shadertoy: wip

src/shadertoy.c

@@ -143,7 +143,7 @@ int main()
   glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
   //glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, GLFW_TRUE);
 
-  GLFWwindow* window = glfwCreateWindow(1600, 1200, "LearnOpenGL", NULL, NULL);
+  GLFWwindow* window = glfwCreateWindow(720, 480, "LearnOpenGL", NULL, NULL);
   if (window == NULL) {
     const char* description;
     glfwGetError(&description);
@@ -153,7 +153,7 @@ int main()
   }
   glfwMakeContextCurrent(window);
 
-  glViewport(0, 0, 1600, 1200);
+  glViewport(0, 0, 720, 480);
   //glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 
   unsigned int vertex_buffer = make_buffer(GL_ARRAY_BUFFER,

src/shadertoy.fp.glsl

@@ -1,54 +1,73 @@
 #version 120
 
-varying vec2 pos_out;
+varying vec2 uv0;
 
 uniform float time;
 
-/*
+vec3 palette(float d) {
-vec3 palette(float t) {
+  vec3 v = d + vec3(0.25, 0.40625, 0.5625); // 40 45 49
-  vec3 a = vec3(0.5, 0.5, 0.5);
+  v = v * 6.28318548202514648438;
-  vec3 b = vec3(0.5, 0.5, 0.5);
+  v = cos(v);
-  vec3 c = vec3(1.0, 1.0, 1.0);
+  return vec3(0.5, 0.5, 0.5) * v + vec3(0.5, 0.5, 0.5); // 48
-  vec3 d = vec3(0.263, 0.416, 0.557);
+}
-
+
-  return a + b * cos(6.28318548202514648438 * (c * t + d));
+float length2(vec2 v)
+{
+  float n = dot(v, v);
+  n = 1.0 / sqrt(n);
+  return 1.0 / n;
+}
+
+float pow_(float x, float n)
+{
+  x = log2(x);
+  x = x * n;
+  return exp2(x);
+}
+
+float sin_(float x)
+{
+  x = x * 0.159154936671257019043 + 0.5; // 48
+  x = fract(x); // nop
+  x = sin((x - 0.5) * 6.28318548202514648438); // presubtract (omod)
+  return x;
 }
-*/
 
 void main()
 {
-  vec2 uv = pos_out;
+  vec2 uv = uv0; // temp[1]
-  //gl_FragColor = vec4(uv, 0, 1);
-  //gl_FragColor = gl_Color;
-  float d = length(uv);
 
-  //d -= 0.5;
+  vec4 final_color = vec4(0, 0, 0, 1);
-  //d = abs(d);
-  //d = step(0.1, d);
-  //d = smoothstep(0.0, 0.1, d);
 
-  gl_FragColor = vec4(d, 0, 0, 1);
+  vec3 col2;
 
-  /*
+  for (float i = 0.0; i < 1.0; i++) {
-  vec3 col = vec3(1.0, 2.0, 3.0);
+    uv = uv * 1.5;            // 60
+    uv = fract(uv);
+    uv = uv - 0.5;            // 48
 
-  d = sin(d * 8.0 + time)/8.0;
+    float l = length2(uv0);
-  d = abs(d);
-  d = 0.02 / d;
 
-  col *= d;
+    float d = i * 0.4 + l;    // const[0].a
+    d = time * 0.4 + d;       // const[0].a
 
-  gl_FragColor = vec4(col, 1);
+    vec3 col = palette(d);
-  */
+    col2 = col;
-  /*
+    break;
-  vec3 col = palette(d + time);
 
-  d = sin(d * 8.0 + time)/8.0;
+    d = exp(-l);
-  d = abs(d);
-  d = 0.02 / d;
 
-  col *= d;
+    l = length2(uv);
+    d = l * d;
+    d = d * 8.0 + time;       // 80
+    d = 0.125 * sin_(d);      // omod
+    d = 1.0 / abs(d);
+    d = 0.01 * d;             // const[0].b
+    d = pow_(d, 1.2);         // const[0].g
 
-  gl_FragColor = vec4(col, 1);
+    final_color.xyz = col * d + final_color.xyz;
-  */
+  }
+
+  //gl_FragColor = final_color;
+  gl_FragColor = vec4(col2, 1);
 }

src/shadertoy.vp.glsl

@@ -2,11 +2,10 @@
 
 attribute vec3 position;
 
-varying vec2 pos_out;
+varying vec2 uv0;
 
 void main()
 {
   gl_Position = vec4(position, 1);
-  pos_out = vec2(position.x * 4.0 / 3.0, pos_out.y);
+  uv0 = vec2(position.x * 720.0 / 480.0, position.y);
-  //gl_FrontColor = vec4(position.xy, 0, 1);
 }