Update

smarts/core/glsl/occlusion.frag

@@ -1,9 +1,28 @@
+#version 330 core
 // Visibility check
 
 // -----------------------------------------------
 #define STEP_LENGTH 0.2
 #define CENTER_COORD iResolution.xy * 0.5
+//#define SHADERTOY
 
+#ifdef SHADERTOY
+float get_texture_max( vec2 uv ) {
+   return texture(iChannel0, uv).x;
+}
+#else
+// Output color
+out vec4 p3d_Color;
+
+uniform vec2 iResolution;
+uniform sampler2D iChannel0;
+uniform sampler2D iChannel1;
+uniform sampler2D iChannel2;
+
+float get_texture_max( vec2 uv ) {
+   return texture(iChannel0, uv).x + texture(iChannel1, uv).x;
+}
+#endif
 
 void mainImage( out vec4 fragColor, in vec2 fragCoord )
 {
@@ -14,20 +33,20 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
     vec2 offset_norm = normalize(offset);
     float offset_dist = length(offset);
 
-    if (texture(iChannel1, vec2(0.5)).x <= 0.0){
+    if (texture(iChannel2, vec2(0.5)).x <= 0.0){
         fragColor = vec4(0.0, 0.0, 0.0, 1.0);
         return;
     }
 
-    float center_height = texture(iChannel0, vec2(0.5)).x * TOPOLOGY_SCALING_FACTOR + DEVICE_HEIGHT;
-    float target_height = texture(iChannel0, p).x * TOPOLOGY_SCALING_FACTOR;
+    float center_height = get_texture_max(vec2(0.5)) * TOPOLOGY_SCALING_FACTOR + DEVICE_HEIGHT;
+    float target_height = get_texture_max(p) * TOPOLOGY_SCALING_FACTOR;
 
     float target_slope = (target_height - center_height) / offset_dist;
 
     float total = STEP_LENGTH;
     while (total < offset_dist - 0.01 ) {
         vec2 intermediary_coord = (CENTER_COORD + offset_norm * total) * rec_res;
-        float intermediary_height = texture(iChannel0, intermediary_coord).x * TOPOLOGY_SCALING_FACTOR;
+        float intermediary_height = get_texture_max(intermediary_coord) * TOPOLOGY_SCALING_FACTOR;
 
         if ( target_slope < ((intermediary_height - center_height) * TOPOLOGY_SCALING_FACTOR ) / total){
             fragColor = vec4(0.0, 0.0, 0.0, 1.0);
@@ -40,4 +59,10 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
 
 
     fragColor = vec4(1.0,1.0,1.0,1.0);
-}
+}
+
+#ifndef SHADERTOY
+void main(){
+    mainImage( p3d_Color, gl_FragCoord.xy );
+}
+#endif

smarts/core/glsl/simplex.frag

@@ -1,13 +1,4 @@
 #version 330 core
-#define DEVICE_HEIGHT 0.8
-#define TOPOLOGY_SCALING_FACTOR 1.0
-#define CENTER vec2(0.5)
-//#define SHADERTOY
-//#define SPOT_CHECK
-
-#define DENSITY_U 1.6 * 0.1
-#define DENSITY_V 1.2 * 0.1
-
 // The MIT License
 // Copyright © 2013 Inigo Quilez
 // Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
@@ -25,6 +16,13 @@
 
 
 // -----------------------------------------------
+
+//#define SHADERTOY
+
+#define DENSITY_U 1.6 * 0.1
+#define DENSITY_V 1.2 * 0.1
+
+
 #ifndef SHADERTOY
 vec2 hash( vec2 p ) // replace this by something better
 {
@@ -66,8 +64,8 @@ out vec4 p3d_Color;
 uniform vec2 iResolution;
 uniform float iHeading;
 uniform vec2 iTranslation;
-
 #endif
+
 void mainImage( out vec4 fragColor, in vec2 fragCoord )
 {
     vec2 uv = ( gl_FragCoord.xy - .5 * iResolution.xy ) / iResolution.y;

smarts/core/glsl/surface_facing.frag

@@ -1,7 +1,25 @@
+#version 330 core
 // Surface direction check
 
 // -----------------------------------------------
 
+#ifdef SHADERTOY
+float get_texture_max( vec2 uv ) {
+   return texture(iChannel0, uv).x;
+}
+#else
+// Output color
+out vec4 p3d_Color;
+
+uniform vec2 iResolution;
+uniform sampler2D iChannel0;
+uniform sampler2D iChannel1;
+
+float get_texture_max( vec2 uv ) {
+   return texture(iChannel0, uv).x + texture(iChannel1, uv).x;
+}
+#endif
+
 float cross_magnitude(vec2 lp1, vec2 lp2, vec2 p1){
     vec2 v1 = lp2 - lp1;
     vec2 v2 = lp2 - p1;
@@ -21,23 +39,26 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
     vec2 direction = normalize(p - CENTER);
     vec2 uv_offset_to_closer_p = direction * (interpolate_delta)*vec2(aspect,1.0);
 
-	float surface_end_height = texture(iChannel0, p).x * TOPOLOGY_SCALING_FACTOR;
+	float surface_end_height = get_texture_max(iChannel0, p) * TOPOLOGY_SCALING_FACTOR;
 
     // inspect fragments near mouse	
 
     {
-        float surface_start_height = texture(iChannel0, p - uv_offset_to_closer_p).x * TOPOLOGY_SCALING_FACTOR;
+        float surface_start_height = get_texture_max(p - uv_offset_to_closer_p) * TOPOLOGY_SCALING_FACTOR;
 
-        float viewer_height = texture(iChannel0, CENTER).x * TOPOLOGY_SCALING_FACTOR + DEVICE_HEIGHT;
+        float viewer_height = get_texture_max(CENTER) * TOPOLOGY_SCALING_FACTOR + DEVICE_HEIGHT;
         vec2 line_start = vec2(distance(p - uv_offset_to_closer_p, CENTER), surface_start_height);
         vec2 line_end = vec2(distance(p, CENTER), surface_end_height);
         vec2 viewer_loc = vec2(0, viewer_height);
 
 
         float cross_mag = cross_magnitude(line_start, line_end, viewer_loc);
         fragColor = vec4(vec3(-cross_mag), 1.0);
-        //if (cross_mag <= 0.0){
-        //    fragColor = vec4(1.0);
-        //}
     }
-}
+}
+
+#ifndef SHADERTOY
+void main(){
+    mainImage(p3d_Color, gl_FragCoord.xy);
+}
+#endif

smarts/core/renderer_base.py

@@ -25,7 +25,7 @@
 import logging
 from dataclasses import dataclass
 from enum import IntEnum
-from typing import Tuple
+from typing import List, Tuple
 
 import numpy as np
 
@@ -42,6 +42,12 @@ class DEBUG_MODE(IntEnum):
     ERROR = 5
 
 
+class RendererNotSetUpWarning(UserWarning):
+    """This occurs if a renderer is used without being set up."""
+
+    pass
+
+
 @dataclass
 class OffscreenCamera:
     """A camera used for rendering images to a graphics buffer."""
@@ -90,6 +96,22 @@ def teardown(self):
         raise NotImplementedError
 
 
+@dataclass
+class ShaderStepDependency:
+    """Forwards the texture from a given camera to the"""
+
+    camera_id: str
+    script_variable_name: str
+
+
+@dataclass
+class ShaderStep(OffscreenCamera):
+    """A camera used for rendering images using a shader and a fullscreen quad."""
+
+    shader_file: str
+    dependents: List[OffscreenCamera]
+
+
 class RendererBase:
     """The base class for rendering
 
@@ -174,3 +196,15 @@ def build_offscreen_camera(
     ) -> str:
         """Generates a new off-screen camera."""
         raise NotImplementedError
+
+    def build_shader_step(
+        self,
+        name: str,
+        fshader_path: str,
+        camera_dependencies: Tuple[ShaderStepDependency],
+        priority: int,
+        height: int,
+        width: int,
+    ) -> str:
+        """Generates a new shader camera."""
+        raise NotImplementedError