9 files changed, 355 insertions, 0 deletions
diff --git a/pbr/lighting/build.sh b/pbr/lighting/build.sh
new file mode 100755
index 0000000..2cd71b7
--- /dev/null
+++ b/pbr/lighting/build.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+. ../../config
+TARGET='lighting'
+set -x
+gcc -o $TARGET $CFLAGS $INCLUDE $LFLAGS $TARGET.c $LIBS
diff --git a/pbr/lighting/default.frag b/pbr/lighting/default.frag
new file mode 100644
index 0000000..9351a1b
--- /dev/null
+++ b/pbr/lighting/default.frag
@@ -0,0 +1,15 @@
+#version 330 core
+
+in vert_t {
+	vec2 tex_coords;
+} vert;
+
+out vec4 frag_color;
+
+uniform sampler2D colorbuffer;
+
+void main(void)
+{
+	vec3 color = vec3(texture(colorbuffer, vert.tex_coords));
+	frag_color = vec4(color, 1.0);
+}
diff --git a/pbr/lighting/default.vert b/pbr/lighting/default.vert
new file mode 100644
index 0000000..1b953d7
--- /dev/null
+++ b/pbr/lighting/default.vert
@@ -0,0 +1,17 @@
+#version 330 core
+
+layout(location = 0) in vec3 position;
+layout(location = 2) in vec2 tex_coords;
+
+out vert_t {
+	vec2 tex_coords;
+} vert;
+
+uniform mat4 model;
+
+void main(void)
+{
+	gl_Position = model * vec4(position, 1.0);
+
+	vert.tex_coords = tex_coords;
+}
diff --git a/pbr/lighting/hdr.frag b/pbr/lighting/hdr.frag
new file mode 100644
index 0000000..01650ae
--- /dev/null
+++ b/pbr/lighting/hdr.frag
@@ -0,0 +1,18 @@
+#version 330 core
+
+in vert_t {
+	vec2 tex_coords;
+} vert;
+
+out vec4 frag_color;
+
+uniform sampler2D colorbuffer;
+
+void main(void)
+{
+	const float gamma = 2.2;
+	vec3 color = vec3(texture(colorbuffer, vert.tex_coords));
+	color /= color + vec3(1.0);
+	color = pow(color, vec3(1.0 / gamma));
+	frag_color = vec4(color, 1.0);
+}
diff --git a/pbr/lighting/hdr.vert b/pbr/lighting/hdr.vert
new file mode 100644
index 0000000..1b953d7
--- /dev/null
+++ b/pbr/lighting/hdr.vert
@@ -0,0 +1,17 @@
+#version 330 core
+
+layout(location = 0) in vec3 position;
+layout(location = 2) in vec2 tex_coords;
+
+out vert_t {
+	vec2 tex_coords;
+} vert;
+
+uniform mat4 model;
+
+void main(void)
+{
+	gl_Position = model * vec4(position, 1.0);
+
+	vert.tex_coords = tex_coords;
+}
diff --git a/pbr/lighting/lighting b/pbr/lighting/lighting
new file mode 100755
index 0000000..a68bd2b
--- /dev/null
+++ b/pbr/lighting/lighting
diff --git a/pbr/lighting/lighting.c b/pbr/lighting/lighting.c
new file mode 100644
index 0000000..d2a941d
--- /dev/null
+++ b/pbr/lighting/lighting.c
@@ -0,0 +1,157 @@
+#include "GL/glew.h"
+#include "GLFW/glfw3.h"
+#include "common.h"
+
+int main(void)
+{
+	state_t state = init_state(1600, 800);
+
+	init_glfw(&state);
+	init_gl();
+
+	/* meshes */
+	Mesh *sphere = mesh_load_obj(state.arena, "../../data/models/sphere.obj");
+	Mesh *quad = mesh_gen_quad(state.arena);
+
+	/* shaders */
+	add_shader("default.vert", "default.frag", 0);
+	add_shader("pbr.vert",     "pbr.frag",     0);
+	add_shader("hdr.vert",     "hdr.frag",     0);
+
+	light_t lights[4] = {
+		{{-6.0f,  0.0f,  7.0f}, {300.0f, 300.0f, 300.0f}},
+		{{-4.0f,  0.0f,  6.0f}, {300.0f, 300.0f, 300.0f}},
+		{{ 1.0f,  0.0f,  5.0f}, {300.0f, 300.0f, 300.0f}},
+		{{ 3.0f,  0.0f,  8.0f}, {300.0f, 300.0f, 300.0f}},
+	};
+
+	/* framebuffers */
+	U32 hdr_fbo, hdr_colorbuffer, hdr_rbo;
+	glGenFramebuffers(1, &hdr_fbo);
+	glGenTextures(1, &hdr_colorbuffer);
+	glBindTexture(GL_TEXTURE_2D, hdr_colorbuffer);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, state.width, state.height, 0, GL_RGBA, GL_FLOAT, 0);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glGenRenderbuffers(1, &hdr_rbo);
+	glBindRenderbuffer(GL_RENDERBUFFER, hdr_rbo);
+	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, state.width, state.height);
+	glBindFramebuffer(GL_FRAMEBUFFER, hdr_fbo);
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, hdr_colorbuffer, 0);
+	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, hdr_rbo);
+	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+		die("failed to create framebuffer");
+	glBindRenderbuffer(GL_RENDERBUFFER, 0);
+	glBindTexture(GL_TEXTURE_2D, 0);
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	
+	F32 time = 0;
+
+	S32 show_gamma = 0;
+
+	while (!glfwWindowShouldClose(state.window)) {
+		handle_glfw_events(state.window, &state.input);
+		F32 dt = lock_framerate(60);
+		fps_info(dt, 10);
+
+		/* update */
+		update_camera_first_person(&state.camera, &state.input, dt, 2.0f);
+		F32 limit = 4.0f;
+		for (U32 i = 0; i < (sizeof(lights) / sizeof(lights[0])); i++)
+			lights[i].position.y = sinf(time + i) * limit;
+		time += dt;
+
+		if (key_first_press(state.input.jump))
+			show_gamma = 1 - show_gamma;
+
+		/* render */
+		F32 ar = 0;
+		if (show_gamma) {
+			ar = (F32)state.width / 2.0f / (F32)state.height;
+		} else {
+			ar = (F32)state.width / (F32)state.height;
+		}
+		MAT4 projection = camera_persp(state.camera, ar);
+		MAT4 view = get_view_matrix(&state.camera);
+
+		glClearColor(0.16f, 0.16f, 0.16f, 1.0f);
+
+		glBindFramebuffer(GL_FRAMEBUFFER, hdr_fbo);
+		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+		U32 shader = find_shader("pbr");
+		if (!shader) die("wha");
+		glUseProgram(shader);
+		shader_set_mat4fv(shader, "projection", projection);
+		shader_set_mat4fv(shader, "view", view);
+		shader_set_3fv(shader, "camera", state.camera.pos);
+		shader_set_3fv(shader, "color", v3f(0.04, 0.04, 0.04));
+		shader_set_1f(shader, "ao", 1.0f);
+		for (U32 i = 0; i < (sizeof(lights) / sizeof(lights[0])); i++) {
+			char str[512];
+			snprintf(str, 512, "lights[%d].position", i);
+			shader_set_3fv(shader, str, lights[i].position);
+			snprintf(str, 512, "lights[%d].color", i);
+			shader_set_3fv(shader, str, lights[i].color);
+		}
+		S32 rows = 7;
+		S32 cols = 7;
+		F32 offset = 3.0f;
+		for (S32 row = 0; row < rows; row++) {
+			shader_set_1f(shader, "metallic", (F32)row / (F32)rows);
+			for (S32 col = 0; col < cols; col++) {
+				shader_set_1f(shader, "roughness", clamp(0.05f, (F32)col / (F32)cols, 1.0f));
+				V3F pos = {(col - cols / 2.0f) * offset, (row - rows / 2.0f) * offset, 0.0f};
+				MAT4 model = mat4_make_translate(pos);
+				shader_set_mat4fv(shader, "model", model);
+				mesh_draw(sphere);
+			}
+		}
+
+		for (U32 i = 0; i < (sizeof(lights) / sizeof(lights[0])); i++) {
+			MAT4 model = mat4_make_scale(v3f(0.5f, 0.5f, 0.5f));
+			model = mat4_translate(model, lights[i].position);
+			shader_set_mat4fv(shader, "model", model);
+			mesh_draw(sphere);
+		}
+
+		glUseProgram(0);
+
+		glBindFramebuffer(GL_FRAMEBUFFER, 0);
+		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+		if (show_gamma) {
+			shader = find_shader("default");
+			if (!shader) die("!");
+			glUseProgram(shader);
+			glBindTexture(GL_TEXTURE_2D, hdr_colorbuffer);
+			MAT4 model = mat4_make_scale(v3f(0.5f, 1.0f, 1.0f));
+			model = mat4_translate(model, v3f(-0.5f, 0.0f, 0.0f));
+			shader_set_mat4fv(shader, "model", model);
+			mesh_draw(quad);
+			glUseProgram(0);
+
+			shader = find_shader("hdr");
+			if (!shader) die("!");
+			glUseProgram(shader);
+			glBindTexture(GL_TEXTURE_2D, hdr_colorbuffer);
+			model = mat4_make_scale(v3f(0.5f, 1.0f, 1.0f));
+			model = mat4_translate(model, v3f(0.5f, 0.0f, 0.0f));
+			shader_set_mat4fv(shader, "model", model);
+			mesh_draw(quad);
+			glUseProgram(0);
+		} else {
+			shader = find_shader("hdr");
+			if (!shader) die("!");
+			glUseProgram(shader);
+			glBindTexture(GL_TEXTURE_2D, hdr_colorbuffer);
+			shader_set_mat4fv(shader, "model", mat4_identity());
+			mesh_draw(quad);
+			glUseProgram(0);
+		}
+
+		glfwSwapBuffers(state.window);
+	}
+
+	return 0;
+}
diff --git a/pbr/lighting/pbr.frag b/pbr/lighting/pbr.frag
new file mode 100644
index 0000000..db9edea
--- /dev/null
+++ b/pbr/lighting/pbr.frag
@@ -0,0 +1,105 @@
+#version 330 core
+
+in vert_t {
+	vec3 position;
+	vec3 normal;
+} vert;
+
+out vec4 frag_color;
+
+uniform vec3 camera;
+
+uniform vec3 color;
+uniform float metallic;
+uniform float roughness;
+uniform float ao;
+
+struct light_t {
+	vec3 position;
+	vec3 color;
+};
+
+const int light_count = 4;
+uniform light_t lights[light_count];
+
+const float PI = 3.14159265358; 
+
+vec3 fresnel_shlick(float costheta, vec3 f0)
+{
+	return f0 + (1.0 - f0) * pow(1.0 - costheta, 5.0);
+}
+
+float distribution_ggx(vec3 n, vec3 h, float roughness)
+{
+	float a = roughness * roughness;
+	float a2 = a * a;
+	float ndoth = max(dot(n, h), 0.0);
+	float ndoth2 = ndoth * ndoth;
+
+	float num = a2;
+	float denom = (ndoth2 * (a2 - 1.0) + 1.0);
+	denom = PI * denom * denom;
+
+	return num / denom;
+}
+
+float geometry_shlick_ggx(float ndotv, float roughness)
+{
+	float r = roughness + 1.0;
+	float k = r * r / 8.0;
+
+	float num = ndotv;
+	float denom = ndotv * (1.0 - k) + k;
+	
+	return num / denom;
+}
+
+float geometry_smith(vec3 n, vec3 v, vec3 l, float roughness)
+{
+	float ndotv = max(dot(n, v), 0.0);
+	float ndotl = max(dot(n, l), 0.0);
+	float ggx2 = geometry_shlick_ggx(ndotv, roughness);
+	float ggx1 = geometry_shlick_ggx(ndotl, roughness);
+
+	return ggx1 * ggx2;
+}
+
+void main(void)
+{
+	vec3 n = vert.normal;
+	vec3 v = normalize(camera - vert.position);
+
+	vec3 lo = vec3(0.0);
+	for (int i = 0; i < light_count; i++) {
+		vec3 l = normalize(lights[i].position - vert.position);
+		vec3 h = normalize(v + l);
+		float ndotv = max(dot(n, v), 0.0);
+		float ndotl = max(dot(n, l), 0.0);
+
+		float distance = length(lights[i].position - vert.position);
+		float attenuation = 1.0 / (distance * distance);
+
+		vec3 radiance = lights[i].color * attenuation;
+
+		vec3 f0 = vec3(0.04);
+		f0 = mix(f0, color, metallic);
+		vec3 f = fresnel_shlick(max(dot(h, v), 0.0), f0);
+
+		float ndf = distribution_ggx(n, h, roughness);
+		float g = geometry_smith(n, v, l, roughness);
+
+		vec3 numerator = ndf * g * f;
+		float denominator = 4.0 * ndotv * ndotl;
+		vec3 specular = numerator / max(denominator, 0.001);
+
+		vec3 ks = f;
+		vec3 kd = vec3(1.0) - ks;
+
+		kd *= 1.0 - metallic;
+
+		lo += (kd * color / PI + specular) * radiance * ndotl;
+	}
+	
+	vec3 ambient = vec3(0.03) * color * ao;
+	frag_color = vec4(ambient + lo, 1.0);
+}
diff --git a/pbr/lighting/pbr.vert b/pbr/lighting/pbr.vert
new file mode 100644
index 0000000..e6e3800
--- /dev/null
+++ b/pbr/lighting/pbr.vert
@@ -0,0 +1,21 @@
+#version 330 core
+
+layout(location = 0) in vec3 position;
+layout(location = 1) in vec3 normal;
+
+out vert_t {
+	vec3 position;
+	vec3 normal;
+} vert;
+
+uniform mat4 projection;
+uniform mat4 view;
+uniform mat4 model;
+
+void main(void)
+{
+	gl_Position = projection * view * model * vec4(position, 1.0);
+
+	vert.position = vec3(model * vec4(position, 1.0));
+	vert.normal = normalize(mat3(transpose(inverse(model))) * normal);
+}