pyOpenGL how to draw 2d image?

user_19373486 0
Viewed 44

I tried many things and found out how to get data using pillow and numpy. Even if I looked around, I could only see how to make vertex and fragments in 3d, and I couldn't find a way to actually draw a 2d image.

texture = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, texture)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
tex = Image.open("Resources/bg55.png")
mode = "".join(Image.Image.getbands(tex))
data = tex.tobytes("raw", "RGBA", 0, -1)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex.width, tex.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data)
glGenerateMipmap(GL_TEXTURE_2D)

Is this code correct? How can I continue? glfw and pyopengl is in use.

glfw pyopengl python
1 Answers

You need to draw a rectangle and wrap the texture on it. This is the usual way to proceed. OpenGL renders primitives and does not draw images. See the very basic example:

image 

import pygame
from pygame.locals import *
from OpenGL.GL import *
from OpenGL.GLU import *
from PIL import Image
from numpy import array

def loadTexture(texture):
    try:
        text = Image.open(texture)
    except IOError as ex:
        print("Failed to open texture file: ", texture)
        text = Image.open("0.png")

    textData = array(list(text.getdata()))
    textID = glGenTextures(1)
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1)
    glBindTexture(GL_TEXTURE_2D, textID)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, text.size[0], text.size[1], 0, GL_RGBA, GL_UNSIGNED_BYTE, textData)
    text.close()
    return textID

def drawQuad(centerX, centerY, textureID):
    verts = ((1, 1), (1,-1), (-1,-1), (-1,1))
    texts = ((1, 0), (1, 1), (0, 1), (0, 0))
    surf = (0, 1, 2, 3)

    glEnable(GL_TEXTURE_2D)
    glBindTexture(GL_TEXTURE_2D, textureID)

    glBegin(GL_QUADS)
    for i in surf:
        glTexCoord2f(texts[i][0], texts[i][1])
        glVertex2f(centerX + verts[i][0], centerY + verts[i][1])
    glEnd()
    
    glDisable(GL_TEXTURE_2D)

def main():
    pygame.init()
    disp = (200, 200)
    pygame.display.set_mode(disp, DOUBLEBUF|OPENGL)
    gluPerspective(45, (disp[0] / disp[1]), 0.1, 50.0)
    glTranslatef(0.0, 0.0, -5)
    textID = loadTexture("0.png")

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                quit()
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
        drawQuad(0, 0, textID)
        pygame.display.flip()
        pygame.time.wait(10)
        
main()
user_55777650
Related