From 2c3c200d922cb528d3d815d12c69062b72b93a6b Mon Sep 17 00:00:00 2001
From: havoc <havoc@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Thu, 11 Jan 2007 04:45:12 +0000
Subject: [PATCH] implemented detection of GL_EXT_blend_subtract

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@6682 d7cf8633-e32d-0410-b094-e92efae38249
---
 glquake.h    | 17 +++++++++++++++++
 vid_shared.c | 17 +++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/glquake.h b/glquake.h
index b27cd252..32b76f2d 100644
--- a/glquake.h
+++ b/glquake.h
@@ -399,6 +399,23 @@ extern int gl_support_clamptoedge;
 extern void (GLAPIENTRY *qglActiveStencilFaceEXT)(GLenum);
 extern int gl_support_stenciltwoside;
 
+//GL_EXT_blend_minmax
+extern int gl_support_ext_blend_minmax;
+#ifndef GL_FUNC_ADD_EXT
+#define GL_FUNC_ADD_EXT                   0x8006 // also supplied by GL_EXT_blend_subtract
+#define GL_MIN_EXT                        0x8007
+#define GL_MAX_EXT                        0x8008
+#define GL_BLEND_EQUATION_EXT             0x8009 // also supplied by GL_EXT_blend_subtract
+extern void (GLAPIENTRY *qglBlendEquationEXT)(GLenum); // also supplied by GL_EXT_blend_subtract
+#endif
+
+//GL_EXT_blend_subtract
+extern int gl_support_ext_blend_subtract;
+#ifndef GL_FUNC_SUBTRACT_EXT
+#define GL_FUNC_SUBTRACT_EXT              0x800A
+#define GL_FUNC_REVERSE_SUBTRACT_EXT      0x800B
+#endif
+
 //GL_ARB_texture_non_power_of_two
 extern int gl_support_arb_texture_non_power_of_two;
 
diff --git a/vid_shared.c b/vid_shared.c
index 200f4458..6599d711 100644
--- a/vid_shared.c
+++ b/vid_shared.c
@@ -44,6 +44,10 @@ int gl_support_anisotropy = false;
 int gl_max_anisotropy = 1;
 // GL_EXT_stencil_two_side
 int gl_support_stenciltwoside = false;
+// GL_EXT_blend_minmax
+int gl_support_ext_blend_minmax = false;
+// GL_EXT_blend_subtract
+int gl_support_ext_blend_subtract = false;
 // GL_ARB_shader_objects
 int gl_support_shader_objects = false;
 // GL_ARB_shading_language_100
@@ -248,6 +252,8 @@ void (GLAPIENTRY *qglPolygonStipple)(const GLubyte *mask);
 void (GLAPIENTRY *qglLineWidth)(GLfloat width);
 void (GLAPIENTRY *qglPointSize)(GLfloat size);
 
+void (GLAPIENTRY *qglBlendEquationEXT)(GLenum);
+
 void (GLAPIENTRY *qglActiveStencilFaceEXT)(GLenum);
 
 void (GLAPIENTRY *qglDeleteObjectARB)(GLhandleARB obj);
@@ -519,6 +525,12 @@ static dllfunction_t stenciltwosidefuncs[] =
 	{NULL, NULL}
 };
 
+static dllfunction_t blendequationfuncs[] =
+{
+	{"glBlendEquationEXT", (void **) &qglBlendEquationEXT},
+	{NULL, NULL}
+};
+
 static dllfunction_t shaderobjectsfuncs[] =
 {
 	{"glDeleteObjectARB", (void **) &qglDeleteObjectARB},
@@ -635,6 +647,8 @@ void VID_CheckExtensions(void)
 	gl_support_anisotropy = false;
 	gl_max_anisotropy = 1;
 	gl_support_stenciltwoside = false;
+	gl_support_ext_blend_minmax = false;
+	gl_support_ext_blend_subtract = false;
 	gl_support_shader_objects = false;
 	gl_support_shading_language_100 = false;
 	gl_support_vertex_shader = false;
@@ -692,6 +706,9 @@ void VID_CheckExtensions(void)
 	if ((gl_support_anisotropy = GL_CheckExtension("GL_EXT_texture_filter_anisotropic", NULL, "-noanisotropy", false)))
 		qglGetIntegerv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &gl_max_anisotropy);
 
+	gl_support_ext_blend_minmax = GL_CheckExtension("GL_EXT_blend_minmax", blendequationfuncs, "-noblendminmax", false);
+	gl_support_ext_blend_subtract = GL_CheckExtension("GL_EXT_blend_subtract", blendequationfuncs, "-noblendsubtract", false);
+
 // COMMANDLINEOPTION: GL: -nostenciltwoside disables GL_EXT_stencil_two_side (accelerates shadow rendering)
 	gl_support_stenciltwoside = GL_CheckExtension("GL_EXT_stencil_two_side", stenciltwosidefuncs, "-nostenciltwoside", false);
 
-- 
2.39.2