Membuat Bentuk

3_buat-hexagonal.py

from core.base import Base
from core.openGLUtils import OpenGLUtils
from core.attribute import Attribute 
from OpenGL.GL import * 

class Test(Base):
    def initialize(self):
        print("init...")

        # position merujuk dari referensi associateVariable
        vsCode = """
        in vec3 position;
        void main(){
            gl_Position = vec4(position.x, position.y, position.z, 1.0);
        }
        """

        fsCode = """
        out vec4 fragColor;
        void main(){
            fragColor = vec4(1.0, 1.0, 0.0, 1.0);
        }
        """

        self.programRef = OpenGLUtils.initializeProgram(vsCode, fsCode)
        glLineWidth(4)

        # membuat tempat menyimpan konfigurasi buffer
        # vertex array object
        vaoRef = glGenVertexArrays(1)
        glBindVertexArray(vaoRef)

        positionData = [ 
            [ 0.8, 0.0, 0.0], [ 0.4, 0.6, 0.0],
            [-0.4, 0.6, 0.0], [-0.8, 0.0,0.0],
            [-0.4, -0.6, 0.0], [0.4,-0.6, 0.0] 
        ]


        self.vertexCount = len(positionData)
        # Attribute mengupload data ke GPU
        positionAttribute = Attribute("vec3", positionData)
        # associateVariable Menghubungkan data di GPU dengan variabel `position` di Vertex Shader
        positionAttribute.associateVariable(self.programRef, "position")

    def update(self):
        # mengaktifkan shader program
        glUseProgram(self.programRef)
        # perintah menggambar, bisa diisi 
        # GL_LINES : putus-putus
        # GL_LINE_STRIP : garis terakhir terpisah
        # GL_LINE_LOOP : bersambung
        # GL_TRIANGLES : segitiga per tiga titik
        # GL_TRIANGLE_FAN : segitiga menyebar

        glDrawArrays(GL_LINE_LOOP, 0, self.vertexCount)

Test().run()

attribute.py

from OpenGL.GL import *
import numpy as np 

class Attribute(object):
    def __init__(self, dataType, data):
        self.dataType = dataType
        self.data = data
        # membuat id buffer 
        self.bufferRef = glGenBuffers(1)
        self.uploadData()

    def uploadData(self):
        # ubah list menjadi numpy array
        # ubah ke bentuk 32 bit
        data = np.array(self.data).astype(np.float32)
        # aktifkan buffer 
        glBindBuffer(GL_ARRAY_BUFFER, self.bufferRef)
        # kirim data ke GPU
        # meratakan array menjadi 1 dimensi
        # GL_STATIC_DRAW memberi informasi data tidak sering berubah
        glBufferData(GL_ARRAY_BUFFER, data.ravel(), GL_STATIC_DRAW)

    def associateVariable(self, programRef, variabelName):
        # mencari lokasi variabel di shader berdasar namanya
        variabelRef = glGetAttribLocation(programRef, variabelName)
        if variabelRef == -1:
            return 
        # mengaktifkan buffer
        glBindBuffer(GL_ARRAY_BUFFER, self.bufferRef)
        if self.dataType == 'int':
            glVertexAttribPointer(variabelRef, 1, GL_INT, False, 0, None)
        elif self.dataType == 'float':
            glVertexAttribPointer(variabelRef, 1, GL_FLOAT, False, 0, None)
        elif self.dataType == 'vec2':
            glVertexAttribPointer(variabelRef, 2, GL_FLOAT, False, 0, None)
        elif self.dataType == 'vec3':
            glVertexAttribPointer(variabelRef, 3, GL_FLOAT, False, 0, None)
        elif self.dataType == 'vec4':
            glVertexAttribPointer(variabelRef, 4, GL_FLOAT, False, 0, None)
        else:
            raise Exception("Attribute "+variabelName+" has unknown type "+self.dataType)
        # mengaktifkan tempat di GPU agar data bisa mengalir ke shader saat proses rendering  
        glEnableVertexAttribArray(variabelRef)