vg/vg_tex.h

   1 // Copyright (C) 2021 Harry Godden (hgn) - All Rights Reserved
   2
   3 #define VG_TEXTURE_NO_MIP       0x1
   4 #define VG_TEXTURE_REPEAT       0x2
   5 #define VG_TEXTURE_CLAMP        0x4
   6 #define VG_TEXTURE_NEAREST      0x8
   7
   8 struct vg_tex2d
   9 {
  10         const char *path;
  11         u32 flags;
  12         GLuint name;
  13 };
  14
  15 static void vg_tex2d_bind( vg_tex2d *tex, u32 id )
  16 {
  17         glActiveTexture( GL_TEXTURE0 + id );
  18         glBindTexture( GL_TEXTURE_2D, tex->name );
  19 }
  20
  21 static inline void vg_tex2d_mipmap(void)
  22 {
  23         glGenerateMipmap( GL_TEXTURE_2D );
  24 }
  25
  26 static inline void vg_tex2d_linear(void)
  27 {
  28         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
  29         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  30 }
  31
  32 static inline void vg_tex2d_nearest(void)
  33 {
  34         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
  35         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
  36 }
  37
  38 static inline void vg_tex2d_linear_mipmap(void)
  39 {
  40         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
  41         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  42 }
  43
  44 static inline void vg_tex2d_repeat(void)
  45 {
  46         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
  47         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
  48 }
  49
  50 static inline void vg_tex2d_clamp(void)
  51 {
  52         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
  53         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
  54 }
  55
  56 static GLuint vg_tex2d_rgba( const char *path )
  57 {
  58         int x,y,nc;
  59         stbi_set_flip_vertically_on_load( 1 );
  60
  61         i64 length;
  62         u8 *src_data = vg_asset_read_s( path, &length );
  63
  64         GLuint texture_name;
  65         glGenTextures( 1, &texture_name );
  66         glBindTexture( GL_TEXTURE_2D, texture_name );
  67
  68         if( src_data )
  69         {
  70                 u8 *tex_buffer = stbi_load_from_memory( src_data, length, &x, &y, &nc, 4 );
  71                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, x, y, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_buffer );
  72
  73                 free( tex_buffer );
  74                 free( src_data );
  75         }
  76         else
  77         {
  78                 u32 tex_err[4] =
  79                 {
  80                         0xffff00ff,
  81                         0xff000000,
  82                         0xff000000,
  83                         0xffff00ff
  84                 };
  85
  86                 vg_error( "Loading texture failed (%s)\n", path );
  87                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_err );
  88         }
  89
  90         return texture_name;
  91 }
  92
  93 static void vg_tex2d_init( vg_tex2d *textures[], int num )
  94 {
  95         for( int i = 0; i < num; i ++ )
  96         {
  97                 vg_tex2d *tex = textures[i];
  98                 tex->name = vg_tex2d_rgba( tex->path );
  99                 if( !(tex->flags & VG_TEXTURE_NO_MIP) )
 100                         vg_tex2d_mipmap();
 101
 102                 if( tex->flags & VG_TEXTURE_NEAREST )
 103                 {
 104                         if( tex->flags & VG_TEXTURE_NO_MIP )
 105                                 vg_error( "Invalid texture settings\n" );
 106                         else
 107                                 vg_tex2d_nearest();
 108                 }
 109                 else
 110                 {
 111                         if( tex->flags & VG_TEXTURE_NO_MIP )
 112                                 vg_tex2d_linear();
 113                         else
 114                                 vg_tex2d_linear_mipmap();
 115                 }
 116
 117                 if( tex->flags & VG_TEXTURE_CLAMP )
 118                         vg_tex2d_clamp();
 119                 else
 120                         vg_tex2d_repeat();
 121         }
 122 }
 123
 124 static void vg_tex2d_free( vg_tex2d *textures[], int num )
 125 {
 126         for( int i = 0; i < num; i ++ )
 127         {
 128                 glDeleteTextures( 1, &textures[i]->name );
 129         }
 130 }