Clean up ColorRamp

src/textures/color_ramp.cpp

@@ -46,16 +46,20 @@ ColorRamp texture (:monosp:`color_ramp`)
      - ``nearest``: disable filtering and interpolation. In this mode, the plugin
        performs nearest neighbor lookups of texture values.
 
- * - wrap_mode
-   - |string|
-   - Controls the behavior of texture evaluations that fall outside of the
-     :math:`[0, 1]` range. The following options are currently available:
-
-     - ``repeat`` (default): tile the texture infinitely.
+ * - num_band
+   - |integer|
+   - Specifies the number of color bands used in ColorRamp
 
-     - ``mirror``: mirror the texture along its boundaries.
+* - posx
+   - |float|
+   - Specifies the position of color bands used in ColorRamp
+   - x starts from 0 to num_band - 1
+   - Used for interpolation factor
 
-     - ``clamp``: clamp coordinates to the edge of the texture.
+* - colorx
+   - |Color3f|
+   - Specifies the 3 channels of color bands used in ColorRamp
+   - Used for interpolation color results
 
  * - raw
    - |bool|
@@ -99,18 +103,33 @@ at all.
 
 .. tabs::
     .. code-tab:: xml
-        :name: bitmap-texture
+        :name: color-ramp
 
-        <texture type="bitmap">
+        <texture type="color_ramp">
             <string name="filename" value="texture.png"/>
-            <string name="wrap_mode" value="mirror"/>
+            <string name="mode" value="linear"/>
+            <float name="pos0" value="0.040000"/>
+            <rgb value="0.602237 0.482636 0.000000" name="color0"/>
+            <float name="pos1" value="0.084091"/>
+            <rgb value="0.019626 0.077920 0.174928" name="color1"/>
         </texture>
 
     .. code-tab:: python
 
-        'type': 'bitmap',
+        'type': 'color_ramp',
         'filename': 'texture.png',
-        'wrap_mode': 'mirror'
+        "mode": "linear",
+        "num_band": 2,
+        "pos0": 0.0,
+        "pos1": 1.0,
+        "color0": {
+            'type': 'rgb',
+            'value': [0.0, 0.0, 0.0]
+        },
+        "color1": {
+            'type': 'rgb',
+            'value': [1.0, 1.0, 1.0]
+        },
 
 */
 
@@ -329,7 +348,6 @@ class ColorRamp final : public Texture<Float, Spectrum> {
 
     }
 
-    // m_base_color in principled
     UnpolarizedSpectrum eval(const SurfaceInteraction3f &si,
                              Mask active) const override {
         MI_MASKED_FUNCTION(ProfilerPhase::TextureEvaluate, active);
@@ -368,8 +386,6 @@ class ColorRamp final : public Texture<Float, Spectrum> {
         }
     }
 
-    // m_roughness, m_anisotropic, m_sheen, m_sheen_tint, m_spec_trans, m_flatness,
-    // m_spec_tint, m_clearcoat, m_clearcoat, m_metallic in principled
     Float eval_1(const SurfaceInteraction3f &si,
                  Mask active = true) const override {
 
@@ -672,7 +688,7 @@ class ColorRamp final : public Texture<Float, Spectrum> {
                 m_name);
     }
 
-    /// Construct 2D distribution upon first access, avoid races
+    // Construct 2D distribution upon first access, avoid races
     MI_INLINE void init_distr() const {
         std::lock_guard<std::mutex> lock(m_mutex);
         if (!m_distr2d) {
@@ -681,7 +697,7 @@ class ColorRamp final : public Texture<Float, Spectrum> {
         }
     }
 
-    // Calculate the weight of cardinal and B-splines interpolation
+    // Calculate the weight of cardinal and B-spline interpolation
     // Borrow from Blender
     MI_INLINE void key_curve_position_weights(Float t, Float *data, std::string type) const {
         if(type == "cardinal") {
@@ -1356,7 +1372,6 @@ class ColorRamp final : public Texture<Float, Spectrum> {
     ref<Bitmap> m_bitmap;
     std::string m_name;
 
-
     // Single factor
     ScalarFloat m_factor;
     // Bitmap or color interpolator
@@ -1378,4 +1393,4 @@ class ColorRamp final : public Texture<Float, Spectrum> {
 MI_IMPLEMENT_CLASS_VARIANT(ColorRamp, Texture)
 MI_EXPORT_PLUGIN(ColorRamp, "Color Ramp")
 
-NAMESPACE_END(mitsuba)
+NAMESPACE_END(mitsuba)