From 6566b0489164957581d091119bdf480d66e9ca20 Mon Sep 17 00:00:00 2001
From: Jan Engelhardt <jengelh@inai.de>
Date: Wed, 1 May 2013 09:53:49 +0200
Subject: [PATCH 2/2] Implement color gradient for health bar
References: https://github.com/coelckers/prboom-plus/pull/274

---
 prboom2/src/gl_intern.h |  2 +-
 prboom2/src/gl_main.c   | 31 +++++++++++++++++--------------
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git prboom2/src/gl_intern.h prboom2/src/gl_intern.h
index b4be8d56..8c44d9a7 100644
--- prboom2/src/gl_intern.h
+++ prboom2/src/gl_intern.h
@@ -219,7 +219,7 @@ typedef struct
 
 typedef struct
 {
-  int cm;
+  float r,g;
 
   float x1, x2, x3;
   float z1, z2, z3;
diff --git prboom2/src/gl_main.c prboom2/src/gl_main.c
index e2402e16..0a257ecf 100644
--- prboom2/src/gl_main.c
+++ prboom2/src/gl_main.c
@@ -2334,15 +2334,23 @@ static void gld_AddHealthBar(mobj_t* thing, GLSprite *sprite)
     GLHealthBar hbar;
     int health_percent = thing->health * 100 / thing->info->spawnhealth;
 
-    hbar.cm = -1;
-    if (health_percent <= health_bar_red)
-      hbar.cm = CR_RED;
-    else if (health_percent <= health_bar_yellow)
-      hbar.cm = CR_YELLOW;
-    else if (health_percent <= health_bar_green)
-      hbar.cm = CR_GREEN;
+    hbar.r = hbar.g = -1.0f;
+    if (health_percent <= 0) {
+      hbar.r = 1.0f;
+      hbar.g = 0.0f;
+    } else if (health_percent <= health_bar_red) {
+      hbar.r = 1.0f;
+      hbar.g = (double)health_percent / (health_bar_yellow - health_bar_red);
+    } else if (health_percent <= health_bar_yellow) {
+      hbar.r = (double)(health_bar_yellow - health_percent) /
+               (health_bar_yellow - health_bar_red);
+      hbar.g = 1.0f;
+    } else if (health_percent <= health_bar_green) {
+      hbar.r = 0.0f;
+      hbar.g = 1.0f;
+    }
 
-    if (hbar.cm >= 0)
+    if (hbar.r >= 0)
     {
       float sx2 = (float)thing->radius / 2.0f / MAP_SCALE;
       float sx1 = sx2 - (float)health_percent * (float)thing->radius / 100.0f / MAP_SCALE;
@@ -2366,7 +2374,6 @@ static void gld_AddHealthBar(mobj_t* thing, GLSprite *sprite)
 static void gld_DrawHealthBars(void)
 {
   int i, count;
-  int cm = -1;
 
   count = gld_drawinfo.num_items[GLDIT_HBAR];
   if (count > 0)
@@ -2377,11 +2384,7 @@ static void gld_DrawHealthBars(void)
     for (i = count - 1; i >= 0; i--)
     {
       GLHealthBar *hbar = gld_drawinfo.items[GLDIT_HBAR][i].item.hbar;
-      if (hbar->cm != cm)
-      {
-        cm = hbar->cm;
-        glColor4f(cm2RGB[cm][0], cm2RGB[cm][1], cm2RGB[cm][2], 1.0f);
-      }
+      glColor4f(hbar->r, hbar->g, 0.0f, 1.0f);
 
       glVertex3f(hbar->x1, hbar->y, hbar->z1);
       glVertex3f(hbar->x2, hbar->y, hbar->z2);
-- 
2.31.1