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 #pragma pack(push,1)
  16 struct vg_sprite
  17 {
  18         u16 uvx, uvy, w, h;
  19 };
  20 #pragma pack(pop)
  21
  22 static void vg_tex2d_bind( vg_tex2d *tex, u32 id )
  23 {
  24         glActiveTexture( GL_TEXTURE0 + id );
  25         glBindTexture( GL_TEXTURE_2D, tex->name );
  26 }
  27
  28 static inline void vg_tex2d_mipmap(void)
  29 {
  30         glGenerateMipmap( GL_TEXTURE_2D );
  31 }
  32
  33 static inline void vg_tex2d_linear(void)
  34 {
  35         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
  36         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  37 }
  38
  39 static inline void vg_tex2d_nearest(void)
  40 {
  41         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
  42         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
  43 }
  44
  45 static inline void vg_tex2d_linear_mipmap(void)
  46 {
  47         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
  48         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  49 }
  50
  51 static inline void vg_tex2d_repeat(void)
  52 {
  53         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
  54         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
  55 }
  56
  57 static inline void vg_tex2d_clamp(void)
  58 {
  59         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
  60         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
  61 }
  62
  63 static GLuint vg_tex2d_rgba( const char *path )
  64 {
  65         i64 length;
  66         u8 *src_data = vg_asset_read_s( path, &length );
  67
  68         GLuint texture_name;
  69         glGenTextures( 1, &texture_name );
  70         glBindTexture( GL_TEXTURE_2D, texture_name );
  71
  72         if( src_data )
  73         {
  74                 qoi_desc info;
  75                 u8 *tex_buffer = qoi_decode( src_data, length, &info, 4 );
  76
  77                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, info.width, info.height, 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, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_err );
  94         }
  95
  96         return texture_name;
  97 }
  98
  99 static void vg_tex2d_init( vg_tex2d *textures[], int num )
 100 {
 101         for( int i = 0; i < num; i ++ )
 102         {
 103                 vg_tex2d *tex = textures[i];
 104                 tex->name = vg_tex2d_rgba( tex->path );
 105                 if( !(tex->flags & VG_TEXTURE_NO_MIP) )
 106                         vg_tex2d_mipmap();
 107
 108                 if( tex->flags & VG_TEXTURE_NEAREST )
 109                 {
 110                         if( tex->flags & VG_TEXTURE_NO_MIP )
 111                                 vg_error( "Invalid texture settings\n" );
 112                         else
 113                                 vg_tex2d_nearest();
 114                 }
 115                 else
 116                 {
 117                         if( tex->flags & VG_TEXTURE_NO_MIP )
 118                                 vg_tex2d_linear();
 119                         else
 120                                 vg_tex2d_linear_mipmap();
 121                 }
 122
 123                 if( tex->flags & VG_TEXTURE_CLAMP )
 124                         vg_tex2d_clamp();
 125                 else
 126                         vg_tex2d_repeat();
 127         }
 128 }
 129
 130 static void vg_tex2d_free( vg_tex2d *textures[], int num )
 131 {
 132         for( int i = 0; i < num; i ++ )
 133         {
 134                 glDeleteTextures( 1, &textures[i]->name );
 135         }
 136 }