pygame pyopengl texture a changing polygon with many sides

Question

so with help from this site I recently made a 2d water simulation thingy in pygame/pyopengl. I am now moving on to texturing this water simulation with a water texture I made. However, when I try to do this, the texture doesnt seem to show up properly no matter what I do. It is there but its all stretched out and disorderly. I want the texture to tile and to not be broken, how do I obtain this?

This is my code:

import pygame
import random
from pygame.locals import *

from OpenGL.GL import *
from OpenGL.GLU import *

def loadTexture():
    textureSurface = pygame.image.load('test_image.png')
    textureData = pygame.image.tostring(textureSurface, "RGBA", 1)
    width = textureSurface.get_width()
    height = textureSurface.get_height()

    glEnable(GL_TEXTURE_2D)
    texid = glGenTextures(1)

    glBindTexture(GL_TEXTURE_2D, texid)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height,
                 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData)

    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_MAG_FILTER, GL_NEAREST)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)

    return texid


def draw_water(polygon_points):
    glBegin(GL_POLYGON)
    for i in polygon_points:
        glTexCoord2f(*i)
        glVertex2f(*i)
    glEnd()

class surface_water_particle():
    
    def __init__(self, x,y):
        self.x_pos = x
        self.y_pos = y
        self.target_y = y
        self.velocity = 0
        self.k = 0.04  
        self.d = 0.08
        self.time = 1

    def update(self):
        x =  self.y_pos - self.target_y
        a = -(self.k * x + self.d * self.velocity)

        if self.y_pos > self.target_y:
            self.y_pos -= 0.1
        if self.y_pos < self.target_y:
            self.y_pos += 0.1
        self.velocity = round(self.velocity)

        self.y_pos += self.velocity
        self.velocity += a

        self.time += 1

class water_tile():
    def __init__(self, x_start, x_end, y_start, y_end, segment_length):
        self.springs = []
        self.x_start = x_start
        self.y_start = y_start
        self.x_end = x_end
        self.y_end = y_end - 10
        for i in range(abs(x_end - x_start) // segment_length):
            self.springs.append(surface_water_particle(i * segment_length + x_start, y_end))

    def update(self, spread):
        passes = 4  # more passes = more splash spreading
        for i in range(len(self.springs)):
            self.springs[i].update() 

        leftDeltas = [0] * len(self.springs)
        rightDeltas = [0] * len(self.springs)
        for p in range(passes):  
            for i in range(0, len(self.springs)):
                if i > 0:  
                    leftDeltas[i] = spread * (self.springs[i].y_pos - self.springs[i - 1].y_pos)
                    self.springs[i - 1].velocity += leftDeltas[i]
                if i < len(self.springs):
                    rightDeltas[i] = spread * (self.springs[i].y_pos - self.springs[(i + 1)%len(self.springs)].y_pos)
                    self.springs[(i + 1)%len(self.springs)].velocity += rightDeltas[i]

            for i in range(0, len(self.springs)):
                if round (leftDeltas[i],12) == 0 or round (rightDeltas[i],12) == 0:
                    self.springs[i - 1].y_pos = self.y_end+10
                if i > 0:
                    self.springs[i - 1].y_pos += leftDeltas[i]  
                if i < len(self.springs):
                    self.springs[(i + 1)%len(self.springs)].y_pos += rightDeltas[i]
                
    def splash(self, index, speed):
        if index >= 0 and index < len(self.springs):
            self.springs[index].velocity = speed 

    def draw(self):
        water_surface = pygame.Surface((abs(self.x_end-self.x_start), abs(self.y_start - self.y_end)), depth=8).convert_alpha()
        water_surface.fill((0,0,0,100))
        water_surface.set_colorkey((0,0,0,0))
        polygon_points = []
        polygon_points.append((self.x_start, 360-self.y_start))
        for spring in range(len(self.springs)):
            polygon_points.append((self.springs[spring].x_pos, 360-self.springs[spring].y_pos))
        polygon_points.append((self.springs[len(self.springs) - 1].x_pos, 360-self.y_start))

        return polygon_points
        

class water_object:
    def __init__(self, x_start, x_end, y_start, y_end, segment_length, x_pos, y_pos):
        self.water = water_tile(x_start,x_end,y_start,y_end,segment_length)

    def update(self):
        self.water.update(0.1)
        self.polypoints = self.water.draw()
        
water_list = [water_object(0,276+16,64,0,16,0,20)]

def main():
    pygame.init()
    display = (640, 360)
    pygame.display.set_mode(display, DOUBLEBUF|OPENGL)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    glOrtho(0, display[0], 0, display[1], -1, 1)

    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity()
    loadTexture()
    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                quit()
            if event.type == MOUSEBUTTONDOWN:
                print (len(water.water.springs))
                water.water.splash(random.randint(0, len(water.water.springs) - 1),50)
        glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)
       
        for water in water_list:
            water.update()
            draw_water(water.polypoints)
        pygame.display.flip()
        pygame.time.wait(10)

if __name__ == "__main__":
    main()

Bellow is my texture

Answer 1

If you want to fill the area under the water line, with a color, then I recommend to generate a GL_TRIANGLE_STRIP primitive:

def draw_polygon(polygon_points):
    glBegin(GL_TRIANGLE_STRIP)
    for pt in polygon_points:
        glVertex2f(*pt)
        glVertex2f(pt[0], WINDOW_SIZE[1])
    glEnd()

---

See the example:

import pygame
from OpenGL import *
from OpenGL.GL import *

def draw_polygon(surf_rect, polygon_points):
    #glBegin(GL_LINE_STRIP)
    glBegin(GL_TRIANGLE_STRIP)
    for pt in polygon_points:
        glVertex2f(*pt)
        glVertex2f(pt[0], surf_rect.height)
    glEnd()
    
class WaterParticle():
    def __init__(self, x, y):
        self.x, self.y = x, y
        self.target_y = y
        self.velocity = 0
        self.k = 0.04  
        self.d = 0.08
    def update(self):
        x = self.y - self.target_y
        a = -(self.k * x + self.d * self.velocity)
        #self.p[1] += -0.1 if x > 0 else 0.1 if x < 0 else 0
        self.y += self.velocity
        self.velocity += a

class Water():
    def __init__(self, x_start, x_end, y_start, segment_length, passes, spread):
        n = abs(x_end - x_start + segment_length - 1) // segment_length + 1
        self.particles = [WaterParticle(i * segment_length + x_start, y_start) for i in range(n)]
        self.passes = passes
        self.spread = spread

    def update(self):
        for particle in self.particles:
            particle.update() 

        left_deltas = [0] * len(self.particles)
        right_deltas = [0] * len(self.particles)
        for _ in range(self.passes):  
            for i in range(len(self.particles)):
                if i > 0:  
                    left_deltas[i] = self.spread * (self.particles[i].y - self.particles[i - 1].y)
                    self.particles[i - 1].velocity += left_deltas[i]
                if i < len(self.particles)-1:
                    right_deltas[i] = self.spread * (self.particles[i].y - self.particles[i + 1].y)
                    self.particles[i + 1].velocity += right_deltas[i]
            for i in range(len(self.particles)):
                if i > 0:
                    self.particles[i-1].y += left_deltas[i]
                if i < len(self.particles) - 1:
                    self.particles[i+1].y += right_deltas[i]
 
    def splash(self, index, speed):
        if index > 0 and index < len(self.particles):
            self.particles[index].velocity += speed
                
    def draw(self, surf_rect):
        polygon_points = []
        for spring in range(len(self.particles)):
            polygon_points.append((self.particles[spring].x, self.particles[spring].y))
        glColor3f(0, 0, 1)
        draw_polygon(surf_rect, polygon_points)
        
pygame.init()
window = pygame.display.set_mode((640, 480), pygame.DOUBLEBUF | pygame.OPENGL)
clock = pygame.time.Clock()

glMatrixMode(GL_PROJECTION)
glLoadIdentity()
glOrtho(0, *window.get_size(), 0, -1, 1)
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
glClearColor(1, 1, 1, 1)

water_line_y = window.get_height() // 2
water = Water(0, window.get_width(), window.get_height() // 2, 3, 8, 0.025)

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
        if event.type == pygame.MOUSEBUTTONDOWN:
            velocity = water_line_y - event.pos[1]
            if velocity > 0:
                index = int(len(water.particles) * event.pos[0] / window.get_width())
                water.splash(index, velocity)
    
    water.update()

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    water.draw(window.get_rect())
    pygame.display.flip()
    clock.tick(50)