Merge pull request #177 from tangrams/simplify-spheremap

Simplify spheremap shaders

walkabout-style.yaml

@@ -922,75 +922,40 @@ styles:
         raster: normal
         shaders:
             uniforms:
-                # u_envmap: images/relief-shading-environment-map.jpg
                 u_envmap: images/draw-test10.jpg
-                # u_envmap: https://raw.githubusercontent.com/tangrams/walkabout-style/gh-pages/images/draw-test10.jpg
                 u_contrast: 1.
                 u_brightness: 1.
+                u_zoom_scale: 3.5
             blocks:
                 global: |
                     // Simplified view-independent environment map
-                    vec4 terrainEnvmap (in sampler2D _tex, in vec3 _normal) {
-                        const vec3 eye = vec3(0.,0.,-1.);
-                        vec3 r = reflect(eye, _normal);
-                        r.z += 1.;
-                        float m = 2. * length(r);
-                        vec2 uv = r.xy / m + .5;
-                        return texture2D(_tex, uv);
+                    vec4 applyEnvmap (in sampler2D _tex, in vec3 _normal, in float scale) {
+                        _normal.z *= scale;
+                        return texture2D(_tex, .5*(normalize(_normal).xy + 1.));
                     }
-                    const float e = 2.71828;
                 color: |
-                    // scale up normals with a function
-                    // https://www.desmos.com/calculator/bv4mzh8erz
-                    //float scale = 10./(u_map_position.z-.7) + 1.8;
-                    float scale1 = 20./(u_map_position.z) + 1.5;
-                    normal.z /= scale1; // turn terrain exaggeration up/down
+                    // turn terrain exaggeration up/down
                     // fade out spheremap normals with a function
-                    // https://www.desmos.com/calculator/ptgkzcnfyc
-                    float m = 3.5 * (u_map_position.z - 0.8) * pow(e, u_map_position.z * -.29);
+                    float scale1 = 20./(u_map_position.z) + 1.5;
+                    float m = u_zoom_scale * (u_map_position.z - 0.8) * exp(u_map_position.z * -.29);
                     m = clamp(m, 0., 1.5);
-                    color = terrainEnvmap(u_envmap, normal);
+                    color = applyEnvmap(u_envmap, normal, 1./scale1);
 
-                    // Apply contrast
+                    // apply contrast and brightness
                     float contrast = m;
                     color.rgb = ((color.rgb - 0.5) * max(contrast, 0.)) + 0.5;
-                    // Apply brightness
                     float brightness = .5 - m * .5;
                     color.rgb += brightness;
 
-                    color *= v_color; // apply layer color
+                    // apply layer color
+                    color *= v_color;
 
     terrain-park:
-        base: polygons
-        lighting: false
-        raster: normal
+        mix: terrain
         shaders:
             uniforms:
                 u_envmap: images/walkabout-green1.jpg
-            blocks:
-                global: |
-                    vec4 terrainEnvmap (in sampler2D _tex, in vec3 _normal) {
-                        const vec3 eye = vec3(0.,0.,-1.);
-                        vec3 r = reflect(eye, _normal);
-                        r.z += 1.;
-                        float m = 2. * length(r);
-                        vec2 uv = r.xy / m + .5;
-                        return texture2D(_tex, uv);
-                    }
-                    const float e = 2.71828;
-                color: |
-                    float scale1 = 20./(u_map_position.z) + 1.5;
-                    normal.z /= scale1;
-                    float m = 3.95 * (u_map_position.z - 0.8) * pow(e, u_map_position.z * -.29);
-                    m = clamp(m, 0., 1.5);
-                    color = terrainEnvmap(u_envmap, normal);
-
-                    float contrast = m;
-                    color.rgb = ((color.rgb - 0.5) * max(contrast, 0.)) + 0.5;
-                    float brightness = .5 - m * .5;
-                    color.rgb += brightness;
-
-                    color *= v_color;
+                u_zoom_scale: 3.95
 
     # HSV/RGB functions
     hsv: