Related
cant seem to draw a triangle
import pygame
from pygame.locals import *
import numpy as np
from OpenGL.GL import *
pygame.init()
display = (600,600)
clock = pygame.time.Clock()
pygame.display.set_mode(display, DOUBLEBUF|OPENGL)
positions = [
-0.5, -0.5,
0, 0.5,
0.5, -0.5
]
positions = np.array(positions, dtype=np.float32)
buffer = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, buffer)
glBufferData(GL_ARRAY_BUFFER, positions.size, positions, GL_STATIC_DRAW)
glEnableVertexAttribArray(0)
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 8, 0)
run = True
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
pygame.quit()
if not run:
break
glDrawArrays(GL_TRIANGLES, 0, 3)
pygame.display.flip()
is this a python problem or am i writing it wrong ?
The 2nd argument of glBufferData is the buffer size in bytes:
glBufferData(GL_ARRAY_BUFFER, positions.size, positions, GL_STATIC_DRAW)
glBufferData(GL_ARRAY_BUFFER, positions.size*4, positions, GL_STATIC_DRAW)
The parameter size can be omitted:
glBufferData(GL_ARRAY_BUFFER, positions, GL_STATIC_DRAW)
If a named buffer object is bound, then the 6th parameter of glVertexAttribPointer is treated as a byte offset into the buffer object's data store. But the type of the parameter is a pointer anyway (c_void_p).
So if the offset is 0, then the 6th parameter can either be None or c_void_p(0) else the offset has to be caste to c_void_p(0):
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 8, 0)
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 8, None)
Complete example:
import pygame
from pygame.locals import *
import numpy as np
from OpenGL.GL import *
pygame.init()
display = (600,600)
clock = pygame.time.Clock()
pygame.display.set_mode(display, DOUBLEBUF|OPENGL)
positions = [
-0.5, -0.5,
0, 0.5,
0.5, -0.5
]
positions = np.array(positions, dtype=np.float32)
buffer = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, buffer)
glBufferData(GL_ARRAY_BUFFER, positions, GL_STATIC_DRAW)
glEnableVertexAttribArray(0)
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 8, None)
run = True
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
glClear(GL_COLOR_BUFFER_BIT)
glDrawArrays(GL_TRIANGLES, 0, 3)
pygame.display.flip()
pygame.quit()
It is hard to know what example will work without knowing what GL version your hardware supports (print (glGetString(GL_VERSION))), but here is a compatibility demo that should work, but you should consider modifying it to at least OpenGL3.3/GLSL 330:
import pygame
from pygame.locals import *
import numpy as np
from OpenGL.GL import *
pygame.init()
display = (600,600)
clock = pygame.time.Clock()
pygame.display.set_mode(display, DOUBLEBUF|OPENGL)
positions = [
-0.5, -0.5,
0, 0.5,
0.5, -0.5
]
vertex_shader_source = """#version 120
attribute vec2 aPos;
varying vec2 pos;
void main()
{
gl_Position = vec4(aPos.x, aPos.y, 0, 1);
pos = aPos;
}"""
fragment_shader_source = """#version 120
varying vec2 pos;
void main()
{
gl_FragColor = vec4(pos.x, pos.y,0,1);
}"""
vertex_shader = glCreateShader(GL_VERTEX_SHADER)
glShaderSource(vertex_shader, vertex_shader_source)
glCompileShader(vertex_shader)
if glGetShaderiv(vertex_shader, GL_COMPILE_STATUS) != GL_TRUE:
raise RuntimeError(glGetShaderInfoLog(vertex_shader))
fragment_shader = glCreateShader(GL_FRAGMENT_SHADER)
glShaderSource(fragment_shader, fragment_shader_source)
glCompileShader(fragment_shader)
if glGetShaderiv(fragment_shader, GL_COMPILE_STATUS) != GL_TRUE:
raise RuntimeError(glGetShaderInfoLog(fragment_shader))
shader_program = glCreateProgram()
glAttachShader(shader_program, vertex_shader)
glAttachShader(shader_program, fragment_shader)
glLinkProgram(shader_program)
positions = np.array(positions, dtype=np.float32)
VAO = glGenVertexArrays(1)
VBO = glGenBuffers(1)
glBindVertexArray(VAO)
glBindBuffer(GL_ARRAY_BUFFER, VBO)
# using positions.size * np.dtype(np.float32).itemsize
# to get the size (in bytes) of the vertex data
glBufferData(GL_ARRAY_BUFFER, positions.size * np.dtype(np.float32).itemsize, \
positions, GL_STATIC_DRAW)
glEnableVertexAttribArray(0)
aPos = glGetAttribLocation(shader_program, 'aPos')
glEnableVertexAttribArray(aPos)
# ctypes.c_void_p(0) to specify the offset (0 wont work)
glVertexAttribPointer(aPos, 2, GL_FLOAT, GL_FALSE, 0, ctypes.c_void_p(0))
if glGetProgramiv(shader_program, GL_LINK_STATUS) != GL_TRUE:
raise RuntimeError(glGetProgramInfoLog(shader_program))
glClearColor(0,0,1,1);
run = True
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
pygame.quit()
if not run:
break
glClear(GL_COLOR_BUFFER_BIT)
glUseProgram(shader_program)
glBindVertexArray(VAO)
glDrawArrays(GL_TRIANGLES, 0, 3)
pygame.display.flip()
Result:
this is original 2d 256x256 image i am trying to texture on screen. but for some reason it does not rendering without glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR) line ever. And when its rendering since pic is 2d i send attrib pointer uv is size of 2 with glVertexAttribPointer(attribute_texture, 2, GL_FLOAT, GL_FALSE, 0, None)
but its turns out this.
when i turn it to 3 just for trying sake its like this
what eer i try it did not change any better
what am i doing wrong here? i realy could use another pair of eyes. thank you.
And this is my code:
import glfw
from OpenGL.GL import *
# from OpenGL.GL.shaders import compileShader, compileProgram
import numpy as np
from math import radians
from pyrr import matrix44, Vector3
from PIL import Image
# ----------------------------------------------------------------------
if not glfw.init():
raise Exception("GLFW not initialized")
window = glfw.create_window(800, 600, "personal", None, None)
if not window:
glfw.terminate()
raise Exception("window did not created")
glfw.set_window_pos(window, xpos=200, ypos=50)
glfw.make_context_current(window)
# ----------------------------------------------------------------------
vertices = np.array([-0.7, 0.7, 0.0,
-0.7, -0.7, 0.0,
0.7, -0.7, 0.0,
0.7, 0.7, 0.0], dtype=np.float32)
indices = np.array([0, 1, 3,
3, 1, 2], dtype=np.uint32)
# color = np.array([0.0, 0.0, 0.0,
# 0.0, 0.0, 0.0,
# 0.0, 0.0, 0.0,
# 0.0, 0.0, 0.0], dtype=np.float32)
texture_coord = np.array([0, 0,
0, 1,
1, 1,
1, 0], dtype=np.uint32)
# --------------------------------------------------------------------- TRANSFORMATION CALCULATION
matrix = matrix44.create_identity(dtype=np.float32)
matrix = np.dot(matrix44.create_from_translation(Vector3([0.0, 0.0, 0.0])), matrix)
matrix = np.dot(matrix44.create_from_x_rotation(radians(0)), matrix)
matrix = np.dot(matrix44.create_from_y_rotation(radians(0)), matrix)
matrix = np.dot(matrix44.create_from_z_rotation(radians(0)), matrix)
matrix = np.dot(matrix44.create_from_scale(Vector3([1, 1, 1])), matrix)
# ---------------------------------------------------------------------
vertex_shader_src = """
#version 330 core
layout(location = 0)in vec3 position;
layout(location = 1)in vec2 texture;
//in vec3 color;//for using color equal it to toFColor
uniform mat4 trans;
out vec3 toFColor;
out vec2 passTexCoord;
void main(){
gl_Position = trans * vec4(position.x,position.y,position.z,1.0f);
//toFColor=color;
passTexCoord=texture;
}
"""
# ---------------------------------------------------------------------
fragment_shader_src = """
#version 330 core
//in vec3 toFColor;
in vec2 passTexCoord;
//uniform vec3 triColor;
uniform sampler2D texture_sampler;
out vec4 outColor;
void main(){
//outColor = vec4(toFColor,1.0);
outColor = texture(texture_sampler, passTexCoord);
}
"""
# ---------------------------------------------------------------------PyOpenGL working shader program
# shader_program = compileProgram(compileShader(vertex_shader_src, GL_VERTEX_SHADER),
# compileShader(fragment_shader_src, GL_FRAGMENT_SHADER))
# ---------------------------------------------------------------------tutorial way shader program
vertex_shader_id = glCreateShader(GL_VERTEX_SHADER)
glShaderSource(vertex_shader_id, vertex_shader_src)
glCompileShader(vertex_shader_id)
if glGetShaderiv(vertex_shader_id, GL_COMPILE_STATUS) == GL_FALSE:
print(glGetShaderInfoLog(vertex_shader_id))
print("cant compile shader")
fragment_shader_id = glCreateShader(GL_FRAGMENT_SHADER)
glShaderSource(fragment_shader_id, fragment_shader_src)
glCompileShader(fragment_shader_id)
if glGetShaderiv(fragment_shader_id, GL_COMPILE_STATUS) == GL_FALSE:
print(glGetShaderInfoLog(fragment_shader_id))
print("cant compile shader")
shader_program = glCreateProgram()
glAttachShader(shader_program, vertex_shader_id)
glAttachShader(shader_program, fragment_shader_id)
glBindAttribLocation(shader_program, 0, "position")
glBindAttribLocation(shader_program, 1, "texture")
glLinkProgram(shader_program)
glValidateProgram(shader_program)
glUseProgram(shader_program)
# --------------------------------------------------------------------- my trying for VAO vertex positions
VAO = glGenVertexArrays(1) # generate vao
glBindVertexArray(VAO) # ready VAO to use
VBO1 = glGenBuffers(1) # generate vbo
glBindBuffer(GL_ARRAY_BUFFER, VBO1) # binding vbo for use
glBufferData(GL_ARRAY_BUFFER, vertices.nbytes, vertices, GL_STATIC_DRAW) # setting VBO what to carry
attribute_position = glGetAttribLocation(shader_program, "position") # taking attribute name position from shader
glEnableVertexAttribArray(attribute_position) # ready to use attribute
glVertexAttribPointer(attribute_position, 3, GL_FLOAT, GL_FALSE, 0,
None) # telling OpenGL how to read data on given uniform
# ---------------------------------------------------------------------- indexing positions
EBO = glGenBuffers(1)
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO)
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.nbytes, indices, GL_STATIC_DRAW)
# ---------------------------------------------------------------------- coloring instead of texture
# i am closing this because i will use texture
# VBO2 = glGenBuffers(1)
# glBindBuffer(GL_ARRAY_BUFFER, VBO2)
# glBufferData(GL_ARRAY_BUFFER, color.nbytes, color, GL_STATIC_DRAW)
# attribute_color = glGetAttribLocation(shader_program, "color") # taking uniform name color from shader
# glEnableVertexAttribArray(attribute_color) # ready to use uniform
# glVertexAttribPointer(attribute_color, 3, GL_FLOAT, GL_FALSE, 0,
# None) # telling OpenGL how to read data on given attribute
# ---------------------------------------------------------------------- Texture pressing
TEX_BO = glGenTextures(1)
glActiveTexture(GL_TEXTURE0)
glBindTexture(GL_TEXTURE_2D, TEX_BO)
attribute_texture = glGetAttribLocation(shader_program, "texture")
glEnableVertexAttribArray(attribute_texture)
glVertexAttribPointer(attribute_texture, 3, GL_FLOAT, GL_FALSE, 0, None)
texture = Image.open("../res/pic1.png", "r")
texture = texture.transpose(Image.FLIP_TOP_BOTTOM)
image_data = texture.convert("RGBA").tobytes()
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture.width, texture.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image_data)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
# Set texture filtering parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
# ---------------------------------------------------------------------- TRANSFORMATION MATRIX -------------------------
loc_uniform_transformation = glGetUniformLocation(shader_program, "trans")
# ----------------------------------------------------------------------
while not glfw.window_should_close(window):
glfw.poll_events()
glClearColor(0.15, 0.15, 0.15, 1.0)
glClear(GL_COLOR_BUFFER_BIT)
glUniformMatrix4fv(loc_uniform_transformation, 1, GL_FALSE, matrix44.create_identity())
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, None)
glfw.swap_buffers(window)
# ------------------------------------------------------------------------------ Cleaning
glDeleteTextures(1, int(TEX_BO))
glDetachShader(shader_program, vertex_shader_id)
glDetachShader(shader_program, fragment_shader_id)
glDeleteShader(vertex_shader_id)
glDeleteShader(fragment_shader_id)
glDeleteProgram(shader_program)
glDeleteBuffers(1, int(VBO1))
# glDeleteBuffers(1, int(VBO2)) # if use colors
glDeleteBuffers(1, int(EBO))
glDeleteVertexArrays(1, int(VAO))
# ------------------------------------------------------------------------------
glfw.destroy_window(window)
glfw.terminate()
You have to set glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR) because the default minifying function is GL_NEAREST_MIPMAP_LINEAR. Since you do not generate mipmaps the texture would be "Mipmap Incomplete" if you do not change the minimize function to GL_NEAREST or GL_LINEAR.
The type of the array of texture coordinates must be np.float32 rather than np.uint32:
texture_coord = np.array([0, 0,
0, 1,
1, 1,
1, 0], dtype=np.float32)
You missed to create the buffer object for the texture coordinates:
VBO2 = glGenBuffers(1) # generate vbo
glBindBuffer(GL_ARRAY_BUFFER, VBO2) # binding vbo for use
glBufferData(GL_ARRAY_BUFFER, texture_coord.nbytes, texture_coord, GL_STATIC_DRAW)
attribute_texture = glGetAttribLocation(shader_program, "texture")
glEnableVertexAttribArray(attribute_texture)
glVertexAttribPointer(attribute_texture, 2, GL_FLOAT, GL_FALSE, 0, None)
When glVertexAttribPointer is called, the buffer object currently bound to the target GL_ARRAY_BUFFER is associated to the specified vertex attribute.
I am trying to draw some traingles and render some texts in screen. But I've observed that memory(RAM) is gradually increasing just only for 6 draw calls. I've 8 GB RAM. When I run the program memory usage goes from 4.2 to 6 within 1 minute. Here is the full code.
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GL import shaders
from shader import *
import glfw
import freetype
import glm
import numpy as np
from PIL import Image
import math
class CharacterSlot:
def __init__(self, texture, glyph):
self.texture = texture
self.textureSize = (glyph.bitmap.width, glyph.bitmap.rows)
if isinstance(glyph, freetype.GlyphSlot):
self.bearing = (glyph.bitmap_left, glyph.bitmap_top)
self.advance = glyph.advance.x
elif isinstance(glyph, freetype.BitmapGlyph):
self.bearing = (glyph.left, glyph.top)
self.advance = None
else:
raise RuntimeError('unknown glyph type')
def _get_rendering_buffer(xpos, ypos, w, h, zfix=0.0):
return np.asarray([
xpos, ypos + h, 0, 0,
xpos, ypos, 0, 1,
xpos + w, ypos, 1, 1,
xpos, ypos + h, 0, 0,
xpos + w, ypos, 1, 1,
xpos + w, ypos + h, 1, 0
], np.float32)
def init_chars(shaderProgram,window_height,window_width,font_size=24,fontfile = "Vera.ttf"):
glUseProgram(shaderProgram)
#get projection
shader_projection = glGetUniformLocation(shaderProgram, "projection")
W = window_width
H = window_height
projection = glm.ortho(-W/2, W/2, -H/2, H/2)
glUniformMatrix4fv(shader_projection, 1, GL_FALSE, glm.value_ptr(projection))
#disable byte-alignment restriction
glPixelStorei(GL_UNPACK_ALIGNMENT, 1)
face = freetype.Face(fontfile)
face.set_char_size(font_size*64 )
#load first 128 characters of ASCII set
Characters = dict()
for i in range(0,128):
face.load_char(chr(i))
glyph = face.glyph
#generate texture
texture = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, texture)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, glyph.bitmap.width, glyph.bitmap.rows, 0,
GL_RED, GL_UNSIGNED_BYTE, glyph.bitmap.buffer)
#texture options
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
#now store character for later use
Characters[chr(i)] = CharacterSlot(texture,glyph)
glBindTexture(GL_TEXTURE_2D, 0)
glUseProgram(0)
return Characters
def render_text(window,shaderProgram,text,x,y,scale,Characters,color=(170,250,255)):
r,g,b = color
glUseProgram(shaderProgram)
#configure VAO/VBO for texture quads
VAO = glGenVertexArrays(1)
glBindVertexArray(VAO)
VBO = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, VBO)
glBufferData(GL_ARRAY_BUFFER, 6 * 4 * 4, None, GL_STATIC_DRAW)
glEnableVertexAttribArray(0)
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, None)
glBindBuffer(GL_ARRAY_BUFFER, 0)
glBindVertexArray(0)
glUniform3f(glGetUniformLocation(shaderProgram, "textColor"),r/255,g/255,b/255)
glActiveTexture(GL_TEXTURE0)
glBindVertexArray(VAO)
for c in text:
ch = Characters[c]
w, h = ch.textureSize
w = w*scale
h = h*scale
vertices = _get_rendering_buffer(x,y,w,h)
#render glyph texture over quad
glBindTexture(GL_TEXTURE_2D, ch.texture)
#update content of VBO memory
glBindBuffer(GL_ARRAY_BUFFER, VBO)
glBufferSubData(GL_ARRAY_BUFFER, 0, vertices.nbytes, vertices)
glBindBuffer(GL_ARRAY_BUFFER, 0)
#render quad
glDrawArrays(GL_TRIANGLES, 0, 6)
#now advance cursors for next glyph (note that advance is number of 1/64 pixels)
x += (ch.advance>>6)*scale
glBindTexture(GL_TEXTURE_2D, 0);
glUseProgram(0)
#UNBIND and DELETE VAO/VBO
glBindVertexArray(0)
glBindBuffer(GL_ARRAY_BUFFER, 0)
glDeleteBuffers(1, id(VBO))
glDeleteBuffers(1, id(VAO))
def triangle(shaderProgram,window,x=0,y=0):
vertices = [-0.5, -0.5, 0.0,
0.5, -0.5, 0.0,
0.0, 0.5, 0.0]
vertices = np.array(vertices, dtype=np.float32)
VBO = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, VBO)
glBufferData(GL_ARRAY_BUFFER, vertices.nbytes, vertices, GL_STATIC_DRAW)
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, None)
glEnableVertexAttribArray(0)
#use shader program
glUseProgram(shaderProgram)
#accessing ourColor variable from shaderProgram
vertexColorLoc = glGetUniformLocation(shaderProgram, "ourColor")
glUniform4f(vertexColorLoc, 255, 28/255.0, 20/255.0, 0.7);
#transform matrix
transform = glm.mat4(1)
transform = glm.translate(transform,glm.vec3(x,y,0))
MVP = glGetUniformLocation(shaderProgram, "MVP")
glUniformMatrix4fv(MVP, 1, GL_FALSE, glm.value_ptr(transform))
#drawing trangle
glLineWidth(3)
glDrawArrays(GL_TRIANGLES, 0, 3)
glUseProgram(0)
#UNBIND and DELETE VAO/VBO
glBindVertexArray(0)
glBindBuffer(GL_ARRAY_BUFFER, 0)
glDeleteBuffers(1, id(VBO))
def main():
glfw.init()
window = glfw.create_window(640, 640,"EXAMPLE PROGRAM",None,None)
glfw.make_context_current(window)
#initliaze shader programs
shaderProgram = get_shaderProgram()
text_shaderProgram = get_text_shaderProgram()
#load characters and VAO/VBO for text rendering
Characters = init_chars(text_shaderProgram,640,640)
#window loop
while not glfw.window_should_close(window):
glfw.poll_events()
#screen
glClearColor(0, 0, 0, 1)
glClear(GL_COLOR_BUFFER_BIT)
glEnable(GL_BLEND)
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
#draw functions
render_text(window,text_shaderProgram,"TRIANGLE",-50,-200,1,Characters)
render_text(window,text_shaderProgram,"A",0,180,1,Characters)
render_text(window,text_shaderProgram,"B",-160,-180,1,Characters)
render_text(window,text_shaderProgram,"C",150,-180,1,Characters)
triangle(shaderProgram,window)
triangle(shaderProgram,window,x=0.5,y=0.5)
#swap buffers
glfw.swap_buffers(window)
glfw.swap_interval(1)
glfw.terminate()
if __name__ == '__main__':
main()
The shader program is here. But I think the problems is in buffer object. I've tried to unbind VAO/VBO and delete buffers by following code. But I see no change.
#UNBIND and DELETE VAO/VBO
glBindVertexArray(0)
glBindBuffer(GL_ARRAY_BUFFER, 0)
glDeleteBuffers(1, id(VBO))
glDeleteBuffers(1, id(VAO))
Here is the related problem where accepted answer suggested that glGenBuffers causes memory leak. The alternate function glCreateBuffers is not available in pyopengl. How can I solve this issue?
I can't see any good reason for recreating the Vertex Array Object and Array Buffer Object every time when render_text respectively triangle is called. The vertex specification and the number of vertices doesn't change, so it would be sufficient to update the content of the buffer.
Create the Vertex Array Object and the Array Buffer Object once at initialization:
def init_buffers():
global text_VAO, text_VBO, triangle_VAO, triangle_VBO
text_VAO = glGenVertexArrays(1)
glBindVertexArray(text_VAO)
text_VBO = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, text_VBO)
glBufferData(GL_ARRAY_BUFFER, 6 * 4 * 4, None, GL_STATIC_DRAW)
glEnableVertexAttribArray(0)
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, None)
vertices = [-0.5, -0.5, 0.0,
0.5, -0.5, 0.0,
0.0, 0.5, 0.0]
vertices = np.array(vertices, dtype=np.float32)
triangle_VAO = glGenVertexArrays(1)
glBindVertexArray(triangle_VAO)
triangle_VBO = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, triangle_VBO)
glBufferData(GL_ARRAY_BUFFER, vertices.nbytes, vertices, GL_STATIC_DRAW)
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, None)
glEnableVertexAttribArray(0)
Use then in the functions render_text and triangle:
def render_text(window,shaderProgram,text,x,y,scale,Characters,color=(170,250,255)):
# [...]
glBindVertexArray(text_VAO)
for c in text:
# [...]
glBindBuffer(GL_ARRAY_BUFFER, text_VBO)
glBufferSubData(GL_ARRAY_BUFFER, 0, vertices.nbytes, vertices)
# glDeleteBuffers(1, id(VBO)) <--- DELETE
# glDeleteBuffers(1, id(VAO)) <--- DELETE
def triangle(shaderProgram,window,x=0,y=0):
glBindVertexArray(triangle_VAO)
# [...]
# glDeleteBuffers(1, id(VBO)) <--- DELETE
Invoke init_buffers before the application loop:
def main():
# [...]
init_buffers()
while not glfw.window_should_close(window):
# [...]
I'm trying to add woody texture to the triangle. Code works fine for only triangle. But raises error while I try to add texture. I think the problem is in the GLSL or in creating EBO/VBO (not sure). The whole screen remains black.
Here is the whole code. What am I doing wrong here?
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GL import shaders
import glfw
import numpy as np
from PIL import Image
VERTEX_SHADER = """
#version 330
layout (location = 0) in vec4 position;
in vec2 InTexCoords;
out vec2 OutTexCoords;
void main(){
gl_Position = position;
OutTexCoords = InTexCoords;
}
"""
FRAGMENT_SHADER = """
#version 330
out vec4 FragColor;
uniform vec4 triangleColor;
in vec2 OutTexCoords;
uniform sampler2D sampleTex;
void main() {
FragColor = texture(sampleTex,OutTexCoords);
}
"""
shaderProgram = None
def initialize():
global VERTEXT_SHADER
global FRAGMENT_SHADER
global shaderProgram
#compiling shaders
vertexshader = shaders.compileShader(VERTEX_SHADER, GL_VERTEX_SHADER)
fragmentshader = shaders.compileShader(FRAGMENT_SHADER, GL_FRAGMENT_SHADER)
#creating shaderProgram
shaderProgram = shaders.compileProgram(vertexshader, fragmentshader)
#vertex and indices data
#triangle #texture
vertices = [-0.5, -0.5, 0.0, 0.0,0.0,
0.5, -0.5, 0.0, 1.0,0.0,
0.0, 0.5, 0.0, 0.5,1.0]
indices = [0,1,2]
vertices = np.array(vertices, dtype=np.float32)
indices = np.array(vertices, dtype=np.float32)
#add vertices to buffer
VBO = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, VBO)
glBufferData(GL_ARRAY_BUFFER, vertices.nbytes, vertices, GL_STATIC_DRAW)
#add indices to buffer
EBO = glGenBuffers(1)
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,EBO)
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices, GL_STATIC_DRAW)
position = 0
glVertexAttribPointer(position, 3, GL_FLOAT, GL_FALSE, 24, ctypes.c_void_p(0))
glEnableVertexAttribArray(position)
texCoords = 1
glBindAttribLocation( shaderProgram, texCoords, 'InTexCoords')
glVertexAttribPointer(texCoords,2, GL_FLOAT, GL_FALSE, 24, ctypes.c_void_p(12))
glEnableVertexAttribArray(texCoords)
#creating texture
texture = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, texture)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
image = Image.open("wood.jpg")
img_data = np.array(list(image.getdata()), np.uint8)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 512, 512, 0, GL_RGB, GL_UNSIGNED_BYTE, img_data)
def render(window):
global shaderProgram
glClearColor(0, 0, 0, 1)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glUseProgram(shaderProgram)
glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, None)
glUseProgram(0)
glfw.swap_buffers(window)
def main():
glfw.init()
window = glfw.create_window(640, 640,"EXAMPLE PROGRAM",None,None)
glfw.make_context_current(window)
initialize()
while not glfw.window_should_close(window):
glfw.poll_events()
render(window)
glfw.terminate()
if __name__ == '__main__':
main()
I was trying to follow this tutorial learnopengl. But the tutorial is in C++. Besides, I had slightly different approach. I'm not adding color codes in vertices. But I don't think it is the problem in the way of adding the texture.
The stride argument of glVertexAttribPointer specifies the byte offset between consecutive generic vertex attributes. Your attributes consist of vertex coordinates with 3 components and texture coordinates with 2 components. Hence your stride argument has to 20 (5 * 4 bytes) rather than 24:
glVertexAttribPointer(position, 3, GL_FLOAT, GL_FALSE, 24, ctypes.c_void_p(0))
glVertexAttribPointer(position, 3, GL_FLOAT, GL_FALSE, 20, ctypes.c_void_p(0))
glVertexAttribPointer(texCoords,2, GL_FLOAT, GL_FALSE, 24, ctypes.c_void_p(12))
glVertexAttribPointer(texCoords,2, GL_FLOAT, GL_FALSE, 20, ctypes.c_void_p(12))
The data type of the indices has to be integral. The type in the draw call (glDrawElements(..., ..., GL_UNSIGNED_INT, ...)) has to match this type. Use uint32 rather than float (and vertices -> indices):
indices = np.array(vertices, dtype=np.float32)
indices = np.array(indices, dtype=np.uint32)
Associating a generic vertex attribute index with a named attribute variable (glBindAttribLocation) has to be done, before the program is linked (before glLinkProgram).
I recommend to set the attribute index by a Layout Qualifier:
layout (location = 0) in vec4 position;
layout (location = 1) in vec2 InTexCoords;
I have the following code which should simply draw a green triangle to the screen. It is using Vertex Array Objects and index buffers to draw and has the simplest shader I could make.
At first I was not using index buffers and was simply making the draw call with glDrawArrays which worked fine but when I change it to use glDrawElements then nothing is drawn to the screen (it is entirely black).
from OpenGL.GL import shaders
from OpenGL.arrays import vbo
from OpenGL.GL import *
from OpenGL.raw.GL.ARB.vertex_array_object import glGenVertexArrays, \
glBindVertexArray
import pygame
import numpy as np
def run():
pygame.init()
screen = pygame.display.set_mode((800,600), pygame.OPENGL)
#Create the Vertex Array Object
vertexArrayObject = GLuint(0)
glGenVertexArrays(1, vertexArrayObject)
glBindVertexArray(vertexArrayObject)
#Create the VBO
vertices = np.array([[0,1,0],[-1,-1,0],[1,-1,0]], dtype='f')
vertexPositions = vbo.VBO(vertices)
#Create the index buffer object
indices = np.array([0,1,2], dtype='uint16')
indexPositions = vbo.VBO(indices, target=GL_ELEMENT_ARRAY_BUFFER)
indexPositions.bind()
vertexPositions.bind()
glEnableVertexAttribArray(0) # from 'location = 0' in shader
glVertexAttribPointer(0, 3, GL_FLOAT, False, 0, None)
glBindVertexArray(0)
vertexPositions.unbind()
indexPositions.unbind()
#Now create the shaders
VERTEX_SHADER = shaders.compileShader("""
#version 330
layout(location = 0) in vec4 position;
void main()
{
gl_Position = position;
}
""", GL_VERTEX_SHADER)
FRAGMENT_SHADER = shaders.compileShader("""
#version 330
out vec4 outputColor;
void main()
{
outputColor = vec4(0.0f, 1.0f, 0.0f, 1.0f);
}
""", GL_FRAGMENT_SHADER)
shader = shaders.compileProgram(VERTEX_SHADER, FRAGMENT_SHADER)
#The draw loop
while True:
glUseProgram(shader)
glBindVertexArray(vertexArrayObject)
#glDrawArrays(GL_TRIANGLES, 0, 3) #This line works
glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, 0) #This line does not
glBindVertexArray(0)
glUseProgram(0)
# Show the screen
pygame.display.flip()
run()
If I simply comment out the glDrawElements and uncomment the glDrawArrays line then it works correctly so at least the vertex VBO is being input correctly.
What am I doing wrong here? All the OpenGL documentation I have been able to find suggests that I am doing this correctly so I am obviously misunderstanding something either about OpenGL itself or the PyOpenGL wrapper.
EDIT
Changing the VAO setup to use more direct OpenGL function rather than the VBO wrapper like:
vertices = np.array([[0,1,0],[-1,-1,0],[1,-1,0]], dtype='f')
vertexPositions = glGenBuffers(1)
glBindBuffer(GL_ARRAY_BUFFER, vertexPositions)
glBufferData(GL_ARRAY_BUFFER, vertices, GL_STATIC_DRAW)
#Create the index buffer object
indices = np.array([0,1,2], dtype='uint16')
indexPositions = glGenBuffers(1)
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexPositions)
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices, GL_STATIC_DRAW)
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexPositions)
glBindBuffer(GL_ARRAY_BUFFER, vertexPositions)
glEnableVertexAttribArray(0) # from 'location = 0' in shader
glVertexAttribPointer(0, 3, GL_FLOAT, False, 0, None)
glBindVertexArray(0)
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0)
glBindBuffer(GL_ARRAY_BUFFER, 0)
makes no difference. glDrawArrays still works and glDrawElements still doesn't.
Thanks #NicolBolas. He motivated me to actually take this code and make it work. Instead of theoritizing:)
I have removed vertexArrayObject(it's redundand as we already have VBOs for vertices and indices).
So you just bind index and vertex buffers(along with attributes) prior to glDraw* call.
And of course very important to pass None(null pointer) to glDrawElements indices instead of 0!
from OpenGL.GL import shaders
from OpenGL.arrays import vbo
from OpenGL.GL import *
from OpenGL.raw.GL.ARB.vertex_array_object import glGenVertexArrays, \
glBindVertexArray
import pygame
import numpy as np
def run():
pygame.init()
screen = pygame.display.set_mode((800,600), pygame.OPENGL|pygame.DOUBLEBUF)
#Create the VBO
vertices = np.array([[0,1,0],[-1,-1,0],[1,-1,0]], dtype='f')
vertexPositions = vbo.VBO(vertices)
#Create the index buffer object
indices = np.array([[0,1,2]], dtype=np.int32)
indexPositions = vbo.VBO(indices, target=GL_ELEMENT_ARRAY_BUFFER)
#Now create the shaders
VERTEX_SHADER = shaders.compileShader("""
#version 330
layout(location = 0) in vec4 position;
void main()
{
gl_Position = position;
}
""", GL_VERTEX_SHADER)
FRAGMENT_SHADER = shaders.compileShader("""
#version 330
out vec4 outputColor;
void main()
{
outputColor = vec4(0.0f, 1.0f, 0.0f, 1.0f);
}
""", GL_FRAGMENT_SHADER)
shader = shaders.compileProgram(VERTEX_SHADER, FRAGMENT_SHADER)
#The draw loop
while True:
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)
glUseProgram(shader)
indexPositions.bind()
vertexPositions.bind()
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, False, 0, None)
#glDrawArrays(GL_TRIANGLES, 0, 3) #This line still works
glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, None) #This line does work too!
# Show the screen
pygame.display.flip()
run()