opengl_vbo.c

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/*
 * See Licensing and Copyright notice in naev.h
 */
#include "opengl.h"
 
#define BUFFER_OFFSET( i )                                                     \
   ( (char *)( sizeof( char ) * ( i ) ) ) 

typedef enum gl_vboType_e {
   NGL_VBO_NULL,    
   NGL_VBO_STREAM,  
   NGL_VBO_DYNAMIC, 
   NGL_VBO_STATIC   
} gl_vboType;

struct gl_vbo_s {
   GLuint     id;   
   gl_vboType type; 
   GLsizei    size; 
   char      *data; 
};

static gl_vbo *gl_vboCreate( GLenum target, GLsizei size, const void *data,
                             GLenum usage );

int gl_initVBO( void )
{
   return 0;
}

void gl_exitVBO( void )
{
}

static gl_vbo *gl_vboCreate( GLenum target, GLsizei size, const void *data,
                             GLenum usage )
{
   /* Allocate. */
   gl_vbo *vbo = calloc( 1, sizeof( gl_vbo ) );
 
   /* General stuff. */
   vbo->size = size;
 
   /* Create the buffer. */
   glGenBuffers( 1, &vbo->id );
 
   /* Upload the data. */
   glBindBuffer( target, vbo->id );
   glBufferData( target, size, data, usage );
   glBindBuffer( target, 0 );
 
   /* Check for errors. */
   gl_checkErr();
 
   return vbo;
}

void gl_vboData( gl_vbo *vbo, GLsizei size, const void *data )
{
   GLenum usage;
 
   vbo->size = size;
 
   /* Get usage. */
   if ( vbo->type == NGL_VBO_STREAM )
      usage = GL_STREAM_DRAW;
   else if ( vbo->type == NGL_VBO_DYNAMIC )
      usage = GL_DYNAMIC_DRAW;
   else if ( vbo->type == NGL_VBO_STATIC )
      usage = GL_STATIC_DRAW;
   else
      usage = GL_STREAM_DRAW;
 
   /* Get new data. */
   glBindBuffer( GL_ARRAY_BUFFER, vbo->id );
   glBufferData( GL_ARRAY_BUFFER, size, data, usage );
 
   /* Check for errors. */
   gl_checkErr();
}

void gl_vboSubData( gl_vbo *vbo, GLint offset, GLsizei size, const void *data )
{
   glBindBuffer( GL_ARRAY_BUFFER, vbo->id );
   glBufferSubData( GL_ARRAY_BUFFER, offset, size, data );
 
   /* Check for errors. */
   gl_checkErr();
}

gl_vbo *gl_vboCreateStream( GLsizei size, const void *data )
{
   gl_vbo *vbo = gl_vboCreate( GL_ARRAY_BUFFER, size, data, GL_STREAM_DRAW );
   vbo->type   = NGL_VBO_STREAM;
 
   /* Check for errors. */
   gl_checkErr();
 
   return vbo;
}

gl_vbo *gl_vboCreateDynamic( GLsizei size, const void *data )
{
   gl_vbo *vbo = gl_vboCreate( GL_ARRAY_BUFFER, size, data, GL_DYNAMIC_DRAW );
   vbo->type   = NGL_VBO_DYNAMIC;
 
   /* Check for errors. */
   gl_checkErr();
 
   return vbo;
}

gl_vbo *gl_vboCreateStatic( GLsizei size, const void *data )
{
   gl_vbo *vbo = gl_vboCreate( GL_ARRAY_BUFFER, size, data, GL_STATIC_DRAW );
   vbo->type   = NGL_VBO_STATIC;
 
   /* Check for errors. */
   gl_checkErr();
 
   return vbo;
}

void *gl_vboMap( gl_vbo *vbo )
{
   glBindBuffer( GL_ARRAY_BUFFER, vbo->id );
   return glMapBuffer( GL_ARRAY_BUFFER, GL_WRITE_ONLY );
}

void gl_vboUnmap( gl_vbo *vbo )
{
   (void)vbo;
   glUnmapBuffer( GL_ARRAY_BUFFER );
 
   /* Check for errors. */
   gl_checkErr();
}

void gl_vboActivateAttribOffset( gl_vbo *vbo, GLuint index, GLuint offset,
                                 GLint size, GLenum type, GLsizei stride )
{
   const GLvoid *pointer;
 
   /* Set up. */
   glBindBuffer( GL_ARRAY_BUFFER, vbo->id );
   pointer = BUFFER_OFFSET( offset );
 
   glVertexAttribPointer( index, size, type, GL_FALSE, stride, pointer );
 
   /* Check for errors. */
   gl_checkErr();
}

void gl_vboDestroy( gl_vbo *vbo )
{
   if ( vbo == NULL )
      return;
 
   glDeleteBuffers( 1, &vbo->id );
   gl_checkErr();
   free( vbo );
}