use OGL 1.1 color logic ops in addition to GL_EXT_blend_logic_op
diff --git a/progs/samples/blendxor.c b/progs/samples/blendxor.c
index 7d3285d..6f34e28 100644
--- a/progs/samples/blendxor.c
+++ b/progs/samples/blendxor.c
@@ -19,6 +19,8 @@
GLenum doubleBuffer;
int dithering = 0;
+int use11ops = 0;
+int supportlogops = 0;
GLint windW, windH;
static void Init(void)
@@ -50,6 +52,13 @@
case 'd':
dithering = !dithering;
break;
+ case 'l':
+ if (supportlogops == 3)
+ use11ops = (!use11ops);
+ if (use11ops)
+ printf("Using GL 1.1 color logic ops.\n");
+ else printf("Using GL_EXT_blend_logic_op.\n");
+ break;
default:
return;
}
@@ -62,6 +71,8 @@
int i;
glDisable(GL_BLEND);
+ if (supportlogops & 2)
+ glDisable(GL_COLOR_LOGIC_OP);
(dithering) ? glEnable(GL_DITHER) : glDisable(GL_DITHER);
@@ -83,7 +94,10 @@
glEnd();
glEnable(GL_BLEND);
- glBlendEquationEXT(GL_LOGIC_OP);
+ if (!use11ops)
+ glBlendEquationEXT(GL_LOGIC_OP);
+ else
+ glEnable(GL_COLOR_LOGIC_OP);
glLogicOp(GL_XOR);
/* Draw a set of rectangles across the window */
@@ -142,6 +156,7 @@
GLenum type;
char *s;
char *extName = "GL_EXT_blend_logic_op";
+ char *version;
glutInit(&argc, argv);
@@ -161,10 +176,21 @@
/* Make sure blend_logic_op extension is there. */
s = (char *) glGetString(GL_EXTENSIONS);
+ version = (char*) glGetString(GL_VERSION);
if (!s)
exit(1);
- if (strstr(s,extName) == 0) {
- printf("Blend_logic_op extension is not present.\n");
+ if (strstr(s,extName)) {
+ supportlogops = 1;
+ use11ops = 0;
+ printf("blend_logic_op extension available.\n");
+ }
+ if (strncmp(version,"1.1",3)>=0) {
+ supportlogops += 2;
+ use11ops = 1;
+ printf("1.1 color logic ops available.\n");
+ }
+ if (supportlogops == 0) {
+ printf("Blend_logic_op extension and GL 1.1 not present.\n");
exit(1);
}