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_UNIFORM( NAME, U ) NAME##_auto_uniforms[ STR_STATIC_INDEX( NAME##_auto_names, U ) ]
  23 #define SHADER_UNIFORM_NAME( NAME, UID ) NAME##_auto_names[ UID ]
  24 #define STR_STATIC_INDEX( LIST, STR ) static_str_index( LIST, vg_list_size(LIST), STR )
  25
  26 #define UNIFORMS(...) __VA_ARGS__
  27
  28 #define SHADER_DEFINE( NAME, VERT, FRAG, UNIFORMS )                                                     \
  29         const char * NAME##_shader_names[] = UNIFORMS;                                                          \
  30         GLint NAME##_shader_uniforms[ vg_list_size( NAME##_shader_names ) ];    \
  31         struct vg_shader NAME##_static_shader = {                                                                               \
  32                 .src_vert = VERT, .src_frag = FRAG,                                                                                     \
  33                 .sym = #NAME "_static.shader",                                                                                          \
  34                 .uniform_names = NAME##_shader_names,                                                                           \
  35                 .uniforms = NAME##_shader_uniforms,                                                                                     \
  36                 .uniform_count = vg_list_size( NAME##_shader_names ),                                   \
  37         };
  38
  39 #define SHADER_INIT( NAME ) arrpush( vg_shaders_active, &NAME##_static_shader )
  40
  41 #define SHADER_STATUS_NONE 0x00
  42 #define SHADER_STATUS_COMPILED 0x1
  43
  44 struct vg_shader
  45 {
  46         GLuint program;
  47
  48         const char *src_vert;
  49         const char *src_frag;
  50         const char *src_geo;
  51         const char *sym;
  52
  53         const char **uniform_names;
  54         GLint *uniforms;
  55         u32 uniform_count;
  56         u32 status;
  57 }
  58 ** vg_shaders_active = NULL;
  59
  60 static GLuint vg_shader_subshader( const char *src, GLint gliShaderType )
  61 {
  62         GLint shader = glCreateShader( gliShaderType );
  63         glShaderSource( shader, 2, (const char *[2]){ vg_shader_gl_ver, src }, NULL );
  64         glCompileShader( shader );
  65
  66         int success;
  67         char infoLog[512];
  68         glGetShaderiv( shader, GL_COMPILE_STATUS, &success );
  69
  70         if( !success )
  71         {
  72                 glGetShaderInfoLog( shader, 512, NULL, infoLog );
  73                 vg_error( "Error info:\n%s\n", infoLog );
  74                 return 0;
  75         }
  76
  77         return shader;
  78 }
  79
  80 static int vg_shader_compile( struct vg_shader *shader )
  81 {
  82         vg_info( "Compile shader '%s'\n", shader->sym );
  83
  84         GLuint vert, frag, geo;
  85
  86         vert = vg_shader_subshader( shader->src_vert, GL_VERTEX_SHADER );
  87         frag = vg_shader_subshader( shader->src_frag, GL_FRAGMENT_SHADER );
  88
  89         if( !vert || !frag )
  90                 return 0;
  91
  92         if( shader->src_geo )
  93         {
  94                 geo = vg_shader_subshader( shader->src_geo, GL_GEOMETRY_SHADER );
  95
  96                 if( !geo )
  97                         return 0;
  98         }
  99
 100         shader->program = glCreateProgram();
 101         if( shader->src_geo )
 102                 glAttachShader( shader->program, geo );
 103
 104         glAttachShader( shader->program, vert );
 105         glAttachShader( shader->program, frag );
 106         glLinkProgram( shader->program );
 107
 108         glDeleteShader( vert );
 109         glDeleteShader( frag );
 110
 111         if( shader->src_geo )
 112                 glDeleteShader( geo );
 113
 114         // Check for link errors
 115         char infoLog[ 512 ];
 116         int success_link = 1;
 117
 118         glGetProgramiv( shader->program, GL_LINK_STATUS, &success_link );
 119         if( !success_link )
 120         {
 121                 glGetProgramInfoLog( shader->program, 512, NULL, infoLog );
 122                 vg_error( "Link failed: %s\n", infoLog );
 123                 glDeleteProgram( shader->program );
 124
 125                 return 0;
 126         }
 127
 128         // Complete linkeage
 129         for( int i = 0; i < shader->uniform_count; i ++ )
 130                 shader->uniforms[ i ] = glGetUniformLocation( shader->program, shader->uniform_names[i] );
 131
 132         shader->status |= SHADER_STATUS_COMPILED;
 133         return 1;
 134 }
 135
 136 static void vg_shaders_free(void)
 137 {
 138         for( int i = 0; i < arrlen( vg_shaders_active ); i ++ )
 139         {
 140                 struct vg_shader *shader = vg_shaders_active[i];
 141
 142                 if( shader->status & SHADER_STATUS_COMPILED )
 143                         glDeleteProgram( shader->program );
 144         }
 145
 146         arrfree( vg_shaders_active );
 147 }
 148
 149 static int vg_shaders_compile(void)
 150 {
 151         vg_info( "Compiling shaders\n" );
 152
 153         for( int i = 0; i < arrlen( vg_shaders_active ); i ++ )
 154         {
 155                 struct vg_shader *shader = vg_shaders_active[i];
 156                 if( !vg_shader_compile( shader ) )
 157                 {
 158                         vg_shaders_free();
 159                         return 0;
 160                 }
 161         }
 162
 163         vg_register_exit( &vg_shaders_free, "vg_shaders_free" );
 164         return 1;
 165 }