Implement basic fixed point light source and phong shading

This patch places a single point light source in the scene and
implements view-space phong shading around it. This is in preparation
for texture values being fed in from a set of textures.

1 files changed, 19 insertions, 2 deletions

diff --git a/frag.glsl b/frag.glsl
index c48ee57..41d98ad 100644
--- a/frag.glsl
+++ b/frag.glsl
@@ -2,9 +2,26 @@
 // SPDX-License-Identifier: MIT
 #version 330 core
 out vec4 color;
-in vec3 vcolor;
+in vec3 vnorm;
+in vec3 fpos;
+in vec3 lipos;
 
 void main()
 {
-	color = vec4(vcolor, 1.0);
+	vec3 objco = { 1.0, 0.5, 0.31 };
+	vec3 lico = { 1.0, 1.0, 1.0 };
+
+	float amb = 0.1;
+
+	vec3 norm = normalize(vnorm);
+	vec3 lidir = normalize(lipos - fpos);
+	float dif = max(dot(norm, lidir), 0.0);
+
+	float spestr = 0.5;
+	vec3 vwdir = normalize(-fpos);
+	vec3 redir = reflect(-lidir, norm);
+
+	float spe = spestr * pow(max(dot(vwdir, redir), 0.0), 32);
+
+	color = vec4((amb + dif + spe) * lico * objco, 1.0);
 }