split engine from game

[vg.git] / vg / vg_tex.h

diff --git a/vg/vg_tex.h b/vg/vg_tex.h
new file mode 100644 (file)
index 0000000..4c14540
--- /dev/null
+++ b/vg/vg_tex.h
@@ -0,0 +1,134 @@
+// Copyright (C) 2021 Harry Godden (hgn) - All Rights Reserved
+
+#define VG_TEXTURE_NO_MIP      0x1
+#define VG_TEXTURE_REPEAT      0x2
+#define VG_TEXTURE_CLAMP       0x4
+#define VG_TEXTURE_NEAREST     0x8
+
+struct vg_tex2d
+{
+       const char *path;
+       u32 flags;
+       GLuint name;
+};
+
+struct vg_sprite
+{
+       v4f uv_xywh;
+};
+
+static void vg_tex2d_bind( vg_tex2d *tex, u32 id )
+{
+       glActiveTexture( GL_TEXTURE0 + id );
+       glBindTexture( GL_TEXTURE_2D, tex->name );
+}
+
+static inline void vg_tex2d_mipmap(void) 
+{ 
+       glGenerateMipmap( GL_TEXTURE_2D );
+}
+
+static inline void vg_tex2d_linear(void)
+{
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
+}
+
+static inline void vg_tex2d_nearest(void)
+{
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
+}
+
+static inline void vg_tex2d_linear_mipmap(void)
+{
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
+}
+
+static inline void vg_tex2d_repeat(void)
+{
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
+}
+
+static inline void vg_tex2d_clamp(void)
+{
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
+       glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
+}
+
+static GLuint vg_tex2d_rgba( const char *path )
+{
+       i64 length;
+       u8 *src_data = vg_asset_read_s( path, &length );
+       
+       GLuint texture_name;
+       glGenTextures( 1, &texture_name );
+       glBindTexture( GL_TEXTURE_2D, texture_name );
+       
+       if( src_data )
+       {
+               qoi_desc info;
+               u8 *tex_buffer = qoi_decode( src_data, length, &info, 4 );
+               
+               glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, info.width, info.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_buffer );
+               
+               free( tex_buffer );
+               free( src_data );
+       }
+       else
+       {
+               u32 tex_err[4] =
+               {
+                       0xffff00ff,
+                       0xff000000,
+                       0xff000000,
+                       0xffff00ff
+               };
+       
+               vg_error( "Loading texture failed (%s)\n", path );
+               glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_err );
+       }
+       
+       return texture_name;
+}
+
+static void vg_tex2d_init( vg_tex2d *textures[], int num )
+{
+       for( int i = 0; i < num; i ++ )
+       {
+               vg_tex2d *tex = textures[i];
+               tex->name = vg_tex2d_rgba( tex->path );
+               if( !(tex->flags & VG_TEXTURE_NO_MIP) )
+                       vg_tex2d_mipmap();
+
+               if( tex->flags & VG_TEXTURE_NEAREST )
+               {
+                       if( tex->flags & VG_TEXTURE_NO_MIP )
+                               vg_error( "Invalid texture settings\n" );
+                       else
+                               vg_tex2d_nearest();
+               }
+               else
+               {
+                       if( tex->flags & VG_TEXTURE_NO_MIP )
+                               vg_tex2d_linear();
+                       else
+                               vg_tex2d_linear_mipmap();
+               }
+               
+               if( tex->flags & VG_TEXTURE_CLAMP )
+                       vg_tex2d_clamp();
+               else
+                       vg_tex2d_repeat();
+       }
+}
+
+static void vg_tex2d_free( vg_tex2d *textures[], int num )
+{
+       for( int i = 0; i < num; i ++ )
+       {
+               glDeleteTextures( 1, &textures[i]->name );
+       }
+}