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          vg_error( "Could not find shader source files (%s)\n",
  95                shader->vs.orig_file );
  96
  97          free( avs );
  98          free( afs );
  99          return 0;
 100       }
 101
 102       svs = avs;
 103       sfs = afs;
 104    }
 105
 106         vert = vg_shader_subshader( svs, GL_VERTEX_SHADER );
 107         frag = vg_shader_subshader( sfs, GL_FRAGMENT_SHADER );
 108
 109    if( !static_src )
 110    {
 111       free( avs );
 112       free( afs );
 113    }
 114
 115         if( !vert || !frag )
 116                 return 0;
 117
 118         program = glCreateProgram();
 119
 120         glAttachShader( program, vert );
 121         glAttachShader( program, frag );
 122         glLinkProgram( program );
 123
 124         glDeleteShader( vert );
 125         glDeleteShader( frag );
 126
 127         /* Check for link errors */
 128         char infoLog[ 512 ];
 129         int success_link = 1;
 130
 131         glGetProgramiv( program, GL_LINK_STATUS, &success_link );
 132         if( !success_link )
 133         {
 134                 glGetProgramInfoLog( program, 512, NULL, infoLog );
 135                 vg_error( "Link failed: %s\n", infoLog );
 136                 glDeleteProgram( program );
 137                 return 0;
 138         }
 139
 140    if( shader->compiled )
 141       glDeleteProgram( shader->id );
 142
 143    shader->id = program;
 144         shader->compiled = 1;
 145    if( shader->link )
 146       shader->link();
 147         return 1;
 148 }
 149
 150 static void vg_shaders_free(void)
 151 {
 152         for( int i = 0; i < arrlen( vg_shaders_active ); i ++ )
 153         {
 154                 struct vg_shader *shader = vg_shaders_active[i];
 155
 156                 if( shader->compiled )
 157                         glDeleteProgram( shader->id );
 158         }
 159
 160         arrfree( vg_shaders_active );
 161 }
 162
 163 static int vg_shaders_recompile(int argc, const char *argv[])
 164 {
 165         vg_info( "Compiling shaders\n" );
 166         for( int i = 0; i < arrlen( vg_shaders_active ); i ++ )
 167         {
 168                 struct vg_shader *shader = vg_shaders_active[i];
 169                 vg_shader_compile( shader );
 170         }
 171
 172    return 0;
 173 }
 174
 175 static void vg_shader_register( struct vg_shader *shader )
 176 {
 177    shader->compiled = 0;
 178    shader->id = 0;         /* TODO: make this an error shader */
 179    arrpush( vg_shaders_active, shader );
 180 }