vg/vg_shader.h

   1 // Copyright (C) 2021 Harry Godden (hgn) - All Rights Reserved
   2
   3 const char *vg_shader_gl_ver = "#version 330 core\n";
   4
   5 #pragma GCC diagnostic push
   6 #pragma GCC diagnostic ignored "-Wreturn-type"
   7 static inline int static_str_index( const char *list[], int len, const char *str )
   8 {
   9     for( int i = 0; i < len; i ++ )
  10     {
  11         if( !strcmp(list[i],str) )
  12             return i;
  13     }
  14
  15     #ifndef VG_RELEASE
  16     fprintf( stderr, "That was not a static string index!! (%s)\n", str );
  17     abort();
  18     #endif
  19 }
  20 #pragma GCC diagnostic pop
  21
  22 #define SHADER_USE( NAME ) glUseProgram( NAME##_static_shader.program )
  23
  24 #define SHADER_UNIFORM( NAME, U ) NAME##_shader_uniforms[ STR_STATIC_INDEX( NAME##_shader_names, U ) ]
  25 #define SHADER_UNIFORM_NAME( NAME, UID ) NAME##_shader_names[ UID ]
  26 #define STR_STATIC_INDEX( LIST, STR ) static_str_index( LIST, vg_list_size(LIST), STR )
  27
  28 #define UNIFORMS(...) __VA_ARGS__
  29
  30 #define SHADER_DEFINE( NAME, VERT, FRAG, UNIFORMS )                                                     \
  31         const char * NAME##_shader_names[] = UNIFORMS;                                                          \
  32         GLint NAME##_shader_uniforms[ vg_list_size( NAME##_shader_names ) ];    \
  33         struct vg_shader NAME##_static_shader = {                                                                               \
  34                 .src_vert = VERT, .src_frag = FRAG,                                                                                     \
  35                 .sym = #NAME "_static.shader",                                                                                          \
  36                 .uniform_names = NAME##_shader_names,                                                                           \
  37                 .uniforms = NAME##_shader_uniforms,                                                                                     \
  38                 .uniform_count = vg_list_size( NAME##_shader_names ),                                   \
  39         };
  40
  41 #define SHADER_INIT( NAME ) arrpush( vg_shaders_active, &NAME##_static_shader )
  42
  43 #define SHADER_STATUS_NONE 0x00
  44 #define SHADER_STATUS_COMPILED 0x1
  45
  46 struct vg_shader
  47 {
  48         GLuint program;
  49
  50         const char *src_vert;
  51         const char *src_frag;
  52         const char *src_geo;
  53         const char *sym;
  54
  55         const char **uniform_names;
  56         GLint *uniforms;
  57         u32 uniform_count;
  58         u32 status;
  59 }
  60 ** vg_shaders_active = NULL;
  61
  62 static GLuint vg_shader_subshader( const char *src, GLint gliShaderType )
  63 {
  64         GLint shader = glCreateShader( gliShaderType );
  65         glShaderSource( shader, 2, (const char *[2]){ vg_shader_gl_ver, src }, NULL );
  66         glCompileShader( shader );
  67
  68         int success;
  69         char infoLog[512];
  70         glGetShaderiv( shader, GL_COMPILE_STATUS, &success );
  71
  72         if( !success )
  73         {
  74                 glGetShaderInfoLog( shader, 512, NULL, infoLog );
  75                 vg_error( "Error info:\n%s\n", infoLog );
  76                 return 0;
  77         }
  78
  79         return shader;
  80 }
  81
  82 static int vg_shader_compile( struct vg_shader *shader )
  83 {
  84         vg_info( "Compile shader '%s'\n", shader->sym );
  85
  86         GLuint vert, frag, geo;
  87
  88         vert = vg_shader_subshader( shader->src_vert, GL_VERTEX_SHADER );
  89         frag = vg_shader_subshader( shader->src_frag, GL_FRAGMENT_SHADER );
  90
  91         if( !vert || !frag )
  92                 return 0;
  93
  94         if( shader->src_geo )
  95         {
  96                 geo = vg_shader_subshader( shader->src_geo, GL_GEOMETRY_SHADER );
  97
  98                 if( !geo )
  99                         return 0;
 100         }
 101
 102         shader->program = glCreateProgram();
 103         if( shader->src_geo )
 104                 glAttachShader( shader->program, geo );
 105
 106         glAttachShader( shader->program, vert );
 107         glAttachShader( shader->program, frag );
 108         glLinkProgram( shader->program );
 109
 110         glDeleteShader( vert );
 111         glDeleteShader( frag );
 112
 113         if( shader->src_geo )
 114                 glDeleteShader( geo );
 115
 116         // Check for link errors
 117         char infoLog[ 512 ];
 118         int success_link = 1;
 119
 120         glGetProgramiv( shader->program, GL_LINK_STATUS, &success_link );
 121         if( !success_link )
 122         {
 123                 glGetProgramInfoLog( shader->program, 512, NULL, infoLog );
 124                 vg_error( "Link failed: %s\n", infoLog );
 125                 glDeleteProgram( shader->program );
 126
 127                 return 0;
 128         }
 129
 130         // Complete linkeage
 131         for( int i = 0; i < shader->uniform_count; i ++ )
 132                 shader->uniforms[ i ] = glGetUniformLocation( shader->program, shader->uniform_names[i] );
 133
 134         shader->status |= SHADER_STATUS_COMPILED;
 135         return 1;
 136 }
 137
 138 static void vg_shaders_free(void)
 139 {
 140         for( int i = 0; i < arrlen( vg_shaders_active ); i ++ )
 141         {
 142                 struct vg_shader *shader = vg_shaders_active[i];
 143
 144                 if( shader->status & SHADER_STATUS_COMPILED )
 145                         glDeleteProgram( shader->program );
 146         }
 147
 148         arrfree( vg_shaders_active );
 149 }
 150
 151 static int vg_shaders_compile(void)
 152 {
 153         vg_info( "Compiling shaders\n" );
 154
 155         for( int i = 0; i < arrlen( vg_shaders_active ); i ++ )
 156         {
 157                 struct vg_shader *shader = vg_shaders_active[i];
 158                 if( !vg_shader_compile( shader ) )
 159                 {
 160                         vg_shaders_free();
 161                         return 0;
 162                 }
 163         }
 164
 165         vg_register_exit( &vg_shaders_free, "vg_shaders_free" );
 166         return 1;
 167 }