Perform a depth only clear right before rendering the gun.

port/fast3d/gfx_opengl.cpp

@@ -1065,12 +1065,23 @@ bool gfx_opengl_start_draw_to_framebuffer(int fb_id, float noise_scale) {
     }
 }
 
-void gfx_opengl_clear_framebuffer() {
+void gfx_opengl_clear_framebuffer(bool clear_color, bool clear_depth) {
     glDisable(GL_SCISSOR_TEST);
-    glDepthMask(GL_TRUE);
-    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
-    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-    glDepthMask(current_depth_mask ? GL_TRUE : GL_FALSE);
+    
+    GLbitfield mask = 0;
+    if (clear_color) {
+        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+        mask |= GL_COLOR_BUFFER_BIT;
+    }
+    if (clear_depth) {
+        glDepthMask(GL_TRUE);
+        mask |= GL_DEPTH_BUFFER_BIT;
+    }
+    glClear(mask);
+    if (clear_depth) {
+        glDepthMask(current_depth_mask ? GL_TRUE : GL_FALSE);
+    }
+
     glEnable(GL_SCISSOR_TEST);
 }
 

port/fast3d/gfx_pc.cpp

@@ -2502,6 +2502,10 @@ static void gfx_run_dl(Gfx* cmd) {
             case G_RDPFLUSH_EXT:
                 gfx_flush();
                 break;
+            case G_CLEAR_DEPTH_EXT:
+                gfx_flush();
+                gfx_rapi->clear_framebuffer(false, true);
+                break;
             case G_RDPPIPESYNC:
             case G_RDPFULLSYNC:
             case G_RDPLOADSYNC:
@@ -2659,7 +2663,7 @@ extern "C" void gfx_run(Gfx* commands) {
     gfx_rapi->start_frame();
     gfx_rapi->start_draw_to_framebuffer(game_renders_to_framebuffer ? game_framebuffer : 0,
                                         (float)gfx_current_dimensions.height / SCREEN_HEIGHT);
-    gfx_rapi->clear_framebuffer();
+    gfx_rapi->clear_framebuffer(true, false);
     rdp.viewport_or_scissor_changed = true;
     rendering_state.viewport = {};
     rendering_state.scissor = {};
@@ -2669,7 +2673,7 @@ extern "C" void gfx_run(Gfx* commands) {
 
     if (game_renders_to_framebuffer) {
         gfx_rapi->start_draw_to_framebuffer(0, 1);
-        gfx_rapi->clear_framebuffer();
+        gfx_rapi->clear_framebuffer(true, true);
 
         if (gfx_msaa_level > 1) {
             bool different_size = gfx_current_dimensions.width != gfx_current_game_window_viewport.width ||
@@ -2732,7 +2736,7 @@ extern "C" void gfx_resize_framebuffer(int fb, uint32_t width, uint32_t height,
 
 extern "C" void gfx_set_framebuffer(int fb, float noise_scale) {
     gfx_rapi->start_draw_to_framebuffer(fb, noise_scale);
-    gfx_rapi->clear_framebuffer();
+    gfx_rapi->clear_framebuffer(true, true);
 }
 
 extern "C" void gfx_copy_framebuffer(int fb_dst, int fb_src, int left, int top, int use_back) {

port/fast3d/gfx_rendering_api.h

@@ -44,7 +44,7 @@ struct GfxRenderingAPI {
                                           bool can_extract_depth);
     bool (*start_draw_to_framebuffer)(int fb_id, float noise_scale);
     void (*copy_framebuffer)(int fb_dst, int fb_src, int left, int top, bool flip_y, bool use_back);
-    void (*clear_framebuffer)(void);
+    void (*clear_framebuffer)(bool clear_color, bool clear_depth);
     void (*resolve_msaa_color_buffer)(int fb_id_target, int fb_id_source);
     void* (*get_framebuffer_texture_id)(int fb_id);
     void (*select_texture_fb)(int fb_id);

src/game/zbuf.c

@@ -126,7 +126,6 @@ Gfx *zbufConfigureRdp(Gfx *gdl)
 Gfx *zbufClear(Gfx *gdl)
 {
 #ifdef PLATFORM_N64
-	// no reason to do a Z clear on PC, we already do it at frame start
 	s32 left;
 	s32 right;
 
@@ -150,6 +149,8 @@ Gfx *zbufClear(Gfx *gdl)
 
 	gDPFillRectangle(gdl++, left, 0, right, playerGetFbHeight() - 1);
 	gDPPipeSync(gdl++);
+#else
+	gDPClearDepthEXT(gdl++);
 #endif
 
 	return gdl;

src/include/gbiex.h

@@ -195,6 +195,7 @@
 #define G_COPYFB_EXT            0x41
 #define G_IMAGERECT_EXT         0x42
 #define G_RDPFLUSH_EXT          0x43
+#define G_CLEAR_DEPTH_EXT       0x44
 
 /* G_EXTRAGEOMETRYMODE flags */
 
@@ -300,6 +301,8 @@
 
 #define gDPFlushEXT(pkt) gDPNoParam(pkt, G_RDPFLUSH_EXT)
 
+#define gDPClearDepthEXT(pkt) gDPNoParam(pkt, G_CLEAR_DEPTH_EXT)
+
 #undef gDPFillRectangleScaled
 #define gDPFillRectangleScaled(pkt, x1, y1, x2, y2) gDPFillRectangleEXT(pkt, (x1) * g_ScaleX, y1, (x2) * g_ScaleX, y2)