<gh_stars>0
from OpenGL.GL import *
from OpenGL.GLU import *

from OpenGL.GL import shaders

import glfw
import freetype
import glm

import numpy as np
from PIL import Image
import math
import time


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, zfix, 0.0, 1.0,
        xpos, ypos, zfix, 0.0, 0.0,
        xpos + w, ypos, zfix, 1.0, 0.0,
        xpos, ypos - h, zfix, 0.0, 1.0,
        xpos + w, ypos, zfix, 1.0, 0.0,
        xpos + w, ypos - h, zfix, 1.0, 1.0
    ], np.float32)


VERTEX_SHADER = """
        #version 330 core
        layout (location = 0) in vec4 vertex; // <vec2 pos, vec2 tex>
        out vec2 TexCoords;

        uniform mat4 projection;

        void main()
        {
            gl_Position = projection * vec4(vertex.xy, 0.0, 1.0);
            TexCoords = vertex.zw;
        }


       """

FRAGMENT_SHADER = """
        #version 330 core
        in vec2 TexCoords;
        out vec4 color;

        uniform sampler2D text;
        uniform vec3 textColor;

        void main()
        {    
            vec4 sampled = vec4(1.0, 1.0, 1.0, texture(text, TexCoords).r);
            color = vec4(textColor, 1.0) * sampled;
        }

        """

shaderProgram = None
Characters = dict()
VBO = None
VAO = None

def initliaze():
    global VERTEXT_SHADER
    global FRAGMENT_SHADER
    global shaderProgram
    global Characters
    global VBO
    global VAO

    #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)

    #get projection
    #problem
    
    shader_projection = glGetUniformLocation(shaderProgram, "projection")
    projection = glm.ortho(0.0,640,0.0,640)
    glUniformMatrix4fv(shader_projection, 1, GL_FALSE, glm.value_ptr(projection));
    
    #disable byte-alignment restriction
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    face = freetype.Face("Vera.ttf")
    face.set_char_size( 48*64 )

    #load first 128 characters of ASCII set
    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_RGB,
                     glyph.bitmap.width, glyph.bitmap.rows,
                     0,
                     GL_RGB,
                     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);

    #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, None, GL_DYNAMIC_DRAW);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4, 0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);
    
def render_text(window,text,x,y,scale,color):
    global shaderProgram
    global Characters
    global VBO
    global VAO
    
    face = freetype.Face("Vera.ttf")
    face.set_char_size(48*64)
    glUniform3f(glGetUniformLocation(shaderProgram, "textColor"),
                color[0]/255,color[1]/255,color[2]/255)
               
    glActiveTexture(GL_TEXTURE0);
    

    for c in text:
        ch = Characters[c]
        w,h = ch.textureSize
        w = w*scale
        h = w*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, len(vertices), 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;

    glBindVertexArray(0);
    glBindTexture(GL_TEXTURE_2D, 0);

    glfwSwapBuffers(window);
    glfwPollEvents();
    
def main():
    glfw.init()
    window = glfw.create_window(640, 640,"EXAMPLE PROGRAM",None,None)
    
    glfw.make_context_current(window)

    
    initliaze()
    while not glfw.window_should_close(window):
        glfw.poll_events()
        glClearColor(0,0,0,1);
        glClear(GL_COLOR_BUFFER_BIT);
        render_text(window,'hello',1,1,1,(100,100,100))

        
    glfw.terminate()


if __name__ == '__main__':
    main()
from OpenGL.GL import *
from OpenGL.GLU import *

from OpenGL.GL import shaders

import glfw
import freetype
import glm

import numpy as np
from PIL import Image
import math
import time


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, zfix, 0.0, 1.0,
        xpos, ypos, zfix, 0.0, 0.0,
        xpos + w, ypos, zfix, 1.0, 0.0,
        xpos, ypos - h, zfix, 0.0, 1.0,
        xpos + w, ypos, zfix, 1.0, 0.0,
        xpos + w, ypos - h, zfix, 1.0, 1.0
    ], np.float32)


VERTEX_SHADER = """
        #version 330 core
        layout (location = 0) in vec4 vertex; // <vec2 pos, vec2 tex>
        out vec2 TexCoords;

        uniform mat4 projection;

        void main()
        {
            gl_Position = projection * vec4(vertex.xy, 0.0, 1.0);
            TexCoords = vertex.zw;
        }


       """

FRAGMENT_SHADER = """
        #version 330 core
        in vec2 TexCoords;
        out vec4 color;

        uniform sampler2D text;
        uniform vec3 textColor;

        void main()
        {    
            vec4 sampled = vec4(1.0, 1.0, 1.0, texture(text, TexCoords).r);
            color = vec4(textColor, 1.0) * sampled;
        }

        """

shaderProgram = None
Characters = dict()
VBO = None
VAO = None

def initliaze():
    global VERTEXT_SHADER
    global FRAGMENT_SHADER
    global shaderProgram
    global Characters
    global VBO
    global VAO

    #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)

    #get projection
    #problem
    
    shader_projection = glGetUniformLocation(shaderProgram, "projection")
    projection = glm.ortho(0.0,640,0.0,640)
    glUniformMatrix4fv(shader_projection, 1, GL_FALSE, glm.value_ptr(projection));
    
    #disable byte-alignment restriction
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    face = freetype.Face("Vera.ttf")
    face.set_char_size( 48*64 )

    #load first 128 characters of ASCII set
    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_RGB,
                     glyph.bitmap.width, glyph.bitmap.rows,
                     0,
                     GL_RGB,
                     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);

    #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, None, GL_DYNAMIC_DRAW);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4, 0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);
    
def render_text(window,text,x,y,scale,color):
    global shaderProgram
    global Characters
    global VBO
    global VAO
    
    face = freetype.Face("Vera.ttf")
    face.set_char_size(48*64)
    glUniform3f(glGetUniformLocation(shaderProgram, "textColor"),
                color[0]/255,color[1]/255,color[2]/255)
               
    glActiveTexture(GL_TEXTURE0);
    

    for c in text:
        ch = Characters[c]
        w,h = ch.textureSize
        w = w*scale
        h = w*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, len(vertices), 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;

    glBindVertexArray(0);
    glBindTexture(GL_TEXTURE_2D, 0);

    glfwSwapBuffers(window);
    glfwPollEvents();
    
def main():
    glfw.init()
    window = glfw.create_window(640, 640,"EXAMPLE PROGRAM",None,None)
    
    glfw.make_context_current(window)

    
    initliaze()
    while not glfw.window_should_close(window):
        glfw.poll_events()
        glClearColor(0,0,0,1);
        glClear(GL_COLOR_BUFFER_BIT);
        render_text(window,'hello',1,1,1,(100,100,100))

        
    glfw.terminate()


if __name__ == '__main__':
    main()
#version 330 core
         layout (location = 0) in vec4 vertex; // <vec2 pos, vec2 tex>
         out vec2 TexCoords;
 
         uniform mat4 projection;
 
         void main()
         {
             gl_Position = projection * vec4(vertex.xy, 0.0, 1.0);
             TexCoords = vertex.zw;
         } #version 330 core
         in vec2 TexCoords;
         out vec4 color;
 
         uniform sampler2D text;
         uniform vec3 textColor;
 
         void main()
         {    
             vec4 sampled = vec4(1.0, 1.0, 1.0, texture(text, TexCoords).r);
             color = vec4(textColor, 1.0) * sampled;
         } #compiling shaders #creating shaderProgram #get projection #problem #disable byte-alignment restriction #load first 128 characters of ASCII set #generate texture #texture options #now store character for later use #configure VAO/VBO for texture quads #render glyph texture over quad #update content of VBO memory #render quad #now advance cursors for next glyph (note that advance is number of 1/64 pixels)