Coordinates system should now be simplified and easier to manipulate

src/app/raymarching/value-noise-field/fragment.glsl

@@ -56,12 +56,12 @@ float field_height(vec2 uv) {
 vec3 raymarch_scene(vec3 ray_origin, vec3 ray_direction) {
     float raymarch_dist = 0.0;
     vec3 color = vec3(0.0, 0.0, 0.0);
-    float previous_y = 0.0;
+    float previous_z = 0.0;
     float previous_dist = 0.0;
     for (int i=0; i<u_raymarch_max_steps; i++ ) {
         vec3 scan_pos = ray_origin + raymarch_dist * ray_direction;
-        float field_y = field_height(scan_pos.xz);
-        if (scan_pos.y <= field_y) {
+        float field_z = field_height(scan_pos.xy);
+        if (scan_pos.z <= field_z) {
             return vec3(1.0 - float(i) / float(u_raymarch_max_steps));
         }
         if (u_with_gizmos) {
@@ -80,7 +80,7 @@ vec3 raymarch_scene(vec3 ray_origin, vec3 ray_direction) {
                 color =  max(color, vec3(0.0, 1.0, 1.0));
             }
         }
-        previous_y = field_y;
+        previous_z = field_z;
         previous_dist = raymarch_dist;
         if (u_with_linear_steps) {
             raymarch_dist += u_raymarch_delta * float(i) ; // Trick from https://iquilezles.org/articles/terrainmarching/
@@ -96,16 +96,16 @@ vec3 raymarch_scene(vec3 ray_origin, vec3 ray_direction) {
 void main() {
     vec2 size = gl_FragCoord.xy / v_uv;
     float ratio = size.x / size.y;
-    vec2 canvas_local_pos = (v_uv -0.5) * 2.0; // center coordinates
-    canvas_local_pos *= vec2(ratio, 1.0); // fix width
+    vec2 canvas_local_pos = (v_uv -0.5) * 2.0; // center coordinates, y and x in [-1, 1]
+    canvas_local_pos *= vec2(ratio, 1.0); // fix width, x in [-ratio, ratio] to adapt screen
 
     // Prepare camera rotation matrices
     float yc = cos(radians(u_yaw));
     float ys = sin(radians(u_yaw));
     mat3 yam_rotation = mat3(
-        yc, 0.0, -ys,
-        0.0, 1.0, 0.0,
-        ys, 0.0, yc
+        yc, ys, 0.0,
+        -ys, yc, 0.0,
+        0.0, 0.0, 1.0
     );
     float pc = cos(radians(u_pitch));
     float ps = sin(radians(u_pitch));
@@ -114,22 +114,16 @@ void main() {
         0.0, pc, ps,
         0.0, -ps, pc
     );
+    mat3 camera_transform = yam_rotation * pitch_rotation;
 
     // Camera parameters
     float canvas_distance = u_focal_length;
     vec3 camera_eye = vec3(u_shift_x, u_shift_y, u_shift_z);
-    vec3 camera_target = camera_eye +  pitch_rotation * yam_rotation * vec3(0.0, 0.0, -canvas_distance);
-
-
-    // Transform canvas coordinates
-    vec3 camera_axis_z = normalize(camera_target - camera_eye);
-    vec3 camera_axis_x = normalize(cross(camera_axis_z, vec3(0.0, 1.0, 0.0)));
-    vec3 camera_axis_y = normalize(cross(camera_axis_x, camera_axis_z));
-    mat3x3 camera_transform = mat3x3(camera_axis_x, camera_axis_y, camera_axis_z);
+    vec3 camera_direction = camera_transform * vec3(0.0, 1.0, 0.0);
 
     // Prepare rays
     vec3 ray_origin = camera_eye;
-    vec3 ray_dir = normalize(camera_transform * vec3(canvas_local_pos, canvas_distance));
+    vec3 ray_dir = normalize(camera_transform * vec3(canvas_local_pos.x, canvas_distance, canvas_local_pos.y));
 
     // Cast rays
     vec3 color = raymarch_scene(ray_origin, ray_dir);

src/app/raymarching/value-noise-field/page.tsx

@@ -16,13 +16,13 @@ function ValueNoiseRaymarchControl({controlUiTunnel}: FragmentLogic) {
     const [gain, setGain] = useUniform("u_gain", 0.5);
 
     const [raymarchMaxSteps, setRaymarchMaxSteps] = useUniform("u_raymarch_max_steps", 50);
-    const [raymarchDelta, setRaymarchDelta] = useUniform("u_raymarch_delta", 0.001);
+    const [raymarchDelta, setRaymarchDelta] = useUniform("u_raymarch_delta", 0.01);
     const [withLinearSteps, setWithLinearSteps] = useUniform("u_with_linear_steps", true);
 
     const [focalLength, setFocalLength] = useUniform("u_focal_length", 1.0);
     const [shiftX, setShiftX] = useUniform("u_shift_x", 0.0);
-    const [shiftY, setShiftY] = useUniform("u_shift_y", 1.5);
-    const [shiftZ, setShiftZ] = useUniform("u_shift_z", -2.0);
+    const [shiftY, setShiftY] = useUniform("u_shift_y", 0.0);
+    const [shiftZ, setShiftZ] = useUniform("u_shift_z", 2.0);
 
     const [pitch, setPitch] = useUniform("u_pitch", 0.0);
     const [yaw, setYaw] = useUniform("u_yaw", 0.0);