; simple gl like driver for TinyGL and KolibriOS - porting iadn
struct TinyGLContext
gl_context dd ?
xsize dd ? ;+4
ysize dd ? ;+8
d_x dd ? ;+12
d_y dd ? ;+16
x dd ? ;+20
y dd ? ;+24
ends
;KOSGLContext kosglCreateContext(KOSGLContext shareList, int flags)
;{
; TinyGLContext *ctx;
; if (shareList != NULL) {
; gl_fatal_error("No sharing available in TinyGL");
; }
; ctx=gl_malloc(sizeof(TinyGLContext));
; if (!ctx)
; return NULL;
; ctx->gl_context=NULL;
; return (KOSGLContext) ctx;
;}
;void kosglDestroyContext( KOSGLContext ctx1 )
;{
; TinyGLContext *ctx = (TinyGLContext *) ctx1;
; if (ctx->gl_context != NULL) {
; glClose();
; }
; gl_free(ctx);
;}
; resize the glx viewport : we try to use the xsize and ysize
; given. We return the effective size which is guaranted to be smaller
align 4
proc gl_resize_viewport uses ebx ecx edx edi esi, context:dword, xsize_ptr:dword, ysize_ptr:dword
mov ecx,[xsize_ptr] ; ecx = &xsize
mov edi,[ecx] ; edi = xsize
mov esi,[ysize_ptr] ; esi = &ysize
mov esi,[esi] ; esi = ysize
xor eax,eax
or edi,edi
jnz @f
or esi,esi
jnz @f
mov eax,-1
jmp .end_f
@@:
mov [ecx],edi
dec dword[ecx]
mov ecx,[ysize_ptr]
mov [ecx],esi
dec dword[ecx]
mov ebx,[context]
mov edx,[ebx+GLContext.opaque] ; edx = (TinyGLContext *)context.opaque
mov [edx+TinyGLContext.xsize],edi
mov [edx+TinyGLContext.d_x],edi
mov [edx+TinyGLContext.ysize],esi
mov [edx+TinyGLContext.d_y],esi
; resize the Z buffer
stdcall ZB_resize, dword[ebx+GLContext.zb],0,edi,esi
.end_f:
ret
endp
; we assume here that drawable is a window
align 4
proc kosglMakeCurrent uses ebx ecx, win_x0:dword, win_y0:dword, win_x:dword, win_y:dword, ctx1:dword
mov ebx,[ctx1]
cmp dword[ebx],0 ;if (ctx.gl_context == NULL)
jne .end_f
; create the TinyGL context
mov ecx,[win_x0]
mov [ebx+TinyGLContext.x],ecx
mov ecx,[win_y0]
mov [ebx+TinyGLContext.y],ecx
mov ecx,[win_x]
mov [ebx+TinyGLContext.d_x],ecx
mov ecx,[win_y]
mov [ebx+TinyGLContext.d_y],ecx
; currently, we only support 16 bit rendering
xor eax,eax
stdcall ZB_open, dword[win_x], dword[win_y], dword ZB_MODE_RGB24, eax,eax,eax,eax ;NULL,NULL,NULL
or eax,eax
jnz @f
stdcall dbg_print,sz_kosglMakeCurrent,err_0
xor eax,eax
jmp .err_f
@@:
; initialisation of the TinyGL interpreter
stdcall glInit, eax
call gl_get_context
mov [ebx],eax ;ctx.gl_context = eax
mov [eax+GLContext.opaque],ebx ;ctx.gl_context.opaque = ctx
mov dword[eax+GLContext.gl_resize_viewport],gl_resize_viewport
; set the viewport : we force a call to gl_resize_viewport
dec dword[eax+GLContext.viewport+GLViewport.xsize]
dec dword[eax+GLContext.viewport+GLViewport.ysize]
stdcall glViewport, 0, 0, [win_x], [win_y]
.end_f:
xor eax,eax
inc eax
.err_f:
ret
endp
align 4
proc kosglSwapBuffers uses eax ebx ecx edx esi
; retrieve the current TinyGLContext
call gl_get_context
mov ebx,[eax+GLContext.zb]
mov ebx,[ebx+ZBuffer.pbuf]
mov esi,[eax+GLContext.opaque] ;esi = &context.opaque
mov eax,SF_PUT_IMAGE
mov ecx,[esi+TinyGLContext.d_x]
shl ecx,16
mov cx,word[esi+TinyGLContext.d_y]
mov edx,[esi+TinyGLContext.x]
shl edx,16
mov dx,word[esi+TinyGLContext.y]
int 0x40
ret
endp