
            if event.type == pygame.QUIT:
                pygame.quit()
                quit()
        glRotatef(1, 3, 1, 1,)
        glClearDepth(1.0)
        glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)
        Cube(0,0,0)
        Cube(0,1,0)
        Cube(1,1,1)
        glCullFace(GL_BACK)
        pygame.display.flip()
        time.sleep(.01)    


main()

Answer 1

请注意，几十年来不推荐使用 glBegin/glEnd 序列和固定函数矩阵堆栈进行绘制。

无论如何，我建议使用正交投影绘制 head-up display 个元素。

创建一个在 window 坐标中绘制十字准线的函数：

def Crosshair(x, y, w):
    glColor3f(1.0, 1.0, 1.0)
    glBegin(GL_LINES)
    glVertex2f(x-w, y)
    glVertex2f(x+w, y)
    glVertex2f(x, y-w)
    glVertex2f(x, y+w)
    glEnd()

将投影矩阵应用于投影矩阵堆栈，将模型矩阵应用于模型视图矩阵堆栈。见 glMatrixMode:

glMatrixMode(GL_PROJECTION)
gluPerspective(45, (display[0]/display[1]), 0.1, 100.0)

glMatrixMode(GL_MODELVIEW)
glTranslatef(0.0, 0.0, -5)

由于十字准线始终应位于视图的顶部，因此您必须禁用 depth test。

glDisable(GL_DEPTH_TEST)

mX, mY = pygame.mouse.get_pos()
Crosshair(mX, 600-mY, 20)

glEnable(GL_DEPTH_TEST)

您可能可以更改深度函数 (glDepthFunc) to GL_ALWAYS and change the glDepthMask

使用glLoadIdentity to lad the identity matrix and use glOrtho设置正投影1:1到window坐标；

glLoadIdentity()
glOrtho(0.0, display[0], 0.0, display[1], -1.0, 1.0)

使用glPushMatrix/glPopMatrix存储和恢复矩阵栈上的矩阵：

glMatrixMode(GL_PROJECTION)
gluPerspective(45, (display[0]/display[1]), 0.1, 100.0)

glMatrixMode(GL_MODELVIEW)
glTranslatef(0.0, 0.0, -5)
while True:
    if controls:
        pygame.mouse.set_pos([400, 300])
        pygame.mouse.set_visible(False)
    else:
        pygame.mouse.set_visible(True)

    for event in pygame.event.get():
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_a:
                controls = not controls
        if event.type == pygame.QUIT:
            pygame.quit()
            quit()
    glClearDepth(1.0)
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)

    glRotate(1, 3, 1, 1,)
    Cube(0,0,0)
    Cube(0,1,0)
    Cube(1,1,1)

    glMatrixMode(GL_PROJECTION)
    glPushMatrix()
    glLoadIdentity()
    glOrtho(0.0, display[0], 0.0, display[1], -1.0, 1.0)
    glMatrixMode(GL_MODELVIEW)
    glPushMatrix()
    glLoadIdentity()

    glDisable(GL_DEPTH_TEST)
    mX, mY = pygame.mouse.get_pos()
    Crosshair(mX, 600-mY, 20)
    glEnable(GL_DEPTH_TEST)

    glMatrixMode(GL_PROJECTION)
    glPopMatrix()
    glMatrixMode(GL_MODELVIEW)
    glPopMatrix()

    glCullFace(GL_BACK)
    pygame.display.flip()
    time.sleep(.01)

如何使用 Python 和 PyGame 在 OpenGL 上显示二维形状

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