From 4bbd0cc40408c59d48e615b7cc3276e1069b77b8 Mon Sep 17 00:00:00 2001
From: Alibek Omarov <a1ba.omarov@gmail.com>
Date: Thu, 5 Jan 2023 06:07:56 +0300
Subject: [PATCH] ref: add new special rendermode that specifically used for
 modulate mode in engine's ScreenFade

---
 engine/ref_api.h    | 4 ++++
 ref/gl/gl_backend.c | 4 ++++
 ref/soft/r_draw.c   | 8 ++++++--
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/engine/ref_api.h b/engine/ref_api.h
index c5215541..427b3f05 100644
--- a/engine/ref_api.h
+++ b/engine/ref_api.h
@@ -67,6 +67,10 @@ GNU General Public License for more details.
 #define FWORLD_WATERALPHA		BIT( 2 )
 #define FWORLD_HAS_DELUXEMAP		BIT( 3 )
 
+// special rendermode for screenfade modulate
+// (probably will be expanded at some point)
+#define kRenderScreenFadeModulate 0x1000
+
 typedef enum
 {
 	DEMO_INACTIVE = 0,
diff --git a/ref/gl/gl_backend.c b/ref/gl/gl_backend.c
index da530405..f3f4e2a5 100644
--- a/ref/gl/gl_backend.c
+++ b/ref/gl/gl_backend.c
@@ -417,6 +417,10 @@ void GL_SetRenderMode( int mode )
 		pglDisable( GL_ALPHA_TEST );
 		pglBlendFunc( GL_SRC_ALPHA, GL_ONE );
 		break;
+	case kRenderScreenFadeModulate:
+		pglEnable( GL_BLEND );
+		pglDisable( GL_ALPHA_TEST );
+		pglBlendFunc( GL_ZERO, GL_SRC_COLOR );
 	}
 }
 
diff --git a/ref/soft/r_draw.c b/ref/soft/r_draw.c
index 24ff99f7..22ffe279 100644
--- a/ref/soft/r_draw.c
+++ b/ref/soft/r_draw.c
@@ -165,11 +165,15 @@ void R_DrawStretchPicImplementation( int x, int y, int w, int h, int s1, int t1,
 					pixel_t screen = dest[u];
 					dest[u] = vid.addmap[(src & 0xff00)|(screen>>8)] << 8 | (screen & 0xff) | ((src & 0xff) >> 0);
 				}
+				else if( vid.rendermode == kRenderScreenFadeModulate )
+				{
+					pixel_t screen = dest[u];
+					dest[u] = BLEND_COLOR( screen, vid.color );
+				}
 				else if( alpha < 7) // && (vid.rendermode == kRenderTransAlpha || vid.rendermode == kRenderTransTexture ) )
 				{
 					pixel_t screen = dest[u]; //  | 0xff & screen & src ;
-					dest[u] = BLEND_ALPHA( alpha, src, screen);//vid.alphamap[( alpha << 16)|(src & 0xff00)|(screen>>8)] << 8 | (screen & 0xff) >> 3 | ((src & 0xff) >> 3);
-
+					dest[u] = BLEND_ALPHA( alpha, src, screen );//vid.alphamap[( alpha << 16)|(src & 0xff00)|(screen>>8)] << 8 | (screen & 0xff) >> 3 | ((src & 0xff) >> 3);
 				}
 				else
 					dest[u] = src;