src/nglx.c

   1 /* simple glx like driver for TinyGL and Nano X */
   2 #include <GL/gl.h>
   3 #include <GL/nglx.h>
   4 #include <microwin/nano-X.h>
   5 #include "zgl.h"
   6
   7 typedef struct {
   8         GLContext *gl_context;
   9         int xsize,ysize;
  10         GR_DRAW_ID drawable;
  11         GR_GC_ID gc;
  12         int pixtype; /* pixel type in TinyGL */
  13 } TinyNGLXContext;
  14
  15 NGLXContext nglXCreateContext(NGLXContext shareList, int flags)
  16 {
  17         TinyNGLXContext *ctx;
  18
  19         if (shareList != NULL) {
  20                 gl_fatal_error("No sharing available in TinyGL");
  21         }
  22         ctx=gl_malloc(sizeof(TinyNGLXContext));
  23         if (!ctx)
  24                 return NULL;
  25         ctx->gl_context=NULL;
  26         return (NGLXContext) ctx;
  27 }
  28
  29 void glXDestroyContext( NGLXContext ctx1 )
  30 {
  31         TinyNGLXContext *ctx = (TinyNGLXContext *) ctx1;
  32         if (ctx->gl_context != NULL) {
  33                 glClose();
  34         }
  35         gl_free(ctx);
  36 }
  37
  38
  39 /* resize the glx viewport : we try to use the xsize and ysize
  40    given. We return the effective size which is guaranted to be smaller */
  41
  42 static int glX_resize_viewport(GLContext *c,int *xsize_ptr,int *ysize_ptr)
  43 {
  44         TinyNGLXContext *ctx;
  45         int xsize,ysize;
  46
  47         ctx=(TinyNGLXContext *)c->opaque;
  48
  49         xsize=*xsize_ptr;
  50         ysize=*ysize_ptr;
  51
  52         /* we ensure that xsize and ysize are multiples of 2 for the zbuffer.
  53 TODO: find a better solution */
  54         xsize&=~3;
  55         ysize&=~3;
  56
  57         if (xsize == 0 || ysize == 0) return -1;
  58
  59         *xsize_ptr=xsize;
  60         *ysize_ptr=ysize;
  61
  62         ctx->xsize=xsize;
  63         ctx->ysize=ysize;
  64
  65         /* resize the Z buffer */
  66         ZB_resize(c->zb,NULL,xsize,ysize);
  67         return 0;
  68 }
  69
  70 /* we assume here that drawable is a window */
  71 int nglXMakeCurrent( NGLXDrawable drawable,
  72                 NGLXContext ctx1)
  73 {
  74         TinyNGLXContext *ctx = (TinyNGLXContext *) ctx1;
  75         int mode, xsize, ysize;
  76         ZBuffer *zb;
  77         GR_WINDOW_INFO win_info;
  78
  79         if (ctx->gl_context == NULL) {
  80                 /* create the TinyGL context */
  81                 GrGetWindowInfo(drawable, &win_info);
  82
  83                 xsize = win_info.width;
  84                 ysize = win_info.height;
  85
  86                 /* currently, we only support 16 bit rendering */
  87                 mode = ZB_MODE_5R6G5B;
  88                 zb=ZB_open(xsize,ysize,mode,0,NULL,NULL,NULL);
  89                 if (zb == NULL) {
  90                         fprintf(stderr, "Error while initializing Z buffer\n");
  91                         exit(1);
  92                 }
  93
  94                 ctx->pixtype = MWPF_TRUECOLOR565;
  95
  96                 /* create a gc */
  97                 ctx->gc = GrNewGC();
  98
  99                 /* initialisation of the TinyGL interpreter */
 100                 glInit(zb);
 101                 ctx->gl_context=gl_get_context();
 102                 ctx->gl_context->opaque=(void *) ctx;
 103                 ctx->gl_context->gl_resize_viewport=glX_resize_viewport;
 104
 105                 /* set the viewport : we force a call to glX_resize_viewport */
 106                 ctx->gl_context->viewport.xsize=-1;
 107                 ctx->gl_context->viewport.ysize=-1;
 108
 109                 glViewport(0, 0, xsize, ysize);
 110         }
 111
 112         return 1;
 113 }
 114
 115 void nglXSwapBuffers( NGLXDrawable drawable )
 116 {
 117         GLContext *gl_context;
 118         TinyNGLXContext *ctx;
 119
 120         /* retrieve the current NGLXContext */
 121         gl_context=gl_get_context();
 122         ctx=(TinyNGLXContext *)gl_context->opaque;
 123
 124         GrArea(drawable, ctx->gc, 0, 0, ctx->xsize,
 125                         ctx->ysize, ctx->gl_context->zb->pbuf, ctx->pixtype);
 126 }
 127
 128