From a5262a9504d0ad264d93e1761f5a4123e524cc87 Mon Sep 17 00:00:00 2001
From: Tomasz Kramkowski <tk@the-tk.com>
Date: Fri, 19 Oct 2018 23:42:59 +0300
Subject: Implement specular mapping

---
 faqe.c                 |  3 ++-
 mtl.c                  | 33 +++++++++++++++++++++++----------
 shaders/data.h         |  3 ++-
 shaders/main/frag.glsl | 11 ++++++-----
 4 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/faqe.c b/faqe.c
index afb8bb4..975fffb 100644
--- a/faqe.c
+++ b/faqe.c
@@ -87,7 +87,8 @@ int main(int argc, char **argv)
 
 	gl_prog_use(prog.main.prog);
 	viewport(prog.main.uni.proj, WIDTH, HEIGHT);
-	gl_uni_set1i(prog.main.tex.tex, 0);
+	gl_uni_set1i(prog.main.tex.tdiff, 0);
+	gl_uni_set1i(prog.main.tex.tspec, 1);
 
 	gl_enable(GL_DEPTH_TEST);
 	gl_enable(GL_FRAMEBUFFER_SRGB);
diff --git a/mtl.c b/mtl.c
index 3b46ce7..dc74e01 100644
--- a/mtl.c
+++ b/mtl.c
@@ -13,19 +13,34 @@
 
 struct mtl {
 	char name[50];
-	GLuint diffuse;
+	GLuint diff;
+	GLuint spec;
 };
 
 static struct mtl *mtls;
 static int lmtls;
 static size_t nmtls;
 
-int mtl_load(char *name)
+GLuint tex_file(const char *name, const char *type)
 {
-	struct mtl *m;
 	char loc[100];
+	GLuint ret;
 	FILE *f;
 
+	snprintf(loc, sizeof loc, "assets/%s.%s.png", name, type);
+	f = fopen(loc, "rb");
+	if (f == NULL)
+		eprintf("Could not open '%s':", loc);
+	ret = png2tex(f);
+	fclose(f);
+
+	return ret;
+}
+
+int mtl_load(char *name)
+{
+	struct mtl *m;
+
 	for (int i = 0; i < lmtls; i++)
 		if (strcmp(mtls[i].name, name) == 0)
 			return i;
@@ -35,12 +50,8 @@ int mtl_load(char *name)
 
 	snprintf(m->name, sizeof m->name, "%s", name);
 
-	snprintf(loc, sizeof loc, "assets/%s.diff.png", name);
-	f = fopen(loc, "rb");
-	if (f == NULL)
-		eprintf("Could not open '%s':", loc);
-	m->diffuse = png2tex(f);
-	fclose(f);
+	m->diff = tex_file(name, "diff");
+	m->spec = tex_file(name, "spec");
 
 	return lmtls++;
 }
@@ -54,5 +65,7 @@ void mtl_use(int mtl)
 		return;
 
 	gl_tex_active(GL_TEXTURE0);
-	gl_tex_bind(GL_TEXTURE_2D, mtls[mtl].diffuse);
+	gl_tex_bind(GL_TEXTURE_2D, mtls[mtl].diff);
+	gl_tex_active(GL_TEXTURE1);
+	gl_tex_bind(GL_TEXTURE_2D, mtls[mtl].spec);
 }
diff --git a/shaders/data.h b/shaders/data.h
index e1a71c3..0225212 100644
--- a/shaders/data.h
+++ b/shaders/data.h
@@ -24,7 +24,8 @@
 #undef SH_UNI
 #endif // SH_UNI
 #ifdef SH_TEX
-	SH_TEX(2D, tex)
+	SH_TEX(2D, tdiff)
+	SH_TEX(2D, tspec)
 #undef SH_TEX
 #endif // SH_TEX
 #ifdef SH_OUT
diff --git a/shaders/main/frag.glsl b/shaders/main/frag.glsl
index 6d7a53e..8aa9a6a 100644
--- a/shaders/main/frag.glsl
+++ b/shaders/main/frag.glsl
@@ -9,20 +9,21 @@ in vec3 lipos;
 
 void main()
 {
-	vec3 objco = vec3(texture(tex, fuv));
+	vec3 fdiff = vec3(texture(tdiff, fuv));
+	vec3 fspec = vec3(texture(tspec, fuv));
 	vec3 lico = vec3(1.0, 1.0, 1.0);
 
 	vec3 amb = vec3(0.1, 0.1, 0.1);
 
 	vec3 norm = normalize(fnorm);
 	vec3 lidir = normalize(lipos - fpos);
-	vec3 dif = max(dot(norm, lidir), 0.0) * objco;
+	vec3 diff = max(dot(norm, lidir), 0.0) * fdiff;
 
-	float speen = max(sign(dot(lidir, norm)), 0.0);
+	float specen = max(sign(dot(lidir, norm)), 0.0);
 	vec3 vwdir = normalize(-fpos);
 	vec3 mid = normalize(lidir + vwdir);
 
-	float spe = pow(max(dot(norm, mid), 0.0), 256) * speen;
+	vec3 spec = pow(max(dot(norm, mid), 0.0), 256) * specen * fspec;
 
-	color = vec4((amb + dif + spe) * lico, 1.0);
+	color = vec4((amb + diff + spec) * lico, 1.0);
 }
-- 
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