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FreeType2 및 this online tutorial을 사용하여 문자를 렌더링하려하지만 몇 가지 문제가 있으며 그 결과가 매우 불규칙합니다. 나는이 웹 사이트 here과 here에있는 다른 질문들을 살펴 보았지만 그러한 수정을했지만 여전히 난처한 상태입니다. 나는 끝까지 그것을 만든 적이 있지만 비트 맵이 제대로 표시되지 않습니다OpenGL FreeType2 비트 맵이 렌더링되지 않습니다.
뿐만 아니라,하지만 디스플레이 내가 렌더링하기 위해 노력하고있어 캐릭터에 따라 달라집니다. 일부는 공백으로 표시되고 다른 일부는 사각형으로 표시됩니다. 아래 코드는 모든 조언을 크게 주시면 감사하겠습니다.
메인 프로그램 :
#include <iostream>
#include <fstream>
#include <vector>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#define GLM_FORCE_RADIANS
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtx/transform.hpp>
#include <ft2build.h>
#include FT_FREETYPE_H
#include "OGLT.hpp"
OGLT Toolkit;
GLuint vao, vbo[2], shader, uniform_color, tex, uniform_tex;
static void key_callback(GLFWwindow * window, int key, int scancode, int action, int mods){
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
}
void MyInitialize(){
// Initialize FreeType
FT_Library library;
FT_Face face;
int error = FT_Init_FreeType(&library);
if (error){
std::cout << "An error occurred during library initialization!\n";
}
//error = FT_New_Face(library, "open-sans/OpenSans-Regular.ttf", 0, &face);
error = FT_New_Face(library, "/usr/share/fonts/truetype/droid/DroidSans.ttf", 0, &face);
if(error == FT_Err_Unknown_File_Format){
std::cout << "The font file could be opened and read, but it appears " <<
"that its font format is unsupported.\n";
}
else if(error){
std::cout << "Another error code means that the font file could not be " <<
"opened or read, or that it is broken.\n";
}
else std::cout << "Font file sucessfully loaded!\n";
FT_Set_Pixel_Sizes(face, 0, 100);
// Initialize GLEW and load shaders
Toolkit.StartGLEW();
// OpenGL state initialization
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glPixelStorei(GL_UNPACK_ALIGNMENT,1);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
// Vertex buffer initialization
FT_Load_Char(face, 'W', FT_LOAD_RENDER);
FT_GlyphSlot g = face->glyph;
float x = 0.0f, y = 0.0f;
float sx = 2.0/1000.0;
float sy = 2.0/800.0;
float x2 = x + g->bitmap_left * sx;
float y2 = -y - g->bitmap_top * sy;
float w = g->bitmap.width * sx;
float h = g->bitmap.rows * sy;
static float letter[] = {
x2, -y2, 0.0f,
x2+w, -y2, 0.0f,
x2, -y2-h, 0.0f,
x2+w, -y2-h, 0.0f,
};
static float letter_uv[] = {
0.0f, 0.0f,
1.0f, 0.0f,
0.0f, 1.0f,
1.0f, 1.0f
};
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glGenBuffers(2, vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(letter), letter, GL_STATIC_DRAW);
GLuint VertexAttributeID = 0;
glVertexAttribPointer(VertexAttributeID, 3, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(VertexAttributeID);
glBindBuffer(GL_ARRAY_BUFFER, vbo[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(letter_uv), letter, GL_STATIC_DRAW);
GLuint UvAttributeID = 1;
glVertexAttribPointer(UvAttributeID, 2, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(UvAttributeID);
glBindVertexArray(0);
glBindBuffer(GL_ARRAY_BUFFER, vbo[0]);
glActiveTexture(GL_TEXTURE0);
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, g->bitmap.width, g->bitmap.rows, 0,
GL_RED, GL_UNSIGNED_BYTE, g->bitmap.buffer);
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);
shader = Toolkit.LoadShaders("test_vertex.glsl", "test_fragment.glsl");
uniform_color = glGetUniformLocation(shader, "color");
uniform_tex = glGetUniformLocation(shader, "texture_sampler");
}
void MyDisplay(GLFWwindow * window){
int width, height;
glfwGetFramebufferSize(window, &width, &height);
glViewport(0, 0, width, height);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(shader);
glm::vec4 ColorVec = glm::vec4(0.0f, 1.0f, 0.0f, 1.0f);
glUniform4fv(uniform_color, 1, &ColorVec[0]);
glUniform1i(uniform_tex, 0);
glBindVertexArray(vao);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, tex);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glBindVertexArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindTexture(GL_TEXTURE_2D, 0);
glUseProgram(0);
}
int main(){
// Initialize window
GLFWwindow * window;
// Initialize the library
if(!glfwInit()) return -1;
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
// Create a windowed mode window and its OpenGL context
window = glfwCreateWindow(1000, 800, "Font Test", NULL, NULL);
if(!window){
glfwTerminate();
return -1;
}
// Make the window's context current
glfwMakeContextCurrent(window);
glfwSwapInterval(1);
glfwSetKeyCallback(window, key_callback);
MyInitialize();
// Loop until the user closes the window
while(!glfwWindowShouldClose(window)){
// Render here
MyDisplay(window);
// Swap front and back buffers
glfwSwapBuffers(window);
// Poll for and process events
glfwPollEvents();
}
glfwDestroyWindow(window);
glfwTerminate();
return 0;
}
버텍스 쉐이더 :
#version 330 core
layout (location = 0) in vec3 vertex;
layout (location = 1) in vec2 vertex_uv;
out vec2 uv;
void main(){
gl_Position = vec4(vertex.xyz, 1);
uv = vertex_uv;
}
조각 쉐이더 : 서로 다른 문자를 표시하려고 경우
#version 330 core
in vec2 uv;
uniform vec4 color;
uniform sampler2D texture_sampler;
out vec4 color_out;
void main(){
color_out = vec4(1.0, 1.0, 1.0, texture(texture_sampler, uv).r) * color;
}