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 #include "vg/vg.h"
   6 #include "vg/vg_log.h"
   7
   8 #define VG_TEXTURE_NO_MIP       0x1
   9 #define VG_TEXTURE_REPEAT       0x2
  10 #define VG_TEXTURE_CLAMP        0x4
  11 #define VG_TEXTURE_NEAREST      0x8
  12 #define VG_TEXTURE_ALLOCATED_INTERNAL 0x10
  13
  14 #define QOI_IMPLEMENTATION
  15 #define QOI_MALLOC vg_alloc
  16 #define QOI_FREE   vg_free
  17
  18 #include "phoboslab/qoi.h"
  19
  20 struct vg_tex2d
  21 {
  22         const char *path;
  23         u32 flags;
  24         GLuint name;
  25 };
  26
  27 struct vg_sprite
  28 {
  29         v4f uv_xywh;
  30 };
  31
  32 static void vg_tex2d_bind( vg_tex2d *tex, u32 id )
  33 {
  34    if( !(tex->flags & VG_TEXTURE_ALLOCATED_INTERNAL) )
  35    {
  36       vg_error( "Tried to use '%s' while unloaded!\n", tex->path );
  37       return;
  38    }
  39
  40         glActiveTexture( GL_TEXTURE0 + id );
  41         glBindTexture( GL_TEXTURE_2D, tex->name );
  42 }
  43
  44 static inline void vg_tex2d_mipmap(void)
  45 {
  46         glGenerateMipmap( GL_TEXTURE_2D );
  47 }
  48
  49 static inline void vg_tex2d_linear(void)
  50 {
  51         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
  52         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  53 }
  54
  55 static inline void vg_tex2d_nearest(void)
  56 {
  57         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
  58         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
  59 }
  60
  61 static inline void vg_tex2d_linear_mipmap(void)
  62 {
  63         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
  64          GL_LINEAR_MIPMAP_LINEAR );
  65         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  66 }
  67
  68 static inline void vg_tex2d_repeat(void)
  69 {
  70         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
  71         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
  72 }
  73
  74 static inline void vg_tex2d_clamp(void)
  75 {
  76         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
  77         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
  78 }
  79
  80 static GLuint vg_tex2d_rgba( const char *path )
  81 {
  82         i64 length;
  83         u8 *src_data = vg_asset_read_s( path, &length );
  84
  85         GLuint texture_name;
  86         glGenTextures( 1, &texture_name );
  87         glBindTexture( GL_TEXTURE_2D, texture_name );
  88
  89         if( src_data )
  90         {
  91                 qoi_desc info;
  92                 u8 *tex_buffer = qoi_decode( src_data, length, &info, 4 );
  93
  94                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, info.width, info.height,
  95             0, GL_RGBA, GL_UNSIGNED_BYTE, tex_buffer );
  96
  97                 vg_free( tex_buffer );
  98                 vg_free( src_data );
  99         }
 100         else
 101         {
 102                 u32 tex_err[4] =
 103                 {
 104                         0xffff00ff,
 105                         0xff000000,
 106                         0xff000000,
 107                         0xffff00ff
 108                 };
 109
 110                 vg_error( "Loading texture failed (%s)\n", path );
 111                 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 2, 2,
 112             0, GL_RGBA, GL_UNSIGNED_BYTE, tex_err );
 113         }
 114
 115         return texture_name;
 116 }
 117
 118 static void vg_tex2d_init( vg_tex2d *textures[], int num )
 119 {
 120         for( int i=0; i<num; i ++ )
 121         {
 122                 vg_tex2d *tex = textures[i];
 123                 tex->name = vg_tex2d_rgba( tex->path );
 124                 if( !(tex->flags & VG_TEXTURE_NO_MIP) )
 125                         vg_tex2d_mipmap();
 126
 127                 if( tex->flags & VG_TEXTURE_NEAREST )
 128                 {
 129                         if( tex->flags & VG_TEXTURE_NO_MIP )
 130                                 vg_error( "Invalid texture settings\n" );
 131                         else
 132                                 vg_tex2d_nearest();
 133                 }
 134                 else
 135                 {
 136                         if( tex->flags & VG_TEXTURE_NO_MIP )
 137                                 vg_tex2d_linear();
 138                         else
 139                                 vg_tex2d_linear_mipmap();
 140                 }
 141
 142                 if( tex->flags & VG_TEXTURE_CLAMP )
 143                         vg_tex2d_clamp();
 144                 else
 145                         vg_tex2d_repeat();
 146
 147       tex->flags |= VG_TEXTURE_ALLOCATED_INTERNAL;
 148         }
 149 }
 150
 151 static void vg_tex2d_free( vg_tex2d *textures[], int num )
 152 {
 153         for( int i = 0; i < num; i ++ )
 154         {
 155                 glDeleteTextures( 1, &textures[i]->name );
 156         }
 157 }
 158
 159 #endif /* VG_TEX_H */