Added a shadertoy example

Author: dov

examples/app/CMakeLists.txt

@@ -15,6 +15,7 @@ add_subdirectory(vsganaglyphicstereo)
 add_subdirectory(vsgwindows)
 add_subdirectory(vsgcameras)
 add_subdirectory(vsgvalidate)
+add_subdirectory(vsgshadertoy)
 
 if (vsgXchange_FOUND)
     add_subdirectory(vsghelloworld)

examples/app/vsgshadertoy/CMakeLists.txt

@@ -0,0 +1,9 @@
+set(SOURCES
+    vsgshadertoy.cpp
+)
+
+add_executable(vsgshadertoy ${SOURCES})
+
+target_link_libraries(vsgshadertoy vsg::vsg)
+
+install(TARGETS vsgshadertoy RUNTIME DESTINATION bin)

examples/app/vsgshadertoy/glowmouse.shy

@@ -0,0 +1,31 @@
+// Draw a glowing spot around the mouse position
+
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    // Normalized coordinates (from 0 to 1)
+    vec2 uv = fragCoord / iResolution.xy;
+    
+    // Correct uv using the aspect ratio to ensure the circle's aspect ratio is maintained
+    float aspectRatio = 1.0*iResolution.x / iResolution.y;
+    vec2 correctedUV = vec2(uv.x * aspectRatio, uv.y);
+    
+    // Background gradient: black at the bottom, dark blue at the top
+    vec3 bgColor = mix(vec3(0.0, 0.0, 0.0), vec3(0.0, 0.0, 0.4), uv.y);
+    
+    // Mouse position in normalized coordinates, corrected for aspect ratio
+    vec2 mousePos = iMouse.xy / iResolution.xy;
+    vec2 correctedMousePos = vec2(mousePos.x * aspectRatio, mousePos.y);
+    
+    // Calculate distance from current fragment to mouse position, corrected for aspect ratio
+    float distanceToMouse = distance(correctedUV, correctedMousePos);
+    
+    // Glow effect based on distance to mouse position
+    float glowIntensity = 0.1 / sqrt(distanceToMouse);
+    vec3 glowColor = vec3(1.0, 0.0, 0.0) * glowIntensity;
+    
+    // Combine background and glow color
+    vec3 color = bgColor + glowColor;
+    
+    // Output the color
+    fragColor = vec4(color, 1.0);
+}

examples/app/vsgshadertoy/rgb-balls.shy

@@ -0,0 +1,37 @@
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    // Correct aspect ratio
+    vec2 uv = (fragCoord - 0.5 * iResolution.xy) / iResolution.y;
+    
+    // Background gradient
+    vec3 col = mix(vec3(0.0, 0.0, 0.0), vec3(0.0, 0.0, 0.4), uv.y * 0.5 + 0.5);
+    
+    // Light source direction
+    vec3 lightDir = normalize(vec3(-10.0, -10.0, 20.0));
+    
+    // Sphere properties
+    float sphereRadius = 0.20;
+    vec3 sphereColors[3] = vec3[](vec3(1.0, 0.0, 0.0), vec3(0.0, 1.0, 0.0), vec3(0.0, 0.0, 1.0));
+    
+    // Time factor for rotation
+    float time = iTime * 0.5;
+    
+    // Draw each sphere
+    for(int i = 0; i < 3; i++) {
+        float angle = time + float(i) * 2.0944; // 120 degrees apart
+        vec2 position = vec2(sin(angle), cos(angle)) * sphereRadius * 2;
+        
+        // Sphere shading
+        float dist = length(uv - position);
+        if(dist < sphereRadius) {
+            float diff = dot(lightDir, normalize(vec3(position - uv, sqrt(sphereRadius * sphereRadius - dist * dist))));
+            diff = clamp(diff, 0.0, 1.0);
+            
+            // Combine sphere color with light intensity and background
+            col = mix(col, sphereColors[i] * diff, smoothstep(sphereRadius, sphereRadius - 0.03, dist));
+        }
+    }
+    
+    // Output to screen
+    fragColor = vec4(col,1.0);
+}