/* Freetype GL - A C OpenGL Freetype engine * * Distributed under the OSI-approved BSD 2-Clause License. See accompanying * file `LICENSE` for more details. */ #include #include #include "freetype-gl.h" #include "vertex-buffer.h" #include "shader.h" #include "mat4.h" #include "screenshot-util.h" #include // ------------------------------------------------------- typedef & struct --- typedef struct { float x, y, z; float u, v; float r, g, b, a; float shift, gamma; } vertex_t; // ------------------------------------------------------- global variables --- texture_atlas_t *atlas; vertex_buffer_t *buffer; GLuint shader; mat4 model, view, projection; // --------------------------------------------------------------- add_text --- void add_text( vertex_buffer_t * buffer, texture_font_t * font, char * text, vec4 * color, vec2 * pen ) { size_t i; float r = color->red, g = color->green, b = color->blue, a = color->alpha; for( i = 0; i < strlen(text); ++i ) { texture_glyph_t *glyph = texture_font_get_glyph( font, text + i ); if( glyph != NULL ) { float kerning = 0.0f; if( i > 0) { kerning = texture_glyph_get_kerning( glyph, text + i - 1 ); } pen->x += kerning; int x0 = (int)( pen->x + glyph->offset_x ); int y0 = (int)( pen->y + glyph->offset_y ); int x1 = (int)( x0 + glyph->width ); int y1 = (int)( y0 - glyph->height ); float s0 = glyph->s0; float t0 = glyph->t0; float s1 = glyph->s1; float t1 = glyph->t1; GLuint index = buffer->vertices->size; GLuint indices[] = {index, index+1, index+2, index, index+2, index+3}; vertex_t vertices[] = { { x0,y0,0, s0,t0, r,g,b,a, 0,1 }, { x0,y1,0, s0,t1, r,g,b,a, 0,1 }, { x1,y1,0, s1,t1, r,g,b,a, 0,1 }, { x1,y0,0, s1,t0, r,g,b,a, 0,1 } }; vertex_buffer_push_back_indices( buffer, indices, 6 ); vertex_buffer_push_back_vertices( buffer, vertices, 4 ); pen->x += glyph->advance_x; } } } // ------------------------------------------------------------------- init --- void init( void ) { size_t i; texture_font_t *font = 0; atlas = texture_atlas_new( 512, 512, 3 ); const char * filename = "fonts/Vera.ttf"; char * text = "A Quick Brown Fox Jumps Over The Lazy Dog 0123456789"; buffer = vertex_buffer_new( "vertex:3f,tex_coord:2f,color:4f,ashift:1f,agamma:1f" ); vec2 pen = {{0,0}}; vec4 color = {{0,0,0,1}}; for( i=7; i < 27; ++i) { font = texture_font_new_from_file( atlas, i, filename ); pen.x = 0; pen.y -= font->height; texture_font_load_glyphs( font, text ); add_text( buffer, font, text, &color, &pen ); texture_font_delete( font ); } glGenTextures( 1, &atlas->id ); glBindTexture( GL_TEXTURE_2D, atlas->id ); 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_MAG_FILTER, GL_LINEAR ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR ); glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB, atlas->width, atlas->height, 0, GL_RGB, GL_UNSIGNED_BYTE, atlas->data ); shader = shader_load( "shaders/text.vert", "shaders/text.frag" ); mat4_set_identity( &projection ); mat4_set_identity( &model ); mat4_set_identity( &view ); } // ---------------------------------------------------------------- display --- void display( GLFWwindow* window ) { int viewport[4]; glGetIntegerv( GL_VIEWPORT, viewport ); glClearColor(1,1,1,1); glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); glEnable( GL_TEXTURE_2D ); glEnable( GL_COLOR_MATERIAL ); glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE ); glColor4f( 0, 0, 0, 1 ); glBlendFunc( GL_ONE, GL_ONE_MINUS_SRC_ALPHA ); glBlendColor( 1, 1, 1, 1 ); glEnable( GL_BLEND ); mat4_set_identity( &model ); mat4_translate( &model, 5, viewport[3], 0); glUseProgram( shader ); { glUniform1i( glGetUniformLocation( shader, "texture" ), 0 ); glUniform3f( glGetUniformLocation( shader, "pixel" ), 1.0/atlas->width, 1.0/atlas->height, atlas->depth ); glUniformMatrix4fv( glGetUniformLocation( shader, "model" ), 1, 0, model.data); glUniformMatrix4fv( glGetUniformLocation( shader, "view" ), 1, 0, view.data); glUniformMatrix4fv( glGetUniformLocation( shader, "projection" ), 1, 0, projection.data); glUniformMatrix4fv( glGetUniformLocation( shader, "projection" ), 1, 0, projection.data); vertex_buffer_render( buffer, GL_TRIANGLES ); } glfwSwapBuffers( window ); } // ---------------------------------------------------------------- reshape --- void reshape( GLFWwindow* window, int width, int height ) { glViewport(0, 0, width, height); mat4_set_orthographic( &projection, 0, width, 0, height, -1, 1); } // --------------------------------------------------------------- keyboard --- void keyboard( GLFWwindow* window, int key, int scancode, int action, int mods ) { if ( key == GLFW_KEY_ESCAPE && action == GLFW_PRESS ) { glfwSetWindowShouldClose( window, GL_TRUE ); } } // --------------------------------------------------------- error-callback --- void error_callback( int error, const char* description ) { fputs( description, stderr ); } // ------------------------------------------------------------------- main --- int main( int argc, char **argv ) { GLFWwindow* window; char* screenshot_path = NULL; if (argc > 1) { if (argc == 3 && 0 == strcmp( "--screenshot", argv[1] )) screenshot_path = argv[2]; else { fprintf( stderr, "Unknown or incomplete parameters given\n" ); exit( EXIT_FAILURE ); } } glfwSetErrorCallback( error_callback ); if (!glfwInit( )) { exit( EXIT_FAILURE ); } glfwWindowHint( GLFW_VISIBLE, GL_FALSE ); glfwWindowHint( GLFW_RESIZABLE, GL_FALSE ); window = glfwCreateWindow( 800, 500, argv[0], NULL, NULL ); if (!window) { glfwTerminate( ); exit( EXIT_FAILURE ); } glfwMakeContextCurrent( window ); glfwSwapInterval( 1 ); glfwSetFramebufferSizeCallback( window, reshape ); glfwSetWindowRefreshCallback( window, display ); glfwSetKeyCallback( window, keyboard ); #ifndef __APPLE__ glewExperimental = GL_TRUE; GLenum err = glewInit(); if (GLEW_OK != err) { /* Problem: glewInit failed, something is seriously wrong. */ fprintf( stderr, "Error: %s\n", glewGetErrorString(err) ); exit( EXIT_FAILURE ); } fprintf( stderr, "Using GLEW %s\n", glewGetString(GLEW_VERSION) ); #endif init(); glfwShowWindow( window ); reshape( window, 800, 500 ); while (!glfwWindowShouldClose( window )) { display( window ); glfwPollEvents( ); if (screenshot_path) { screenshot( window, screenshot_path ); glfwSetWindowShouldClose( window, 1 ); } } glDeleteTextures( 1, &atlas->id ); atlas->id = 0; texture_atlas_delete( atlas ); glfwDestroyWindow( window ); glfwTerminate( ); return EXIT_SUCCESS; }