96 lines
2.6 KiB
C
96 lines
2.6 KiB
C
/* Freetype GL - A C OpenGL Freetype engine
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*
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* Distributed under the OSI-approved BSD 2-Clause License. See accompanying
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* file `LICENSE` for more details.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "opengl.h"
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#include "shader.h"
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// ------------------------------------------------------------ shader_read ---
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char *
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shader_read( const char *filename )
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{
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FILE * file;
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char * buffer;
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size_t size;
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file = fopen( filename, "rb" );
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if( !file )
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{
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fprintf( stderr, "Unable to open file \"%s\".\n", filename );
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return 0;
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}
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fseek( file, 0, SEEK_END );
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size = ftell( file );
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fseek(file, 0, SEEK_SET );
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buffer = (char *) malloc( (size+1) * sizeof( char *) );
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fread( buffer, sizeof(char), size, file );
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buffer[size] = 0;
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fclose( file );
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return buffer;
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}
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// --------------------------------------------------------- shader_compile ---
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GLuint
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shader_compile( const char* source,
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const GLenum type )
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{
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GLint compile_status;
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GLuint handle = glCreateShader( type );
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glShaderSource( handle, 1, &source, 0 );
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glCompileShader( handle );
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glGetShaderiv( handle, GL_COMPILE_STATUS, &compile_status );
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if( compile_status == GL_FALSE )
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{
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GLchar messages[256];
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glGetShaderInfoLog( handle, sizeof(messages), 0, &messages[0] );
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fprintf( stderr, "%s\n", messages );
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exit( EXIT_FAILURE );
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}
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return handle;
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}
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// ------------------------------------------------------------ shader_load ---
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GLuint
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shader_load( const char * vert_filename,
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const char * frag_filename )
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{
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GLuint handle = glCreateProgram( );
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GLint link_status;
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if( vert_filename && strlen( vert_filename ) )
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{
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char *vert_source = shader_read( vert_filename );
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GLuint vert_shader = shader_compile( vert_source, GL_VERTEX_SHADER);
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glAttachShader( handle, vert_shader);
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glDeleteShader( vert_shader );
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free( vert_source );
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}
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if( frag_filename && strlen( frag_filename ) )
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{
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char *frag_source = shader_read( frag_filename );
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GLuint frag_shader = shader_compile( frag_source, GL_FRAGMENT_SHADER);
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glAttachShader( handle, frag_shader);
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glDeleteShader( frag_shader );
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free( frag_source );
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}
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glLinkProgram( handle );
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glGetProgramiv( handle, GL_LINK_STATUS, &link_status );
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if (link_status == GL_FALSE)
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{
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GLchar messages[256];
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glGetProgramInfoLog( handle, sizeof(messages), 0, &messages[0] );
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fprintf( stderr, "%s\n", messages );
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exit(1);
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}
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return handle;
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}
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