src/vg/vg_tex.h

   1 /* Copyright (C) 2021-2022 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,
  46          GL_LINEAR_MIPMAP_LINEAR );
  47         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  48 }
  49
  50 static inline void vg_tex2d_repeat(void)
  51 {
  52         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
  53         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
  54 }
  55
  56 static inline void vg_tex2d_clamp(void)
  57 {
  58         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
  59         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
  60 }
  61
  62 static GLuint vg_tex2d_rgba( const char *path )
  63 {
  64         i64 length;
  65         u8 *src_data = vg_asset_read_s( path, &length );
  66
  67         GLuint texture_name;
  68         glGenTextures( 1, &texture_name );
  69         glBindTexture( GL_TEXTURE_2D, texture_name );
  70
  71         if( src_data )
  72         {
  73                 qoi_desc info;
  74                 u8 *tex_buffer = qoi_decode( src_data, length, &info, 4 );
  75
  76                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, info.width, info.height,
  77             0, GL_RGBA, GL_UNSIGNED_BYTE, tex_buffer );
  78
  79                 free( tex_buffer );
  80                 free( src_data );
  81         }
  82         else
  83         {
  84                 u32 tex_err[4] =
  85                 {
  86                         0xffff00ff,
  87                         0xff000000,
  88                         0xff000000,
  89                         0xffff00ff
  90                 };
  91
  92                 vg_error( "Loading texture failed (%s)\n", path );
  93                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 2, 2,
  94             0, GL_RGBA, GL_UNSIGNED_BYTE, tex_err );
  95         }
  96
  97         return texture_name;
  98 }
  99
 100 static void vg_tex2d_init( vg_tex2d *textures[], int num )
 101 {
 102         for( int i = 0; i < num; i ++ )
 103         {
 104                 vg_tex2d *tex = textures[i];
 105                 tex->name = vg_tex2d_rgba( tex->path );
 106                 if( !(tex->flags & VG_TEXTURE_NO_MIP) )
 107                         vg_tex2d_mipmap();
 108
 109                 if( tex->flags & VG_TEXTURE_NEAREST )
 110                 {
 111                         if( tex->flags & VG_TEXTURE_NO_MIP )
 112                                 vg_error( "Invalid texture settings\n" );
 113                         else
 114                                 vg_tex2d_nearest();
 115                 }
 116                 else
 117                 {
 118                         if( tex->flags & VG_TEXTURE_NO_MIP )
 119                                 vg_tex2d_linear();
 120                         else
 121                                 vg_tex2d_linear_mipmap();
 122                 }
 123
 124                 if( tex->flags & VG_TEXTURE_CLAMP )
 125                         vg_tex2d_clamp();
 126                 else
 127                         vg_tex2d_repeat();
 128         }
 129 }
 130
 131 static void vg_tex2d_free( vg_tex2d *textures[], int num )
 132 {
 133         for( int i = 0; i < num; i ++ )
 134         {
 135                 glDeleteTextures( 1, &textures[i]->name );
 136         }
 137 }