terrain

commit 1ae6960c52fd10d39c232361c8e31cc4a31e626f
parent 908b28bb971310e20d375f941df806e1dcf63e19
Author: Christian Ermann <christianermann@gmail.com>
Date:   Mon, 16 Aug 2021 14:50:36 -0500

Flat-shaded perlin caves

Diffstat:
M
shaders/basic.fs
 | 
35
++++++++++++++++++++++++++++++++---
M
shaders/basic.vs
 | 
6
+++---
M
src/main.c
 | 
26
++++++++++++++++++++------

3 files changed, 55 insertions(+), 12 deletions(-)
diff --git a/shaders/basic.fs b/shaders/basic.fs
@@ -1,10 +1,39 @@
 #version 330 core
 
-in vec4 position;
+in vec3 frag_pos;
 
-out vec4 out_color;
+out vec4 frag_color;
+
+const vec3 light_color = vec3(1.0, 1.0, 1.0);
+
+uniform vec3 view_pos;
+uniform vec3 pointlight_pos;
 
 void main()
 {
-    out_color = vec4(1.0, 0.8, 0.6, 1.0);
+    vec3 dx = dFdx(frag_pos);
+    vec3 dy = dFdy(frag_pos);
+    vec3 normal = normalize(cross(dy, dx));
+
+    float slope = (normal.y + 1.0) * 0.5;
+    vec3 object_color = mix(vec3(1.0, 0.8, 0.6), vec3(0.7, 0.7, 0.7), slope);
+
+    float d = length(pointlight_pos - frag_pos);
+    float attenuation = 1.0 / (1.0 + 0.07 * d + 0.017 * d * d);
+
+    vec3 light_dir = normalize(frag_pos - pointlight_pos);
+    vec3 view_dir = normalize(view_pos - frag_pos);
+    vec3 reflect_dir = reflect(-light_dir, normal);
+
+    float ambient_strength = 0.1;
+    vec3 ambient = ambient_strength * light_color * attenuation;
+
+    float diffuse_strength = max(dot(normal, light_dir), 0.0);
+    vec3 diffuse = diffuse_strength * light_color * attenuation;
+
+    float specular_strength = 0.5;
+    float spec = pow(max(dot(view_dir, reflect_dir), 0.0), 32);
+    vec3 specular = specular_strength * spec * light_color * attenuation;
+    
+    frag_color = vec4((ambient + diffuse + specular) * object_color, 1.0);
 }
diff --git a/shaders/basic.vs b/shaders/basic.vs
@@ -2,12 +2,12 @@
 
 layout(location = 0) in vec3 in_position;
 
-out vec4 position;
+out vec3 frag_pos;
 
 uniform mat4 camera;
 
 void main()
 {
-    position = camera * vec4(in_position, 1.0);
-    gl_Position = position;
+    frag_pos = in_position;
+    gl_Position = camera * vec4(in_position, 1.0);
 }
diff --git a/src/main.c b/src/main.c
@@ -1,6 +1,7 @@
 #include "camera.h"
 #include "chunk_manager.h"
 #include "glh/shader.h"
+#include "perlin.h"
 
 #include "glad/glad.h"
 
@@ -27,6 +28,13 @@ void Camera_update(Camera* camera)
     Camera_updateMatrix(camera);
 }
 
+float perlinSDF(const Vec3 p)
+{
+    return perlin(p[0] * 0.01f, p[1] * 0.01f, p[2] * 0.01f)
+        + 0.5f * perlin(p[0] * 0.05f, p[1] * 0.05f, p[2] * 0.05f)
+        + 0.1f * perlin(p[0] * 0.1f, p[1] * 0.1f, p[2] * 0.1f);
+}
+
 float sphereSDF(const float p[3])
 {
     return sqrtf(p[0] * p[0] + p[1] * p[1] + p[2] * p[2]) - 25.0f;
@@ -70,18 +78,21 @@ int main(int argc, char** argv)
     glViewport(0, 0, WIDTH, HEIGHT);
 
     glEnable(GL_DEPTH_TEST);
+    glEnable(GL_CULL_FACE);
 
-    glClearColor(0.4f, 0.4f, 0.6f, 1.0f);
-
-    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
 
-    sphereSDF(camera.position);
-    ChunkManager chunk_manager = ChunkManager_create(camera.position, 1,
-            sphereSDF, 0.0f);
+    ChunkManager chunk_manager = ChunkManager_create(camera.position, 2,
+            perlinSDF, 0.0f);
 
     Shader shader = Shader_create("shaders/basic.vs", "shaders/basic.fs");
     glUseProgram(shader.program);
 
+    GLint view_pos_loc = glGetUniformLocation(shader.program, "view_pos");
+
+    GLint pointlight_pos_loc = glGetUniformLocation(shader.program,
+            "pointlight_pos");
+
     GLint cam_loc = glGetUniformLocation(shader.program, "camera");
 
     SDL_Event window_event;
@@ -112,6 +123,9 @@ int main(int argc, char** argv)
         Camera_update(&camera);
         glUniformMatrix4fv(cam_loc, 1, GL_FALSE, camera.matrix[0]);
 
+        glUniform3fv(view_pos_loc, 1, camera.position);
+        glUniform3fv(pointlight_pos_loc, 1, camera.position);
+
         ChunkManager_recenter(&chunk_manager, camera.position);
         ChunkManager_drawChunks(&chunk_manager);