src/vg/vg_tex.h

   1 /* Copyright (C) 2021-2022 Harry Godden (hgn) - All Rights Reserved */
   2 #ifndef VG_TEX_H
   3 #define VG_TEX_H
   4
   5 #define VG_TEXTURE_NO_MIP       0x1
   6 #define VG_TEXTURE_REPEAT       0x2
   7 #define VG_TEXTURE_CLAMP        0x4
   8 #define VG_TEXTURE_NEAREST      0x8
   9
  10 struct vg_tex2d
  11 {
  12         const char *path;
  13         u32 flags;
  14         GLuint name;
  15 };
  16
  17 struct vg_sprite
  18 {
  19         v4f uv_xywh;
  20 };
  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,
  48          GL_LINEAR_MIPMAP_LINEAR );
  49         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  50 }
  51
  52 static inline void vg_tex2d_repeat(void)
  53 {
  54         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
  55         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
  56 }
  57
  58 static inline void vg_tex2d_clamp(void)
  59 {
  60         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
  61         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
  62 }
  63
  64 static GLuint vg_tex2d_rgba( const char *path )
  65 {
  66         i64 length;
  67         u8 *src_data = vg_asset_read_s( path, &length );
  68
  69         GLuint texture_name;
  70         glGenTextures( 1, &texture_name );
  71         glBindTexture( GL_TEXTURE_2D, texture_name );
  72
  73         if( src_data )
  74         {
  75                 qoi_desc info;
  76                 u8 *tex_buffer = qoi_decode( src_data, length, &info, 4 );
  77
  78                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, info.width, info.height,
  79             0, GL_RGBA, GL_UNSIGNED_BYTE, tex_buffer );
  80
  81                 free( tex_buffer );
  82                 free( src_data );
  83         }
  84         else
  85         {
  86                 u32 tex_err[4] =
  87                 {
  88                         0xffff00ff,
  89                         0xff000000,
  90                         0xff000000,
  91                         0xffff00ff
  92                 };
  93
  94                 vg_error( "Loading texture failed (%s)\n", path );
  95                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 2, 2,
  96             0, GL_RGBA, GL_UNSIGNED_BYTE, tex_err );
  97         }
  98
  99         return texture_name;
 100 }
 101
 102 static void vg_tex2d_init( vg_tex2d *textures[], int num )
 103 {
 104         for( int i = 0; i < num; i ++ )
 105         {
 106                 vg_tex2d *tex = textures[i];
 107                 tex->name = vg_tex2d_rgba( tex->path );
 108                 if( !(tex->flags & VG_TEXTURE_NO_MIP) )
 109                         vg_tex2d_mipmap();
 110
 111                 if( tex->flags & VG_TEXTURE_NEAREST )
 112                 {
 113                         if( tex->flags & VG_TEXTURE_NO_MIP )
 114                                 vg_error( "Invalid texture settings\n" );
 115                         else
 116                                 vg_tex2d_nearest();
 117                 }
 118                 else
 119                 {
 120                         if( tex->flags & VG_TEXTURE_NO_MIP )
 121                                 vg_tex2d_linear();
 122                         else
 123                                 vg_tex2d_linear_mipmap();
 124                 }
 125
 126                 if( tex->flags & VG_TEXTURE_CLAMP )
 127                         vg_tex2d_clamp();
 128                 else
 129                         vg_tex2d_repeat();
 130         }
 131 }
 132
 133 static void vg_tex2d_free( vg_tex2d *textures[], int num )
 134 {
 135         for( int i = 0; i < num; i ++ )
 136         {
 137                 glDeleteTextures( 1, &textures[i]->name );
 138         }
 139 }
 140
 141 #endif /* VG_TEX_H */