From f89054baad446b861e708d8f7391b8dbcb40a08a Mon Sep 17 00:00:00 2001
From: water111 <48171810+water111@users.noreply.github.com>
Date: Wed, 1 Jun 2022 21:00:47 -0400
Subject: [PATCH] [graphics] add missing blend used in final boss fight (#1406)

---
 game/graphics/opengl_renderer/foreground/Generic2.h  |  4 ++--
 .../opengl_renderer/foreground/Generic2_Build.cpp    |  8 +++++---
 .../opengl_renderer/foreground/Generic2_OpenGL.cpp   | 12 ++++++++----
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/game/graphics/opengl_renderer/foreground/Generic2.h b/game/graphics/opengl_renderer/foreground/Generic2.h
index 244f062995..8d1fc8c41e 100644
--- a/game/graphics/opengl_renderer/foreground/Generic2.h
+++ b/game/graphics/opengl_renderer/foreground/Generic2.h
@@ -184,8 +184,8 @@ class Generic2 : public BucketRenderer {
     u32 dma_tags = 0;
   } m_stats;
 
-  static constexpr int ALPHA_MODE_COUNT = 6;
-  bool m_alpha_draw_enable[ALPHA_MODE_COUNT] = {true, true, true, true, true, true};
+  static constexpr int ALPHA_MODE_COUNT = 7;
+  bool m_alpha_draw_enable[ALPHA_MODE_COUNT] = {true, true, true, true, true, true, true};
 
   struct {
     GLuint vao;
diff --git a/game/graphics/opengl_renderer/foreground/Generic2_Build.cpp b/game/graphics/opengl_renderer/foreground/Generic2_Build.cpp
index 40562ce92a..6814b6d19d 100644
--- a/game/graphics/opengl_renderer/foreground/Generic2_Build.cpp
+++ b/game/graphics/opengl_renderer/foreground/Generic2_Build.cpp
@@ -155,10 +155,12 @@ void Generic2::determine_draw_modes() {
         } else if (a == GsAlpha::BlendMode::SOURCE && b == GsAlpha::BlendMode::ZERO_OR_FIXED &&
                    c == GsAlpha::BlendMode::DEST && d == GsAlpha::BlendMode::DEST) {
           current_mode.set_alpha_blend(DrawMode::AlphaBlend::SRC_0_DST_DST);
+        } else if (a == GsAlpha::BlendMode::SOURCE && b == GsAlpha::BlendMode::ZERO_OR_FIXED &&
+                   c == GsAlpha::BlendMode::ZERO_OR_FIXED && d == GsAlpha::BlendMode::DEST) {
+          current_mode.set_alpha_blend(DrawMode::AlphaBlend::SRC_0_FIX_DST);
         } else {
-          // unsupported blend: a 0 b 2 c 2 d 1
-          // lg::error("unsupported blend: a {} b {} c {} d {}", (int)a, (int)b, (int)c, (int)d);
-          //      ASSERT(false);
+          fmt::print("unsupported blend: a {} b {} c {} d {}\n", (int)a, (int)b, (int)c, (int)d);
+          // ASSERT(false);
         }
       }
     }
diff --git a/game/graphics/opengl_renderer/foreground/Generic2_OpenGL.cpp b/game/graphics/opengl_renderer/foreground/Generic2_OpenGL.cpp
index d7536dbc45..21382011fe 100644
--- a/game/graphics/opengl_renderer/foreground/Generic2_OpenGL.cpp
+++ b/game/graphics/opengl_renderer/foreground/Generic2_OpenGL.cpp
@@ -152,7 +152,10 @@ void Generic2::setup_opengl_for_draw_mode(const DrawMode& draw_mode,
       // (Cs - 0) * Ad + Cd
       glBlendFunc(GL_DST_ALPHA, GL_ONE);
       glBlendEquation(GL_FUNC_ADD);
-      color_mult = 0.5f;  // HACK, should probably be 0.5
+      color_mult = 0.5f;
+    } else if (draw_mode.get_alpha_blend() == DrawMode::AlphaBlend::SRC_0_FIX_DST) {
+      glBlendEquation(GL_FUNC_ADD);
+      glBlendFuncSeparate(GL_ONE, GL_ONE, GL_ONE, GL_ZERO);
     } else {
       ASSERT(false);
     }
@@ -296,9 +299,10 @@ void Generic2::do_draws(SharedRenderState* render_state, ScopedProfilerNode& pro
 
   opengl_bind_and_setup_proj(render_state);
   constexpr DrawMode::AlphaBlend alpha_order[ALPHA_MODE_COUNT] = {
-      DrawMode::AlphaBlend::SRC_SRC_SRC_SRC, DrawMode::AlphaBlend::SRC_DST_SRC_DST,
-      DrawMode::AlphaBlend::SRC_0_SRC_DST,   DrawMode::AlphaBlend::ZERO_SRC_SRC_DST,
-      DrawMode::AlphaBlend::SRC_DST_FIX_DST, DrawMode::AlphaBlend::SRC_0_DST_DST,
+      DrawMode::AlphaBlend::SRC_0_FIX_DST,    DrawMode::AlphaBlend::SRC_SRC_SRC_SRC,
+      DrawMode::AlphaBlend::SRC_DST_SRC_DST,  DrawMode::AlphaBlend::SRC_0_SRC_DST,
+      DrawMode::AlphaBlend::ZERO_SRC_SRC_DST, DrawMode::AlphaBlend::SRC_DST_FIX_DST,
+      DrawMode::AlphaBlend::SRC_0_DST_DST,
   };
 
   for (int i = 0; i < ALPHA_MODE_COUNT; i++) {