src/vg/vg_shader.h

   1 /* TODO: TUrn off in release */
   2 #define STB_INCLUDE_IMPLEMENTATION
   3 #define STB_INCLUDE_LINE_GLSL
   4 #include "stb/stb_include.h"
   5
   6 const char *vg_shader_gl_ver = "#version 330 core\n";
   7
   8 struct vg_shader
   9 {
  10         GLuint id;
  11    const char *name;
  12
  13    struct vg_subshader
  14    {
  15       const char *orig_file,
  16                  *static_src;
  17    }
  18    vs, fs;
  19
  20    void (*link)(void);
  21    int compiled;
  22 }
  23 ** vg_shaders_active = NULL;
  24
  25 static GLuint vg_shader_subshader( const char *src, GLint gliShaderType )
  26 {
  27         GLint shader = glCreateShader( gliShaderType );
  28
  29    if( shader == GL_NONE )
  30    {
  31       vg_error( "Could not 'glCreateShader()'\n" );
  32       return 0;
  33    }
  34
  35         glShaderSource( shader, 2, (const char*[2]){ vg_shader_gl_ver, src }, NULL );
  36         glCompileShader( shader );
  37
  38         GLint status;
  39         glGetShaderiv( shader, GL_COMPILE_STATUS, &status );
  40
  41         if( status != GL_TRUE )
  42         {
  43       GLchar info[1024];
  44       GLsizei len;
  45
  46                 glGetShaderInfoLog( shader, sizeof(info), &len, info );
  47                 vg_error( "Error info:\n%s\n", info );
  48                 return 0;
  49         }
  50
  51         return shader;
  52 }
  53
  54 static int vg_shader_compile( struct vg_shader *shader )
  55 {
  56         vg_info( "Compile shader '%s'\n", shader->name );
  57
  58         GLuint program, vert, frag;
  59    const char *svs, *sfs;
  60    char *avs, *afs;
  61
  62    int static_src = 1;
  63
  64    /* If we are compiling this again, we obviously need to try to take the src
  65     * from the disk instead.
  66     *
  67     * Only do this if we have filenames set on the shader, so engine shaders
  68     * dont have to do it (text.. etc).
  69     */
  70    if( shader->compiled )
  71    {
  72       if( shader->vs.orig_file && shader->fs.orig_file )
  73          static_src = 0;
  74       else return 1;
  75    }
  76
  77    if( static_src )
  78    {
  79       svs = shader->vs.static_src;
  80       sfs = shader->fs.static_src;
  81    }
  82    else
  83    {
  84       char error[260];
  85       char path[260];
  86       strcpy( path, shader->vs.orig_file );
  87       avs = stb_include_file( path, "", "../shaders", error );
  88
  89       strcpy( path, shader->fs.orig_file );
  90       afs = stb_include_file( path, "", "../shaders", error );
  91
  92       if( !avs || !afs )
  93       {
  94          free( avs );
  95          free( afs );
  96          return 0;
  97       }
  98
  99       svs = avs;
 100       sfs = afs;
 101    }
 102
 103         vert = vg_shader_subshader( svs, GL_VERTEX_SHADER );
 104         frag = vg_shader_subshader( sfs, GL_FRAGMENT_SHADER );
 105
 106    if( !static_src )
 107    {
 108       free( avs );
 109       free( afs );
 110    }
 111
 112         if( !vert || !frag )
 113                 return 0;
 114
 115         program = glCreateProgram();
 116
 117         glAttachShader( program, vert );
 118         glAttachShader( program, frag );
 119         glLinkProgram( program );
 120
 121         glDeleteShader( vert );
 122         glDeleteShader( frag );
 123
 124         /* Check for link errors */
 125         char infoLog[ 512 ];
 126         int success_link = 1;
 127
 128         glGetProgramiv( program, GL_LINK_STATUS, &success_link );
 129         if( !success_link )
 130         {
 131                 glGetProgramInfoLog( program, 512, NULL, infoLog );
 132                 vg_error( "Link failed: %s\n", infoLog );
 133                 glDeleteProgram( program );
 134                 return 0;
 135         }
 136
 137    if( shader->compiled )
 138       glDeleteProgram( shader->id );
 139
 140    shader->id = program;
 141         shader->compiled = 1;
 142    if( shader->link )
 143       shader->link();
 144         return 1;
 145 }
 146
 147 static void vg_shaders_free(void)
 148 {
 149         for( int i = 0; i < arrlen( vg_shaders_active ); i ++ )
 150         {
 151                 struct vg_shader *shader = vg_shaders_active[i];
 152
 153                 if( shader->compiled )
 154                         glDeleteProgram( shader->id );
 155         }
 156
 157         arrfree( vg_shaders_active );
 158 }
 159
 160 static int vg_shaders_recompile(int argc, const char *argv[])
 161 {
 162         vg_info( "Compiling shaders\n" );
 163         for( int i = 0; i < arrlen( vg_shaders_active ); i ++ )
 164         {
 165                 struct vg_shader *shader = vg_shaders_active[i];
 166                 vg_shader_compile( shader );
 167         }
 168
 169    return 0;
 170 }
 171
 172 static void vg_shader_register( struct vg_shader *shader )
 173 {
 174    shader->compiled = 0;
 175    shader->id = 0;         /* TODO: make this an error shader */
 176    arrpush( vg_shaders_active, shader );
 177 }