Merge pull request #43 from JuliaPlots/sd-fixAMD

fix amd gpu

src/GLVisualize/assets/shader/intensity.frag

@@ -12,13 +12,17 @@ uniform float levels;
 
 vec4 getindex(sampler2D image, vec2 uv){return texture(image, vec2(uv.x, 1-uv.y));}
 vec4 getindex(sampler1D image, vec2 uv){return texture(image, uv.y);}
-float _normalize(float val, float from, float to){return (val-from) / (to - from);}
+float clamp_01(float val, float from, float to){
+    return clamp((val - from) / (to - from), 0.0, 1.0);
+}
 
 vec4 color_lookup(float intensity, sampler1D color_ramp, vec2 norm){
-    return texture(color_ramp, _normalize(intensity, norm.x, norm.y));
+    return texture(color_ramp, clamp_01(intensity, norm.x, norm.y));
 }
+
 #define ALIASING_CONST 0.70710678118654757
 #define M_PI 3.1415926535897932384626433832795
+
 float aastep(float threshold1, float threshold2, float value) {
     float afwidth = length(vec2(dFdx(value), dFdy(value))) * ALIASING_CONST;
     return smoothstep(threshold1-afwidth, threshold1+afwidth, value)-smoothstep(threshold2-afwidth, threshold2+afwidth, value);
@@ -31,16 +35,17 @@ void write2framebuffer(vec4 color, uvec2 id);
 
 void main(){
     float i = float(getindex(intensity, o_uv).x);
-    vec4 color;
-    if(isnan(i)){
-        color = vec4(0);
-    }else{
-        i = _normalize(i, color_norm.x, color_norm.y);
-        float lines = i*levels;
-        lines = abs(fract(lines-0.5));
-        float half_stroke = stroke_width*0.5;
-        lines = aastep(0.5 - half_stroke, 0.5 + half_stroke, lines);
-        color = mix(texture(color_map, i), stroke_color, lines);
+    i = clamp_01(i, color_norm.x, color_norm.y);
+    vec4 color = vec4(0);
+    if(!isnan(i)){
+        color = texture(color_map, i);
+        if(stroke_width > 0.0){
+            float lines = i * levels;
+            lines = abs(fract(lines - 0.5));
+            float half_stroke = stroke_width * 0.5;
+            lines = aastep(0.5 - half_stroke, 0.5 + half_stroke, lines);
+            color = mix(color, stroke_color, lines);
+        }
     }
     write2framebuffer(color, uvec2(o_objectid.x, 0));
 }