From bb7fb685316c973e5cf1c1763299d4eef0e1ec4e Mon Sep 17 00:00:00 2001
From: aap <aap@papnet.eu>
Date: Sat, 20 Feb 2021 00:02:51 +0100
Subject: [PATCH] opengl default pipe: dont do unnecessary alpha test

---
 src/gl/gl3device.cpp         | 14 +++++++++++++-
 src/gl/gl3render.cpp         |  7 +++++--
 src/gl/rwgl3.h               |  2 +-
 src/gl/shaders/header.frag   |  2 ++
 src/gl/shaders/header_fs.inc |  2 ++
 5 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/gl/gl3device.cpp b/src/gl/gl3device.cpp
index 1e511bbd..6d1f95aa 100644
--- a/src/gl/gl3device.cpp
+++ b/src/gl/gl3device.cpp
@@ -136,7 +136,7 @@ int32 u_lightColor;
 int32 u_matColor;
 int32 u_surfProps;
 
-Shader *defaultShader;
+Shader *defaultShader, *defaultShader_noAT;
 
 static bool32 stateDirty = 1;
 static bool32 sceneDirty = 1;
@@ -1829,6 +1829,9 @@ initOpenGL(void)
 	const char *fs[] = { shaderDecl, header_frag_src, simple_frag_src, nil };
 	defaultShader = Shader::create(vs, fs);
 	assert(defaultShader);
+	const char *fs_noAT[] = { shaderDecl, "#define NO_ALPHATEST\n", header_frag_src, simple_frag_src, nil };
+	defaultShader_noAT = Shader::create(vs, fs_noAT);
+	assert(defaultShader_noAT);
 
 	openIm2D();
 	openIm3D();
@@ -1841,6 +1844,15 @@ termOpenGL(void)
 {
 	closeIm3D();
 	closeIm2D();
+
+	defaultShader->destroy();
+	defaultShader = nil;
+	defaultShader_noAT->destroy();
+	defaultShader_noAT = nil;
+
+	glDeleteTextures(1, &whitetex);
+	whitetex = nil;
+
 	return 1;
 }
 
diff --git a/src/gl/gl3render.cpp b/src/gl/gl3render.cpp
index fadbb45a..011475b8 100644
--- a/src/gl/gl3render.cpp
+++ b/src/gl/gl3render.cpp
@@ -149,8 +149,6 @@ defaultRenderCB(Atomic *atomic, InstanceDataHeader *header)
 	InstanceData *inst = header->inst;
 	int32 n = header->numMeshes;
 
-	defaultShader->use();
-
 	while(n--){
 		m = inst->material;
 
@@ -160,6 +158,11 @@ defaultRenderCB(Atomic *atomic, InstanceDataHeader *header)
 
 		rw::SetRenderState(VERTEXALPHA, inst->vertexAlpha || m->color.alpha != 0xFF);
 
+		if(getAlphaTest())
+			defaultShader->use();
+		else
+			defaultShader_noAT->use();
+
 		drawInst(header, inst);
 		inst++;
 	}
diff --git a/src/gl/rwgl3.h b/src/gl/rwgl3.h
index 4d323302..f6e5b3bd 100644
--- a/src/gl/rwgl3.h
+++ b/src/gl/rwgl3.h
@@ -97,7 +97,7 @@ struct InstanceDataHeader : rw::InstanceDataHeader
 
 struct Shader;
 
-extern Shader *defaultShader;
+extern Shader *defaultShader, *defaultShader_noAT;
 
 struct Im3DVertex
 {
diff --git a/src/gl/shaders/header.frag b/src/gl/shaders/header.frag
index da58bba7..ba50165a 100644
--- a/src/gl/shaders/header.frag
+++ b/src/gl/shaders/header.frag
@@ -23,6 +23,8 @@ out vec4 fragColor;
 
 void DoAlphaTest(float a)
 {
+#ifndef NO_ALPHATEST
 	if(a < u_alphaRef.x || a >= u_alphaRef.y)
 		discard;
+#endif
 }
diff --git a/src/gl/shaders/header_fs.inc b/src/gl/shaders/header_fs.inc
index b0284985..802bb4f7 100644
--- a/src/gl/shaders/header_fs.inc
+++ b/src/gl/shaders/header_fs.inc
@@ -24,7 +24,9 @@ const char *header_frag_src =
 
 "void DoAlphaTest(float a)\n"
 "{\n"
+"#ifndef NO_ALPHATEST\n"
 "	if(a < u_alphaRef.x || a >= u_alphaRef.y)\n"
 "		discard;\n"
+"#endif\n"
 "}\n"
 ;