1 files changed, 126 insertions, 0 deletions
diff --git a/advanced_lighting/5.parallax_mapping/shaders/parallax.frag b/advanced_lighting/5.parallax_mapping/shaders/parallax.frag
new file mode 100644
index 0000000..6813a30
--- /dev/null
+++ b/advanced_lighting/5.parallax_mapping/shaders/parallax.frag
@@ -0,0 +1,126 @@
+#version 330 core
+
+in VS_OUT {
+	vec3		frag_pos;
+	vec2		tex_coords;
+	vec3		tangent_light_pos;
+	vec3		tangent_view_pos;
+	vec3		tangent_frag_pos;
+} fs_in;
+
+out vec4		frag_color;
+
+uniform sampler2D	diffuse_texture;
+uniform sampler2D	normal_map;
+uniform sampler2D	depth_map;
+
+uniform float hscale;
+
+vec2 parallax_mapping(vec2 tex_coords, vec3 view_dir)
+{
+	float	h;
+	vec2	p, r;
+
+	h = texture(depth_map, tex_coords).r;
+	p = view_dir.xy/view_dir.z*h*hscale;
+	r = tex_coords-p;
+
+	return r;
+}
+
+vec2 step_parallax_mapping(vec2 tex_coords, vec3 view_dir)
+{
+	float	minsteps, maxsteps, nsteps, step, dstep, depth;
+	vec2	p, cur_tex_coords, dtex_coords;
+
+	minsteps = 8.0;
+	maxsteps = 32.0;
+	nsteps = mix(maxsteps, minsteps, max(dot(vec3(0.0, 0.0, 1.0), view_dir), 0.0));
+
+	dstep = 1.0/nsteps;
+	step = 0.0;
+
+	p = view_dir.xy*hscale;
+	dtex_coords = p/nsteps;
+
+	cur_tex_coords = tex_coords;
+	depth = texture(depth_map, cur_tex_coords).r;
+
+	while (step < depth) {
+		cur_tex_coords -= dtex_coords;
+		depth = texture(depth_map, cur_tex_coords).r;
+		step += dstep;
+	}
+
+	return cur_tex_coords;
+}
+
+vec2 parallax_occlusion_mapping(vec2 tex_coords, vec3 view_dir)
+{
+	float	minsteps, maxsteps, nsteps, step, dstep, depth,
+		after_depth, before_depth, weight;
+	vec2	p, cur_tex_coords, dtex_coords, prev_tex_coords, result;
+
+	minsteps = 8.0;
+	maxsteps = 32.0;
+	nsteps = mix(maxsteps, minsteps, max(dot(vec3(0.0, 0.0, 1.0), view_dir), 0.0));
+
+	dstep = 1.0/nsteps;
+	step = 0.0;
+
+	p = view_dir.xy*hscale;
+	dtex_coords = p/nsteps;
+
+	cur_tex_coords = tex_coords;
+	depth = texture(depth_map, cur_tex_coords).r;
+
+	while (step < depth) {
+		cur_tex_coords -= dtex_coords;
+		depth = texture(depth_map, cur_tex_coords).r;
+		step += dstep;
+	}
+
+	prev_tex_coords = cur_tex_coords+dtex_coords;
+
+	after_depth = depth-step;
+	before_depth = texture(depth_map, prev_tex_coords).r-step+dstep;
+
+	weight = after_depth/(after_depth-before_depth);
+	result = prev_tex_coords*weight+cur_tex_coords*(1.0-weight);
+	
+	return result;
+}
+
+void main(void)
+{
+	vec3	color, light_color,
+		normal, view_dir, halfway_dir, light_dir,
+		ambient, diffuse, specular, result;
+	vec2	tex_coords;
+	float	diff, spec;
+
+	view_dir = normalize(fs_in.tangent_view_pos-fs_in.tangent_frag_pos);
+	tex_coords = parallax_occlusion_mapping(fs_in.tex_coords, view_dir);
+	if ((tex_coords.x > 1.0) || (tex_coords.y > 1.0) || (tex_coords.x < 0.0) || (tex_coords.y < 0.0))
+		discard;
+
+	color = vec3(texture(diffuse_texture, tex_coords));
+	normal = vec3(texture(normal_map, tex_coords));
+	normal = normalize((normal*2.0)-1.0);
+
+	light_color = vec3(1.0);
+
+	ambient = vec3(0.01);
+
+	light_dir = normalize(fs_in.tangent_light_pos-fs_in.tangent_frag_pos);
+	diff = max(dot(light_dir, normal), 0.0);
+	diffuse = diff*light_color;
+
+	halfway_dir = normalize(light_dir+view_dir); 
+	spec = pow(max(dot(halfway_dir, normal), 0.0), 64.0);
+	specular = spec*light_color;
+
+	result = (ambient+diffuse+specular)*color;
+
+	frag_color = vec4(result, 1.0);
+}