120 lines
3.6 KiB
C++
120 lines
3.6 KiB
C++
#include "BitmapFont.h"
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#include <ft2build.h>
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#include FT_FREETYPE_H
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#include <glm/gtc/matrix_transform.hpp>
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#include <iostream>
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BitmapFont::BitmapFont(std::string fontLocation)
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{
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FT_Library ft;
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if (FT_Init_FreeType(&ft))
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{
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std::cout << "ERROR::FreeType: Could not init FreeType Library" << std::endl;
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}
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FT_Face face;
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if (FT_New_Face(ft, fontLocation.c_str(), 0, &face))
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{
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std::cout << "ERROR::FreeType: Failed to load font" << std::endl;
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}
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FT_Set_Pixel_Sizes(face, 0, 48);
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1); //Disable byte-alignment restriction
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for (GLubyte c = 0; c < 128; c++)
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{
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//Map bitmaps to chars
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if (FT_Load_Char(face, c, FT_LOAD_RENDER))
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{
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std::cout << "ERROR::FreeType: Could not load Glyph: " << c << std::endl;
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continue;
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}
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GLuint texture;
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glGenTextures(1, &texture);
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glBindTexture(GL_TEXTURE_2D, texture);
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glTexImage2D(
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GL_TEXTURE_2D,
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0,
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GL_RED,
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face->glyph->bitmap.width,
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face->glyph->bitmap.rows,
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0,
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GL_RED,
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GL_UNSIGNED_BYTE,
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face->glyph->bitmap.buffer);
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// Set texture options
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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Character character = {
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texture,
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glm::ivec2(face->glyph->bitmap.width, face->glyph->bitmap.rows),
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glm::ivec2(face->glyph->bitmap_left, face->glyph->bitmap_top),
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face->glyph->advance.x};
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characters.insert(std::pair<GLchar, Character>(c, character));
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}
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glPixelStorei(GL_UNPACK_ALIGNMENT, 4); //Reset byte-alignment restriction
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FT_Done_Face(face);
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FT_Done_FreeType(ft);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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projection = glm::ortho(0.0f, 800.0f, 0.0f, 600.0f);
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glGenVertexArrays(1, &VAO);
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glGenBuffers(1, &VBO);
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glBindVertexArray(VAO);
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glBindBuffer(GL_ARRAY_BUFFER, VBO);
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glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * 6 * 4, NULL, GL_DYNAMIC_DRAW);
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glEnableVertexAttribArray(0);
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glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), 0);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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glBindVertexArray(0);
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}
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void BitmapFont::drawText(Shader &s, std::string text, GLfloat x, GLfloat y, GLfloat scale, glm::vec3 color)
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{
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s.Use();
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s.SetVector3f("textColor", color, true);
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s.SetMatrix4("projection", projection, true);
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glActiveTexture(GL_TEXTURE0);
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glBindVertexArray(VAO);
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// Iterate through all characters
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std::string::const_iterator c;
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for (c = text.begin(); c != text.end(); c++)
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{
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Character ch = characters[*c];
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GLfloat xpos = x + ch.bearing.x * scale;
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GLfloat ypos = y - (ch.size.y - ch.bearing.y) * scale;
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GLfloat w = ch.size.x * scale;
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GLfloat h = ch.size.y * scale;
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// Update VBO for each character
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GLfloat vertices[6][4] = {
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{xpos, ypos + h, 0.0, 0.0},
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{xpos, ypos, 0.0, 1.0},
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{xpos + w, ypos, 1.0, 1.0},
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{xpos, ypos + h, 0.0, 0.0},
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{xpos + w, ypos, 1.0, 1.0},
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{xpos + w, ypos + h, 1.0, 0.0}};
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// Render glyph texture over quad
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glBindTexture(GL_TEXTURE_2D, ch.texID);
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// Update content of VBO memory
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glBindBuffer(GL_ARRAY_BUFFER, VBO);
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glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertices), vertices); // Be sure to use glBufferSubData and not glBufferData
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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// Render quad
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glDrawArrays(GL_TRIANGLES, 0, 6);
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// Now advance cursors for next glyph (note that advance is number of 1/64 pixels)
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x += (ch.advance >> 6) * scale; // Bitshift by 6 to get value in pixels (2^6 = 64 (divide amount of 1/64th pixels by 64 to get amount of pixels))
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}
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glBindVertexArray(0);
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glBindTexture(GL_TEXTURE_2D, 0);
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}
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