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 struct vg_sprite
  16 {
  17         v4f uv_xywh;
  18 };
  19
  20 static void vg_tex2d_bind( vg_tex2d *tex, u32 id )
  21 {
  22         glActiveTexture( GL_TEXTURE0 + id );
  23         glBindTexture( GL_TEXTURE_2D, tex->name );
  24 }
  25
  26 static inline void vg_tex2d_mipmap(void)
  27 {
  28         glGenerateMipmap( GL_TEXTURE_2D );
  29 }
  30
  31 static inline void vg_tex2d_linear(void)
  32 {
  33         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
  34         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  35 }
  36
  37 static inline void vg_tex2d_nearest(void)
  38 {
  39         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
  40         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
  41 }
  42
  43 static inline void vg_tex2d_linear_mipmap(void)
  44 {
  45         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
  46         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  47 }
  48
  49 static inline void vg_tex2d_repeat(void)
  50 {
  51         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
  52         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
  53 }
  54
  55 static inline void vg_tex2d_clamp(void)
  56 {
  57         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
  58         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
  59 }
  60
  61 static GLuint vg_tex2d_rgba( const char *path )
  62 {
  63         i64 length;
  64         u8 *src_data = vg_asset_read_s( path, &length );
  65
  66         GLuint texture_name;
  67         glGenTextures( 1, &texture_name );
  68         glBindTexture( GL_TEXTURE_2D, texture_name );
  69
  70         if( src_data )
  71         {
  72                 qoi_desc info;
  73                 u8 *tex_buffer = qoi_decode( src_data, length, &info, 4 );
  74
  75                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, info.width, info.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_buffer );
  76
  77                 free( tex_buffer );
  78                 free( src_data );
  79         }
  80         else
  81         {
  82                 u32 tex_err[4] =
  83                 {
  84                         0xffff00ff,
  85                         0xff000000,
  86                         0xff000000,
  87                         0xffff00ff
  88                 };
  89
  90                 vg_error( "Loading texture failed (%s)\n", path );
  91                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_err );
  92         }
  93
  94         return texture_name;
  95 }
  96
  97 static void vg_tex2d_init( vg_tex2d *textures[], int num )
  98 {
  99         for( int i = 0; i < num; i ++ )
 100         {
 101                 vg_tex2d *tex = textures[i];
 102                 tex->name = vg_tex2d_rgba( tex->path );
 103                 if( !(tex->flags & VG_TEXTURE_NO_MIP) )
 104                         vg_tex2d_mipmap();
 105
 106                 if( tex->flags & VG_TEXTURE_NEAREST )
 107                 {
 108                         if( tex->flags & VG_TEXTURE_NO_MIP )
 109                                 vg_error( "Invalid texture settings\n" );
 110                         else
 111                                 vg_tex2d_nearest();
 112                 }
 113                 else
 114                 {
 115                         if( tex->flags & VG_TEXTURE_NO_MIP )
 116                                 vg_tex2d_linear();
 117                         else
 118                                 vg_tex2d_linear_mipmap();
 119                 }
 120
 121                 if( tex->flags & VG_TEXTURE_CLAMP )
 122                         vg_tex2d_clamp();
 123                 else
 124                         vg_tex2d_repeat();
 125         }
 126 }
 127
 128 static void vg_tex2d_free( vg_tex2d *textures[], int num )
 129 {
 130         for( int i = 0; i < num; i ++ )
 131         {
 132                 glDeleteTextures( 1, &textures[i]->name );
 133         }
 134 }